Page 816 - Problem-Based Feline Medicine

808 PART 10 CAT WITH SIGNS OF NEUROLOGICAL DISEASE

Prescription Diet feline k/d, Hill’s Pet Nutrition), with Clinical signs
added carnitine, taurine and arginine, antibiotics (e.g.
History of feeding all-fish diets (containing thiamin-
metronidazole 7.5 mg/kg PO q 12 h, or neomycin 22
ase), diets consisting of entirely cooked meat (thiamine
mg/kg PO q 8–12 h, or amoxicillin 22 mg/kg PO q 12
destruction by heating), poor-quality, thiamine-deficient
h) and lactulose (0.25–0.5 ml/kg PO q 8–12 h). See page
commercial diets, commercial food stored for long
821, The Cat With Stupor or Coma, for further details.
periods of time or in excessively hot conditions or, pet
Surgical treatment including ligation or use of an meat preserved with sulfur dioxide which destroys
occlusive device offers the best chance for long-term thiamine.
control of clinical signs. This must be performed by an
Depression and inappetence are initial signs. Later
experienced surgeon to decrease the risk of excessive
mydriasis with poor pupillary light response, but usu-
ligation which may cause rapid post-operative death
ally without blindness and central vestibular dysfunc-
due to portal hypertension and bowel ischemia. Like in
tion occur with head tilt, loss of balance, spastic gait
dogs, severe seizures may develop in the first few post-
and tremors. Terminally, semicoma, crying, opisthotonos
operative days, and some cats have remained epileptic
with limb spasticity and death result.
for months and years afterwards.
True seizures are uncommon and must be differen-
tiated from periods of opisthotonic posturing with
Prognosis paddling, and from the spasmodic ventroflexion of
the neck and body contorsions that may be induced
Prognosis is good if surgical treatment is feasible, for when the cat is picked from the ground. These are
example with a single extrahepatic shunt, and is not likely due to marked spatial disorientation because
complicated by portal hypertension. Recurrence of of the bilateral vestibular dysfunction.
signs appears to be more common in cats than in dogs
and occurs in more than 40–50% after a few years. It
may be due to the persistence of shunting through Diagnosis
a partially ligated vessel or the development of mul-
Diagnosis is based on a history of dietary deficiency
tiple secondary shunts because of chronic portal
and response to thiamine supplementation (10–20
hypertension.
mg thiamine IM q 8– 12 h, then orally).
Prognosis is guarded with medical treatment as the
condition often worsens over time.
CEREBROVASCULAR ACCIDENTS**

Classical signs
THIAMINE DEFICIENCY***
● Peracute and rapidly resolving cerebral
Classical signs signs.
● Inappetence, depression, intermittent
vomiting. Pathogenesis
● Central vestibular signs (reluctance to
Cerebrovascular accidents are rare in cats.
walk, nystagmus, loss of balance).
● Mydriasis with poor pupillary light Vascular events result in acute ischemic lesions.
reflexes. Vascular events include spontaneous hemorrhage from
● Spasmodic ventroflexion of the neck or coagulopathies, thrombocytopenia and hypertension
opisthotonos. associated with chronic renal failure and hyperthy-
roidism. They also include thrombosis (e.g. poly-
See main references on page 848 (The Cat With Head cythemia hyperviscosity syndrome) and embolization
Tilt, Vestibular Ataxia or Nystagmus) and page 899 including septic and metastatic from rapidly growing
(The Cat With Neck Ventroflexion). cell type tumors.