Flashcards in Exam 1 Deck (216):
Does anorexia in adult animals result in significant hypoproteinemia?
Mechanisms of decreased protein production
Mechanisms of protein loss
Common presenting complaints of patients with hypoproteinemia
Peripheral limb swelling
Causes of hypoglobulinemia
Failure of passive transfer
Which values on a chemistry panel are indicators of liver function?
Medical concerns associated with hypoproteinemic animals
Fluid overload (decreased oncotic pressure, consider colloids or plasma)
Anesthesia (protein bound anesthetic agents)
Why are hypoproteinemic animals prone to thromboembolism?
Loss of protein also leads to loss of antithrombin
Consider giving clopidogrel
Congenital causes of hypoproteinemia
Failure of passive transfer
Infectious causes of hypoproteinemia
Inflammatory causes of hypoproteinemia
Inflammatory bowel disease
Metabolic causes of hypoproteinemia
Renal disease (PLN)
Definition of heat stroke
Severe illness characterized by core temperatures of >104 F in humans and >105.8 F in dogs as well as CNS dysfunction
Two classifications of heat stroke
Patient predisposing factors for heat stroke
What are the protective mechanisms the body uses against heat illness?
Acute phase response
Heat shock response proteins
Heat dissipation mechanisms
Sensible response (conduction, convection, radiation)
Insensible response (evaporative cooling (panting))
70% of total body heat loss in dogs and cats is due to which mechanisms?
Radiation and convection
What is the insensible response to heat?
Evaporative cooling via panting
Activation of hypothalamic panting center causes mucosal vasodilation
Partial air system uses unidirectional air flow in through nose and out of mouth to maximize evaporative cooling and heat loss
Salivation further increases evaporative cooling
Physiologic effects of increased body temp
Inc. sympathetic tone -> inc. HR and CO -> dec splanchnic circulation -> cutaneous vasodilation -> inc muscle blood supply -> inc cutaneous circulation -> heat loss via radiation, conduction, convection
Evaporative cooling via panting
At what point does evaporative cooling fail?
Environmental temp > body temp
Humidity > 80%
How does dehydration affect heat dissipation?
Decreases evaporative heat loss because less water is available for respiratory system
Decreases heat dissipation through radiation and convection due to decreased blood flow to periphery
What is acclimatization and how long does this process take in dogs?
Adaptive physiologic response to environment and climatic change
Partial acclimatization in 10-20 days
Full acclimatization in 60 days
How does the body acclimatize to a higher environmental temperature? (7 things)
Increased ability to resist rhabdomyolysis
Body water conservation via aldosterone and ADH
Activation of RAAS
Plasma volume expansion
Enhanced CV performance (inc HR and CO)
What does the acute phase response work (heat stroke)?
Stimulation of anti-inflammatory acute phase proteins in liver
Inhibits production of reactive oxygen species
Inhibits release of proteolytic enzymes from activated leukocytes
Promotes wound healing and repair by stimulating endothelial cell adhesion, proliferation, and angiogenesis
What are heat shock proteins (HSP) and what do they do?
Protective proteins produced with cell stress (heat, ischemia, endotoxemia, oxidative/nitrosative stress)
Increase levels of HSPs allow a transient state of tolerance to otherwise lethal stage of heat stress allowing cells to survive
Reduced numbers of heat shock protein have been found with
Lack of acclimatization
Certain genetic polymorphisms
What are the physiologic effects of heat shock proteins?
Prevents protein breakdown and assists in refolding of denatures proteins into normal configuration
Prevents loss of epithelial barriers and prevents endotoxin leakage
Interferes with oxidative stress and blocks apoptotic cell signaling pathway
Prevents arterial hypotension to decrease cerebral ischemia and neural damage
Offer CV protection by regulating baroreceptor reflex response to abate hypotension and bradycardia
How does heat shock cause cardiovascular collapse?
Decreased central venous pressure and CO (circulatory shock)
Decreased plasma volume and hypoperfusion
Indirect myocyte injury
What effects can heat stroke have on the respiratory system?
Direct pulmonary epithelial damage
Increased pulmonary vasculature resistance
Can result in non-cardiogenic pulmonary edema, DIC, ARDS
What effect does heat stroke have on the kidneys?
Direct thermal injury
Indirect injury - hypoxia, microthombi
Rhabdomyolysis (nephrotoxic myoglobin)
What effects can heat stroke have on the brain?
Indirect injury due to edema, hemorrhage, infarcts
What effects does heat stroke have on GI system?
Hypovolemia and splanchnic pooling can cause microthrombi -> hypoxia and ischemia
Causes loss of GI integrity (ulceration and sloughing)
Results in bacterial translocation, sepsis, and endotoxemia
How does heat stroke affect the liver?
Decreased hepatic blood flow and thermally-altered hepatocyte function leads to decreased blood detoxification
Can cause centrilobular necrosis and cholestatic liver disease
How does heat stroke affect coagulation?
Direct damage to vascular endothelium -> release of cytokines and inflammatory responses, adherence of leukocytes and platelets to damaged endothelium
Release of tissue factor (activating clotting cascade, producing uncontrolled systemic coagulation)
Depletion of coagulation factors and platelets
Reduced synthesis of coagulation factors from hepatocytes
Development of DIC
Hemoconcentration due to dehydration
Most consistent clinical signs of heat stroke
Dry, hyperemic MM
Hyperdynamic femoral pulses
Can by hyper, normo, or hypothermic!
Bloodwork findings with heatstroke
Inc. muscle enzymes
Treatment for heatstroke
Rapid cooling - whole body wetting with water combined with muscle massage and fans, IV fluids
CV support (control hypotension, arrhythmias)
management of secondary complications (shock, hypoglycemia, DIC, ARDS, renal failure)
When should you stop active cooling techniques in heat stroke patient?
Should you use alcohol to cool a patient with heat stroke?
Risk of fire if need to defibrillate
What are exogenous pyrogens?
Drugs (e.g. tetracyclines)
Do not directly cause an increase in body temp, but cause an increase in endogenous pyrogens
What are endogenous pyrogens?
IL-1, IL-6, TNF, INF
Bind to vascular endothelial cells within anterior hypothalamus ->
Cause PGE1 and PEG2 production ->
Alters the set temperature (thermostat) within the hypothalamus
3 most common causes of FUO
What are the risks associated with therapeutic trials for patients with FUO?
Continued disease progression
Drug toxicity/side effects
Exacerbating underlying diseae
How to treat a fever?
Artificial cooling techniques
When should you use anti-pyretic agents?
Fever > 106F
Which fungi are dimorphic?
Which fungi have broad-based budding?
Even though Blastomyces is present in all soil, why don’t all animals contract this disease?
Soil organisms destroy blastomyces in the soil
What environmental conditions precede highest incidence periods of blastomyces infection?
How is blastomyces transmitted?
Contamination of puncture wounds/open sores
Which dogs are prone to getting blastomyces?
Males > females
Sporting dogs and hounds
Transformation from blastomyces conidia to yeast occurs where?
What important virulence factors does blastomyces have?
BAD-1 (cell surface glycoprotein tht binds to host cell receptors on macrophages and allows fungus to evade host immune system)
Common clinical signs associated with blastomyces infection
Respiratory signs (cough, dyspnea, exercise intolerance)
Ocular disease (anterior uveitis, chorioretinitis, endophthalmitis, optic neuritits)
Skin disease (cutaneous/SQ nodules, draining tracts)
Definitive diagnosis of blastomyces infection is based on
Cytological, histopathologic, or culture demonstration of organism
Diagnostic tests for blastomyces?
ELISA Ag assay - may cross react with histoplasma
Thoracic rads are abnormal in what % of blastomyces cases?
Treatment for blastomyces infection
Treat for at least 60-90 days and continue 1-2 mo past resolution of clinical signs
Prognosis for blastomyces infection
~80% cured, 20% relapse
Prognosis poor if CNS involvement
Most common systemic mycoses in the cat
Which fungus is narrow-budding?
Route of transmission of cryptococcus?
Hematogenous spread to extra-pulmonary sites
How does cryptococcus evade host immune system?
Polysaccharide capsule inhibits phagocytosis, plasma cell function, and leukocyte migration
Most common clinical signs seen with cryptococcosis in cats?
Sneezing and nasal discharge (50-8%)
Cutaneous/SQ masses (40-50%)
Ocular lesions (20-25%)
Non-specific signs (lethargy, anorexia)
CNS signs (20%) (blindness, depression, behavior changes, seizures)
Most common clinical signs of cryptococcosis in dogs?
CNS (dull mentation, blindness, hypermetria, cranial nerve deficits)
Skin nodules/draining lesions
How do you diagnose cryptococcosis?
Latex agglutination for Ag in serum, aqueous humor, or CSF
Useful to monitor response to therapy
Treatment for cryptococcosis
Fluconazole (in cats)
Amphotericin B (for systemic or refractory disease or those with ocular or CNS involvement)
Continue for at least 1-2 months past resolution of clinical signs and negative titers
Mean treatment time ~8.5 mo
Primary reservoir for histoplasma
Bat (guano and GI tract)
Decaying avian guano (esp. blackbird/starling roosts, chicken coops)
NOT found in fresh feces or shed feces of birds
Pathophysiology of histoplasma infection
Inhaled microconidia transform into yeast at body temperature
Yeast binds to CD-11 -18 integrins on alveolar macrophages and are phagocytized
Replicate within and destroy macrophages
Spread via hematogenous or lymphatics
*Most animals’ immune system is able to clear infection
Clinical signsof histoplasma infection in dogs
Large bowel diarrhea
Diagnostic tests used to diagnose histoplasma infection
Cytology (rectal scrape, BAL)
ELISA Ag assay (urine)
Treatment for histoplasma infection
Amphotericin B (cases with CNS involvement or disseminated disease)
Treat for 60-90 days or at least 1-2 mo past resolution of measurable signs
Prognosis of histoplasma infection
Excellent with only pulmonary involvement
Guarded to fair with dissemination
Which fungus has a sperule containing multiple endospores?
Which fungus prefers dry, warm climates and sandy soils at low elevation (Ca, NM, AZ, UT, NV)?
Infection of coccidiodes follows what type of environmental condition?
Moist conditions followed by a dry period, then soil disruption
Clinical signs of coccidiodes infection in dogs?
Cough, weakness, lethargy, anorexia, weightloss, fever
Lameness with painful, swollen bone lesions
Clinical sign of coccidiodes infection in cats?
Diagnosis of coccidiodes
ANTIBODY serology (IgM detectable 2-5 wks, IgG detectable 8-12 wks)
Bony lesions - may be more proliferative than lytic
Treatment of coccidiodes
Treat for 6 months minimum
Fluconazole (if CNS involvement)
Bony lesions -> amputation
Enophthalmitis -> enucleation
What organism causes nasal aspergillosis?
What organism causes disseminated aspergillosis?
Why are german shepherds more prone to aspergillosis than other breeds?
Most consistent clinical findings with disseminated aspergillosis?
Vertebral pain, paraparesis, paraplegia, lameness with swelling, draining tracts, kidney disease
Other non-specific signs
Diagnosis of aspergillosis
Serological test -aspergillus glactomannan antigen
PCR for *definitive diagnosis*
Treatment for systemic aspergillosis?
Static disease rather than cure more common, poor prognosis
Transmission of sporothrix
Usually cutaneous and SQQ inoculation of organism through puncture wound
Can follow inhalation
Clinical signs of sporothrix infection
Cats > dogs
Male cats > female cats
Cutaneous lesions on nose and nasal planum
Spread of which fungal disease is facilitated through contaminated claw/bite wounds and autoinoculation during grooming?
Which fungus is cigar shaped with a double wall?
Which fungus is round with a double wall?
Treatment of sporothrix
Supersaturated KI/NaI (old treatment) for 30 days beyond remission
Which fungus is potentially zoonotic?
“Large, infrequently septate hyphae with non-parallel walls” describes which organisms?
Phythium and lagenidium
In what ways are oomycets not like fungus?
No chitin or ergosterol in cell wall
Pathophysiology of pythiosis
Infective, motile flagellate zoospore attracted to damaged tissue
Encysts in damaged skin or GI mucosa
What are the two disease spectrums of lagenidium
Chronic nodular dermopathy
Fatal dermatologic and disseminated disease
Main body systems affected by pythium vs lagenidium
Pythuim: cutaneous and GI
Lagenidium: cutaneous and vascular/lymphatic
Diagnosis of pythium/lagenidium
Why is it important to diagnose the species when dealing with phythium/langenidium?
Need to know species to determine
Prediction of behavior
Treatment for pythium/lagenidium
Aggressive surgical resection
Combination antifungal therapy
Newer generation azoles
Caspofungin, mefenoxam (novel agents)
Prognosis poor without resection,
What are basidiobolus and connidiobolus?
Zygomycetes (actual fungi) that can cause skin, nasopharynx, GI lesions and sometimes lower respiratory dz.
How do you treat basidiobolus and connidiobolus?
Aggressive surgical excision and anti-fungal medication
How do you diagnose basidiobolus and connidiobolus?
What is phaeohyphomycosis?
Cutaneous, SQ, cerebral or disseminated infections caused by cutaneous inoculation with pigmented ( diatiaceous) fungi containing melanin in their cell walls
What is hyalohyphomycosis?
Non-pigmented (hyaline or transparent) fungal infection in tissue that can cause systemic, disseminated disease
How do you diagnose phaeohyphomycosis/hyalohyphomycois?
Culture + PCR
How do you treat phaeohyphomycosis/hyalohyphomycois?
Phaeohyphomycosis: aggressive surgical resection, itraconazole/posaconazole for 3-6 mo after surgery
Hyalohyphomycois: challenging due to systemic disease, poor prognosis
Derived from penicillium
Used for dermatophytosis
Oral administration (give with fatty meal)
Side effects: GI, BM suppression, teratogenic
Derived from streptomyces
Binds sterols -> inc wall permeability
Acute toxicity - vomiting, myalgia, fever, anaphylaxis
Poor penetration of bones, brain, eyes
How can you reduce nephrotoxicity of amphotericin B?
Monitoring renal values before each treatment
Ensure hydration before administration
What fluid type should Amphotericin B be administered with when given IV? Sq?
IV: 5% dextrose, Give NaCl or LRS AFTER
SQ: Give in 2.5% dextrose + 4.5% NaCl
How does lipid bound amphotericin B work?
Taken up by macrophages and taken to site of inflammation
Achieves greatest concentrations in liver, spleen, and lung (spares kidneys)
Still need to monitor renal values!
Fluorinated pyrimidine that inhibits DNA/RNA synthesis
Good oral absorption
Penetrates BBB/CSF, use in severe CNS disease
Dogs -> drug eruption
Cats -> thrombocytopenia
Mechanism of action of azoles
Inhibits cytochrome p-450
NEED TO TREAT BEYOND CLINICAL SIGNS OF DZ
hY should you not use antacids concurrently with azoles?
Azoles need acid for absorption
Oral administration (fatty meal)
Poor penetration of brain and eye
Topical administration for candida and malassezia
Side effects: GI, hepatotoxicity, thrombocytopenia, cortisol suppression
How are azoles metabolized?
Oral administration (capsules -> fatty food, liquid -> fasted)
Does not penetrate CNS
Side effects: nausea, vomiting, inappetence, hepatotoxicity, cutaneous drug rxn
Which fungal diseases can itraconazole treat?
(Pretty much all of them)
Good oral bioavailability
DOES penetrate brain, eye
Which antifungal is the drug of choice for crypto?
What fungal diseases can fluconazole treat?
Good oral bioavailabilty
More potent than itraconazole, fluconazole
Which fungal disease can posaconazole treat?
Main use of topical azoles (clotrimazole, enilconazole)?
Primary nasal aspergillus
Side effects of topical azoles
What is clotrimazole used for?
Non-responsive candida cystitis
Renal pelvis infusions (renal aspergillosis)
Iodides as antifungal therapy
Used for sporothrix
Not commonly used
Mechanism of action of terbinafine
Inhibits ergosterol synthesis
Commpnly used for dermatophytosis
Good oral bioavailability
Side effects: GI, hepatotoxicity, pancytopenia
Which drugs are chitin synthesis inhibitors?
Which drug is a glucan inhibitor?
*slow onset of action, expensive*
What is mefenoxam?
Inhibits RNA polymerase
Effective against plant pathogen oomycets
Has been used to tx pythium
What is the MIC?
Minimum inhibitory concentration
Lowest concentration of a drug that inhibits growth of the organism cultured
NOT the concentration that kills the organism
When do you consider anti-fungal sensitivity testing?
Minimal $$ constraints
Why is nasal discharge not noticed until underlying cause is fairly advanced?
Usually the animal will swallow the discharge, so seeing it come out the nose means that the capacity of the mucociliary clearance has been exceeded
Differentials for unilateral nasal discharge
Tooth root abscess
Differentials for bilateral nasal discharge
Differentials for epistaxis
Are large populations of bacteria seen on nasal cytology concerning?
No, can be normal
Diagnostic test that is most likely to yield a specific diagnosis if there is primary nasal disease
Test that are recommended before performing nasal boipsy
How do you prevent penetrating the calvarium via cribiform plate during nasal biopsies?
Measure the distance between the nostril and the medial canthus of the eye with the biopsy instrument and do not advance past that
3 primary biopsy techniques used in nasal biopsy
Traumatic nasal flushing
Clinical signs of nasal tumors
Decreased airflow through nostril
Deformation of nasal bones, hard palate, or maxillary dental arcade
Non-specific signs such as weightloss and anorexia
Treatment of choice for benign nasal tumors? Malignant tumors?
Benign: surgical excision
Malignant: radiation, NSAIDs
Survival time for malignant nasal tumors treated with radiation?
Clinical signs of nasal polyp
Upper airway obstruction
Signs of otitis externa/media/interna (horner’s, head tilt, nystagmus)
Primary pathogens in bacterial rhinitis
How can cardiac disease cause coughing?
1. Chamber enlargement putting pressure on airway
2. Congestion or pulmonary edema
T/F: fecal examination should be done on almost all patients presenting for chronic cough
Most common complication associated with pulmonary aspirates
Main use of bronchoscopy
Facilitate collection of samples from the lower respiratory tract
What should you do is your patient experiences transient hypoxemia after tracheal wash or BAL?
This is normal
Will respond to oxygen therapy, crackles are normally heard for several hours after and are not of concern if other respiratory parameters are WNL
Diseases that present with an acute cough
Canine infectious respiratory disease
Non-cardiogenic pulmonary edema
How do you definitively diagnose canine infectious respiratory disease?
Best antibiotic choices for canine infections respiratory disease?
When should you use antibiotics with aspiration pneumonitis?
No improvement after 2-3 days
Inflammatory leukogram getting worse
Animal has been on H2 blockers or PPIs
Causes of chronic cough
Canine chronic bronchitis
Primary ciliary dyskinesis
What radiographic view can you see intrathoracic tracheal collapse? Extrathoracic?
Intra: expiratory films
Extra: inspiratory films
Emergency management of a patient with tracheal collapse and in respiratory distress should include:
Anti-inflammatory (short-acting steroids)
Intubation or tracheostomy
Medical management of tracheal collapse includes:
Replace collar with harness
Reduction of inhaled irritants
When should surgery be considered for a patient with tracheal collapse?
Only in cases where medical management has failed and owners are prepared to accept negative outcomes
Most common clinical sign of canine chronic bronchitis
A dry cough exacerbated by excitement and exercise
Treatment for chronic canine bronchitis includes:
Bronchodilators (B agonists or methylxanthines)
What is bronchiectasis?
Permanent dilation of the bronchi and is commonly a complication of chronic respiratory disease such as chronic bronchitis
What is primary ciliary dyskinesis?
Congenital defects in the ciliary microtubule structure, resulting in reduced clearance of respiratory secretions, inhaled particles, and infectious agents.
Dogs < 2 yrs, English Pointers and Springer Spaniels
Usually also infertile because cilia on sperm and fallopian tubes are abnormal
Diagnosed with electron microscopy
What is eosinophilic bronchopneumopathy?
Used to describe a variety of conditions which share the central feature of eosinophilic infiltration of lung and bronchial mucosa
Cause is usually not identified
Treatment for eosinophilic bronchopneumopathy?
5 mechanisms by which hypoxemia occurs
1. Decreased inspired O2
3. Diffusion abnormalities
4. Anatomic shunts
5. V/Q mismatch
Clinical signs of laryngeal paralysis
Treatment for laryngeal paralysis
Components of brachycephalic airway syndrome
Elongated soft palate
Everted laryngeal saccules and laryngeal collapse
Diagnosis of laryngeal collapse
Surgery can help with which components of brachycephalic airway syndrome?
Elongated soft palate
Everted laryngeal saccules
Primary diseases that have been associated with PTE
Clinical signs of PTE
Sudden onset of dyspnea in an animal previously not know to have respiratory disease
Acute dyspnea, tachypnea, depression
Diagnosis of PTE
Treatment of PTE
Anticoagulants (heparin, warfarin)
What should you know about the use of heparin for treatment of PTE?
Heparin prevents the deposition of fibrin and platelets on the thrombus surface.
For heparin to be effective, adequate concentrations of antithrombin III must be present in the plasma.
High variation between patients.
How do you monitor effects of heparin in treatment for PTE?
Activated partial thromboplastin time
What is the prognosis for PTE?
Usually associated with underlying disease
Physical exam findings with feline asthma
1. Increased expiratory effort
2. Increased expiratory time
3. Expiratory wheeze
4. Crackles (+/-)
Treatment for feline asthma
Causes of non-cardiogenic pulmonary edema
Upper airway obstruction
Inhalation of toxins
How does near drowning result in severe pulmonary damage?
Water dilution of pulmonary surfactant leading to alveolar collapse and reduced compliance
Clinical signs associated with smoke inhalation
Thermal injury to airways (inflammation, edema)
Direct toxic effects with certain chemicals
Suppression of pulmonary mucociliary and macrophage mechanism
How much fluid does it take for clinical signs of pleural effusion to become apparent?
Reasons for negative tap (thoracocentesis)
No fluid present
Fluid in walled off pocket or on contralateral side of chest
Very thick fluid
Fluid more ventral or deeper than needle
What are transudates?
Fluids with low protein (< 2.5 - 3 g/dL) and low nucleated cell counts (<500 - 1000/ ul)
What are modified transudates?
Fluids with protein concentrations up to 3.5 g/dl and cell counts up to 5000/ul
What starling forces result in transudates or modified transudates?
Increased hydrostatic pressure
Decreased oncotic pressure
Increased vascular permeability
What are exudates?
Fluids with protein > 3 g/dl and cell count >5000/ul
Differentials for non-septic exudate pleural effusion
Lung lobe torsion
Chronic diaphragmatic hernia
Resolving septic exudate
Differentials for septic exudate pleural effusion
Migrating grass foreign body
Extension of bacterial pneumonia
Treatment for pyothorax
Antibiotics(IV ampicillin, enrofloxacin initially, then orals)
Comparing what component of pleural fluid and serum can help identify chyle?
Common causes of chylothorax
Most are idiopathic
Lung lobe torsion
Treatment for chylothorax
Medical treatment - low fat diet, rutin, intermittent chest taps
Differentials for hemothorax
Systemic bleeding disorders
Lung lobe torsion
What is the only neoplasia that readily exfoliates into effusions?
What is a tension pneumothorax?
One-way valve is formed by the tissue at the site of the leak, allowing air to move into pleural space during inspiration but prevents it from moving out during expiration
Most common cause of pneumomediastinum?
Rupture of airways
How is pneumomediastinum diagnosed radiographically?
When you are able to see
1. Dorsal and ventral tracheal walls
2. Cranial branch of aorta
3. Longissimus dorsi muscle
Treatment of pneumomediastinum?
Strict cage rest
Bronchoscopy to locate lesion
Surgery (esophageal laceration)
How can mediastinal masses cause respiratory distress?
Displacing lung tissue and decreasing lung volume
Displacing tracheal lumen
Causing pleural effusion
CT finding most consistent with nasal aspergillosis?
Loss of turbinate density
Diseases that would benefit from cough suppressants
Chronic allergic or sterile bronchitis
What causes crackles?
Fluid in the small airways/alveoli
Opening or collapse of small airways/alveoli
What does an end-expiratory grunt indicate?
Air trapping and/or obstruction of lower airways
Disease that cause inspiratory distress?
Brachycephalic airway syndrome
Pleural space disease
Diseases that cause expiratory distress?