Flashcards in Medicine Deck (144):
List the 4 syndromes of visceral pain.
3. Mesenteric tension
4. Increased intraluminal pressure in hollow viscera
What are the common causes of chest pain?
Usually parietal pleural.
What are the possible causes of headshaking?
1. Trigeminal neuralgia
Significant increase in body temperature where the core body temperature set point is unaltered.
Significant increase in temperature where temperature set point is elevated.
List some causes of hypothermia.
1. Accidental eg. cold damp environment, surgery
2. Pathological eg. sepsis, shock, intracranial disease, hypothyroidism
Describe possible treatment options for a headshaking horse.
1. Trigeminal neurectomy (?)
2. Caudal compression of infraorbital nerve
3. Avoidance of stimuli eg. tinted contact lenses, face masks/hoods/nets
4. Cyproheptadine +/- carbamazine (together may have short effect and cause drowsiness)
5. Permanent tracheostomy- avoids stimulating airflow in nasal cavity
What empirical antibiotics should be used to treat neonatal pneumonia?
What are the potential sequelae to fractured ribs in the foal?
List the differentials for neonatal respiratory disease.
Prepartum EHV-1 infection
Inadequate lung maturation
Outline the pathology and clinical signs of Rhodococcus equi infection in the growing foal.
Multifocal pulmonary abscessation +/- abscessation in other organs e.g. GIT.
How might you treat Rhodococcus equi infection in the foal?
A/bs: macrolide (erythromycin) + rifampin
How can you prevent Rhodococcus equi infection in a group of growing foals?
1. Improve husbandry e.g. reduce stocking density, prevent dusty areas, rotate paddocks
2. Administer appropriate prophylactic antibiotics
3. Administer specific hyperimmune serum
List the clinical signs of strangles.
Bilateral purulent nasal discharge
Define 'bastard strangles'.
Abscessation in other tissues besides usual LNs- including mediastinal + mesenteric LNs, joints. Dramatic weight loss and pyrexia occurs.
List the potential sequelae following a strangles infection.
Guttural pouch emphysema
What is the aetiological agent of strangles?
Streptococcus equi var equi
What disease does EHV-1 cause?
Reproductive disease (abortion) and encephalomyelopathy
What disease does EHV-2 cause?
What causes recurrent airway obstruction (RAO)?
Airway inflammatory response to organic dust particles (endotoxins, moulds, particulates) inhaled from poorly conserved hay/straw
List the clinical signs of recurrent airway obstruction (RAO).
Bilateral mucopurulent nasal discharge
How is recurrent airway obstruction (RAO) treated?
1. Turn out or house in dust-free enviro e.g. shavings/paper bedding, haylage/chopped dred alfalfa/cubed diet, ventilation
2. Bronchodilators e.g. atropine
4. Maintain hydration
What causes summer pasture associated obstructive pulmonary disease (SPAOD)?
Affects pastured horses with NO access to hay/straw in the Spring-Autumn. May be hypersensitivity to inhaled polens or outdoor moulds?
Where does bleeding originate from in exercise-induced pulmonary haemorrhage (EIPH)?
On bronchoscopy of a horse with EIPH, what might you expect to find post-exercise at:
i) 30 minutes
ii) few days
iv) What would you find on BALF/tracheal aspirates after a few months?
i) Fresh blood in trachea
ii) Blood in large bronchi
iii) Haemosiderin tinged secretions
iv) Macrophages containing haemosiderin
List the clinical signs of pulmonary abscesses/pleuropneumonia.
What parasite causes lungworm infestation in horses?
List the causes of poor performance in the athletic horse.
3. Lack of fitness
4. Unrealistic expectations (of horse/rider)
5. Inappropriate training
7. Other e.g. medical, neuro
Describe the features of atrial fibrillation i) on auscultation and ii) on ECG.
i) irregular rhythm with LOUD 3rd heart sound and NO 4th heart sound, may be tachycardic if secondary to mitral regurgitation
ii) irregularly irregular rhythm with no p-waves and atrial fluttering- 'f-waves'
Describe the treatment options for atrial fibrillation.
DO NOT TREAT if: only diagnosed 2-3 days ago (may spontaneously resolve), no effect on exercise or if there is evidence of heart failure.
1. Quinidine sulphate via nasogastric tube every 2 hours (beware toxicity).
2. Electric defibrillation via direct shock under GA
Describe the ECG features of i) premature atrial beats, ii) premature ventricular contraction and iii) 3rd degree AV block.
i) abnormal p-wave shape, early p-wave and QRS complexes
ii) no p-wave with wide bizarre QRS complexes
iii) multiple p-waves with no QRS complexes
List the causes of pericardial effusion.
Idiopathic fibrinous/effusive pericarditis
List the causes of cardiac murmurs.
Acquired valvular: mitral regurgitation, tricuspid regurgitation, aortic insufficiency
Congenital: ventricular septal defect
Which pathology produces a pansystolic murmur loudest over the 5th intercostal space?
Which pathology produces a soft grade 2-3 pansystolic murmur loudest on the RHS?
Which pathology produces a diastolic musical murmur loudest over the 5th LHS intercostal space?
Describe the aetiology of tricuspid regurgitation.
LV failure -> pulmonary hypertension -> RV overload
Describe the aetiology of aortic insufficiency.
Progressive thickening and fibrosis of valve leaflets in older (>10yo) horses.
List the potential causes of mitral regurgitation.
Ruptured chordae tendinae
Any condition causing dilation of valve annulus e.g. DCM, aortic insufficiency, VSD
Congenital malformation of valve
Eccentric hypertrophy and increased blood volume
Degenerative thickening of the valve leaflets.
List the causes of icterus.
Regurgitation icterus: reduced excretion of bilirubin with liver of biliary tract disease
Haemolytic/prehepatic icterus: increased production of bilirubin with haemolytic anaemia
Hepatic icterus: reduced conjugation or hepatic uptake of bilirubin with liver disease
List the methods which can be used to determine the cause of icterus.
1. Relative amounts of conjugated vs. unconjugated bilirubin
e.g. >25% conjugated = heptaocellular disease, >30% conjugated = cholestasis
2. Liver-derived enzymes- to assess if assoc w/ liver damage
3. Bile acids- to assess if assoc w/ liver failure
4. PCV + RBCC- to assess if assoc w/ haemolysis
What is the likely cause of icterus with increased unconjugated bilirubin in the serum and reduced PCV?
What is the likely cause of icterus with increased unconjugated bilirubin in the serum, normal PCV and liver enzymes?
What is the likely cause of icterus with increased unconjugated and conjugated bilirubin in the serum and rincreased liver enzymes and bile acids?
Which liver-derived enzymes are specific to hepatocytes?
GLDH (spec), AST
Which liver-derived enzymes are specific to the biliary tract?
GGT (spec), AP
What are the clinical signs of equine liver disease?
Hepatic encephalopathy -> neuro signs e.g. dull vacant expression, yawning, ataxia, tremors, circling, head pressing, aggression
Bilateral laryngeal paralysis -> dyspnoea, stridor at rest
Describe how you would treat hepatic encephalopathy.
Sedate with low dose alpha-2 agonists
Correct metabolic, fluid and electrolyte abnormalities
Reduce GIT production/absorption of potential neurotoxins through laxative and oral neomycin/metronidazole
Lactulose- reduce intestinal neurotransmitter production/absorption
What would a negative response on the thoracolaryngeal reflex suggest?
Possibly recurrent laryngeal neuropathy
Describe where you would perform a CSF tap in horses.
1. Atlantooccipital (AO)
Always tap closest to the lesion!
What is the most common cause of equine brain disease in the UK?
What is the causative agent of leukoencephalomalacia?
Fusarium species mycotoxicosis from mouldy feed.
What is the cause of polyneuritis equii?
Chronic granulomatous inflammation of extradural nerve roots of many peripheral nerves.
What are the clinical signs of polyneuritis equii?
Cranial nerve deficits (VII/VIII first)- progressive
What is the cause of temperohyoid osteoarthropathy?
Proliferative osteopathy of unknown cayse of temporal and hyoid bone and temperohyoid joint. Tongue movement can fracture the temporal or stylohyoid bone which damages facial and vestibulocochlear nerves.
What are the clinical signs of temperohyoid osteoarthropathy?
Vestibular/facial nerve signs
Which cranial nerves are most commonly affected by guttural pouch mycosis?
7, 8-sympathetic, 9, 10, 12
Describe the clinical signs of cerebellar ataxia.
Loss of subconcious proprioception ONLY (so will still replace legs in normal positions if moved abnormally)
Describe the clinical signs of vestibular ataxia.
Wide based stance (world is spinning!!)
Increased extensor tone on 1 side
What are the most common causes of equine ataxia in the UK?
Spinal cord trauma
Cervical vertebral malformation
Define type 1 cervical vertebral malformation.
Large young horses with developmental narrowing of canal at C3-4.
Define type 2 cervical vertebral malformation.
Large older horses with arthritis of the caudal cervical vertebrae compressing the spinal cord.
How is cervical vertebral malformation treated?
On radiography: vertebral canal width should be >50% width of vertebral body.
What is the aetiological agent of equine herpes myeloencephalopathy?
Equine herpes virus (EHV-1)
Where is the reservoir for EHV-1 in latently affected horses?
Trigeminal nerve ganglia.
What are the clinical signs of equine herpes myeloencephalopathy?
Penis out if male
Poor anal/tail tone
Pelvic > thoracic ataxia
Poor urinary function
CSF = xanthochromic (due to breakdown products)
How is equine herpes myeloencephalopathy treated?
Dexamethasone and oral antivirals
What is the causal agent of equine protozial myeloencephalitis?
What are the clinical signs of equine protozoal myeloencephalitis?
Atrophy of muscles of mastication
What are the causes of weight loss/failure to gain weight?
Mangement/physiology e.g. poor nutrition, increased metabolic demands- pregnancy, old age
Disease e.g. dysphagia, maldigestion, increased consumption v. loss
How would you treat a generalised case of weight loss?
Assess weight and set date for re-evaluation
Stop/start any long-term medications e.g. bute may cause colitis/protein loss
Anthelmintic therapy- larvicidal dfoses of anthelmintics even if apparently adequate worming regime
What 2 diagnostic tools are used to evaluate equine metabolic syndrome?
Fasting blood glucose and insulin: increased insulin = insulin resistance, increased gluc = severe insulin resistance/DM
Oral glucose tolerance test (OGTT): blood gluc should double within 2 hours of IV gluc admin then reduce to norm levels within 6 hours
How might you advise treating equine metabolic syndrome?
Control calorific intake e.g. feeds with low glycaemic index
Medicate for obesity ????
Treat identifiable underlying cause
Define polyuria in the horse.
Define polydipsia in the horse.
What are the causes of PU/PD in the horse:
Equine cushing's syndrome
Psychogenic salt consumption
What is a water deprivation test and when would you use it?
Take all fluid away and measure urine specific gravity over succeeding hours if no signs of renal or cushings disease. Tests the ability of the kidneys to concentrate urine when water deprived.
What are the causes of urinary incontinence in the horse?
What are the causes of haematuria in the horse?
Idiopathic renal haematuria
Neoplasia of bladder/urethra/penis/sheath
Vaginal varicosities (in gravid mares)
Exercise induced haematuria
Non-urinary systemic disease e.g. acute myopathies
What causes equine cushing's disease?
Overproduction of proopiomelanocortin (POMC) peptides from pars intermedia (PI) which causes increased ACTH levels causing dysregulated cortisol production
List the clinical signs of cushing's disease.
What are the key diagnostic tools for cushing's disease?
Basal glucose >5.5mmol
Basal insulin >36IU/ml
Dexamethasone stimulation test (DST): give dex at 5pm then 12pm next dat, cortisol >1ug/dl at second test
Thyrotropin-releasing hormone (TRH) response test: measure basal cortisol, inj TRH IV, measure cortisol 30m post-injection, +ve if 66% increase
How can equine cushing's disease be treated?
Conservative: clip hair, regular laminitis monitoring/farriery, exercise if no chronic othopaedic disease
Medicate: if early case with hx of laminitis OR resting hyperglycaemia and sig increased insulin.... pergolide (dopamine agonist)
Which agents cause pediculosis?
LICE: Damalinia equi (biting) and Haematopinus asini (sucking)
Which agent causes chorioptic mange?
What is the horse mite?
Describe the skin disease caused by oxyuris equi.
Pinworms which migrate from the small colon/rectum and lay eggs on perianal skin. Causes pruritis and tail rubbing.
Describe onchoceral dermatits.
Type 1/3 hypersensitivity to Onchocerca cervicalis microfilaria, transmitted by biting insects.
Describe the treatment of sweet itch.
Manage skin lesions
Prevent midges biting e.g. stabling at dawn/dusk, hooded rugs, insect-proof stables w/ ventilation
Which agent causes mud fever and rain scald?
Which agents cause ringworm in horses (and which is zoonotic)>
Trichophytan equinum var equinum/autotriphicum
Microspora gypseum/equinum/canis - ZOONOTIC
What causes purpura haemorrhagica?
Immune-mediated vasculitis associated with recovery from URT infection.
What are the clinical signs of purpura haemorrhagica?
Oedema of limbs
Marked skin erosions
petechial/ecchymotic H+ of skin/mucosa
Depressed + inappetant
List the different types of chronic rhabdomyolysis.
Recurrent exertional rhabdomyolysis
Idiopathic chronic exertional rhabdomyolysis
Polysaccharide storage myopathy (PSSM)- type 1 + 2
Glycogen branching enzyme deficiency
Which type of rhabdomyolysis is commonly seen in Quarter Horses?
Polysaccharide storage myopathy
How can chronic rhabdomyolysis be diagnosed?
Exercise tests: 3 days after returning to work, take a blood sample pre and 3-6 hours post-exercise. Is the response of the muscle to exercise normal?
Fractional electrolyte excretion test
Genetic testing for specific myopathies
How can chronic rhabdomyolysis be treated?
Dietary- reduced CHO diet with oils for supplementation if needed, don't feed in anticipation of work.
Adequate warm-ups for exercise
Supplement with salt if intense exercise
Vit E/Se to soak up free radicals
What are the clinical signs of rhabdomyolysis?
These occur immediately post-exercise:
Hot painful tense muscles- particularly femoral, gluteal and lumbar muscles
Slight gait change to full on reluctance to move
How can acute rhabdomyolysis be diagnosed?
Serum increased CK/AST/lactate dehydrogenase
How is acute rhabdomyolysis treated?
Fluids- correct electrolyte balance
Calcium carbonate/gluconate if severe muscle damage
Sedatives to relieve anxiety and stop muscle spasm
How is botulism transmitted and caused?
Through forage (preformed toxin in big bale silage), toxicoinfection botulism (growth in GIT), wound botulism.
Clostrisium botulinum toxin- blocks Ach releasae at neuromuscular junctions and peripheral cholineric nerve terminals
What are the clinical signs of botulism?
Dirty weak tongue
What are the clinical signs and cause of shaker-foal syndrome?
Toxicoinfectious botulism in foals
Reduced tail tone
Constipation and urine retention
How is botulism diagnosed and treated?
Identify toxin in serum/GI contents/silage
Treat: a/bs if toxicoinfectious/wound, antitoxin (US)
How is tetanus caused?
Clostridium tetani exotoxins:
Tetanolysin: local tissue necrosis
Tetanospasm: prevents release of inhibitory neurotransmitters in CNS causing spasmic contractions of striated muscle
What are the clinical signs of tetanus?
Extended head and neck (stiff)
Generalised muscle contractions provoked by stimuli e.g. touch, sound
How can tetanus be treated?
If recumbent- euthanise.
Management: quiet gentle handing, dark stable, soft moist food with elevated food/water troughs
ACP (reduces stimuli)
Which factors may influence clinical pathology results?
Breeds: athletic v. drafts/ponies
Which enzyme is liver-specific in horses?
Glutamate dehydrogenase (GLDH)
Which enzymes indicate liver damage in horses?
AP, GGT, GLDH
Which enzymes indicate biliary stasis in horses?
AP + GGT
Which enzymes indicate muscle damage in horses?
CK, AST and lactate dehydrogenase
What are the causes of leucocytosis?
2. Adrenaline release
Whats the normal specific gravity of equine urine?
Give examples of cases where antibiotics are usually NOT needed.
Strangles with only lymphadenopathy
Why shouldn't TMPS be used with alpha-2 agonists?
Risk of fatal cardiac arrhythmias
What are the adverse effects of using aminoglycosides in horses?
IM- muscle irritation
What is the vaccination regime for equine influenza?
1st from 4-6m, 2nd = 3-12 weeks later, 3rd = 5-7m later. Annual boosters
What is the vaccination regime for tetanus?
Toxoid- 2 vaccinations 1 month apart, then boosters every 2-3 years.
Antitoxin to all foals if mare not vacc within 24hr birth.
What is the vaccination regime for equine herpes?
Initial course 1 month apart, then boosters every 6m. Pregnant mares at 2/5/7/9m preg.
Which part of the passport must be signed for a horse to be declared not intended for human consumption?
Section 9 - must be signed by owner
What are the IgG levels for a normal foal, a foal with partial FPT and a foal with full-blown FPT?
Partial = 4-8g/L
What is the treatment of a foal with FPT?
24 hours: 1-2L equine plasma IV (1L over 1hr, then the rest more slowly)
Which alloantigens do foals with neonatal isoerythrolysis have?
Aa and Qa
What are the signs of neonatal isoerythrolysis?
Anaemia with weakness
Collapse + death
How is neonatal septic meningioencephalitis diagnosed?
Increased CSF protein
What are the causes of patent urachus?
Increased abdominal pressure e.g. due to straining with retained meconium
What is the urachus?
Structure connecting foetal bladder to allantoic cavity
What is foal heat diarrhoea?
Transient self-curing D+ occuring due to altered colonic microflora during milk to grass fed diet transition
What is the most common cause of D+ in the foal?
How is rotavirus prevented?
Vaccination in 8/9/10th month of gestation
What are the causes of gastroduodenal ulceration in the foal?
Iatrogenic e.g. NSAIDs
What treatment is given for neonatal gastroduodenal ulcers?
What are the clinical signs of meconium retention?
Lying on back and rolling
How is meconium retention treated?
Warm soapy water enema with soft tube inserted 10-12 inches + GRAVITY!
If doesn't work- oral paraffin stomach tubed
What is the cause of uroperitoneum in the foal?
Ruptured bladder (from increased abdo pressure during parturition)
What are the clinical signs of uroperitoneum in the foal?
Mild abdo pain
How is uroperitoneum diagnosed?
Peritoneal fluid analysis demonstrates creatinine : serum ratio > 2:1
How is uroperitoneum treated?
Drain abdo, admin IV saline and dextrose, a/bs. When stable- surgical bladder closure.
Describe the clinical signs of african horse sickness.
Affects endothelial cells causing visceral/body cavity effusions.
PULMONARY = PYREXIA, severe dyspnoea, peracute, 95% mortality- death within hours
CARDIAC = PYREXIA, s/c oedema of head/neck, acute, 50% mortality- death within 4-8d
Can also have mix of the above or 'Horse sickness fever' = subclin or with pyrexia and anorexia
What is the cause of ryegrass staggers?
Certain weather- endophytes in grasses produce neurotoxic alkaloids causing staggers in grazing animals to prevent overgrazing
What are the clinical signs of ryegrass staggers?
Ataxic eyeball movements
What are the clinical signs of monensin poisoning?