Senility in cats is a relatively common neurological disease characterised by unusual behaviour with no definable cause, that may be repetitive or untoward. Unlike humans, cats do not show the normal degenerative brain changes seen in the brain, and senility usually has a metabolic cause.
These causes include:
- - Restlessness associated with azotemia, due to chronic renal disease
- - Restlessness associated with elevated metabolic rate due to hyperthyroidism
- - Ischaemic encephalopathy - infarcts, vascular spasms, aortic thromboembolism due to cardiomyopathy
- - Cerebrovascular accidents
- - Congenital anomalies, e.g. hydrocephalus
- - Hepatic encephalopathy
- - Hypoglycaemia - insulin overdose, insulinoma, sepsis, terminal hepatitis
- - Hypocalcaemia
- - Brain tumours
- - Thiamine deficiency
- - Non-suppurative meningoencephalomyelitis
- - FIP
- - Toxoplasma gondii
- - Cryptococcus neoformans
- - Toxins - including pyrethrins, OPs, strychnine, lead, acetaminophen (Panadol), aspirin
- - Cuterebra infection (USA)
- - Epilepsy
- - FIV encephalopathy
Most cats with seizures, compulsive circling or changed behaviour from neurological disease have a forebrain (thalamocortex) lesion.
Seizures are most often associated with tumours, encephalitides and inactive lesions (e.g. glial scar), while extracranial causes (metabolic and toxic) and idiopathic epilepsy are rare.
Compulsive circling is caused by any kind of lesion located in the frontal lobe or rostral thalamus, although trauma, tumours and ischaemic encephalopathy are the most common causes. Circling is usually toward the side of the lesion.
Changed or abnormal behaviour usually consists of subtle personality changes, and is most often associated with tumours, head trauma, ischaemic encephalopathy, congenital and inherited forebrain anomalies, hepatic encephalopathy, FIP, and FIV-encephalopathy.