Page 840 - Problem-Based Feline Medicine

832 PART 10 CAT WITH SIGNS OF NEUROLOGICAL DISEASE

● Diagnosis of a structural intracranial abnormality in (1/2–2 ml IV, 20–50% dextrose) to effect. The insulin
the hypothalamus or pituitary region is most readily dose should be decreased by 50% or stopped if the cat
accomplished with computed tomography or mag- is in remission. Accidental causes of overdose should
netic resonance imaging of the brain. be resolved.
Cats with hypoglycemia associated with neoplasia,
Differential diagnosis including insulinoma should be managed with fre-
quent feeding and corticosteroids (0.5–6 mg/kg/day in
Rule out other inflammatory, neoplastic and traumatic
divided doses) to antagonize insulin action. See page
causes of intracranial disease.
962 (The Cat With Generalized Weakness) for further
treatment details. Surgical removal of a pancreatic
Treatment insulin-secreting tumor may normalize serum glucose
concentrations.
Treatments should be directed at the underlying meta-
bolic abnormality. Treatment for hypernatremia centers on slowly
decreasing serum sodium through fluid administra-
Medical treatment of hepatic encephalopathy cen-
tion. This is most safely accomplished with oral
ters on frequent small meals of a low-protein diet,
administration of water. If the hypernatremia has
antibiotics (metronidazole 7.5 mg/kg PO q 12 h and
evolved slowly, extreme caution should be exercised
neomycin sulfate 20 mg/kg PO q 8–12 h), l-carnitine
when attempting to decrease serum sodium with fluid
(250–500 mg/cat/day PO as aqueous solution), tau-
therapy. As a rule, slowly decreasing serum sodium
rine (250–500 mg/cat/day in food), arginine (250 mg
concentrations (over 2–3 days) is safe, however,
q 12 h in food), vitamins B, K and E and lactulose
l serum sodium should be measured frequently to avoid
(1–3 ml/cat PO q 8–12 h to produce a soft stool,
rapid decreases in sodium which can result in life-
beginning at the lowest dose and increasing as neces-
threatening cerebral edema. Do not decrease serum
sary). If the cat is severely depressed, lactulose should
sodium by more than 0.5 mmol (mEq)/L/h (12
be given as a retention enema for the first 1–2 days. A
mmol/L/day) if the hypernatremia is chronic.
solution of three parts lactulose to seven parts water is
dosed at 18 ml/kg q 4–6 h. The solution is instilled via If metabolic encephalopathy results in cerebral edema,
a Foley catheter as cranially in the colon as possible. mannitol (1 g/kg IV bolus) and furosemide (0.7 mg/kg
The solution must be aspirated after 15–20 minutes. IV) can be given provided the cat is not dehydrated.
Fluid and electrolyte status should be monitored care- Indications for therapy are severe signs or lack of
fully to avoid dehydration and hypernatremia. improvement after 4–6 hours of appropriate medical
Benzodiazepine receptor antagonists (e.g. flumazenil) treatment.
may be useful in cats with severe encephalopathy, but
are unproven. Prognosis
If the clinical signs of hepatic encephalopathy are Prognosis depends upon the ability to treat the underly-
severe, or do not improve within 4–6 hours after insti- ing disease process.
tution of medical treatment, and if the animal is not
dehydrated, mannitol (1–2 g/kg IV) followed by
THIAMINE DEFICIENCY*
furosemide (0.7 mg/kg IV) can be administered as
a treatment for possible secondary cerebral edema.
Classical signs
Surgical correction of a congenital portosystemic shunt
● Initially, lethargy, inappetence and ataxia.
may result in a permanent cure.
● Later signs include weakness, ventral
Diabetic cats with marked signs of hypoglycemia flexion of the neck, dilated pupils, stupor,
should be treated initially at home with honey or and coma.
a sugar-solution designed for human diabetics
poured on the owner’s finger and rubbed on the cat’s See main reference on page 848 for details (The Cat
buccal mucosa. In hospital, treatment is with dextrose With a Head Tilt, Vestibular Ataxia or Nystagmus).