Neurologic diseases of sheep and goats (Proceedings)

Cerebral diseases

Clinical signs

     • Depressed mental state, cortical blindness, circling/leaning, head pressing, opisthotonus, vocalization, seizures, bizarre behavior

Differential diagnoses

     • Polioencephalomalacia

          o Thiamine-responsive

          o Sulfur-induced

          o Lead toxicity

     • Vitamin A deficiency (Blind)

     • Salt Toxicity/Water Depriv.

     • Rabies

     • C. perfringens C/D enterotoxemia

     • Lidocaine toxicity

     • Bacterial Meningitis

     • Scrapie

     • CAE/OPP virus

     • Urea Toxicity

     • Hepatoencephalopathy

     • West Nile Virus

     • Hydrocephalus/Hydranencephaly

          o Veratrum, BTV, Border disease, Cache Valley, Akabane [FAD]

     • Heat Stress

     • Listeriosis

     • Sinusitis

     • Cerebral Edema

     • Hypoxia

     • Hypoglycemia

     • Acid-base derangement

     • Uremia

     • Hypocalcemia

     • Grass Tetany

     • Hypokalemia

     • Brain Abscess

     • Pituitary Abscess

     • Pregnancy Toxemia

     • Milk Fever

     • Brain Abscess

     • Pituitary Abscess

     • Aberrant Parasite Migration

          o P. tenuis

          o Neospora

          o Toxoplasma

     • Toxic Plants

     • Caprine Leukoencephalomyelitis

     • Borna Disease

     • Louping Ill [FAD]

     • Dandy-Walker Malformation

     • Holoprosencephaly

     • Meningocele

     • Anencephaly

     • Neoplasia

Cerebellar diseases

Clinical signs

     • Ataxia without paresis, mentally alert, intention tremors, nystagmus, truncal sway, base-wide stance, hypermetria, pick up feet and slam down hard, excellent muscle tone, fall over backwards, no conscious proprioceptive deficits, may lack menace response but have normal vision

Differential diagnoses

     • Cerebellar Hypoplasia

          o BTV, Border Disease, Cache Valley, Rift Valley, Wesselbron disease

     • Cerebellar Abiotrophy

     • Cerebellar Ataxia/Hereditary Hypomyelinogenesis

     • Grass Staggers

          o Rye, Dallis, Bermuda, Canary Grasses

     • Neoplasia

     • Dandy-Walker Malformation

Brainstem diseases/central vestibular diseases

Clinical signs

     • Depression, mania, ataxia and paresis, cranial nerve deficits, irregular respiration, head tilt, eyelid droop, circling, hemiparesis, nystagmus, ataxia with weakness, recumbency (lesion side down) with contralateral limbs hyperextended and hyperreflexic, loss of appetite

Differential diagnoses

     • Listeriosis

     • Aberrant Parasite Migration

     • Neoplasia

Peripheral vestibular diseases

Clinical signs

     • Usually not depressed, head tilt, ear droop, leaning, circling all towards lesion, horizontal nystagmus, ataxia without weakness, bright, alert, good appetite

Differential diagnoses

     • Bacterial otitis media/interna/externa

     • Ear ticks

     • Mites: Psoroptes, Sarcoptes

Spinal cord diseases

Clinical signs

     • Paresis, ataxia, dysmetria, recumbency, mentally normal

Differential diagnoses

     • Trauma

     • Pathologic Fracture

     • Vertebral Body Abscess

     • Epidural Abscess

     • Aberrant Parasite Migration

     • Neoplasia

     • Ascending Myelitis

     • Botulism

     • Tetanus

     • Spastic Paresis

     • CAE/OPP Virus

     • Caprine Leukoencephalomyelitis

     • Polyradiculoneuritis

     • Enzootic Ataxia/Swayback

          o Copper deficiency

     • Grass Staggers

     • Tick Paralysis

     • Organophosphate Toxicity

     • Plant Toxicity

          o Conium, Lupinus, Nicotinia

     • Neoplasia

     • Spina Bifida

     • Arnold-Chiari Malformation

Peripheral nerve diseases

Clinical signs

Weakness, paralysis, decreased muscle tone, muscle atrophy

     • Obturator

          o Clinical Signs: Cannot adduct hind limbs – splay hind legs

          o Cause: Dystocia, splits, pelvic fracture

     • Sciatic

          o Clinical Signs: Extended stifle, flexed hip, flexed or extended hock or fetlock

          o Causes: Trauma, inappropriate IM injections, lumbosacral fracture, proximal acetabular fracture, femoral fracture

     • Femoral

          o Clinical Signs: Flexed stifle, extended hip, crouching stance

          o Causes: Trauma, extreme hindlimb extension, injection site reaction

     • Peroneal

          o Clinical Signs: Extended hock, flexed fetlock

          o Causes: Trauma, sciatic damage

     • Tibial

          o Clinical Signs: Partially knuckled fetlock, flexed hock

          o Causes: Trauma, sciatic damage

     • Suprascapular

          o Clinical Signs: Short strided gait, abduction of the leg and shoulder during weight bearing, atrophy of supraspinatus and infraspinatus mm.

          o Causes: Trauma

     • Radial

          o Clinical Signs: Dropped elbow to complete forelimb paralysis

          o High damage: can't bear weight, flexed elbow and fetlock

          o Low damage: can bear weight, flexed fetlock

          o Causes: Trauma, rib or humeral fracture, avulsion of brachial plexus

Storage diseases

Clinical sign

     • May have clinical signs referable to any or all of the CNS segments

Differential diagnose

     • β mannosidosis – Nubian, Nubian X

     • GMI Gangliosidosis – Suffolk

     • Generalized Glycogenolysis – Suffolk

     • β galactosidase deficiency – Suffolk

     • Globoid Cell Leukodystrophy – Polled Dorset

     • Krabbe's Disease – Polled Dorset

     • Galactocerebrosidosis – Polled Dorset

References available upon request.