Neurological disease Flashcards
1
Q
Clinical signs in small mammals
A
- head tilt
- weakness
- paresis
- swaying
- ataxia
- tremor
- seizures
- circling
- exopthalmos
- ocular discharge
- mydriasis
- nystagmus
- urinary incontinence
- loss of anal tone
- faecal impaction
2
Q
Clinical signs in reptiles
A
- loss of righting reflex
- loss of withdrawal reflexes
- loss of cloaca tone
- limb paresis (hind most common)
- reduced grip (snakes)
- generalised or localised weakness
- tremors and convulsions
- blindness
- circling
- head tilt
3
Q
Clinical signs in birds
A
- loss of withdrawal reflexes
- loss of cloacal tone
- limb paresis
- reduced foot grip
- generalised weakness
- tremors and convulsions
- circling
- head tilt
4
Q
Differentials in small mammals
A
- viruses e.g. herpes virus (encephalitis)
- fungal e.g. encephalitozoon cuniculi
- bacterial e.g. bacterial otitis media/interna. spinal abscess
- parasitic e.g. toxoplasmosis
- degenerative e.g. spondylosis, OA, intervertebral disc protrusion
- trauma e.g. vertebral fracture/luxation
- husbandry e.g. hypovitaminosis A, heat stroke
- toxicity e.g. antibiotic (aminoglycosides), lead, Fipronil, Pyrethrin/permethrin
- metabolic e.g. azotaemia, electrolyte imbalance, pregnancy toxaemia, hypocalcaemia
- other e.g. neoplasia, rat pituitary glad adenoma, peripheral and central vestibular dz, cerebrovascular accident, splay leg, hypoxia, idiopathic epilepsy
5
Q
2 types of vestibular disease
A
- central
- peripheral
6
Q
Central vestibular dz signs
A
- nystagmus (vertical or horizontal)
- no Horner’s of facial nerve paralysis
- can show other CNS signs
7
Q
Peripheral vestibular dz signs
A
- nystagmus (horizontal, fast away from lesion)
- can show Horner’s or facial nerve paralysis
- doesn’t show any other CNS signs
8
Q
Ddx for central vestibular dz
A
- E.cuniculi
- toxoplasma
- neoplasia
9
Q
Ddx for peripheral vestibular dz
A
- otitis media (e.g. Pasteurella or S.aureus)
10
Q
Otitis media
A
- lop rabbits predisposed
- inner ear infection
- infection penetrates through the tympanic membrane, progression from otitis externa
- causes ataxia, circling, head tilt
- prey animals so hide the pain of otitis externa
- ear anatomy and lack of ventilation in lop eared breeds predisposed to this, often an incidental finding
- when the inner ear is infected is when you start to see clinical signs of neurological dz
11
Q
Aural base abscess
A
- lop rabbits are predisposed
- always palpate and look inside rabbit ears with a scope
- palpate between the base of the ear and the eye
- crud and debris builds up in the aural base pouch
- it can extend which is painful and you get a big swelling that looks like an abscess
- if not infected it can be pushed gently back up, if left it will get infected
12
Q
Encephalitozoon Cuniculus
A
- fungi spread in rabbit urine mostly, so kidney dz the first thing that happens
- over 50% healthy rabbits are carriers
- clinical signs are due to inflammation (due to the body’s response to the fungi and killing the healthy tissue around it)
13
Q
Clinical signs of E.cuniculi
A
- CNS damage: hindlimb paralysis/weakness, torticollis (head tilt), urinary incontinence, tremors
- kidney damage: PUPD, weight loss, anorexia, cataracts and uveitis
14
Q
Pathogenesis/pathway of E.cuniculi
A
- pathogen ingested in contaminated food and water
- pathogen moves via the blood stream into the kidneys
- pathogen intermittently passed in urine
- pathogen then moves into the spine -> hindlimb paresis
- pathogen then moves up the spine to the brain -> head tilt
15
Q
Floppy bunny syndrome
A
- generalised flaccid paralysis BUT the rabbit is often still very alert with a good appetite
- exact cause unknown
- majority of rabbits recover within 3-4d with supportive care
- why if presented with a generalised flaccid paralysis it could be worth waiting a few days to see if it is this
16
Q
Rabbit Fipronil toxicity
A
- Fipronil products such as Frontline spot on for cats and dogs
- Fipronil blocks GABA receptors in the CNS -> stops chloride ion uptake -> excessive CNS stimulation -> death
- clinical signs: seizures, tremors, hyperactivity, D+, hyper salivation, hypothermia, death
- delay in seizures -> seen 3-9d after exposure
17
Q
Differentials in reptiles
A
- viruses e.g. IBD, ophidian paramyxovirus, adenovirus
- fungal e.g. cryptococcus neoformans
- bacterial e.g. bacterial meningoencephalitis, spinal osteoarthropathy
- parasitic e.g. acanthamoebic meningoencephalitis
- degenerative e.g. OA
- trauma e.g. spinal fractures or compression
- husbandry e.g. exposure to freezing temperatures, thiamine deficiency, vit B deficiency, hypocalcaemia, MBD causing spinal fractures
- toxicity e.g. organophosphate toxicity, cedar shavings, drug reaction (ivermectin, metronidazole)
- metabolic e.g. gout due to kidney dz
- other e.g. SOL (egg binding, bladder stones)
18
Q
Inclusion Body Disease neurological signs
A
- head tremor
- uneven pupils
- muscle spasms (head can arc backward aka stargazing)
- lethargy
- reduced mental activity
- poor righting reflex
- reduce muscle tone
- constipation
19
Q
Adenovirus neurological signs
A
- stargazing
- twitching/seizures
- ‘poor doer’
- secondary infections (e.g. resp)
20
Q
Ophidian paramyxovirus
A
- virus has very similar neurological signs to IBD
- but unlike IBD, it causes mainly resp signs not GI signs
21
Q
Ivermectin toxicity
A
- can cause depression, paralysis and death in chelonia
- sensitivities reported in other reptiles spp
- supportive tx (helps but doesn’t always work): IV lipid emulsion, GI lavage, charcoal
22
Q
Metronidazole toxicity
A
- high doses (>100mg/kg)
can cause vestibular dz (head tilt, circling, disequilibrium) - with supportive tx can recover
- particular spp are susceptible at lower doses e.g. indigo snakes
23
Q
Differentials in birds
A
- viruses e.g. Bornavirus (PDD), paramyxovirus, herpes virus, avian influenza, marek’s dz
- fungal e.g. isospora serini, aspergillosis, cryptococcus neoformans
- bacterial e.g. Psittacosis (Chlamydophila), listeria, mycobacteria
- parasitic e.g. toxoplasma
- degenerative e.g. OA
- trauma e.g. fractured spine, head trauma
- husbandry e.g. hypocalcaemia, hyperlipidaemia, atherosclerosis, hypovitaminosis B, vit E/selenium deficiency
- toxicity e.g. organophosphates, heavy metal toxicity (lead, zinc, copper)
- metabolic e.g. hypoglycaemia, hyperglycaemia
- other – SOL pressing on the nerves e.g. in coelomic cavity pressing on the nerves to the legs
24
Q
Viruses in birds
A
- avian paramyxovirus: PMV 1 (Newcastle dz NOTIFIABLE), PMV2 and PMV3
- avian influenza (NOTIFIABLE)
- Marek’s dz in chickens (herpes virus 1)
25
Q
Avian paramyxovirus
A
- PMV2&3 seen esp in wildlife
- signs: circling, head flicking, twisting of the neck, swollen heads, resp signs
26
Q
Avian influenza
A
- high and low pathogenic strains
- high tends to cause mortality within a couple of days (36h)
- high signs: anorexic, coughing, sneezing, swollen heads, depressed, sometimes have diarrhoea, neurological signs anywhere from mild encephalitis to motor disturbances, in a coma
27
Q
Clinical signs of Marek’s dz
A
- lameness/leg paralysis
- wing paralysis
- weight loss/wasting
- eye changes (less common, brown discolouration to the pigment of the eyes)
- tumours (skin/feathers, liver, spleen, kidney, lung, gonads, heart, muscle)
- older chickens are fairly resistant to Marek’s dz
28
Q
Hyperlipidaemia (which birds are affected, clinical signs)
A
- birds that are fed a pot diet (e.g. parrots on seed diets)
- obesity/overweight
- tremors/seizures
- weakness
- signs associated with liver damage e.g. diarrhoea/green faeces
29
Q
How can pet birds get heavy metal toxicity?
A
- inquisitie parrots swallowing metal toy components
- lead based paint
- old metal cages
- wires
30
Q
How can wildlife get heavy metal toxicity?
A
- waterfowl ingesting fishing gear (lead weight, baits)
- birds of prey eating shot prey (lead shot)
31
Q
Clinical signs of heavy metal toxicity
A
- clinical signs affect the GIT, renal, urinary and CNS
- regurgitation, lethargy, weakness, anorexia, weight loss, anaemia, PD, D+, haemoglobinuria
- CNS clinical signs: depression, seizures, head tilt, blindness
- lead has to go through the GIT to cause toxicity
32
Q
Signs of airborne toxicity
A
- (e.g. teflon pan on the hob and bird in the kitchen)
- tend to show respiratory signs and sudden death, rather than CNS signs
33
Q
Head trauma (examples, clinical signs)
A
- wild bird getting hit by a car
- birds flying head first into a window or obstacle
- falling off perches or hitting head on something e.g. seizures
- depressed/stunned
- blindness (do ophthalmic exam)
- head tilt (not common)
- normal birds eyes have pectin (black blob), it supplies blood to the retina
- with head trauma the pectin may get broken up and so will see lots of little blobs
- damage to the pectin can cause reduced vision/blindness
- sometimes it’s totally destroyed and no longer visible at all
34
Q
Psittacosis
A
- caused by bacteria Chlamydia psittaci (zoonotic)
- very contagious, via faeces, urine and respiratory secretions
- mild-severe, depending on bird
35
Q
Clinical signs of psittacosis
A
- respiratory: dyspnoea, oculonasal discharge
- GIT: bright green faeces, regurgitation
- CNS: tremors, twisting of the head & body
- sudden death (esp lovebirds)
- any system in the body can be affected
36
Q
Diagnostic options
A
- clinical exam e.g. head trauma
- history e.g. toxicities
- imaging (radiography, CT, MRI?)
- blood testing (haematology & biochemistry - looking for metabolic causes, organ damage, infection, blood loss (trauma) and signs of toxicity e.g. anaemia)
37
Q
Pathogen testing options
A
- antibody testing
- antigen testing
- PCR/ELISA
- bacteriology (C&ST)
- histology (which organs?)
- samples? blood, urine, swabs, FNA/aspirate, biopsies
38
Q
Otitis media diagnostics
A
- otoscopic exam
- ear base palpation
- imaging (radiographs/CT)
39
Q
Heavy metal toxicity diagnosis
A
- history + clinical signs
- blood work can make you suspect toxicity
- radiographs to identify metal in the GIT
- but absence of metal in the GIT doesn’t rule out toxicity
40
Q
Hepatic lipidosis diagnosis
A
- bloods: grossly lipaemic if severe, cholesterol & liver values raised
41
Q
E.cuniculi diagnosis
A
- blood test antibody serology (ELISA):
– if exposed in past will have antibodies
– IgM (acute) vs IgG (chronic)
– very high levels can be diagnostic - moderate levels: re-test in 4 weeks
– if increased in 4w = diagnostic - urine antigen test (PCR):
– unreliable as intermittently shed
– used for screening groups - histology (kidney PCR):
– PM if housed with other rabbits
42
Q
Marek’s dz diagnosis
A
- presumptive diagnosis on clinical signs and gross PM examination
- histopathology (brain, eyes, masses/tumours, sciatic nerve)
- PCR available
- why diagnose if no tx -> diagnosis aids prevention e.g. only purchasing vaccinated chickens in the future
43
Q
Psittacosis diagnosis
A
- PCR (conjunctival/cloacal swab or faeces)
44
Q
IBD diagnosis
A
- PM histology (liver, kidney, pancreas samples)
- PCR (mouth or cloacal swab)
45
Q
Ophidian paramyxovirus diagnosis
A
- PM histology (lung or brain)
- PCR (mouth or cloacal swab)
46
Q
Adenovirus diagnosis in lizards
A
- clinical signs
- PM histology (liver biopsy)
47
Q
General tx principles
A
- supportive care e.g. GI support, fluids, warmth
- remove toxins if possible e.g. wash fur or remove metal from GIT
- pain relief if needed
- kill/tx the pathogen/infection if possible
- euthanasia if poor QoL or contagious with no cure
- consider other animals in the household
- prevention is better than cure
48
Q
Otitis externa and media tx
A
- antibiotic ear drops (can use eye drops as hard to find an ear drop without steroid)
- analgesia (NSAID)
- C&ST (Pasteurella very common)
- ear flush under sedation if needed (lots of pus/debris)
- aural base ‘abscesses’ can be gently massaged to remove the build up of debris, may require flushing or surgery if not successful
49
Q
What to do if rabbit ear infections are recurrent or non-responsive to treatment?
A
- partial or total ear canal ablation with lateral bulla osteotomy
- risks include facial nerve paralysis and vestibular dz
50
Q
E.cuniculi tx
A
- tx eases symptoms by reducing inflammation, but doesn’t reverse damage already done
- biosecurity: isolate, disinfect environment (F10 & bleach)
- kill pathogen: Fenbendazole 20mg/kg PO SID (28d standard dose)
- vertigo: prochlorperazine?, darkness, support with rolled up towels
- inflammation: NSAIDs (with fluids to support kidneys), short acting steroids (1 off dose if about to PTS unless radical change)
- gut support
51
Q
Hepatic lipidosis tx
A
- diet changes slowly over 6m
- they will stop eating with sudden changes in diet
- starvation causes potentially fatal fat release from the liver into the blood
- liver supplements e.g. milk thistle, Hepatosyl, lactulose
52
Q
Heavy metal toxicity tx
A
