Page 1348 - Problem-Based Feline Medicine

1340 PART 15 CAT WITH EYE PROBLEMS

If there is generalized muscle stiffness, the cat may Tetanus antitoxin binds to circulating toxin, and cannot
have an increased temperature associated with the dislodge toxin within peripheral nerves. Its main pur-
muscle contraction. pose is to neutralize circulating toxin outside the nervous
system. If the signs are localized and non-progressive,
administering tetanus antitoxin systemically is not
Diagnosis
likely to be beneficial, and is associated with a risk of
Diagnosis is based on the characteristic clinical signs. anaphylaxis.
● The dose of antitoxin is usually about 1000 U/kg
EMG testing of affected muscles is strongly suggestive
IV administered slowly over 5–10 minutes, with
of tetanus if it demonstrates persistent spontaneous
some (1000 U) injected locally in the wound. As most
motor unit potentials.
tetanus antiserums are generally prepared in equines,
consideration should be given to the pre-emptive use
Differential diagnosis of corticosteroids and antihistamine to prevent possi-
ble anaphylaxis. Give a test dose (0.1–0.2 ml) intra-
Any condition which causes bilateral third eyelid
dermally or subcutaneously 15–20 minutes before IV
prominence such as haws or dysautonomia should be
administration and check for a wheal.
considered. However, facial muscle or limb rigidity is
not seen with these conditions. Muscle relaxants such as diazepam can be used to
control the muscle rigidity and make the cat more
Mild hypocalcemia in late pregnancy or following
comfortable. Efficacy of the drug varies between indi-
whelping could be confused with tetanus, especially as
vidual cats. Alternatively, small doses of acepro-
the reproductive tract may be a site of infection and
mazine (1.25–2.5 mg/cat PO q 6 hours as required),
toxin production. Rapid response to intravenous cal-
chlorpromazine (IV) or phenobarbital may be
cium in pregnancy-associated hypocalcemia will rule
effective in reducing muscle stiffness.
out tetanus.
Other supportive treatment should be given as indi-
Meningoencephalitis or encephalopathy including
cated, e.g. alimentation, intravenous fluids.
thiamine deficiency may occasionally have tetanic
spasms worsened with touch or sound. In these animals Keep the cat in a quiet, dark area to reduce the mus-
mentation is usually depressed and other neurological cle spasms, which are stimulated by touch or sound
signs are evident.
Difficulty urinating or defecating may occur, and needs
to be managed.
Treatment
Prognosis
Treatment involves appropriate antibiotic therapy,
The prognosis is generally good with appropriate
wound care, supportive treatment, and use of
treatment, and full resolution of signs usually occurs
tetanus antitoxin.
within 2–3 months.
It is important to debride necrotic tissue, so the tissue
Prognosis is poorer if signs develop very rapidly.
environment is less attractive for persistence of the
organism and toxin production.
PROLAPSED GLAND OF THE THIRD
Antibiotics with anaerobic activity especially metronida-
EYELID
zole (10 mg/kg, q 8 h), and those belonging to the peni-
cillin group, e.g. amoxicillin or amoxycillin/clavulanate
Classical signs
are indicated to prevent further proliferation of bacteria in
the wound. ● Pink to red mass protruding from behind
● Metronidazole has been shown to be superior to the third eyelid.
penicillin G and tetracycline. It is bactericidal against ● Variable inflammation and discharge.
most anaerobes and achieves effective therapeutic ● Rare and only reported in Burmese cats.
concentrations even in anaerobic tissues.