Feline Neuro problems

Feline:Your next appointment is a neuro consult. A 10-year-old castrated male Domestic Shorthair cat presents with a 6-week history of pacing and circling to the left at home. In the exam room, he constantly paces but there is no detectable ataxia or weakness. A head tilt is absent. When given some canned food to eat, chewing and swallowing appear normal with no intention tremor observed. What is the most likely neuroanatomic location for this cat's brain lesion?

The correct answer is left forebrain. Given the history of pacing and circling at home, and the observation of pacing in the exam room, this is likely a true abnormal finding. Pacing occurs most commonly with dysfunction of the forebrain (prosencephalon).

Circling can occur with either forebrain or vestibular lesions (both peripheral and central) toward the side of the lesion, but because there is no ataxia, weakness, or head tilt, vestibular disease is less likely.

The answer option of right forebrain is incorrect since the cat is known to circle to the left.

Given the lack of ataxia, head tilt, hypermetria, and intention tremors, a cerebellar lesion is unlikely.

The correct answer is left forebrain. Given the history of pacing and circling at home, and the observation of pacing in the exam room, this is likely a true abnormal finding. Pacing occurs most commonly with dysfunction of the forebrain (prosencephalon).

Circling can occur with either forebrain or vestibular lesions (both peripheral and central) toward the side of the lesion, but because there is no ataxia, weakness, or head tilt, vestibular disease is less likely.

The answer option of right forebrain is incorrect since the cat is known to circle to the left.

Given the lack of ataxia, head tilt, hypermetria, and intention tremors, a cerebellar lesion is unlikely.

Feline:A 5-year old female spayed domestic short haired cat presents for a right sided head tilt, vertical nystagmus, and circling to the right. Where is the lesion in this cat?

The correct answer is right central vestibular disease. Vertical nystagmus is seen only in central vestibular disease. Head tilt and circling are usually toward the side of the lesion (unless the animal has paradoxical vestibular disease in which case the head tilt and circling is away from the lesion).

Feline:A 5-week old domestic short hair kitten is presented for ataxia and tremors. The owner notes that the kitten was found several weeks ago and has always had tremors and difficulty keeping its balance. On physical exam, the kitten is ataxic, hypermetric, has a wide based stance, and head tremors. The kitten is otherwise normal on physical exam. What is the neuroanatomic location of the kitten's lesion?

The correct answer is cerebellum. Cerebellar dysfunction results in inability to regulate and measure motor function. Clinical signs of cerebellar lesions include ataxia, dysmetria, vestibular signs, delayed postural reactions, and sometimes upper motor neuron signs in the limbs. In utero or perinatal infection of kittens with feline panleukopenia virus often results in cerebellar hypoplasia, leading to the clinical signs mentioned in the question.

Feline:

Porcine:You are called to a farm that just purchased 500 head of feeder pigs averaging 55 lb. The pigs arrived 3 days ago and everything seemed fine until today. Today there are 6 pigs that are lying down on their sides and paddling and a few others that are weak and staggering. What should you do next?

1. A.Check the feed for mycotoxins

2. B.Check antibiotics used in the ration

3. C.Check for signs of rodent infestation

4. D.Check water availability in all pens

5. E.Check feed availability

The correct answer is to check water availability in all pens. The clinical presentation is very typical for water deprivation/salt toxicity. Water deprivation will result in acute cerebral edema due to the accumulation of sodium ions in the brain. To prevent further water damage, water must be turned back on slowly (small amounts frequently) to prevent further cerebral edema from occurring as the animals become re-hydrated.

Porcine:

This 2-year old pot belly pig in the picture presents for eating a box of cooking salt. It is very thirsty at presentation, but otherwise clinically normal. Its blood sodium concentration is 175 mEq/dl. What is the best treatment for this pig?

1. A.Send the pig home and have the owner bring the pig back if it starts to show neurologic signs

2. B.Give Normosol R IV slowly to decrease the blood sodium concentration

3. C.Give IV diazepam to suppress seizures and wait for the excess salt to be excreted by the kidneys

4. D.Give unlimited amounts of drinking water

5. E.Give a bolus of 50ml/kg of D5W (5% dextrose in sterile water) as an intravenous infusion to quickly lower the blood sodium concentration

The correct answer is to administer Normosol R IV slowly to decrease the blood sodium concentration. Salt poisoning in pigs occurs as a consequence of water deprivation (reduced amount of free water in the animal), or too much salt intake. When the blood sodium concentration is too high, water from the brain diffuses into the vasculature. The brain responds by forming hyperosmolar (idiogenic osmoles) particles to draw water back into the brain to prevent dehydration of its cells. Giving large amounts of free water in the form of drinking water or as a bolus of D5W intravenously will quickly drop the blood sodium concentration, causing a large amount of water to diffuse into the brain cells due to the hyperosmolar particles formed. Cerebral edema then ensues and neurologic signs result. Treatment should be aimed at slowly decreasing blood sodium concentration by about 1 meq/hr to prevent cerebral edema. This is best done by using a replacement fluid that approximates normal levels of sodium so as to not create too large of an osmotic gradient. Pigs showing clinical signs of brain disease usually die despite treatment.