Dogs and Cats 24 Flashcards
Discospondylitis what is it, main pathogens and entry
- Intervertebral disc infection ○ Vertebral endplates infection ○ Bacterial § Staphylococcus spp, Steptococcus spp, Brucella ○ Fungal § German Shepherd dogs § Aspergillus ○ Entry § Haematogeneous = urinary tract infections… § Foreign bodies + grass awn… § Iatrogenic = surgery
Discospondylitis signalment, location and symptoms/signs
- Epidemiology ○ Older, male, medium-to-large breed dogs ○ Thoraco-lumbar , L7-S1 ○ 40.7% multiple sites - Symptoms and signs ○ Pain - very painful ○ Pyrexia - distinction from other diseases above ○ Neurological deficits
Discospondylitis diagnosis
○ CBC
○ Radiographs
§ No changes before 2-4 weeks - cannot rule out
○ MRI>CT - better
○ Looking for the microbe, negative in 50%
§ Disk aspirate
§ Blood, urine, prostatic fluid culture
§ Submit fungal culture if GSD! - IMPORTANT
§ Rapid agglutination test for Brucella (zoonosis!)
Discospondylitis treatment
○ Antibiotics § Cefalexine § Culture results § IV if paralysed or pyrexic § Mean duration = 53.7 weeks ○ Antifungal if required § ++ poor prognosis ○ Pain relief ○ Imaging follow-up
Steroid-responsive meningitis-arteritis what type of disease, what occurs and signalment (hallmark)
- Auto-immune disease ○ Aseptic suppurative infiltration § Monocytic if protracted ○ Targeting arteries ○ Meninges, joints, guts, pericardium - Young adults ○ Medium-to-large breed dogs ○ Beagle, Boxer, Bernese mountain dogs ○ “Beagle pain syndrome” - beagles with neck pain + pyrexia = HALLMARK
Steroid-responsive meningitis-arteritis signs
○ Neurologic § (Wax and waning) neck pain § CNS signs if protracted ○ Systemic § (Wax and waning) pyrexia ○ Other body systems § Polyarthritis (neutrophilic), enteritis, pericarditis
Steroid-responsive meningitis-arteritis diagnosis
○ CSF tap - generally enough (with neck pain and pyrexia)
§ Demonstrate neutrophilic inflammation
□ Other times this occurs is with bacterial infection of spinal cord - very rare
§ Aseptic suppurative pleocytosis - NON-DEGENERATE NEURTOPHILS
§ Monocytic if protracted
○ Serum/CSF IgA
○ Joint tap? - can do at the same time of CSF tap
○ Brain + neck MRI?
Steroid-responsive meningitis-arteritis treatment and follow up
- Treatment
○ Have to treat others die from systemic inflammatory infection
○ Steroids (Steroid responsive)
§ First immunosuppressive, then taper down (need to be systematic - use guidelines)
§ Can take months to resolve
○ + azathioprine if relapse (need to go back to steroid immunosuppressive) - Follow-up
○ CSF taps - before taper need to ensure getting better
○ C-reactive protein
Fibro-cartilagineous embolism what occurs, signlament - EXAM
- Embolisation in arterial spinal cord supply -> ischaemic area of the spinal cord that the artery supplies
○ Fibrocartilage
○ From intervertebral dis - Adult non-chondrodystophic dogs
○ But all sizes and ages described - mainly large breed besides:
○ Miniature Schnauzer
○Also cats
Fibro-cartilagineous embolism signs - EXAM
○ Ataxia and paresis
○ Hyper-acute to acute < 24h -> peck of clinical signs generally within minutes (sometimes under 24hours) then start to recover
○ Sometimes -> Exercise induced
○ Sudden pain when it occurs then non painful
○ Often asymmetric
○ Intumescences often affected - more arteries to these areas -> more likely for embolism to occur in one of these
Fibro-cartilagineous embolism diagnosis and prognosis - EXAM
- Diagnosis
○ Myelography and CT
§ Swelling of the cord
○ MRI - only one can see the ischemia of the spinal cord (generally geometric (shape) lesion - characteristic of ischemia)
§ + prognosis value
○ Lumbar CSF tap
§ Non specific - just spinal cord injury reflects - Self-improving condition - Good prognosis - takes a few weeks
○ 85-90%
what are some common toxins that cause tremors, diagnosis and when important
Toxins that cause tremors
- Snail baits - metaldehyde, carbamate
- Tremogenic mycotoxins - garbage, compost, mouldy food
- Chocolate
- Cane toad poisoning
- Pyrethroids
- Tetanus
Diagnosis
- Generally presentation, history and clinical signs
- Toxic assays generally not reliable as made for humans and animals can metabolise into different molecules
Most of the time won’t know what is causing - just give supportive treatment
BUT TOXINS BELOW NEED SPECIFIC TREATMENT - so need to identify these and treat accordingly
What toxins need specific treatment - list the 5
1) cane toad
2) tetanus
3) pyrethroids
4) snake envenomation
5) tick paralysis
Cane toad poisonings what is it, toxins from where and presentation
- Rhinella marina ○ Toxins -> secrete from skin from the parotid salivary gland (how to identify) - Presentation ○ More common in endemic area ○ Young dogs ○ Terriers - love to snap and bite at the toads -> hunters ○ Toads are nocturnal ○ Summer > winter
Cane toad toxin mechanism of action
- Absorbed through mucous membranes -> doesn’t have to eat the toad
- Different toxins
1. Bufotoxins and bufogenins
○ digitalis-like - cardiac tachyarrhythmias
2. Bufotenines
○ serotonergic substance -> hallucination, hyperaesthesia, seizures
3. Catecholamines
○ adrenaline -> arrhythmias, hypertension, tachycardia, bronchoconstriction
Cane toad toxin clinical signs and diagnosis
Clinical signs - Hyperaemic mucous membranes and salivation - first ones to see - GENERALLY PRESENT WITH - Hyperaesthesia seizures, ataxia, tremors, depressed or altered mental state - Tachycardia and cardiac arrhythmias - Vomiting - Respiratory distress ○ Can have aspiration pneumonia Diagnosis - History - Access to toads - Clinical signs
Can toad toxin treatment with 4 options and prognosis
Treatment
1. Manage life threatening problems
○ IV catheter -> give diazepam
§ Tremors/seizures
§ Respiratory compromise
§ Arrhythmias
2. Decontaminate
○ Wash gums thoroughly - rinse and wipe until salivation has stopped (5-20mins)
○ Decontamination of the stomach if required
§ If toad swallowed (unlikely) need to get out of the stomach - endoscopy with sedation
3. Cyproheptadine - cannot induce vomiting when seizures or tremors
4. Supportive care
Prognosis
- Prognosis is good if veterinary treatment is sought early
- About 90% survival
Tetanus what toxin from, how common, what occurs and what does the toxin do, susceptibility of species
Clostridium tetani
○ Ubiquitous
○ Spores enter a wound and develop if conditions are anaerobic
§ Young dogs during teething is common - breaking of epithelial barrier
○ Exotoxin = tetanospasm
§ Tetanospasm spreads via the blood and is taken up by nerves (CNS)
§ Prevents CNS inhibitory neurotransmitter release - signs of hyperexcitability
□ Glycine and gamma-amminobutyric acid (GABA)
§ Bound toxin is irreversible
○ Susceptibility: horse and humans > dogs > cats
Tetanus onset of clinical signs, and examples of clinical signs
- Onset of clinical signs may take up to 3 weeks -> so may not find the wound (always look but not always there)
○ Signs are progressive
§ Earlier the
○ Loss of inhibition of motor neurons -> sustained spasm - May be generalised or localised (esp. cats) - can localise in one limb (looks like aorta thromboembolism (BUT will have pulse, be warm and have blood flow in the leg)
- Examples
○ Stiff gait - trouble getting up, moving around
○ Saw-horse stance
○ Ears drawn together
○ Muscle spasm in response to stimuli
○ TEL protrusion
○ Salivation
○ Regurgitation
○ Opisthotonus
○ Respiratory difficulty
○ Trismus
○ Recumbency - Generally gets worse before it gets better
Tetanus diagnosis and treatment
Diagnosis
- History - wound, parturition, teething, surgery
- Clinical signs are very specific but can be subtle
○ WHEN WE WANT TO TREAT
- If don’t know JUST TREAT AS IF IT IS ANYWAY -> because consequences if you don’t is very severe
Treatment
- SUPPORTIVE CARE
○ Sedation, muscle relaxants
○ Analgesia
○ Minimise external stimuli
- Metronidazole (or clindamycin)
- Debride the wound
- Anti-toxin (mop up any free toxin - DOESN’T STOP THE ONE ALREADY BOUND)
Tetanus complications and prognosis
Complications - Hypertension - Tachycardia - Spasticity of respiratory muscles - Aspiration pneumonia - Lack of nutrition - Urinary and faecal retention Prognosis - GUARDED - Most patients will deteriorate further before they improve - Recovery can be prolonged (7-14 days) - EXPENSIVE - Survival rate in dogs 50-92% with adequate support
Pyretrhoids what toxic to, found in, absorption, mechanism of actin and metabolism
- Toxic to cats
- Flea products
○ Dog spot on is the main culprit
○ Often get multiple cats from the same household - Rapid absorption
- Slows down activation and inactivation of sodium channels
○ -> repetitive firing of action potentials - Metabolised by liver via glucuronidation
Pyrethroid clinical signs and diagnosis
Clinical signs - Salivation - Vomiting - Hyper-excitability - Hyperaesthesia - Tremors - Seizures - Respiratory difficulty - Weakness Diagnosis - History ○ Signs are noticed about 3 hours after a spot on product has been applied ○ Occasionally an owner will be reluctant to confess - Clinical signs ○ Look for an oily substance on fur with characteristic smell
Pyrethroid treatment and prognosis
Treatment - Decontaminate by washing copiously with lukewarm water (too warm vasodilate will absorb more) and dish water detergent - Anti-seizure medication - Muscle relaxants - Supportive care - Lipid therapy? Prognosis - Recovery usually takes 24-48 hours - Good prognosis if prompt and adequate care
List 10 toxins that decrease activity of the nervous system
- Snake envenomation
- Tick paralysis
- Ethylene glycol
- Barbiturate - scavenging the euthanasia carcass
○ Present as in under general anaesthesia -> supportive care will generally get better - Intermediate or delayed presentation of organophosphate and carbamate
- Baclofen
- Monensin
- Alpha-latrotoxin
- Tetrodotoxin
- Botulism
Snake envenomation what are the 6 main toxins and snakes wtihin, which most common and why
- Peduonaja (brown snakes)
- Botechis (tiger snakes)
- Pseudechis (black snakes)
- Austelaps (copperheads)
- Oxyuranus (taipans)
- Acanthophis (death adders)
Top 3 most common as more common in areas where humans are around
What are the 5 main toxins found in snake venom and how classified
- Classified according to their site of action ○ Neurotoxins - ○ Myotoxins ○ Procoagulants ○ Anticoagulants ○ Cytotoxins
Neurotoxins in snake venom what snakes found within,mechanism of action, clinical signs
- All major venomous genera
- Pre-synaptic and post-synaptic toxicity
○ Depresses the ACh release (irreversible damage)
○ Prevents ACh receptor interaction (reversible)
○ Post-synaptic -> generally reversible with anti-toxins
§ Black adders -> mainly post so will see more rapid recovery with anti-toxin - Takes some time to get clinical signs but takes days to recover from
○ Weakness, ataxia, flaccid paralysis
§ Can be from mild - severe -> can get full paralysis within 1 hour
□ Severe need to put on ventilator
○ Tongue protruding - mainly in cats
○ Dilated non-responsive pupils
Myotoxins in snake venom which snakes within, what do they cause, general presentation within cats and dogs and how does myopathy form
- NOT in brown snakes, mainly an issue in tiger snake
- Delayed myotoxicity generally -> next day afterwards generally present
- Causes progressive rhabdomyolysis -> marked increase in CK levels
○ Not high within 12 hours, more of an increase the next 12 hours - General presentation with cats
○ Don’t notice the cat out hunting and gets bitten
○ That night doesn’t eat meal, next day still within the same spot
○ Return from work still hasn’t moved -> take to the vet - TYPICAL CAT SNAKE BITE
§ May have full paralysis by this point - Presentation in dogs
○ Generally don’t see the dog getting bitten but see near the snake or after killed the snake
Myotoxins in snake venom what occurs with myopathy and secondary complications
- Myopathy
○ Slow onset of weakness
○ Myoglobinura (dark red urine)
○ Generalised pain - cannot do pain scores - JUST
○ Hyperkalaemia and renal failure are possible secondary complications - NEED TO FLUSH OUT THE PIGMENT FROM KIDNEYS
Procoagulants in snake venom what snake common in, what does it cause, when return to normal and clinical signs before paralysis
- Most common in brown snakes
- Causes coagulopathy by depleting clotting factors - can occur within 15 mins
○ Can see just bleeding into organs - can get brain haemorrhage - Markedly prolonged clotting times
○ Indicates significant envenomation - Clotting returns to normal after 24-36 hours
- DON’T DO FOR THE JUGULAR FOR BLOOD
○ Peripheral veins if possible as can put pressure bandage on - Pre-paralytic signs
○ Vomiting, urination, defecation, sudden collapse and apparent recovery
○ -> INDICATES significant envenomation - NEED ANTI-VENOM
○ Generally vomiting, collapse and recover
What snakes are the following toxins found within 1. haemolysins 2. cytotoxins 3. anticoagulants
Haemolysins - black snakes, copperheads, tigers
Cytotoxins - black snakes -> swelling
Anticoagulants - black snakes -> inhibit blood clotting, reversible
Snake bite diagnosis
- History
- Clinical signs
- Clotting times - aPTT (or ACT) if acute
- Snake venom detection kit - if acute
○ Can only pick up free venom -> within the first 12 hours most will be bound
§ Cannot detect venom bound to receptors sites
§ Cannot detect venom bound with anti-venom
○ Detects immuno-type, there is cross reaction
○ Detects very low levels of venom
○ Specific - able to tell you the type of snake and therefore type of anti-venom
○ But not sensitive - CK - if delayed (only if myolysins are present)
snake bite treatment what treat with, how and how much to give
- Antivenom ○ Most effective in first 12 maybe 24 hours ○ Use if systemic signs are apparent ○ Dilute in saline 1:10 or to 10ml/kg which ever is less ○ Give over 20-30mins ○ Give the appropriate immunotype How much antivenom § Non clinical bites □ If not showing systemic signs -> observe § Dose per bite NOT PER KG □ Mild envenomation □ Moderate envenomation □ Severe envenomation
snake bite treatment how to choose an antivenom and how to know which snake
○ Choosing antivenom
§ Tiger-brown combination - tiger, brown, copperhead and most black snakes - MOST COMMON
§ Mulga (king brown) snakes - black snake av not as common now
§ Taipans - taipan av (NORTHERN AUSTRALIA)
§ Death adders - death adder av
§ Polyvalent antivenom treats all venous aussie snakes - very expensive
○ Which snake
§ Local knowledge
§ Appearance (unreliable)
§ Clinical signs (unreliable)
§ Morphological identification (scale counting)
□ Required the head and tail of the snake to be intact
§ SVDK
§ If still unsure consider polyvalent antivenom
monitoring a dog with a snake bite how long for and what monitoring
○ Even without clinical signs monitor for 24 hours because if will see signs generally then ○ Monitoring for: § Hypoxaemia/hypoxia § Ventilatory failure § Hyperkalaemia § Renal function § Anaemia § Coagulopathy - generally gets better with time so generally don't need to use blood products (only if SEVERE anaemia or bleeding into lungs)
Tick paralysis what is the main tick, where found, how much needed to kill and distinct morphological features
- Ixodes holocyclus ○ East coast of australia ○ One female to kill ○ Many nymphs need to kill ○ Hundreds of larvae need to kill morphological - Forelimbs and hindlimbs are dark - Middle legs are more light
Tick paralysis mechanism of action
- Holocyclotoxin - from the salivary glands of the tick when she feeds
- Neurological effect
○ Decreased ACh release at NMJ - Cardiac effect
○ Diastolic heart failure
○ Arrhythmias - can lead to sudden death
Clinical signs of tick paralysis
- Signs develop about 5-7 days after tick attachment
- Change in voice - one of the most common early signs
- Coughing/hacking/retching
- Expiratory grunt
- Salivation
- Regurgitation
- Stumbling/weakness
- Progressive paralysis leading to complete collapse
- Respiratory difficulty - multifactorial issues (therefore management needs to be multifactorial) - PUT ON VENTILATOR
○ Respiratory muscle paralysis
○ Respiratory fatigue
○ Laryngeal paralysis
○ Pooling of saliva
○ Regurgitation - due to megaoesophagus
○ Aspiration pneumonia
○ Pulmonary oedema
Tick paralysis diagnosis
- History of visitation to an endemic tick area
- Clinical signs
- Finding an ixodes holocyclus tick (tick search)
- Finding a “tick crater” - once leaves, leaves inflammation behind
○ SHAVE TO VISULIASE AND REMOVE ANY TICKS (just because found one doesn’t mean there isn’t another)
§ Need to look in ears, around mouth and anus
○ Pyrethrin wash as well
