DL: Neuro Cases (Holgar and Piercey) Flashcards Preview

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Flashcards in DL: Neuro Cases (Holgar and Piercey) Deck (49):
1

What type of neuro problems do horses get?

- spinal/proprioceptive only!!

2

How does weakness manifest in horses?

- toe drag
- stumbling
- shuffly steps
> but can be d/t lameness/other ataxia too

3

How do proprioceptive tests in cats differ to dogs?

- much less sensitive in cats than dogs
- use table for concious proprioception in cats
- extensor postural thrust used more commonly in cats

4

How do CN reflexes/responses differ in cats cf. dogs?

- ^ Symp tone so poor PLR
- menace badly (make sure you do palpebral in between each meance)

5

Ddx for CSF with ^ protein, cell count esp neutrophils in a kitten?

> infectious
- FIP (viral) test for corona virus but hard to dx d/t mutation (new test for specific protein coming out)
- toxoplasma gondii (protozoa) PCR/serology
- bacterial meningitis (very rare)
- fungal [Cryptococcus, hyalohyphomycosis, phaemohyphomycosis] (very rare)

6

Neuro signs associated with FIP?

- acute painful myelopathy
- brainstem and cerebellar most common
- seizures poss
- dry form = pyogranulomatous and immune complex mediated vasculitis -> gelatinousi nfiltrate into ventricles
- "inside and outside" affected -> meningitis and ventricles d/t blocked CSF outflow
(pdf:

7

How long can a horse be recumbent (down without being able to get up) for before you give up on it

24-48hours

8

What may ^WBCS and neutrophils on bloods be indivcative of?

Stress leucogram

9

Which bones protect the brainstem in horses? When may these be damaged?

- basisphenoid and basioccipital bones, rectus capitus m. underlies these
- should be in line, v thick bones
- can be fx if horse goes over backwards and hits head on floor
> do not ocnfused symphysis of bones for a fx

10

Damage to what n. may -> DDSP?

Glossopharyngeal (IX)

11

Where does the facial nerve course?

- stylomastoid foramen
- vertical ramus of the mandible
- across the masseter
> if muzzle only place affected = distal portion of facial n. affected (section overlying masseter)

12

Tx of progressive brainstem lesion?

- ^ dose steroids (no evidence for head trauma but do it anyway?)
- hyertonic saline/mannitol - only really useful in acute phase of disease
- NSAIDs
- fluids
-

13

What does nystagmus indicate?

Acute onset as will compensate after a while
> peripheral vestibular lesion = horizontal
> central vestibular lesion = anything!!

14

Tx FIP?

None
- steroids and IFNw for palliative tx

15

What does hopping test detect mainly in horses?

Strength rather than coordination

16

Dx of FIP based on..?

- FCov Ab titre/IHC
- Alb: Glob ratio v (globulins in serum v high, A:G >0.8 r/o FIP, 0.4-0.8 consider other parameters)
- AGP (acid glycoprotein, an acute phase protein) levels >1500ug/ml
- haem: lymphopenia, non-regenerative anaemis, HCT

17

Clinical signs of head trauma in horses

- haemorrhage/CSF from skull (ear, nostril, mouth)
- blindness (sudden onset, fixed dilated pupils, papilloedema and retinl haemorrhage)
- longus capitus rupture -> caudo-medial aspect GP
- basisphenoid bone fx

18

Tx head trauma in the horse

- NSAIDs
- IV mannitol/hypertonic saline
- ?corticosteroids (no evidence, everyone does)
- IVFT
- supportive nursing care (decubital/corneal ulcers, pneumonia)

19

3 [potential diseases classified as MUO?

(meningitis of unknown origin)
= meningoencephalomyelitis
> GME: granulomatous meningoencaphalitis
> NME: necoritising meningoencephalitis
> NLE: necrotising leukoencephalomyelitis

20

PDF for GME

- any breed but esp toy and terriers
- mean age ~5yrs
- females

21

3 forms of GME?

> Diffuse
- most common, multifocal disease
> focal
- single SOL, ddx neoplasia
> ocular
- optic n. affected
- can progress -> focal/disseminate

22

Tx GME

- procarbazine +- pred
- radiation + pred
- cytarabine + pred
- cyclosporine +- steroids +- ketoconazole (best outcome)

23

What is NME? pdf?

> necortising meningioencaphalitis
= pug dog encephalitis (though other breeds shih Tzu, Lhasa apso, Chihuahua can get)
- 6mo-7yrs, mean 19months
- esp fawn coloured females

24

Clinical course of NME?

- few days/months before presentation
- FOREBRAIN signs (cerebrum +- thalamus)
- mean survival 93d (1-680d)

25

What is NLE? pdf?

> necrotising leucoencephalitis
- 1-10yrs mean 4.5yrs
- no sex predilection
- esp yorkies but others too

26

Clinical course of NLE?

- highly variable, usually chronic and progressive
- FOREBRAIN and BRAINSTEM
- altered mentation, seizures, central blindness, central vestibular signs

27

Viral causes of encephalitis

> Canine distemper encephalitis (CDE)
= immature/mature dogs = old dog encephalitis = chronic relapsing encephalomyelitis = post vaccinal CDE
- acute (most common) and chronic forms
- URT/GIT signs + myoclonus rhythmical contractions seen acutely
> Rabies
- furious (more common in cats, cerebral signs + aggression)
- dumb/paralytic form (brainstem signs, dropped jaw and swallowing difficulty)

28

Who should be contacted in a suspect rabies case?

Defra

29

Protozoal causes of encephalitis?

> Toxoplasmosis/Neosporosis
- toxoplasma gondii [dog and cat], neospora caninum [dog], sarcocystis neurona [horse]
- pathogenesis by ingestion of infected tissue

30

Clinical signs associated with toxoplasmosis/neosporosis?

- seizures and cerebellar signs, neuromuscular
- systemic and ocular involvement

31

Disgnosis of toxoplasmosis/neopsporosis?

- IgM/G serology
- MRI/CT
- CSF mixed cell pleiocytosis
- PCR on CSF

32

Tx toxoplasmosis/neopsporosis?

> 8-12 weeks
- TMPS 15mg/kg/BID
- Clindamycin 20mg/kg BID

33

Bacterial causes of encephalitis? Diagnostic indicators and Tx?

VERY RARE in dogs, cts and horses
- haematogenous/local invasion
- severe neutrophilic pleiocytosis
- intracellular bacteria/bacterial culture from CSF
- aggressive Abx to tx, ideally based on culture

34

Parasitic causes of encephalitis?

> A. vasorum (metastrongyloid nematode) -> coagulopathy

35

Clinical signs of a. vasorum encephalopathy?

- mainly young dogs
- cough + dyspnoea (essentially d/t interstitial pneumonia)
- subcut swelling/haemorrhage
- coagulopathy and thrombocytopenia

36

Outline the lifecycle of A> Vasorum

> L1-L3 development in the snail
> eaten by dog
> penetrates GIT and develops in mesenteric LNs -> L5
> Liver, portal v. -> Pulm a. and RV (10d post infection)
> in heart , maturation in ~ 1month post-infect
> adults shed eggs
> develop -> L1 in pulm aa.
> L1 penetrate cepillaries and alveolar walls
> coughed up and swallowed
> pooped out
-> Cycling beings again

37

How can A. Vasorum cause a coagulopathy? What linical parameter is this associated with?

- eosinophilia -> hypersensitivity
- cellular response
- deposition of immune complexes d/t adults irritating BVs
- inappropriate activation of clotting uses up platelets
- eggs hatching also inhibit thrombocytopoeisis
> intravascular consumptive coagulopathy overall
- prolonged APPT time observed clinically

38

Causes of head tilt in horses?

- trauma eg. basisphenoid bone fx
- idiopathic
- temporohyoid osteoarthropathy
- otitis media/interna (rare)

39

What is head tilt often seen in association with in horses?

facial n. signs

40

Aetiology of temporohyoid osteoarthropathy?

> theories
- chronic otitis media/interna
- infection spreads to tympanohyoid joint and stylohyoid bnoe
- inflame fuses tympanohyoid joint
- degenerative hanges over time
- muscle contraction mechanimal forces (swallowing/mastication) induce pathological fx extending into petrous temporal bone

41

Tx temporohyoid Osteoarthropathy?

- cefquinome/TMPS
- NSAIDs
- ceratohyoid bone removal

42

Prognosis for temporohyoid osteoarthropathy?

guarded
- 67% survival
~ 50% will have residual vestibular +/+- facial deficits
- recovery takes >1yr
- risk of relapse

43

How can thiamine levels be assessed ?

- pyridoxal diphosphate assay on whole blood by HPLC (high performance liquid chromatography)

44

Blood thiamine ref range?

136-332nmol/l

45

Pathogensis of thiamine deficiency?

> thiamine (vit B1) important for oxidative metabolism of many nutrients
- 4 reasons:
> reduced uptake
- anorexia/V+
- thiamine deficient food d/t overheating
- thiaminase activity of fish, bracken etc.
- sulphur dioxide
> v absorption
- D+
>altered utilisation
- hepatopathy
> ^ consumption
- fever
- infection
- diuresis

46

Clinical signs of thiamine deficiency?

- anorexia/lethargy
- vestibular signs
- pupillary dilation/absent PLR
- seizures
- cats = head ventroflexion

47

Diagnostic tools for thiamine deficiency

- MRI: bilat symmetrical lesionin brainstem nuclei
- transketolase activity in erythrocytes
- ^ certain urinary organi acids (2-oxo/hydroxyadipate)

48

Tx thiamine deficiency?

> thiamine!
- 12.5-50mg/dog
- 12.5-25mg/cat
- sc q24hrs until oral supplemetns can be given

49

What is the difference between LA and SA with vit B1 thiamine deficiency?

> Cattle: Polioencephalomalacia
- thiamine deficiency often d/t ^ carb diet -> overgrowth of thiaminase producing bacteria/ingestion of bracken/high sulphur intake/clostridium
- young large animals
- clinical signs: profuse transient D+, listlessness, circling, opisthotonus, muscle tremors