Fits, Seizures, or "Funny Turns" - Tests That Might Help

Fits (seizures) or "funny turns" (so-called absences) can be due to many causes. Broadly these are grouped into metabolic problems such as liver and kidney disease, hypoglycaemia (reduced blood sugar concentration), hypocalcaemia (reduced blood calcium concentration) or diseases directly involving the central nervous system (CNS). These can include inflammation, infection, or tumours (cancer) in the brain or spine.

Toxins, trauma and generalised infections may also result in seizure activity. Sometimes seizures may be of unknown cause. This is known as idiopathic and sometimes may be hereditary (idiopathic epilepsy).

How do we attempt to find the cause of the problem?

As with any veterinary problem a thorough history and physical examination is the first step. These may point to the underlying cause. For example a puppy that is the "runt of the litter" (i.e. much smaller than its litter mates), and who shows convulsive or decreased activity after eating, may have a congenital liver problem such as a portosystemic shunt. On the other hand, a bitch with a large litter of puppies that starts convulsing may be suffering from calcium deficiency (hypocalcaemia). The dog that is known to scavenge can suddenly start seizuring as a result of ingestion of toxin etc, etc.

During the clinical examination samples of blood, urine and sometimes faeces are obtained.

What are these samples used for?

The blood sample can be used to provide a complete blood count (CBC). This gives an evaluation of red blood cells, white blood cells and the platelet components of the blood. If for example, the total white cell count (WBC) is raised, this may be an indication of an inflammatory or infectious problem affecting the central nervous system (CNS). If the platelet count is low, this may be associated with bleeding episodes which, if they occur in the brain, can be responsible for seizures.

The serum (liquid part of the blood) will provide serum biochemistry results. These provide us with an indication of the state of the liver and kidneys, which if not functioning correctly, could be responsible for the seizures. In addition, serum biochemistry will indicate levels of blood glucose and calcium. Either of these, if low, could be responsible for the seizures.

Urine analysis is useful when interpreted in relation to the serum biochemistry results particularly if we are concerned regarding possible kidney related problems being responsible for the fits.

Are there other tests that may be necessary?

Once CBC and serum biochemistry results have been obtained, it may be necessary to undertake more specific tests. For example in the case of suspected liver problems (e.g. portosystemic shunts), tests to measure serum bile acids may be necessary. If WBCs are raised, this may indicate a possible infectious cause and specific tests to establish causative organisms may be necessary, including feline leukaemia virus (FeLV) feline immunodeficiency virus (FIV) toxoplasmosis etc. 

The malfunction of the adrenal glands is sometimes a cause of seizures. An ACTH stimulation test may be performed to confirm hypoadrenocorticism (Addison's disease). Conversely if the screening tests do not point to any specific metabolic, infectious or inflammatory cause it may be necessary to undertake further testing including cerebrospinal fluid (CSF) analysis. 

Alternatively it may be considered necessary to refer the pet to a specialised centre for imaging studies using computer tomography (CT) or magnetic resonance imaging (MRI) to investigate whether underlying tumours or congenital problems may be present in the brain or spinal cord.