Page 844 - Problem-Based Feline Medicine

836 PART 10 CAT WITH SIGNS OF NEUROLOGICAL DISEASE

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● Congenital pendular nystagmus (p 848)
Nystagmus is due to a congenital defect in the visual pathways observed mainly in Siamese and
Himalayan cats. Nystagmus persists for life and is oscillatory in character.

NEOPLASTIC
● Neoplasia (p 845)
Chronic and progressive onset of a head tilt. The head tilt may be associated with facial nerve
paralysis, decreased lacrimation and/or Horner’s syndrome if the tumor is invading the tympanic
bulla (squamous cell carcinoma is the most common tumor of the middle ear), or with somno-
lence, +/− ipsilateral proprioceptive deficits, +/− trigeminal and facial nerve deficits may occur if
the tumor is intracranial at the level of the brainstem.

NUTRITIONAL
● Thiamine deficiency (p 848)
Acute onset of bilateral central vestibular signs (lethargy, pupillary dilatation, poor to absent physi-
ological nystagmus, reluctance to move, and side-to-side exaggerated head movements), in cats fed
a fish-based diet containing thiaminase or pet mince containing the preservative sulfur dioxide.
Signs may also occur following a period of anorexia. A characteristic posture with ventro-flexion
of the neck is present.

INFLAMMATORY (INFECTIOUS)
● Otitis media-interna (p 840)
Ipsilateral head tilt, with or without nystagmus, and with varying degrees of ataxia. Unilateral
deafness may result. Neurological structures in the middle ear may also be affected leading to an
ipsilateral facial paresis/paralysis, decreased lacrimation and/or a Horner’s syndrome. Signs may
appear 48–72 hours after an ear flush. Very rarely extension of the infection to the central nervous
system occurs.

● Feline infectious peritonitis (FIP) (p 844)
History of chronic illness (fever, inappetence, weight loss, lethargy) that has been unresponsive to
antibiotics. Ocular lesions may be present. The neurological disease is variable and depends on the
location and extent of the central nervous system lesion. Seizures, changed behavior and head
tremor are common. If head tilt is present it is always associated with somnolence, with or without
cerebellar signs.
● Cryptococcosis (p 847)
Head tilt and altered mental status are associated with systemic manifestations such as anorexia,
upper respiratory tract disease or skin disease. Chorioretinitis and optic neuritis often observed.
The neurological disease is variable and depends on the location and extent of the central nervous
system lesion.

INFLAMMATORY (NON-INFECTIOUS)
● Middle ear polyps (p 842)
Chronic, progressive onset of a head tilt, facial paresis/paralysis, decreased lacrimation, Horner’s
syndrome and unilateral deafness. Polyps can occur bilaterally. Upper respiratory signs may be
present. A mass may be visualized in the external ear canal or the oropharynx.