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medsurg
wendy freeman

neurologic diseases in small 
ruminants

group these practically - by age
neonatal
1 week to one year

adult

now, not to be a grim reaper but pretty much every neurologic 
small ruminant is a dead small ruminant. but there are a couple of things 
we can treat. 
mostly these things are tough to work up and tough to 
diagnose.

how do we approach a neurologic disease in a sheep or goat?


probably the most important part in addition to PE is history. a really 
good history. find out signalment - age, breed, sex, use - how long 
problem has gone on, etc. part of the history is to ask about potential 
for trauma. clients don't talk about it unless you ask - where the 
animals alone? on a truck? etc.

typically neuro diseases are single 
animal problems, not outbreaks. 

combine history w/PE and neuro exam...


neuro exam of small ruminant is a bit easier than with equine or bovine

start at the head.
get an idea of the mental status. some diseases cause 
CNS signs, others cause only cord signs so that the animal is bright, 
alert, responsive. if dull, depressed - or maniacal - you can tell. then 
do good cranial nerve exam b/c we commonly see dz affecting these nerves. 
look at eyes, ears, nose, respiration, palpebral reflexes, ear position, 
etc. then go on and look at cord - can animal walk, normally? stand 
normally? how is the gait? how is the stance? how is the balance? look at 
proprioception - can easily knuckle all four feet and the typical 
sheep/goat will correct immediately and pull leg away from you. you can 
wheelbarrow them if they're small enough. the bigger they are the harder 
it is to do this stuff. can put in lateral recumbency and check reflexes 
- hard to do in adults because they do get somewhat tense/stressed, but 
you should try. a normal animal will fight you, so it's difficult. easier 
in lambs/kids.

diagnostics - routine blood work - WBC, chemscreen to 
rule out metabolic/infectious problem. if you find a cord or CNS problem 
you can start with CSF taps (in lumbosacral area) - infrequently this 
will give you a diagnosis. but it will tell you if fluid is abnormal or 
not. in most cases, won't tell you what disease you have unless it is 
paralephastrongylus tenuis where there may be eosinophilia in the CSF. 


radiographs may reveal bony changes, tumor, abscess - can xray spine 
pretty easily or can do CT or MRI b/c animal is small enough, though most 
clients won't want to do that. people have asked for MRI/CT on llama - 
this is difficult b/c they don't really fit in the machine. 

looking at 
head for sign of altered mental state - signs of general depression - 
excess vocalization, crying a lot for no reason - aimlessly walking 
around, head pressing, showing aggression. these animals aren't normally 
aggressive. if they attack you there is a problem. teeth grinding - tells 
you two things - either the animal is in pain or it has a neurologic 
disease affecting CNS. usually depression, head pressing, teeth grinding, 
sometimes aimless walking. soemtimes hyperactive aggressive animals, not 
often.

cranial nerves - look for ear droops, eyelid droops, problems 
prehending food, dysphagia, drooling, blindness (polio), head tilt, 
deafness (can't really assess this)

signs of involuntary activity 
associated with neuro disease: muscle tremors (differentiate from 
shivering due to fear)(most neuro tremors aren't generalized but are only 
one part), convulsions, nystagmus, itchiness (you won't see them chewing 
and biting, but may see wool loss, excoriations, rubbing on fence)

gait 
abnormalities - watch for basewide stance, crossing limbs, circling, 
hypermetria (goosestepping esp in goats with CAE in brain), ataxia, 
incoordination.

postural abnormalities - opisthotonos (head/neck arched 
back, limbs rigid extension), hind end weakness, front end weakness, 
weakness mimicking lameness, paralysis

slide: normal sheep - alert, 
bright, looking at you
slide: dull, depressed neonate, ear droopy, not 
alert, weak
slide: obvious head tilt in this ewe, very weak, recumbent - 
listeria
slide: dysphagia, hay falling out mouth. mentally dull goat

slide: arched back, wide based stance, has cord disease, having trouble 
staying standing. 
slide: sheep rubbing against wall, leaning with butt 
on wall to help stay standing. not able to walk well on her own. 

CSF 
taps - to do these you clip some wool from lumbosacral area, everyone 
likes to do this but they don't usually give you that much information 
really. to be complete, they are worthwhile insofar as telling you if 
it's normal or not but it costs about $70 and you could spend that money 
elsewhere. mostly the money is a big factor and this won't tell you much 
so you're probably better off spending the money elsewhere. if you do it, 
clip, scrub, block with lidocaine under skin, usually have to sedate and 
sit into a frog legged position to open lumbosacral space. then put 
spinal needle down into lumbosacral space , hopefully will get some CSF 
without blood. if there's blood, it'snot that helpful at all. 

most of 
your neuro cases end up dead. try to get to do necropsies. note that with 
neuro disease, however, finding an answer is less likely even at 
necropsy. if there are likely to be brain lesions, maybe you will find 
something. but if it is a cord, and you don't see a gross lesion, then 
you have to decide where to take sections, and you'll probably never find 
it. but you won't ever get a dx if you do not look

Neonates:

birth to 
one week of age

if these animals are showing neuro signs, think of 
hypoglycemia/hypothermia. very common in goat kids, lambs, crias. they're 
born, they get cold, damp, chilled, burn off all their fat stores, 
seizure from low BG, go blind. may present seizuring and blind. the first 
thing to think is hypoglycemia. 

this little cria was born in the 
morning during the rain, got chilled, couldn't get up to nurse, found her 
five PM, body temp really low, seizuring from low BG. mom ok.

on top of 
this, you can get septicemia. these neonates also got bacterial 
infections on top of things. also in septic lambs, you probably see a 
very depressed animal, even after treatment. treat, give glucose, warm 
up, mental state returns to nromal, temp comes up, they are fine. septic 
lambs, you do the same thing but then they retain an abnormal mental 
state and stay depressed. WBC is high. 

so those are the two most common 
things in neonates. the other thing you might see in maybe a 2 week old 
is meningoencephalitis from disbudding of goat kids. sometimes people are 
overzealous when burning the buds and they burn too far and heat goes 
through skull to brain and you get two circles of necrosis of meninges or 
brain. they might die suddenly that day, or start showing CNS signs in a 
couple of hours after disbudding - depression, seizures, gait 
abnormalities, etc. may not show up for several weeks. how to dx? any 
goat kid presenting with CNS signs in first few weeks and has signs like 
blindness, circling, difficulty moving around - check head carefully. if 
you check horn buds may see pus underneath. if they die suddenly, 
necropsy will show you two circles of dead tissue under where horn buds 
were. you will probably see a few of these year by year. tx for 
meningoencephalitis is rarely successful. broad spectrum abx, 
antiinflammatories, keep quiet, dimly lit, no animals at NBC have 
survived so px is very poor, almost always they die. 

In older lamb, 
growing lamb, kid, cria one month to one year of age:

brain abscess, 
meningitis, meningoencephalitis
one common thing that can happen is 
infection at tail docking or castration or umbilicus; bacteria get in 
there somehow, and sometimes there is no obvious route of infection at 
all but we still see meningitis or abscess. mostly, these animals present 
with CNS signs of ADR, blindness, circling, aimless walking, not eating 
well...sometimes signs can wax and wane with tx of antiinflammatories 
helping and then animal gets worse again, etc. 
dx is difficult. CSF tap 
may help with dx b/c will be abnormal, probably will have neutrophils in 
it, but mostly you dx based on ruling out other diseases which you can 
treat. tx of brain abscess or bacterial meningitis is unrewarding. px 
very poor. may stabilize or even improve briefly but you won't cure them, 
they get sicker and sicker and then they die or are euthanized.

another 
common neuro disease you see is encephalitic form of CAE: a retroviral 
disease which has an encephalitic form which is most often seen in goats 
2-6 mos of age. ovine counterpart, OPP, can cause this too. OPP also in 
2-6 mos old lambs. these animals present mostly with trouble getting up 
at first, needing some assistance x 1 week, then trouble with hind legs, 
paralysis of hind legs, then forelimb paresis/paralysis - so usually 
ascending paresis/paralysis. these animals usually are BAR, eating well. 
you have this little tetraplegic guy sitting there eating well, very 
alert, but not getting up. progression takes weeks from weakness to 
recumbency. no tx for this. again, you r/o other things you could treat, 
then give up. dx - CSF not diagnostic, but will be abnormal. serology - 
can look for CAE/OPP titers - should be positive but not always. 
sometimes they seroconvert back to a negative state. positive form not 
totally diagnostic either. need to do necropsy and find lymphocytic 
infiltrate throughout spinal cord for definitive dx. 

vertebral body 
abscesses also seen in young, growing animals. abscess forming either 
around the cord or in the vertebral body around the cord. can invade bone 
or dura, soft tissue around cord. present the same way. location defines 
signs. in lumbar area we see hindlimb signs. in neck, we see 
tetraparesis. usually start similar to CAE with onset of weakness in 
hindlimbs then progression to paralysis. even if it is up in the neck, 
hindlimbs are affected first. you may see an animal with neck pain but 
not usually. early early on the abscesses are forming and the animals 
show no clinical signs - may have a couple of days of being febrile, off 
feed - but usually no one notices that. may be grinding teeth, painful, 
but usually alert, eating well.
dx - xrays will find bony abscess, not 
soft tissue abscess
tx rarely successful. poor prognosis.

what can we 
treat in this group of animals? 
this disease - polioencephalomalacia. 
makes you look like a star. young animal, blind, bloated, opisthotonos - 
polio. give thiamine IV. give DMSO. will get up and run away. polio is 
common - just a thiamine imbalance. these guys when they try to become 
ruminants are making thiamine and thiaminase in their rumens. we're not 
sure what the trigger for this is but there is some imbalance in the 
amount of thiamine being made, and the amount of thiaminase. animals on 
high doses of amprolium, a thiaminase, will also get this. and some 
plants out west contain thiaminase. sometimes they have history of feed 
change or diarrhea episode. it affects animals over one month and under 
one year of age. cardinal sign is blindness. will have PLR but no menace. 
often the client first sees the animals standing in the barn, "stuck," or 
running into the walls. or fails to run away from you b/c they don't see 
you. then they start stargazing. often they are bloated b/c GI motility 
is affected, not eructating. often have strabismus. 
tx thiamine (B1)
dx 
gross necropsy is really the only way so basically dx by response to 
therapy. if you suspect polio, give some thiamine, you're not going to 
hurt anything. give 5-10 mg/kg but if you forget that, it's ok. you're 
not going to OD him. she gave a cc b/c she couldn't remember the dose. 
note that when given IV it MAY cause anaphylaxis - so dilute with saline 
and give slowly IV. 
thiamine deficiency causes cerebral swelling. give 
the thiamine to reverse the deficiency, and give some kind of 
antiinflammatory - can give DMSO IV which is time consuming, or give some 
dexamethasone IV or IM. most patients respond quickly and get up on their 
feet within hours. vision may take a couple of weeks to come back. one 
caution - thiamine will make any neurologic animal with CNS signs appear 
slightly better so if you treat and animal starts getting a bit better 
but not totally better and then relapses the next day, chances are it 
wasn't polio. but give some thiamine anyway b/c this is how you dx. polio 
rule outs - tetanus, lead poisoning. continue thiamine IM BID x four 
days.owner can do this tx. this is the one dz we can treat, has a very 
good px. if seizing, can give valium IV to relax while thiamine is 
kicking in. 

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forging on.

two more diseases you may see.


enzootic ataxia you might see out west - copper deficiency problem. this 
isn't our problem, we have copper toxicity here, but out west there is a 
lot of molybdenum in the forage. copper deficiency causes a progressive 
ataxia, starting at rear limbs and progressing forward, animals initially 
can stand but later can't. may have tremors and shaking of the head, so 
you see nodding and shaking. usually you don't see CNS signs, animals are 
BAR, eating. looks like a cord problem, but it's a copper deficiency 
causing multifocal cord effects.
dx: look at plasma copper levels - will 
be under .06 ppm.  (check that in notes, did she say 6/10 or 6-10?). may 
also see some depigmentation. but it isn't seen in this area except in 
one flock where a woman was giving a lot of molybdenum b/c she'd had a 
lot of copper toxicity problems. 

the other disease which presents as a 
down animal is white muscle disease - you know this is selenium 
deficiency, a musculoskeletal disease, but historically the clients will 
tell you the lamb can't stand, and once up, can't walk, and you need to 
look at if it's neuro or musculoskeletal. hard to tell sometimes. so 
consider this. this is easy to dx - blood selenium will be low, and b/c 
it is a muscle problem and not a neuro problem if you suspect it you can 
run a CPK and in white muscle dz this will be elevated, >50,000 or 
higher. most recumbent small ruminants of this age won't have such a high 
CPK even if recumbent for a few days. 

so you are presented with four 
month old recumbent small ruminant. you do a PE. animal has no CNS signs 
- BAR, eating well, eructating, not blind - you think there is a cord 
problem. ddx: white muscle disease, vertebral body abscess, encephalitic 
CAE/OPP, trauma/fracture, enzootic ataxia. what do you do? what could you 
treat? not much. you could give vitamin E/selenium, you could give copper 
(assuming bloodwork showed deficiencies). trauma you may dx on PE or rads 
but can't treat. often there are limited funds. client says no 
diagnostics. you tell client there is poor px and you give some vit E 
selenium, give some copper. if it gets better, great. 

if you see CNS 
signs - blindness, aimless walking, ataxia - not recumbent but difficulty 
ambulating - give thiamine b/c polio is the only disease causing these 
signs which is treatable. if no response, meningitis could be attempted 
to be treated with abx but probably will die. listeria can try to tx but 
probably not successful too. you can just tell the owners that you can 
give this thiamine, and it will get better or not. give antibiotics, it 
will get better or not.

In Adults, the picture is even bleaker. a 
tremendous number of undiagnosed cases appear. most common is 
listeriosis. you will see this. we see it every year, it's an infectious 
dz caused by listeria monocytogenes, happens to affect the CNS, animals 
get it from environment, don't really spread it to each other. localizes 
in brainstem, medulla and pons. causes microabscesses, so neuro signs are 
referable to the location of the abscesses, mostly cranial nerves VII, 
VIII, X. most animals present with some CN dysfunction. ear droop, loss 
of blink. one side of face will droop. one nostril moves, one doesn't. 
one side of lip droops. one eye can't blink. one ear droops. often 
drooling b/c can't swallow and if they want to eat, which most don't b/c 
of infection in the brain causing depression, but if they do they may be 
able to grab food but can't swallow it. b/c they have CN VII, VIII and 
other nerves affected, they have hard time walking, usually circling as 
if had inner ear infection but more depressed. eventually become 
recumbent, lying on side with head bent around. 

slides: goat with 
listeria, very depressed, appears asleep. tend to lie with head bent 
around touching the flank. if you move the head, they move it back. if 
you flip them to the other side they struggle to flip over to the first 
side and bend head around because they feel more comfortable that way. 
ear droop, loss of palpebral reflex, head bending to that side. signs can 
be very subtle early on. client may call and say aniaml is off feed, not 
acting right, a bit depressed. sometimes very subtle so look carefully. 
tx success is dependent on early intervention and treatment. 

tongue 
protruding, drooling - some clients report animal is fine in AM, acutely 
down or circling in PM with tongue hanging out, drooling, ears droop - 
clients will shoot them and bring them in b/c they think they have 
rabies. most drooling small ruminant animals with tongue hanging out have 
listeria, not rabies. 

sometimes they are flat in lateral recumbency - 
can have neuro form and septicemic form at the same time. they may show 
cranial nerve signs or not, often seizing, febrile, and totally 
recumbent. usually they die in 24 hrs.

dx: CSF tap would be abnormal 
with mononuclear infiltrate but not diagnostic. presumptive dx on 
clinical signs of unilateral CN signs. if animal dies and 50% will, most 
likely, you can culture it from the brainstem (medulla/pons). culture 
success is directly related to length of tx with abx. after 5-6 days of 
therapy, harder to culture. but if you remove brain, take culture, then 
freeze brain, and thaw in two weeks and reculture, that second culture 
may be positive even if first one was negative. histologically there are 
microabscesses in the brainstem, suggestive of listeria. definitive dx 
only on necropsy.

prognosis is guarded - 50-50 at initial presentation. 
with acute onset, fine yesterday and down today - no better than 50-50 
chance. with gradual onset and animal is up but circling, a bit better 
chance. slower onset has better prognosis. general impression is that 
goats have more acute onset than sheep. most goats are totally flat out 
w/in 24 hrs. 

if they stabilize in 24 hrs, then px may be a bit better; 
most of these cases benefit from hospitalization, IV cath, fluids b/c 
they can't swallow, penicillin or tetracycline (doesn't matter which - 
start one, if not helping, switch). put on DMSO in fluids as 
antiinflammatory initially, that may help some. tube periodically to 
maintain rumen function, once or twice daily. usually in hospital 5-10 
days and most never return to totally normal. usually keep doing some 
circling - walk a straight line ten yards, then do three circles, etc. 
but never tell the client there is a good prognosis. make sure they know 
the px is poor and bill is high.

Tetanus: the only thing to say is, the 
only time you see this is in animals that are not vaccinated. small 
ruminants aren't that susceptible. horses, humans, more susceptible. most 
people do vaccinate anyway, so you see even less. when you do see it, 
very rigid, hyperreactive to stimuli, stiff stilted gait if walks, over 
react and fall over if you make sudden noise. dx of exclusion and hx of 
not vaccinated. tx penicillin and antitoxin in dark, quiet environment. 


P. tenuis: parasitic dz common in small ruminants, treatable if caught 
early. present with some type of limb problems - paresis, recumbency, 
etc. generally starts with a hind limb problem looking like lameness, 
progressing to weakness, to paralysis, etc. moves to front. eventually 
recumbent but BAR, eating. history of living near white tailed deer. also 
access to low lying water, ponds, streams, marshy areas where there are 
snails, slugs - intermediate host. must eat snail, slug to get disease. 
but owner may say there are no deer or no snails and sheep could still 
have this b/c snails sneak around.

slide: p.tenuis animal - ok in front 
limbs, can't use hind limbs. proprioceptive deficits in hind limbs, no 
control over them. 

tx of p.tenuis, dx of p.tenuis - CSF tap can 
actually be diagnostic if there is eosinophilia - 10-17% of cells are 
eosinophils. if you don't see that, could still have p.tenuis. definitive 
dx is necropsy - find parasite or tracts. tx: prognosis is good if early 
tx, so if you suspect this or see an adult with spinal cord signs - since 
this is the only disease causing those signs that you can treat, you may 
as well treat with fenbendazole or ivermectin because it works. 
fenbendazole 10 mg/kg SID x 5 days works well. you'll also need to give 
steroids b/c dying parasites cause inflammation. tx dexamethasone SID x 8 
days. 
people ask how much steroid to give - about .25 mg/lb or less. 
maybe start 8-10 mg dexamethasone(for avg sized animal) for 2-3 days in a 
row, then start to taper. supportive care required - turn, sling, help 
up, help move to avoid myositis, most will get better. 

another dz you 
may see - scrapie - a prion disease a la BSE or TME or CJD. this is a 
sheep disease. this is why clients with down small ruminants have 
problems getting rid of the carcass. renderers won't take them. scrapie 
is seen most often in suffolk or blackface breeds; a chronic, 
debilitating dz, animals lose weight, eat well, get thin, get weakness, 
become recumbent eventually once very thin, due to neuro dysfunction and 
thinness. wool loss over back. easily knocked down when flock runs by. no 
antemortem tests, some genetic marker tests, and it's a big deal if you 
dx this with respect to farm b/c it is reportable, flock quarantine 
ensues, etc.
brain lesions - similar to polio.
dx on brain lesions

other 
neuro diseases in adults - 
trauma esp during breeding season. 
there are 
vertebral body abscesses in adults, but not common
LSA of spine - signs 
referable to location
rabies, very rarely - only rabid small ruminant 
seen by Dr F looked like meningitis patient - chewed hole in her 
shoulder, head butted everything, had furious form of rabies. any array 
of neuro signs can occur but this one looked like she had meningitis. 
usually small ruminants get the dumb form. 
demyelinating diseases can 
occur - found on necropsy - no particular disease
also we've seen the 
rare case of polyradiculoneuritis 


bottom line: a down adult small 
ruminant is a dead small ruminant in most situations unless you dx 
p.tenuis or listeria. p.tenuis has best px, listeria some can get better. 
the rest, you won't get them better. 

what about llamas? they are worse 
than sheep. a down llama is a dead llama, b/c they get myositis so fast 
regardless of why they are down. say they are down with heat stress - 
that kills them too. they don't have to be down very long before they get 
this severe myositis which is hard to reverse.

p.tenuis though can occur 
in llamas and it is just like in sheep/goats. 
the difference in llamas 
is that we routinely tx with ivermectin once a month to prevent problems, 
and so there is very little p.tenuis seen. used to see it all the time, 
but now we never see it. llamas use a dung pile and go in one place every 
day and graze away from it, so parasite control in camelids is much 
easier - no haemonchus or ostertagia problems. in sheep/goats, we 
couldn't do this b/c we'd have haemonchus resistance to ivermectin 
occuring. so we take our chances with the meningeal worms instead of 
putting them on monthly ivermectin. probably haemonchus in camelids is 
resistant, but we don't have problems b/c they do not get infected.
if 
you do see llama with p.tenuis, tx as a sheep but add in anti-ulcer meds 
to go with the steroids - add in cimetidine which doesn't decrease acid 
that much but helps clinically. omeprazole is better but way more 
expensive. also many camelids with what looks like p.tenuis are pregnant 
females - then you can't use steroids - use banamine or bute. usually 
banamine.

the other thing never diagnosed in llamas but suspected to 
occur is EPM. some llamas have asymmetric deficits in hind limbs 
progressing to front which is tx'd with TMP-sulfa and resolves. not sure 
if it is EPM but it is EMP-like. if you see camelid having hind end 
trouble, not walking well - you don't want it to start lying down all the 
time. you'll see it sstands with legs wide-based, knuckles, allows you to 
touch legs which is abnormal by camelid standards. if you walk along 
beside them and pull tail they may stumble, fall. those animals - you can 
do CSF tap to look for p.tenuis - generally start fenbendazole, steroids, 
and TMP-sulfa. 

the other disease we see in llamas - equine herpesvirus 
- causes neuro signs in llamas though in horses generally just 
respiratory. except old horse. but in llama we see blindness and ataxia, 
progressing to recumbency. this happened to a large group of them in NY, 
dx on necropsy. so for camelids living on horse farms with transient 
horse populations like breeding farms, show farms, it's recommended to 
vaccinate for equine rhinopneumonitis (equine herpesvirus). not sure if 
that works and not everyone does it but it's a recommendation. 

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