Neurological diseases of cattle Flashcards
What should be done on clinical exam of neurologic cattle?
- History
- Inspection of surroundings
- Assessment from distance
- General clinical exam
- Neurological exam
- Acillary tests
What should be examined regarding surroundings?
- Lead (old batteries / paint)
- Ration - quality of silage
- Poisonous plants
- Cadavers
What should be observed from a distance?
- Behaviour - circling, head-pressing, blindness
- Consciousness - over-excited, stupour, coma
- Stance - rapid contractions of muscles
- Locomotion - decreased coordination, weakness
- Orthopaedic or neurological =
-if carrying limb = ortho
-if dragging limb = neuro
What is normal function of the CNS?
- Brain = conscious functions = behviour, awareness, vision, eating, drinking, recognition of senses
- Brain stem / cranial nerves = cranial nerve functions, breathing
- Cerebellum = unconscious = proprioceptive, smoothing movements
- Spinal cord / peripheral nerves = limb strength + movement
What nerves does the nasal septum stimulation test test?
- CN v + thalamocortex
-should pull its head away
What does the menace response test?
- CN II + VII, cortex + cerebellum
-should be present from a week old
What does the PLR test?
- CN II + III
What are 3 types of ataxia?
- Vestibular
-always head tilt, hypermetra + hypertonia
-lesion on same side as head tilt - Cerebellar
-no proprioceptive deficits - Proprioceptive
-spinal cord disease, + weakness
What are different spinal reflexes?
- Extensor reflex of the front limb
- Patellar reflex
- Flexor reflexes
- Muscle tone
- Perineal reflex
- Cutaneous trunci reflex
What are different diagnostic tests?
- Biochem + haematology
- BOHB
- TP - colostrum transfer
CSF tap - lumbosacral - 4 inch needle
What are CS of cerebrum lesions?
- Opisthotonos - stargazing
- Apparent blindness (intact PLR)
- Abnormal mentation
- Change in behaviour
- Aimless wandering or compulsive circling
- Seizures
- Abnormal vocalisation
What are CS of cerebellar lesions?
- Ataxia without weakness – gait is controlled by the cerebellum, brainstem, spinal cord and peripheral nerves. Test for presence of absence of muscle strength – hold onto tail whilst the animal is moving can you pull it off course?
- Truncal sway – not specific as this can also happen in animals with spinal cord lesions
- Hypermetria – easiest to see in the front limbs
- Absent menace
- Wide base stance – not specific
- Intention tremors
What are clinical signs of vestibular lesions? Peripheral vs central
- Peripheral =
-head tilt towards lesion
-falling/ circling towards lesion - Central =
-head tilt towards lesion
-falling/ circling towards lesion
-nystagmus
-proprioception deficits towards lesion
-depression / anorexia
What are common CS localised to cranial nerves?
- CN II = blindness + absence of PLR + dilated pupils
- CN V = loss of sensation to head
- CN VI = ventromedial strabismus + inability to retract globe
- CN VII = motor muscles to face = droopy ears, eyelids, lips
- CN VIII = head tilt, circling, leaning towards lesion
- CN IX + X = inability to swallow
- CN XII = inability to retract tongue
What are clinical signs of problems with thalamus, hypothalamus?
- Depression. Altered mentation
- Difficulty regulating body temperature
- Depressed Respiration
What are clinical signs of spinal cord lesions?
- C1 - C5 – altered head and neck movements with no CN abnormalities. Reflexes of FL and HL are exaggerated
- C6 -T2 – depressed or absent reflexes with reduced muscle tone in the FLs and exaggerated HL reflexes with normal muscle tone in the HLs.
- T3 - L3 – Reflexes FLs normal, HL reflexes exaggerated. Pro-prioreceptive deficits in the HLs with ataxia
- L4 - L6 – absence of HL reflexes and decreased muscle tone
- S1 - S3 – decreased anal tone, loss of sensation to perineal region
What are acute diseases of the cortex?
- Cerebro-Cortical Necrosis (CCN)
- Lead poisoning - APHA
- Nervous ketosis
- Hypocalcaemia
- Hypomagnesemia (Grass staggers)
- Salt poisoning
- IBR / MCF (sporadic)
- Pseudorabies (Aujesky’s) - APHA
- Rabies - APHA
What are chronic diseases of the cortex?
- Brain abscess
- Bovine Spongiform Encephalopathy (BSE) - APHA
- Hypovitaminosis A
- Brain tumour (very rare) - APHA