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Flashcards in Respiration Deck (116)

Describe sino Nasal or Nasal tumours.

Canine nasal tumours account for approx 1% of neoplasms. Approximately 60-80% of all respiratory tumours are nasal or sino nasal tumours. typically an older medium to large breed dog. possibl risk factors for dogs - doliocephalic breeds, urban environments at higher risk, exposure to tobacco smoke and indoor exposure to fossil fuel combustion productions, risk factors for cats are unknown although chronic rhinitis may be an initiating factor. cats with lymphoma are typically FeLV negative. the most common types of nasal tumours are carcinomas including adenocarcinomas. Sarcomas comprise most of the remaining 1/3 including fibrosarcomas, osteosarcomas, chondrosarcomas.. Carcinomas approx 2/3. the most common type in cats is lymphoma (B cell > T cell) although carcinoma is common as well. sarcomas are rare.


Describe the biologic behaviour of nasal tumours

Most nasal tumours are characterised by progressive local invasion and late onset of metastasis. there is low rate of metastatic disease at the time of diagnosis, however the metastatic rate may be as high as 30-46% at the time of death - sites include local lymph nodes and lung, rarely other sites such as brain,kidneys, liver, skin and bones. in cats with nasal lymphoma, disease recrudescence often occurs systemically months to years following definitive treatment.


Describe the clinical signs of nasal tumours

it is very important to remember that while neoplasia is on the ddx - other nassal diseases can cause overlapping signs. Most dogs and cats present with a history of Clinical signs attributable to nasal disease however cats often also present with inappetence and weight loss. clinical signs of nasal disease may include nasal discharge, congestion, epistaxis, sneezing reverse sneezing, coughing, nasal deformity in cats, pawing at the face, stertor, ocular discharge and abnormalities, obtunded or seizures (rare). Epistaxis has many differentials - it does not automatically imply neoplasia.


What is the initial diagnostic approach to nasal tumours?

A thorough history is important when trying to determine an underlying aetiology or at least help to determine appropriate tests. information from the history should include duration and progression of signs, location of discharge, type of discharge should be characterised, response to previous treatment may be helpful, especially in a referral setting, seasonal incidence or association with another stimulus. The goal is to rule out systemic disease before doing a nasal workup.


What diagnostic tests should be done for nasal disease?

Complete blood count, chemistry profile, urinalysis, FeLV/FIV (cats), T4 (cats), BMBT( ACT, PT, PTT if indicated or severe epistaxis). Additional tests if needed depending on differentials, geographic location, risks of dog or cat, cross match and typing is severe epistaxis, blood pressure (uncommon for hypertension to be sole causE), tick titers to rule out ehrlichiiosis, particularly in cases of thrombocytopenia and epistaxis. testing for feline herpesvirus (FHV-1), feline coronavirus, chlamydia felis, cryptococcus if indicated.


Describe diagnostic imaging for nasal disease

Nasal radiographs - require general anaesthesia for accurate patient positioning. evaluation should include an assesment of 1) symmetry 2)bone or turbinate destruction 3) masses of variations in opacity 4) soft tissue changes. the boundaries of the nasal cavity should be assessed however difficult due to superimposition of structures, extensive compartmentalization, intricate nasal anatomy and wide variation in appearance of k9 and feline skulls. Nasal CT - CT is suprerior to radiographs & aids in defining the nature of disease including 1) location, 2)presence or absence of a solid or cavitated soft tissue mass, 3) osseous involvement 4) extent of disease 5) invasion into important adjacent structures (soft palate, nasopharynx, orbit, cranial vault). many staging schemes now are based on the extent of disease defined by CT.


Why is biopsy/rhinoscopy done?

Perform imaging first so that haemorrhage does not interfere with image interpretation. rhinoscopy permits direct visualization of lesions (plaques, masses), foreign bodies, and allows one to obtain biopsies with guidance. hwoever, in most dogs and cats with nasal neoplasia, rhinoscopy is unnecessary and blind pinch biopsies provide enough tissue for diagnosis. one exception may be cats with pharyngeal tumours in which retro flexing the scope is often helpful. Tissue biopsy - definitive diagnosis usually requires biosy and there are several ways to obtain - vigorous nasal flushing, blind nasal biopsy using pinch forceps, rhinoscopy guided techniques, trephination of the frontal sinus, surgical biopsy. Epistaxis will occur secondary to nasal biopsy. cytologic examination is not reccomended for definitive diagnosis.


How are nasal tumours staged?

Standard staging should include CBC, chemistry, urinalysis, FeLV, FIV, T4, 3 view thoracic radiographs, fine needle aspirates of regional lymph nodes, in cats that are diagnosed with nasal lymphoma it is very important to determine if they have true local disease or if they have any systemic disease. thus complete staging in cats with lymphoma should include all of the above plus: felv/FIV test, abdominal ultrasound, fine needle aspiration cytology if abnormalities, bone marrow aspirate, a general oncologic rule is to treat local disease with local therapies and systemic disease with systemic therapies.


What is the treatment of nasal tumours in dogs?

Radiation therapy is considered the standard of care treatment for nasal tumours. radiation is administered with external beam radiation units (cobalt-60 or linear accelerator) the prescription is typically such that patients are treated daily with RT daily for 2-4 weeks. the median survival time for dogs undergoing RT is 13-18 months. almost all tumours recur and dogs die of local disease. long term survival is possible. most dogs have an excellent quality of life following rt but suffer acute effects during and shortly after treatmnet. surgery alone is not recommended due to short benefit.


Describe the treatment of nasal tumours in cats

Radiation therapy is generally considered an integral part of treatment for cats with nasal tumours. it is the standard of care for treatment of cats with nasal carcinomas. median survival is 11-12 months. cats do extremely well with RT and have fewer side effects than dogs. chemotherapy is often administered in conjunction with RT for cats with nasal lymphoma. cats with nasal lymphomas treated with RT alone have median surviva. 1.5-2 years most cats have relapse after a few years and it typically is systemic. Radation therapy and chemotherapy for lymphoma - multidrug chemotherapy protocols are used - typically treatment is 6 months in duration. median survival time is 1.5 year.


Describe primary lung tumours

Uncommon in the dog and even more uncommon in the cat. metastatic tumours to the lungs are much more common than primary tumours in the lung in both dogs and cats. average age at diagnosis is 10-11 for dogs and 11-12 for cats. no gender predilection in dogs however older female cats may be more affected. bracycephalic dogs at increased risk. aetiology is unknown but some factors may increase risk including: bracycephalic breeds, urban environment, exposure to tobacco smoke, plutonium and other inhaled forms of radiation. Most primary lung tumours in dogs and cats are adenocarcinomas or carcininomas (20%) most primary lung tumours are solitary in the dog. up to 25% of cats can have diffuse lung involvement at the time of diagnosis. cats more likely to have metastais. cats have more undifferentiated or poorly differentiated tumours. primary lung tumours can metastasize via lymphatic or haematogenous routes or via transmigration through the airway.


Describe the route of metastasis of primary lung tumours

Via lymphatic or haematogenous routes or via transmigration through the airway. intrathoracic metastasis typically involves the tracheobronchial lymph nodes, other lung lobes. pleura, mediastinum, pericardium and other cardiac structures. intrathoracic metastasis is common but extrathoracic metastasis is rare in dogs. intrathoracic metastasis is slightly more common than extrathoracic metastasis in cats. sites of extrathoracic metastasis include liver, kidneys, spleen, bone, spinal cord and brain although any organ can be affected.


What are the clinical signs of lung tumours?

25-30% asymptomatic. common signs: coughing, dyspnea, lethargy, weight loss, inappetance ( in cats), wheezes( in cats), weakness, vomiting (cats), hemoptysis can occur but is relatively rare with primary lung tumours. many will present for signs relative to metastatic disease from the primary lung tumour e.g neurologic signs. paraneoplastic syndromes are uncommon but have been noticed; hypertrophic osteopathy - swollen limbs, lameness, heat upon palpation, significant pain. periosteal proliferation along long bones -s tarts distally and moves proximally. pathogenesis not understood. associated with lung pathology such as primary lung tumours, heartworm disease, esophageal tumours, metastatic tumours to the lungs. other signs - pneumoniia., severe leukocytosis, hypercalcaemia, fever may be a paraneoplastic syndrome, tumour induced secretin of ACTH (rare). cats often present for signs related to metastatic disease as opposed to respiratory signs.


What is lung digit syndrome?

Cats with primary lung tumorus usually sCC but other carcinomas too can present with digital lesions due to metastasis to multiple digits. in 1 report of cats with digital carcinomas, 88% were metastatic from a primary lung tumour while only 12% of cats had a primary digital carcinoma. Check thoracic radoiographs if a cat presents with digital carcinoma. approx 25% of cats present for digital lesions rather than pulmonary signs it is important to palpate libs and digits. management is aimed at controlling discomfort. amputation of the digits is rarely helpful and often additional digits become affected. overall survival time is short.


How is diagnosis of Lung tumour made with thoracic radiographs?

Always obtain 3 views (R lat, L lat, VD). The lower limit of detection of pulmonary nodules is 3-5 mm although lesions that are 1cm can be missed due to location, overlying structures, or presence of pleural effusion or atelectasis. lung masses are usually a solitary soft tissue spherical mass although some can be cavitated. caudal lung lobes are more often affected. in dogs, approximately 50-70% involve one lung lobe, 25-30% of cats have pleural effusion, with advanced signs of disease it can be difficult to determine if the animal has primary lung tumour with metastasis or metastatic disease from another site. If pleural effusion is present, always have a fluid analysis performed if thoracocentesis performed. most often it is nondiagnostic, if malignant pleural effusion is diagnosed, prognosis very poor. once a nodule is discovered; do baseline database, ultrasound, institute supportive care & monitoring, FNA aspiration for pperipherally located lung masses, CT guded FNA for centrally located lesions, transthoracic aspiration in cases of diffuse involvement carry a higher risk, aspiration cytology of the primary mass yields a diagnosis in >80-90% of cases but it rarely changes deifinitive treatment. Differentials for a lung mass do not just include neoplasia. they also include granuoma, cyst, infarct, localized haemorrhage, focal pneumonia, abscess, lung lobe torsion, differentials for disseminated interstitial nodules include: neoplasia, fungal disease, bacterial or parasitic granulomatous disease. Ct can identify tracheo bronchial lymph nodes and help to define true extent of disease. bronchoscopy can also be useful and brush cytology may yield a diagnosis in some cases.


What is the treatment & prognosis with lung tumours?

Surgery is the treatment of choice. lung lobectomy in most cases although partial lung lobectomy is sufficient for pierpheral tumours. thoracoscopic lung lobectomy can be performed for small peripherally located tumours. If tracheobronchial lymph nodes are abnormal or large or the primary mass is adjacent to these nodes, nodal extirpation should be done.Prognostic factors identified in dogs with primary lung tumours include: presence of metastasis to the lymph nodes, pleural effusion, tumours >5cm, presence of clinical signs, squamous cell carcinoma, poorly differentiated tumours. in cats prognostic factors > poorly differentiated tumours, metastasis to the digits, probably presence of metastasis to the lymph nodes. Long term survival is possible for dogs with solitary small well differentiated tumours that have not metastasized. cats tend to do worse than dogs.


What are the palliative measures for primary lung tumours?

Antitussives, bronchodilators, appetite stimulants, NSAIDS, anti angiogenics, and analgesics.


Describe Why metastatic tumours to the lung occur

The lungs are the frequent site of metastasis for both carcinomas and sarcomas. there are a number of theories as to why this is true. the lung may provide a fertile ground for development of tumours. the pulmonary capillary bed may cause lodging of tumour emboli in the lung thus encouraging tumour cells to extravasate and grow.


What are the tumours with high predilection for metastasis to the lungs

Metastatic tumours to the lungs are more ommon than primary lung tumours in both dogs and cats. tumours with high predilection for metastasis to the lungs include canine haemangiosarcoma, canine appendicular osteosarcoma, canine and feline mammary carcinomas, canine oral and nailbed melanomas, tonsillar squamous cell carcinomas in dogs, undifferentiated sarcomas and carcinomas of any origin. clinical signs are highly variable and often depend on the underlying primary tumour. coughing and excercise intolerance are often absent even in dogs with large tumour burdens. cats may present with open mouth breathing. nonspecific signs predominate 3-view thoracic radiographs reommended. Can have a variable appearance from structures to unstructured interstitial to alveolar.


What is the therapy for metastatic lung tumours?

Therapy is generally aimed at controlling clinical signs and may b e palliative in nature. chemotherapy - usually broad spectrum anticancer drugs are chosen. surgical removal of metastatic lesions is not typically performed, however there are certain cases in which metastectomy may be performed, control of primary tumour >300-360 days. <3 metastatic lesions to be removed at surgery Bisphosphonates may be used in some cases, especially canine osteosarcoma as there is some evidence to suggest its use slows the growth of metastatic lesions. bisphosphonates are drugs that reduce bone resorption. often used in people with osteoporosis. Ultimately prognosis is poor 2-3 month survival time. exceptions are with metastatic thyroid carcinomas and occasionally other slow growing neuroendocrine tumours.


Describe cardiac tumours?

Rare in dogs and even more rare in cat. tumour types: haemangiosarcoma, aortic body tumour, lymphoma, sarcoma, mesothelioma, carcionoma. haemangiosarcoma is the most common primary tumour of the heart in the dog - seen in golden retrieverrs, GSDs, typically present on emergency with pericardial effusion. aortic body tumours arise from chemoreceptors cells at the heart base. lymphoma is the most common tumour of the heart in the cat. any tumour (mammary, pulmonary, salivary gland, melanoma, squamous cell carcinoma, sarcoma) can metastasise to the heart. most dogs present clinically ill, rarely an incidental finding. Therapy generally limited - palliative eg pericardial window, chemotherapy, anti arryhthmics. definitive - surgical removal (rarely possible.) generally prognosis is poor for cardiac tumours, exceptoon is chemodectomas, survival advantage if pericardiectomy.


What is stertor

An inspiratory snoring noise associated with partial occlusion of the nasal passages, choanae or nasopharynx.


What is stridor?

A high pitched inspiratory noise associated with partial occlusion of the larynx or trachea.


What is a sneeze?

A forceful expiration that results in expulsion of foreign material from the nasal passages.


What is reverse sneezing

A paroxysmal inspiratory choking noise designed to clear foreign material from the nasopharynx.


What is epistaxis?

Nose bleed - may occur in association with local disease e.g trauma, foreign body or may be due to a systemic disease (coagulopathy, hypertension).


When is nasal discharge seen?

May be seen in association with inflammatory diseases (rhinitis) or obstructive diseases (foreign body, mass)


Describe the different types of Nasal discharge?

Serous nasal discharge is clear and acelllular. it may go undetected due to the animal licking it away. Causes - primary viral infections, allergic rhinitis, lymphocytic-plasmacytic rhinitis, foreign bodies. Sneezing can lead to discharge becoming blood tinged. mucoid n nasal discharge is clear and acellular but contains more protein than serous discharge. it reflects hyperplasia of the mucoid glands within the nasal cavity and is typically associated with the chronic disease processes such as rhinitis or adenocarcinoma. purulent discharge is tenaceous and yellow to green in coloud. cytology reveals numerous neutrophils and usually bacteria purulent discharges are sen with secondary bacterial infections, pneumonia, dental disease and congenital abnormalities such as cleft palate and immotile cilia syndrome. sanguinous reflects blood tingeing to a primary type of discharge. May be caused by sneezing where violent expulsion of air causes small capillaries to rupture or in association with conditions that cause erosion of blood vesse,s such as neoplasia or fungal infections. epistaxis represents copious bleeding where the PCV of the discharge is similar to blood. any condition causing coagulopathy may manifest with epistaxis as can hypertension and hyper viscosity syndromes such as multiple myeloma. Profound bleeding may also be seen if neoplasms or fungal plaques erode a major vessel and in association with dental disease.


Describe what Physical examination of the nose should include

patency of nasal passages - hold a cold slide infront of the nostrils and assess for condensation. Facial deformity - may suggest neoplasia, fungal infection or dental abscessation. facial pain: may be seen with neoplasia, fungal infection, trauma, foreign body. Sinus percussion: decreased resonance on percussion of the frontal sinus may reflect an accumulation of fluid or soft tissue within the sinus. apparent pain may also be detected. Nasal depigmentation may suggest fungal infection. Palatine deformity - ventral bowing suggests a nasopharyngeal mass e.g tumour, polyp, cleft palate, should be apparent. Mucous membranes - petehciation may suggest thrombocytopenia or thrombocytopathia. occular examination: check for conjunctivitis/ocular discharge, uveitis, retinal vessel tortuosity (hypertension) retinal detachment (hypertesion, trauma) retinal haemorrhage (hypertension, coagulopathy, trauma) or Exopthalmos (trauma, neoplasia, retrobulbar abscessation) lymph nodes: sub mandibular lymph nodes enlargement may be seen with neoplasia, infection, dental disease. A full examination may require general anaesthesia, in order that the dentition and palate can be fully evaluated.


Name the potential infectious causes of nasopharyngeal disease

Viral - canine distemper, adenovirus, parainfluenza virus
Feline - herpes virus 1, calicivirus
Bacterial - mixed commensals - common secondary component
Chlamydophila felis, bordetella bronchiseptica, mycoplasma spp
Fungal - aspergillus, pencilliosis, (D>C) cryptococcus (C>D)


Name the inflammatory causes of nasopharyngeal disease

Allergic rhinitis, lymphocytic Plasmacytic rhinitis, eosinophilic rhinitis


What types of detal disease can cause nasopharyngeal disease?

Tooth root infection, oro nasal fistula


What types of neoplasia may cause nasopharyngeal disease?

Adenocarcinoma, lymphoma, firbsoarcoma, osteosarcoma.


Name other miscellaneous causes of nasopharyngeal disease?

Trauma, stenotic nares, nasopharyngeal polyps, nasal foreign body, cleft palate, nasal poolyps, nasopharyngeal stenosis, parasites (pneumonyssus caninum), primarily ciliary dyskinesia (immotile cilia syndrome).


What is the management of acute epistaxis?

First aid may be required to address this problem. Keep calm and quiet. assess blood pressure - if elevated start management for hypertension. consider sedation, w ill reduce BP and lower anxiiety, topical adrenaline will cause local vasoconstriction. ice pack ca be applied over bridge of nose - causes vasoconstriction of nasal mucosal vessels, may need blood transfusion or ligation of carotid arteries.


What can be detected on blood tests for nasal disease?

Routine haematology and biochemistry is unlikely to give a specific diagnosis but is important with regard to establishing the overall health status of the patient especially if potentially hepatotoxic or renotoxic medications are to be given. also consider establishing retrovirus status of cats and performing clotting profile prior to performing nasal biopsies.


How should you investigate infectious agents in nasal disease?

Oropharyngeal swabs may be submitted for virus isolation or PCR. culture of nasal swabs is generally not very useful as commensal organisms will almost certainly be grown. culture of nasal flush fluid may be slightly more useful. serological testing may be performed for both Aspergillus and cryptococcal infections. a positive Aspergillus titre is supportive, but not diagnostic for fungal rhinitis whereas a positive LCAT (latex cryptotoccoal antigen test) has high specificity.


What may you detect on imaging of the nasal cavity

A complete radiographic view evaluation should comprise several films. lateral and dorso ventral views of the skull may enable radioopaque foreign bodies to be identified but superimposition of the structures means that intra oral view of the maxilla should be taken to evaluate the nasal turbinates. if intra oral film is nota vailable then an open mouth view may be obtainde. a rostro caudal skyline view also enables assessment of the frontal sinuses. where it is available, radiography has been superseded by ct, due to superior assessment of turbinate destruction and soft tissue mass lesions. Thoracic radiographs should ideally be obtained if there is suspicion of a neoplastic process.


What does rhinoscopy involve?

This procedure involves Normograde rhinoscopy of the nasal meati and a retroflex evaluation of the caudal nasopharynx. although invasive (risks include GA, haemorrhage and damage to the cribiform plate). It allows biopsy material to be obtained to enable a specific diagnosis to be made. samples may also be collected from the frontal sinuses following trephination


What is acute rhinitis?

Clinical signs - sneezing, nasal dischage, ocular discharge, pyrexia, inappetance. Viral infections bordetella, Chlamydophila, mycoplasma. Diagnosis - clinical signs, history, oropharyngeal, conjunctival swab. Treatment - supportive, hydration, nutrition, anti bacterial cover, nebulisation.


What is chronic bacterial rhinitis?

May be episodic, sneezing, nasal discharge. usually secondary to previous FHV-1 infection (cats) or aspergillosis (dogs) resulting in turbinate destruction, trauma, ciliary dyskinesia. Diagnosis - prior history of infection, exclusion of other causes. Treatment - pulse dose of antibacterials, anti viral therapy, nebulisation, nasal flushes, rhinotomy and turbinectomy.


What s inflammatory rhinitis?

Usually young to middle aged dogs, generally systemically well, sneezing and or nasal dishcarge (mucoid- muco purulent.) aetiology - may be idiopathic, allergic response to fungal antigens, inhaled irritants, infiltrate usually lymphocytic- plasmacytic, but may be eosinophilic (breed predisposition in husky type breeeds). Diagnosis - histopathology of bioppsy. treatment - glucocorticoids or cyclosporin, antibiotics as required for secondary infection.


What is fungal rhinitis?

Young to middle aged doliocephalic dogs with unilateral or bilateral sero-sanguinous or sanguinos nasal discharge. Facial pain and depigmentation of the planum nasale may be present. cats- no predispositions. facial deformity may be present. aetiology most commoonly aspergillus fumigatus in dogs and cryptococcus neoformans in cats. Impression smear of nasal discharge + Positie LCAT. histopathology and fungal culture of nasal biopsy for aspergilllus. supportive features would include destruction of nasal turbinates on radiography/CT and positive asperggillus serology.. treatment - topical infusion of clotrimazole via nasal catheters, systemic itraconazole, repeated topical infusion of clotrimazole via nasal catheters, systemic itraconazole. Repeated topical infusions increase the chance of a cure. systemic treatment may be required to be continued for -5 months. some patients may be left with chronic rhinitis due to turbinate destruction.


Describe neoplasia of the nasal cavity?

Signs - nasal discharge, usually unilateeral but may progress to bilatera, facial deformity, cats often present with stertor as lymphoma tends to occur in the nasopharynx causing bilateral obstruction. most commonly adenocarcinoma in dogs, lymphoma in cats, diagnosis based on histopathology of biopsy. treatment - radiation therapy, chemotherapy, surgical debulking in sarcomas. Discharge often sero-sanguinous.


What Can dental disease present like when invading the nasal cavity?

Clinical signs - unilateral or bilateral mucopurulent nasal discharge, halitosis, dysphagia, oral pain. aetiology - severe periodontal disease - osteomyelitis and tooth root abscessation, oro nasal fistula formulation following dental extraction (usually canine tooth) diagnosis - thorough evaluation of dentition under general anaesthesia, dental radiography, treatment - extraction of affected teeth, antibiotic cover


Describe the clinical signs of a foreign body

Typically acute episode of sneezing associated with inhalation of FB, progressing to chronic, unilateral nasal discharge. Gagging or retching may be seen if FB has been ingested and then vomited/regurgitated into the nasopharynx. usually inhaled but may arise from ingestion and vomiting e.g blades of grass in nasopharynx in cats. diagnosis - radio opaque foreign bodies (needles, gun shot pellets) will be apparent radiographically. retraction of soft palate with a spay hook may allow visualisation of naso pharyngeal FBs, But rhinoscopy may be required for visualisation. Physical removal with forceps, or flushing or may require rhinotomy


What is a nasopharyngeal polyp

typically young cats affected. stertorous respiration possibly accompanied by nasal discharge and dysphagia or retching/gagging. may be accompanying signs of otitis due to location of the polyp within the Eustachian tube. thought to be associated with chronic inflammation although no definitive association with 1 aetiological agent has been identified. diagnosis may be visualised on otoscopic exam or by retracting the soft palate. soft tissue mass may be identified on radiography. treatment is traction avulsion - to remove the polyp. recurrence is relatively common but may be reduced by peri procedural steroid theerapy. bulla osteotomy may be required if middle ear involvement.


What is the most common history with respiratory cases

Most common clinical presentations of respiratory cases are coughing, tachypnoea and dyspnoea but these are also cardinal features of cardiac disease. Respiratory cases can also present with sneezing & naso ocular discharges, invariably indicating nasal disease but might be present with pneumonia, vomiting & retching, gagging and chocking, haemoptysis, excercise intolerance, lethargy and weakness, collapsing & syncope, likely to be cardiac, cyanosis, obesity, abdominal enlargement and respiratory disabilities. The predominant clinical presenting sign should be noted and its severity, frequency, chronicity and rate of development and progression recorded. the presence of other potentially significant factors int he patients clinical history should be identified even if they have occured sevearl years previously e.g thoracic trauma.


Why should signalment be taken into account with respiratory disease?

The breed and age of the patient are important considerations when investigating the respiratory case, and there are well recognised examples of breed and age related respiratory conditions. breed association is particularly useful in diagnosis of cardiac disease but less useful for respiratory disease. tracheael collapse is seen almost exclusively in toy breeds and other anatomical abnormalities such as hypoplastic trachea, laryngeal collapse, extended soft palate are more common in toy and brachycephalic dogs. chronic bronchitis and crhonic pulmonary interstitial disease (idiopathic pulmonary fibrosis) appear to be more common in terrier breeds. Chronic bronchitis, laryngeal paralysis and pulmoonary neoplasia are primarily diseases of middle to old age dogs and there is possibly a higher incidence of primary neoplasia in larger breeds. Classic examples - middle age onset chronic cough in a Yorkshire terrier - tracheal collapse. 2 middle to old age onset of dyspnoea, excercise intolerance and coughing with obvious inspiratory crackles in a WHWT - idiopathic pulmonary fibrosis. old age onset intermittent exercise intolerance with stridor typically associated with excitement in lab - laryngeal paralysis.


A middle age Yorkshire terrier presents with chronic cough what is this most likely diagnosis?

Tracheal collapse.


A middle age/older WHWT presents to you with excercise intolerance and coughing with obvious inspiratory crackles what is the most likely diagnosis?

Idiopathic pulmonary fibrosis


An old lab presents to you with intermittent excercise intolerance with stridor typically associated with excitement, with or without dysphonia, what is most likely condition?

Laryngeal paralysis


How does the environment play a role in respiratory disease?

Role of environmental pollutants unknown. important in livestock. little evidence for passive cigarette smoke inhalation to contribute to respiratory disease in dogs. Dogs have low incidence of chronic bronchitis and l ung cancer compared to human population. the main type of primary lung tumour in dogs is adenocarcinoma and while nearly all adenocarcinomas in human patients are smoke related, adenocarcinoma is also the main form of lung cancer seen in human patients who have smoked fewer than 1-- cigarettes in their life time. Potential exposure to infective agents eg boarding kennels, vaccination and worming status and geographical distribution of respiratory parasites. Air quality in the home environment might not be might not be the cause of respiratory disease but might contribute to disability once disease is present.


What should be done in physical examination when presented with respiratory disease?

Pay particular attention to general body condition - obesity or weight loss. assess the colour of the occular and oral mucosa . Identify presence of naso ocular discharges and patency of external nares. palpate the larynx and extra thoracic trachea. check for lymphadenopathy and other masses close to the extra thoracic airways. palpate abdomen paying particular attention to identification of masses and hepatomegaly. check body temperature and hydration status and note overall demeanour. Breathing pattern should be noted including resp rate and presence of respiratory effort or difficulty. observe at a distance.


What does chest percussion allow?

Percussion and coupage allows identification of variation or changes in chest resonance and is particularly useful iin identifying asymmetric lesions (pathology located to one side of thorax) and air fluid soft tissues (pleural effusion and pneumothorax). normally there is a reduction in resonance moving dorsally to ventrally but it is a distinct and sudden change in resonance that is suggestive of abnormality. both sides of the chest must be percussed. a repeatable initiation of coughing when applying coupage to one side of the chest makes it highly suspicious the pathology is located on that side. the activation of coughing by coupage in its self is diagnostically useful for respiratory disease such as pneumonia and can be used therapeutically.


Describe auscultation of the respiratory system

The respiratory system is auscultated from the external nares to the lung periphery. it should be remembered that abnormal sounds audible in the chest may be referred from the upper airway. The problems associated with panting and excitement in properly auscultating the airways has to be appreciated. in many respiratory diseases chest auscultation sounds are within the acceptable limits of normality and caution should be exercised in over interpreting them. when there are clearly identifiable abnormalities then reasonable conclusions can be amde, but confirmatory diagnostic tests are usually neeeded.


What are crackles?

Inspiratory because they are due to re opening of the airways that have closed during expiration. they can be fine or coarse and sometimes compared to the sound of velcro. classic causes are IPF, chronic bronchitis and pulmonary oedema.


What are wheezes?

High pitched sounds that can be inspiratory or expiratory and are due to narrowing of the bronchial lumen. they are often intermittent and can vary in location. the best example of a cause is feline asthma. they are fairly uncommon in dogs.


What are rhonchi?

Low pitched sounds due to high airflow velocity through the larger airways and can be inspiratory or expiratory, can be normal if exercise or excitement associated. In disease they can arise because of anything necessitating increased respiratory effort with pneumonia and pulmonary oedema bing a good example.


What are stridor and stertor?

Rhonchus sounds produced in the larynx and nasal passage respectively. for stridor laryngeal paralysis is the best example. a combination of sounds can exist giving complex harmonics that are not readily identified or classified. in this case the best description is mixed respiratory sounds.


How do you differentiate respiratory from cardiac disease?

They share common clinical signs - coughing, dyspnoea, exercise intolerance and dyspnoea in the cat. differentiation can be achieved during initial examination. The presence of sinus arrhthmia in a dog is highly suggestive that the clinical presentation is nt due to cardiac disease even if there is a readily audible murmur. Normal peripheral indicators of cardiac function are highly supportive of a respiratory cause in both dogs and cats. Thoracic radiography can be useful in excluding a cardiac cause in the dog. cardiac biomarker can provide additional supportive evidence for three points aboveve, but should not be used exclusively.


What diagnostic investigative techniques?

Haematology, biochemistry, serology & biomarkers, blood gas analysis, ultrasonography & echocardiography, other sampling techniques, faecal analysis, lung biopsy, thoracic radiography, computed tomography, bronchosocpy and airway sampling.


What is tracheal collapse?

Seen in Yorkshire terrier, toy breeds. Lack of structural integrity increases the collapse of the trachea. clinical signs mainly apparent in middle age, with severe tracheal abnormality causing problems in young dogs. Coughing (goose honk or seal bark), associated with excitement, exercise and lead pulling easily be elicited on gentle tracheal compression, obesity is often present in these dogs. Inspiratory dyspnoea occurs if the extra thoracic trachea is prone to collapse while expiratory dyspnoea is caused by intra thoracic tracheal collapse. Variable degree of exercise intolerance. Variable degree of exercise intolerance . Cyanosis and syncope during particularly severe coughing and dyspnoeic attacks. complicated by chronic bronchitis and chronic pulmonary insterstitial changes. Radiography might demonstrate collapse of the trachea, primarily at the thoracic inlet and the cranial mediastinal area and can be best observed at end expiration. Bronchoscopy demonstrates dorso ventral flattening of the trachea and redundancy of the dorsal membrane and is diagnostic. Treatment and management is by controlling obesity use of a harness and avoidance of excessive exercise and stressful situations. surgical correction and or intra luminal stenting of the collapse can be of value and may be the only course of action. control of secondary chronic bronchial and lung problems with glucocorticosteroids and bronchodilators can be of some benefit in the later stages of the disease.


What is acute tracheobronchitis?

Most common cause of coughing, infectious, contagious, self limmiting. acute tracheobronchitis is the most common cause of coughing in dogs. infective material is transmitted by direct contact, as aerosolised infective respiratory secretions and via fomites and animal handlers. infectious agents include bordetella bronchiseptica. Secondary bacterial and mycoplasma organisms can be also implicated. paroxysms of harsh non productive coughing, exacerbated by exercise or excitement. Mild pyrexia, lethargy and inappetance, and naso ocular discharge may be noted. Condition is usually self limiting with the clinical signs persisting for up to three weeks. with canine distemper infection, a purulent nasal discharge, bronchopneumona and gastro intestinal and neurological signs may be present. Tetracyclines and potentiated sulphonamides are usually effective in reducing the duration of clinical signs, but antibacterial therapy is not necessarily required. anti tussives will alleviate excessive coughing, as will avoidance of dusty environments and restriction of excercise. affected dogs should be kept separate from susceptible animals. Vaccination prior to expected exposure is a worthwhile precaution, but may not be effective. complete recovery usually occurs, but prognosis is guarded if canine distemper virus is involved. residual coughing may be present.


What is canine influenza?

With possible strep zooepidemicus involvement. the recent reports of transmission of equine influenza virus to kennelled dogs and the possibility that transmission has also occurred between dogs. no clear evidence that this virus has entered the pet population in the UK. the presence of respiratory infection with clinical signs varying from mild to severe might raise suspiscion of canine influenza infection. Potential involvement of streptococcus spp in the generation of severe disease might need to be considered, particularly in context of a kennelled population, strep zooepidemicus has been reported in severe cases of bronchopneumonia in some of these cases pulmonary haemorrhage has resulted in the expectoration of blood.


What is chronic tracheobronchial syndrome? (chronic bordetellosis)

A sporadically Occurring condition, recognised primarily in dogs that have had kennel cough. might still culture B bronchiseptica from airway samples, there appears to be a heightened cough reflex, resulting in paraoxysms of harsh, non productive cough, often associated with excitement and lead pulling, clinical signs usually appear several weeks after apparent resolution of kennel cough with no other clinical abnormalities in uncomplicated cases. Radiography a mild to moderate increase in bronchial markings is noted in most cases. bronchoscopy and bronchial cytology finding are normal in the majority of dogs. no specific therapy is recommended spontaneous resolution over a period of months may occur with the use of anti tussives, a harness rather than a collar may help. if Bordatella positive wash then 3 week course of doxycycline should be tried. dogs can continue to cough for several years, spontaneous resolution can occur while in a small minority chronic bronchitis may develop.


What is chronic bronchitis?

A mucus hypersecretory disorder affecting the bronchi but may extend rostrally to the trachea. excessive mucus production is a reaction to airway inflammation and a cause of further bronchopulmonary problems. (loss of ciliated epithelium reducing the cleraance of debriis from the airways, accumulation of viscid mucous entrapping debris compromising airway hygiene). Recurrent bouts of bacterial bronchitis and bronchopneumonia causes irreversible damage leading to alveolar fibrosis and respiratory failure. Primarily middle to old aged dogs and the incidence appears highest in small to medium sized dogs and in the terrier breeds. Exact cause is not known but probably reflects a chronic airway reaction to a variety of factors and circumstances. There is marked variation in the severity of chronic bronchitis, chronic coughing, episodes of acute bronchpneumonia, tachypnoea, dyspnoea and Exercise intolerance and general debility and cachexia. Radiography - a prominent bronchial pattern is often present and cardiac right side changes may also be noted. Bronchoscopy - marked airway changes with excessive quantities of airway mucus, roughened and blanched mucosal surface. bronchoscopy is required for a definitive diagnosis to be made. bronchial cytology excessive quantities of mucus with a variable and mixed cellular component, depending on degree of active inflammation. Treat with bronchodilator and glucocorticosteroid therapy. Antibacterials Required periodically. mucolytics may give additional benefit but chest physiotherapy, with steam inhalation or steam nebulisation. anti tussives should not be used under any circumstances. once diagnosed the owner must be made aware of the progressive nature of the condition and owner compliance in the management is crucial to successful management.


What is bronchomalacia?

Similar clinical presentation as chronic bronchitis, identified on bronchoscopy, misshapen larger airways (bronchi) that easily collapse during expiration, concurrent evidence of chronic bronchitis might be present, cause un known but probably loss of airway architectural rigidity associated with ageing. No specific treatment other than controlling concurrent respiratory disease. possible use of anti tussives if coughing is a particular problem.


What is feline asthma syndrome?

Probably a Type I immediate type hypersensitivity reaction to inhaled allergens. clinical signs can vary from mild coughing to severe dyspnoea, cyanosis and death. paroxysmal coughing, wheezing usually associated with the coughing attacks. dyspnoea and tachypnoea with head extension and open mouth breathing. Haematology circulating eosinophiilia may be found and is highly supportive of diagnosis. radiography findings vary from mild bronchial markings to severe interstitial changes with right middle lobe collapse/consolidation. Bronchial cytology can give a mixed cellular reaction is found in the majority of cats but presence of large number of eosinophils is highly diagnostic but might not always be present. main differential is aleurostrongylus abstrusus infection, which can cause an airway eosinophilia. The majority of cats are controlled with oral low dose alternate day prednisolone. Nebulized glucocorticoids eg fluticasone with or without a B adrenoreceptor agonist are advocated by some. Avoidance of putative aeroalelrgens can be useful, severe attacks are treated with oxygen therapy, intravenous steroids, methylxanthines, B2 adrenoceptor agonists (terbutaline oral/injectable), salmeterol (inhaled) and less commonly atropine and adrenaline. additional anti leukotriene therapy has been advocated by some but no evidence. Cats show a good response to prednisolone are usually easy to control but may require life long therapy.


What airway/lung parasites may occur in dogs & cats?

The incidence appears to be low and disease is sporadic but the prevalence of infection is not known. Different methods of transmission (oslerus, dam to offspring; crenosoma and aleurostrongylus, intermediate host, snails, slugs, small rodents). Reactive tracheitis, bronchitis and alveolitis results giving the clinical signs. paroxysmal episodes of harsh cough, dyspnoea if airways are occluded or infection is widespread. Hamatology is circulating eosinophilia may be present in some cases. radiography usually normal, reactive nodules may be seen at the carina ((oslerus), interstitial pattern if significant lung eosinophil infiltration. bronchoscopy grey brown to white ish reactive nodules visible at carina., with associated mucosal inflammatory reaction (oslerus) free worms in bronchi (rare). Bronchial cytology - adult worms, larvae and embryonate eggs, with a mixed inflammatory or eosinophilic rich reaction (diagnostic) faecal analysis and identification of larvae also confirms diagnosis but commonly gies false negative results. treatment - benzimidazole anthelmintics are effective and spot on preparations used to treat ecto parasites, try to prevent eating snails, slugs and hunting in cat for oslerus osleri asymptomatic dam and siblings and close contacts should be treated. Oslerus osleri - dog, crenosoma vulpis (dog, aleurostrongylus abstrusus (cat), angiostrongylus vasorum


Describe the effects of airway foreign bodies

Rare, usually cereal seed heads, acute cough becoming chronic, halitosis after weeks to months, lodge in right main stem bronchus, usually retrievable with bronchoscopy. Small twigs/sticks/other vegetation, small stones and other solid object. small items bypass the carina and become lodged in the mainstem or lobar bronchi. larger objects may get caught at the rima glottis or rostral to the carina, causing severe inspiratory airflow ostruction, hypoxaemia, hypercapnia, cyanosis and asphyxiation. inflammatory reaction develops in response to the presence of the foreign body; chronic localised bronchial changes and localised bronchopneumonia, pleurisy and pyothorax if foreign body migrates. Acute onset of coughing that can be continuous, harsh and very distressful subsides over subsequent days and becomes chronic. pronounced halitosis will develop. signs typical of acute bronchopneumonia or pleural effusion can develop in complicated cases. Radio lucent foreign bodies will not be seen radio dense objects usually easy to see. bronchoscopy allows identification of the foreign body, its exact location and retrieval. bronchial cytology - mixed inflammatory cell population will be present. retrieval by bronchoscopy is the usual preferred method. Retrieval by thoracotomy may be required as well as lung lobectomy if severe lobe consolidation. the prognosis for most foreign bodies located in mainstem and lobar bronchi is very good and chronic problems rarely arise.


Describe pneumonia and its clinical signs & diagnosis

Inflammatory diseases of the lung parenchyma including the interstitium, alveolar spaces and the smaller bronchi, bronchioles and respiratory bronchioles are grouped together as pneumoia. viral and primary bacterial agents causes are not that important int he aetiology. secondary bacterial infection is important and typical agents include pasturella, klebsiella and proteus spp and E. coli. actinomyces and Nocardia spp occasionally are involved. Often secondary to other diseases, chronic bronchitis, diseases causing inhalation of foreign material, systemic illness. Coughing, nasal discharge, tachypnoea, dyspnoea and exercie intolerance, pyrexia, lethargy and inappetance or anorexia, debility and cachexia, cyanosis. History of dysphagia, regurgitation or vomiting associated with oesophageal and gastro intestinal disorders. Leucocytosis with Neutrophilia and left shift suggestive of bacterial bronchopneumonia. Radiography - mixed bronchial, interstitial and alveolar pattern may be present. an alveolar pattern with distinctive air bronchograms is usually attributed to bronchopneumonia. Bronchoscopy - mucopurulent material in the air ways , without chronic airway mucosal changes. bronchial cytology - inflammatory cellular reaction with variable numbers of leucocytes and macrophages. management - with a localised lobar bronchopneumonia there is little danger to the patient, while acute bronchopneumonia with diffuse pathology is potentially fata. empirical antibacterial therapy is acceptable and agents should have broad spec of activity. potentiated sulphonamides, fluoroquinolones, cephalosporins, clindamycin are most versatile agents, and can be used in combination in severe cases. anti tussives are contraindicated as coughing and is valuable protective mechanism. mucolysis using nebulised solutions and steam vapour can be useful but simple chest physiotherapy is often as effective. hospitalisation and attention to hydration and nutrition status with or without supplemental oxygen coupled with good nursing care needed. prognosis is good if underlying cause can be corrected.


What is pulmonary infiltration with eosinohilia? (PIE)

A group of respiratory diseases in which the eosinophil is the predominant cell type found in bronchial washes. PIE is believed to be a hypersensitivity reaction to inhaled allergens or migrating ascarid parasites. clinical signs can vary from mild to severe depending on the degree of airway and lung inflammation. no matter how severe the signs are - affected dogs usually clinically normal otherwise. coughing seen in most cases, with tachypnoea, dyspnoea and exercise intolerance found with severe lung inflammation. haematology is mild to marked circulating eosinophilia in some cases. the presence of a circulating basophilia probably more significant. radiographic pattern typical of many other respiratory diseses. bronchoscopy evidence of active airway inflammation can be present with increased secretions. bronchial cytology the predominance of eosinophils in samples is diagnostic, providing parasitism is excluded. Glucocorticoids usually rapidly effective and appropriate response supports diagnosis. response is most rapid with dexamethasone i/v, followed by oral prednisolone at anti inflammatory dose reducing over 3 weeks to alternate day for up to 6 weeks. prognosis can vary with some dogs responding to a single treatment.


What is idiopathic pulmonary fibrosis?

Seen in WHWT - terrier breeds, cairn terrier, also in others. Lung fibrosis might be secondary to underlying chronic respiratory disease, brachycephalic airway syndrome, bronchopneumonia, toxins, normal ageing change, but true IPF is likely to have a primary cause. Marked variability in the severity of clinical signs which correlates with extent o flung pathology. gradual onset and progressive deterioration over a period of months to years. coughing, tachypnoea, dyspnoea, and exercise intolerance, cyanosis. marked crackles are audible on chest auscultation, but usually otherwise very healthy. generalised and diffuse increase in interstitial density correlating with the degree of respiratory impairment. CT best method of diagnosis with characteristic changes including ground glass appearance, sub pleural fibrosis, parenchymal bands, traction bronchiectasis and occasionally honey comb appearance to the lung. echocardiography can identify signs of pulmonary hypertension in 50% of cases; right ventricular hypertorphy, pulmonary artery distension and raised tricuspid and pulmonic valve regurgitant blood flow elocities. collapse of lobar bronchi during expiration might be seen. condition is irreversible and progressive. treatment glucocorticosteroid therapy beneficial in some cases and some dogs seem to benefit from additional bronchodilator therapy. sildenafil and pimobendan for those with pulmonary hypertension gives some symptomatic relief.


What is primary pulmonary neoplasia

Seen in older dogs and cats. majority of primary neoplasms are of epithelial origin, lung is the major metastatic site for malignant neoplasms elsewhere int he body. cause coughing by compresison of adjacent bronchi. vessel erosion by the mass causes bleeding into the airway and lung. paraneoplastic changes, such as debility anc cachexia and hypertrophic pulmonary osteoarthopathy can occur. usually >5 yo, coughing, expectoration of blood, tachypnoea, dyspnoea, excercise intolerance. Well delineated consolidated masses most common finding on radiography, lung lobe consolidation and hilar and sternal lymphadenopathy diffuse interstitial and alveolar changes with air bronchograms. CT useful to identify extent of disease, local lung metastasis and extent of lymph node involvement. blood tinged mucus and dynamic collapse of major airways on expiration is often seen on bronchoscopy. thoracocentesis - transthoracic needle sampling of a mass will allow diagnosis but is not succesful in all instances and might not be feasible. Alleviation of clinicl signs with glucocorticosteroids will allow palliation for several weeks to months. surgical removal can be attempted if the mass is localised to single lobes and there is no gross evidence of metastases in the other parts of the lung. This disease is terminal. even if lobectomy has ben undertaken - metastatic spread is presumed to have occurred by time of diagnosis.


What are pleural effusions?

Consequence of several diseases. irrespective of the cause it results in the same clinical signs with dyspnoea being most important. effusion types include true transudate, modified transudate, exudate, chyle, also consider blood (haemothorax) and air (pneumothorax) pleural effusion restricts lung expansion resulting in varying degrees of tachypnoea, dyspnoea and excercise intolerance. with severe effusions cyanosis either at rest or after mild exertion may develop. debility and cechexia develops with long standing pleural effusion. pyrexia may be present with pyothorax. muffling of res and cardiac sounds and alteration in chest percussion can be found. Thoracocentesis sampling from the pleural space allows identification of the effusion type and culture of infective organisms. check for nocardia and actinomyces and bacteroides spp. biochemistry for identification of hypoalbuminaemia sufficient to cause a transudate as well as evidence of hepatic dysfunction. serum triglyceride levels can be compared to levels in effusions. Typical findings on radiography include a homogenous ground glass appearance to the lung field, pleural fluid lines, lung lobe border delineation, lung lobe compression. Prognosis depends on underlying cause.


Describe transudate

Clear, colourless, pale yelow, translucent, serous.
Hypoalbuminaemia, congestive heart failre


What is modified transudate

Yellow/pink, translucent, true transudates become modified with increased cell numbers and protein content the longer they are in the pleural space. causes: cardiac disease, hypoalbuminaemia, obstruction of lymphatic drainage, inflammatory, reactions neoplasia, herniation of abdominal contents.


What is exudate

Exudate - yellow, opaque, highly cellular,
Causes: inflammation, infection, neoplasia


What is chyle?

White/pink, opaque lymphocyte and lipid rich.
Causes: trauma, neoplasia, infections, idiopathic, congenital, CHF.


What is the general effusion management plan?

Avoid unnecessary excitement and provide supplemental oxygen if tolerated. postpone thoracic radiography if in severe respiratory distress or cyanosed, or alternatively obtain a standing lateral or dorso ventral view. perform Thoracocentesis and withdraw sufficient fluid to allow a noticeable improvement in respiratory function. Retain some fluid for analysis, cytology and culture. In the event that significant re accumulation of effusion occurs, pleural catheter placement, and intermittent drainage. In situ pleural catheters also allow easy access for pleural lavage. Pleural drainage is continued until only small quantities of a serous effusion can be collected, or untill medical methods of management have been identified.


What is the treatment of true transudate and modified transudate?

Underlying cause, such as hypoproteinaemia or congestive heart failure should be treated accordingly


What is the treatment of exudate

Pyothorax - Treat with intermittent or continuous chest drainage, the latter gives a higher survival rate, this also allows chest lavage with warmed normal saline. long term antibacterial therapy on the basis of culture and sensitivity testing. penicillins, other lactam agents cindamycin, potentiated sulphonamides for dealing with anaerobic infections. Neoplasia - palliative thoracocentesis and pleural drainage to alleviate respiratory symptoms. euthanasia should be considered if frequent pleural drainage is required.


How is chylothorax treated?

Managed by a combination of dietary control of fat intake and surgical ligation of the thoracic duct. treatment of underlying infections and neoplastic diseases, benzopyrones in the treatment of chylothorax in dogs may be be may b e of potential benefit but their efficacy is still being asses and no definite recommendation on their use is available yet.


How is pneumothorax treated?

Mild to moderate pneumothorax might not cause appreciable respiratory distress and can resolve spontaneously. thoracocentesis is required if symptomatic or there is persistent re appearance of air in the pleural space. in the latter instance water seal drainage is advised usually 3-4 days is sufficient. Surgical correction of an identifiable cause of recurrent pneumothorax should be considered.


Describe mediastinal disease?

Extension To involve the thoracic vertebrae and spinal cord causing pain and hindlimb paresis. interfere with the trachea, mainstem bronchi and oesophagus causing coughing, dyspnoea, dysphagia and regurgitation. compress major vessels causing head, neck and forelimb oedema, ascites and hindlimb oedema or chylothorax. Can damage sympathetic ganglia, the vago sympathetic trunk and recurrent laryngeal nerves causing horners syndrome and laryngeal dysfunction.The presence of inflammatory disease in the mediastinum itself, in addition to the signs caused by damage to the adjacent structures might also result in pain, discomfort and pyrexia.


What is pneumomediastinum?

the presence of free gas within the mediastinum enables visualisation of structures not normally seen on radiography. these include the outer walls of the trachea, the oesophagus, cranial vena cava and azygous vein. the causes include tracheal or oesophageal rupture, iatrogenic puncture of the trachea or bronchi during airway sampling, idiopathic pneumediastinum is found, although it may be associated with forceful respiratory manoeuvres such as coughing, vomiting and sneezing. deep neck wounds, with air migrating along the neck muscle facial planes. Eventually the air reaches the subcutaneous tissues around the head, giving a puffed appearance. In uncomplicated cases, pneumomediastinum is not harmful and the condition is usually self limiting however marked increases in mediastinal pressure can compromise venous return to the heart and in the event of mediastinal rupture a life threatening pneumothorax may occur.


What is mediastinal widening?

Obesity or an enlarged thymus, neoplasia including lymphoma, heart base tumours, lipomas, thymoma, thyroidal tumours and metastases from other tumour sites. abscesses, granulomas and other infectious/inflammatory disorders (mediastinitis). oesophageal dilation, impaction and foreign bodies, oedema and haemorrhage in association with pleural effusion.


What are the major respiratory defence mechanisms?

The nasal cavity turbinates provide the surface area required for warming and humidifying inspired air and the mucosa traps and filters particulate material. the mucociliary apparatus allows cranial clearance and is augmented by mucus secreted goblet cells and ciliary function. Activity is increased by irritation and B adrenergic stimulation. as a major defence mechanism, irritation can activate receptors and trigger a sneeze, cough and laryngospasm reflex. For the lower airways, smooth muscle contraction, goblet cell production of mucus, the mucociliary escalator and the cough reflex all act to protect the lung. at the respiratory bronchiole and alveolar level the main protective mechanisms include rostral movement of material using capillary action, followed by cough and trans epithelial trasnsport using the alveolar macrophage system. the latter can also involve polymorphonuclear leucocytes (typically neutrophils.) material entering the alveolar interstitium is either sequestrated at that site or carried away via lymphatics.


How does regulation of bronchial smooth muscle tone occur?

This is mediated via reciprocal relationship between cAMP and cGMP. increased levels of one of these second messengers are associated with decreased levels of the other and increase cAMP promotes relaxation whereas increased cGMP promotes bronchoconstriction. cAMP is increased by B adrenoceptor stimulation, H2 receptor stimulation and decreased levels of phosphodiesterases, and decreased by a-adrenergic stimulation. cGMP is increased by muscarinic (M3) receptor stimulation i.e by aCH from vagus and by histaminergic (H1) stimulation


How do respiratory disorders occur?

In the norma lun the interaction between sensory receptors and mediators of bronchial tone is balanced. disruption of such balance results in bronchospasm, b ronchoconstriction, inflammation, increased mucus secretion and changes in mucus viscoelasticity. this may lead to bronchial wall oedema, mucus accumulation and airway obstruction. chronic cases progress towards fibrosis and emphysema.


What are bronchodilators?

Temporary abnormal contraction of the smooth muscle of the bronchi that results in an acute narrowing and obstruction of the respiratory airways is characteristic of asthma and might also be seen with respiratory infection and chronic lung disease. the main purpose of treatment is to induce smooth muscle relaxation using bronchodilators which include B adrenoreceptor agonists, methylxanthines and cholinergic antagonists. all these drugs have desirable effects and undesirable effects.


What do the B agonists do?

They relax airway smooth muslce. they are the most effective bronchodilators regardless of the stimulus. some of them may also modulate mediator release from mast cells and TNF-a release from monocytes. B receptors also stimulate airway mucus secretion. specifics B2 agonists include short acting agents such as salbutamol, turbutaline and clembuterol. Maximum effects occur within minutes and are therefore preffered drugs to treat severe acute asthma. duration of action is 4-6 hs. salbutamol and terbutaline have been used in small animals. clenbuterol is a licensed veterinary drug and used in horses with little value in small animals. Longer acting agents include salmeterol which is administered by inhalation with duration of action of 12 hours. Unwanted side effects can include refractoriness with chronic use, more viscid mucus and interfering with cilia movement and hypokalaemia, tremors, nausea, vomiting, tachycardia.


What are the methylxanthines?

They act by reducing cAMP breakdown via PDE inhibition. advantages over other bronchodilators include increased respiratory muscle strength, decreasing effort associated with breathing, which may be important in animals with chronic pulmonary disease, but this can be at the expense of increased oxygen consumption (including CNS stimulation). This class includes caffeine, theobromine, Theophylline and the salt preparations include aminophylline, etamiphylline. longer elimination 1/2 life in horses than in humans and small animals. there is a high risk of side effects such as tachycardia, agitation, cardiac arrhthmias, hyptension, seizures and even death, and their overall effects on bronchomotor tone has been questioned.


How is anti inflammatory therapy used to treat respiratory disease?

Mainly involves the use of glucocorticoids but also NSAIDS. glucocorticoids reduce airway inflammation and decrease pulmoonary eosinohpils infiltration via decreaseed cytokine formation, which make them the preferrerd drugs to treat asthma and respiratory disease where eosinophil infiltration predominates. they also enhance bronchodilation via B2 upregulation. dexamethasone is most effective against oesinophils and can be followed but oral prednisolone aiming for alternate day low dosing and eventual withdrawal. delivery of glucocorticoids with an added bronchodilator can overcome systemic effects. Fluticasone with salmeterol is commonly used in dogs and cats for inhalation.


How are NSAIDS used for anti inflammatory therapy?

NSAIDs are often used to assist with controlling airway and lung inflammation but the problem of blocking protective eicosanoid pathways is a consideration. often they have value in controlling pyrexia in pneumonia cases treatment in combination with antibacterial therapy. Flunixil, ketoproten and carprofen have been used sucessfuly as adjuncts to antibacterial treatment of bovine respiratory disease but whther the same benefits can occur in cats and dogs is unknown.


What are mucolytics?

Mucus is produced by different cells in the respiratory system e.g goblet cells and submucosal gland.s under steady state the mucus confers protection against shear stress and chemical damage to respiratory system. mucus production, secretion rate and properties are severely affected in chronic inflammatory conditions and this leads to decreased capacity of the lungs and increased respiratory work. mucolytics break down thick dry mucus. They may act on mucus secreting cells or on mucus directly. modifiers of mucus synthesis includ ebromhexine and dembrexine often used to treat chronic bronchitis. they reduce the viscosity of secreted mucus possibly by increasing lysosomal breakdown of mucopolysacharide within the gland cell. true mucolytics include acetylecysteine and work by reducing viscosity by breaking or blocking formation of disulphide bridges, often administered as an aerosol limiting their penetration into the distal airways.


What are the anti tussives?

They can act centrally (depressing the cough center in the brain) or peripherally depressing cough receptors in the airay. only the centrally acting drugs are of use in veterinary patients and include narcotic opiate analgesics (codeine, hydrocodone, butorphanol) and non narotic opioids (dextromethoprhan, diphenyxoylatE). their use is limited to those casese where coughing is of little value, cannnot be controlled by other means or is causing significant discomfort to the dog. care should be exercised when coughing is of benefit such as chronic bronchitis and pneuumonia. they can be used to suppress coughing in cardiac patients where cardiac drugs are ineffective in controlling cough. tolerance can develop to the opiate drugs and can be overcome by intermittent drugs.


Describe anti bacterial drugs used in respiratory infection

Typically bacteria in respiratory disease reflect over growth of the normal commensal population, usually gram negative aerobes. An antibiotic can be selected on an empirical basis and is likely to be effective eg fluoroquinolones but concurrent infection with gram positive organisms an aerobes must be considered in severe pneumonia and so a combination of antibiotics are needed. Pradofloxacin enhances anti gram positive activity. more traditionally - three of clindamycin, cephalosporin, potentiated sulphonamides, and an early generation fluoroquinolone. clavulanate potentiated amoxicillin is often used in general practice and can be effective for simple infections but is rarely efficacious in severe pneumonia cases. It has poor penetration into infected lung. may be considerd to be used intravenously in severe infections prior to oral administration of B lactam. When mycoplasma is suspected then use doxycycline. Gentamycin can be considered for highly resistant pseudomonas infection but parenteral fluoroquinolones or ticarcillin are more feasible.


What is the duration of antibacterial therapy?

Dependent on the severity of disease. in severe bronchopneumonia treatment should be for a minimum of 4 weeks , with cessation of therapy only if there has been complete resolution of clinical signs and radiographic evidence suggesting a cure. Otherwise therapy should be extended for a further 4 weeks providing the first four weeks did give significant improvement. in the case of a partially responsive chronic lobar pneumonia, lung lobectomy is a reasonable approach and better than life long antibacterial therapy. In recurrent infections such as with chronic bronchitis intermittent courses of antibiotics will be needed to avoid catastrophic pneumonia developing.


What are the anti pulmonary hypertension drugs?

Pulmonary hypertension is now readily recognised in chronic fibrotic lung diseases e.g IPF and secondarily to left sided congestive heart failure. a standard drug treatment is combination of sildenafil and pimobendan likely acting as PDE5 inhibitors.


What anthelmintics are used in respiratory disease?

Respiratory parasitism is increasingly recognised in dogs and to a lesser extent in cats. the usual classes of drugs used effectively to treat lung parasitism, and control reinfestation include the benzimidazole anthelmintics (e.g fenbendazole, panacur) and spot on preparations (advocate) more routinely used to control ectoparasites e.g imidacloprid and moxidectin.


List two common causes of acute onset dyspnoea in the cat?

Feline asthma, trauma, pleural effusion are the 3 most common causes of acute onset dyspnoea.


What is brachycephalic airway syndrome

Seen in brachycephalic breeds, in young - middle age, no sex predisposition, signs: stertor, cyanosis, dyspnoea, exercise intolerance, primary disorders, stenotic nares and elongated soft palate, secondary disorders: everted laryngeal saccules and tracheal collapse, investigation:history, physical exam, imaging, take bloods. Vertical wedge resection of stenotic nares, excision of excess soft palate, excise sacculus and medical management for tracheal collapse.


How would you investigate pleural effusion further?

Perform a thoracocentesis to remove the fluid and see what kind of fluid it is e transudate, modified transudate, exudate, chyle, culture for bacteria, check for norcardia and actinomycosis, check for hypoalbuminaemia on biochemistry, check history for possible trauma, check cardiac health by auscultating, check rates, ECG.


what are the potential causes of oronasal fistula?

Trauma, maxillary tooth extraction (canine), dental disease (abscess, neoplasia and fungal infection from nasal cavity (destroys bone).


Describe primary lung tumours

brachycephalics may be at increased risk, most in dog are adenocarcinoma or carcinoma. most pprimary are solitary. Cats more likely to have metastasis. Most present with coughing, dyspnoea, lethargy, weight loss, inappetence and wheezes in cats. Haemoptysis can occur but relatively rare. Hypertrophiic osteopathy seen in dogs -- swollen limbs, lameness, heat on palpation, hypercalcaemia, fever, Cats - lung digit syndrome. Diagnosis - thoracic radiographs. Caudal lung lobes more often affected. If pleural effusion present - have thoracocentesis. if malignant pleural effusion diagnosed - poor prognosis. Ultrasound guided FNA aspiration cytoogy can be done for peripherally located lung masses. risks include pneumothorax. CT guided FNA for more centrally located lesions. transthoracic aspiration in case of diffuse lung involvement have higher risk. DDX - granuloma, cyst, infarct, haemorrhage, focal pneumonia, abscess, lung lobe torsion, fungal disease, bacterial or parasitic granulomatous disease. Treatment - lung lobectomy. Long term survival possible for dogs with small masses that have not metastasized. Cats do worse than dogs. Palliative measures include antitussives, bronchodilators, appetite stimulants, NSAIDs, anti angiogenics, analgesics.


Describe metastatic tumours to the lung

The lungs are the frequent site of metastasis for both carcinomas and sarcomas - the lung may provide a fertile ground for development of tumours - growth factors, oxygen, nutrients. thep pulmonary capillary bed may cause lodging of tumour emboli in the lung, thus encouraging tumour cells to extravasate and grow. tumours with high predilaection for metastasis to lungs - canine haemangiosarcoma, appendicular osteosarcoma, feline and canine mammary carcinoma, oral and nailbed melanoma, tonsilar squamous cell carcinoma. Signs referable to lower urinary tract disease such as coughing or excercise intolerance usually absent. Non specific signs. chemotherapy - usually broad spectrum anticanccer drugs are chosen such as carboplatin, doxorubiin, surgical removal of metastatic lesions not typically performed. Bisphosphonates may be used in some cases especially canine osteosarcoma. Generally poor prognosis.


Describe cardiac tumours

Rare. tumour types - haemangiosarcoma, aortic body tumour, lymphoma, sarcoma, mesothelioma, carcinoma, haemangiosarcoma most common primary tumour type of the heart in the dog - golden retrievers, GSDS, typically present on emergency with pericardial effusion, aortic body tumours (chemodectomas, parangiomas) arise from chemoreceptors cells at heart base. lymphoma is most common tumour of the heart the cat. any tumour, can metastasise to the heart, most dogs present clinically ill, rarely an incidental finding. Therapy generally limited - palliative eg pericardial window, chemotherapy, anti arrhthmics, surgical removal. Poor prognosis ecept for chemodectomas.


How is bronchial smooth muscle tone regulated?

cAMP is increased by B2 adrenoceptor stimuation, H2 receptor stimulation and decreased levels of phosphodiesterases and decreased by a-adrenergic stimulation. cGMP is increased by muscarinic m3 receptor stimulation and by histaminergic H1 stimulation. Increased cAMP promotes relaxation whereas increased cGMP promotes bronchoconstriction.


What are bronchodilators? How do the b2 agonists work?

The main purpose is to induce smooth muscle relaxation using bronchodilators which include B-adrenoceptor agonists, methylxanthines and cholinergic antagonists. B agonists relax airway smooth muscle. They are the most effective bronchodilators, regardless of stimulus, some of them may also modulate mediator release from mast cells and TNF -a release from monocytes. B receptors also stimulate airway mucus secretion. Specifi B2 agonists include salbutamol, terbutaline and clenbuterol. Maximum effects occur within minutes.


Describe the methylxanthines?

Act by reducing cAMP breakdown via PDE inhibition. advantages over other bronchodilators include nicreased respiratory muscle strength, decreasing effort associated with breathings, which may be important in animals with chronic pulmonary disease, - includes caffiene, theobromine, theophyllines. High risk of side effects such as tachycardia, agitation, cardiac arrythmias, hypotension, seizures and even death.


Why are anti inflammatory drugs used in respiratory disease?

Glucocorticoids - reduce airway inflammation and decrease pulmonary eosinophil infiltration via dcreased cytokines formation which makes them the preferred drugs to treat ashtma and respiratory disease where eosinophil infiltration predominates. they also enhance bronchodilation via b2 upregulation. dexamethasone most effective followed by oral prednisolone.


What are mucolytics?

Mucus is produced by different cells in the respiratory system eg goblet cells and submucosal glands, under steady state the mucous confers protection against shear stress and chemical damage to the respiratory system. mucus production secretion rate and properties are severaly affected in chronic inflammatory conditiosn and thiis leads to decreased capacity of the lungs and increased respiratory work. mucolytics breaks down thick dry mucous. they may act on mucus secreting cells or on mucus directly. modifiers of mucus synthesis include bromhexine and dembrexiine and are offten used to treat chronic bronchitis. they reduce the viscosity of secreted mucus posisibly by increasing lysosoma breakdown of mucopolysaccharide.


What are anti tussives?

Can act centrally depressing the cough center int he brain or peripherally depressing cough receptors in the airways. only the centrally acting drugs are of certain use including narcoptic opiate analgesics (codeine, hydrocodon, butorphanol) and non narcotic opioids. their use is limited to those cases where coughing is of little value, cannot be controlled by other means or is causing significant discomfort to the dog. care should be exercise in their use when coughing is of benefit eg in chronic bronchitis and pneumoonia.


Describe sino nasal or nasal tumours - the incidence, signalment, risk factors, biologic behaviour, clinical signs, diagnostic tests.

Risk factors - doliocphalic breeds, urban environments, expoosurre to tobacco smoke. most common types - carcinomas, including adenocarcinoma, squamous cell carcinoma, undifferentiated or poorly differentiated carcinomas. In cats - lymphoma most common. Other tumours in both can include haemangiosarcoma, melanoma, mast cell tumour, fibroma. Most nasal tumours are characterised by progressive local invasion and late onset of metastasis. Low metastatic rate at time of diagnosis but higher at time of death - sites include LN lung and rarely brain,kidneys, livver, skin and bones. Most present with nasal discharge, conestion, epistaxis, sneezing, reverse sneezing, coughing, nasal deformity, pawing at the face , stertor, ocular discharge, obtunted or seizures. Diagnostic tests - complete blood count, chemistry profile, felv/fiv, b,bt, blood pressure, tick titers to rule out erhlichiosis, testing for FHV1 FCV, chlamydophila felis, cryptococcus. Nasal radiographs - symmetry, turbinate destruction, variations in opacity. Nasal ct - location, presence of solid mass, osseous involvement, exent of disease. Biopsy/rhinoscopy - visualisation of masses, fbs, obtain biopsy, blind pinch biopsy also possible. Treatment - radiation. surgery alone not recommended. chemotherapy often administered in conjunction with RT in cats.