Adrenal Disease in Cats

Presenter – Sarah M. A. Caney BVSc PhD DSAM(Feline) MRCVS RCVS Specialist in Feline Medicine

Last week’s veterinary webinar covering adrenal disease in the cat was one of those discussions that makes you realise there have been  a number of mystery cases you’ve encountered in practice that now seem to make a bit more sense.

The highly respected Sarah Caney led this veterinary webinar and focused her attention on three diseases of the adrenal gland which although are uncommon in the cat, are diseases we are most familiar with. These included hyperadrenocorticism (Cushing’s disease), hyperaldosteronism (Conn’s disease) and hypoadrenocorticism (Addison’s disease).

Conn’s disease was one of the conditions Dr Caney thought we may see more frequently than we realise. She asked the audience how many people thought they had seen a case of Conn’s disease. 91% said no, 2% said possibly, 5% with 1 confirmed case and 2% with 2-5 confirmed cases. According to Dr Caney, Conn’s disease is a condition that could be being under-diagnosed and we are more than likely to come across this condition at some point in our career.

Hyperaldosteronism is caused by an adrenal tumour over secreting aldosterone and most cases will present with a hypokalaemic myopathy and/or prolonged systemic hypertension. These two features do not have to be seen together, with some cases just presenting with hypertension or hypokalaemia. Hypertension is now being diagnosed frequently in our older feline patients and Dr Caney encouraged us to consider Conn’s disease as a possible underlying cause. Also we tend to think of hypokalaemic cats presenting with classic ventroflexion of the neck but Dr Caney explained that we don’t actually see this type of presentation very often. Many of these hypokalaemic cats will present only with exercise intolerance and/or shifting lameness and once again Conn’s disease should be considered when cats present with these clinical signs.

Diagnosis of Conn’s disease is made by measuring serum aldosterone which is now routinely done within specialist laboratories. An adrenalectomy is the most successful way of treating these cases but medical treatment with anti-hypertensive treatment, potassium supplementation and aldosterone antagonism using spironolactone can also be good for stabilising cases if owners are reluctant to go ahead with surgery. In Dr Caney’s experience, medically treated cases tend to remain stables for months and in some cases for up to two years.

We are likely to encounter Cushing’s disease and Addison’s disease even less frequently than Conn’s disease, but it is possible for us to see an occasional case. Our practice recently encountered a case of an unstable diabetic which went on to sustain some extensive skin tear injuries. Could this cat have been cushingoid? Dr Caney explained 80% of cushingoid cats will also be diabetic and if a cat is difficult to stabilise then Cushings should be on our list of differentials. Unfortunately the case seen in practice was euthanased for a variety of reasons but I was reassured to find out that cats suffering from fragile skin are extremely difficult to control both from a cushingoid and diabetic perspective, and euthanasia in these cases may sometimes be the kindest option.

Dr Caney went  into more detail covering each of the three afore mentioned diseases and also gave advice on what to do if you happen to find an adrenal mass when performing imaging for reasons unrelated to obvious adrenal disease. This was a very informative veterinary webinar organised by ‘The Webinar Vet’ and although we may not come across these conditions very often , the more we are aware of them the more likely we are to diagnose them and that can only be a step in the right direction.

The Stethoscope (MRCVS)