Case Story: Hyperthyroidism and cardiac disease in cats
Bobbi is a 15-year-old female neutered tortoiseshell cat that was brought in for a check-up as her owner was worried that she had been losing weight for the last couple of months despite eating more.
Bobbi’s owner also noted that that she was drinking more water and was more vocal at home. She was otherwise very happy, playful and did not have any vomiting or diarrhoea. However, Bobbi’s owner was particularly worried on the morning of her consultation because they noted that her respiratory rate and effort were slightly increased.
During Bobbi’s consultation it was noted that she was breathing faster and with more increased effort than normal. On cardiac auscultation a heart murmur was detected. Bobbi was also underweight. Any breathing difficulty in an animal is always considered a serious emergency, so Bobbi’s heart and lungs were immediately scanned with an ultrasound. The ultrasound sadly showed that Bobbi had advanced cardiac disease and was in heart failure, which was resulting in a build-up of fluid inside her lungs (pulmonary oedema) and surrounding her lungs (pleural effusion) – both of which meant that she was struggling to breathe appropriately.
Bobbi’s owners consented to further treatment and stabilization but were aware that she was very poorly and unstable but that we would do our best to help her breathing improve. Bobbi was sedated and 250ml of fluid were drained from the space surrounding her lungs (pleural space) and she was given a diuretic intravenously to help with the drainage of the fluid inside her lungs. After the procedure Bobbi´s breathing markedly improved and her respiratory rate and effort went back to normal.
Geriatric cats are unfortunately prone to developing cardiac disease which can, though not in all cases, progress to cardiac failure. The most common cardiac disease in cats is hypertrophic cardiomyopathy (HCM). This condition has a strong genetic component. However, some cats will develop cardiac disease secondary to other diseases such as hyperthyroidism, acromegaly or hypertension. Bobbi’s thyroid levels were tested as she was showing multiple signs consistent with hyperthyroidism- weight loss despite a ravenous appetite, increased vocalization and activity levels, increased thirst and urination. Her thyroid levels came back very elevated. We also tested her kidney parameters, electrolytes and liver values to make sure that she had no other concurrent diseases that could be contributing to her weight loss and to further determine if it was safe to start her on long-term diuretics to manage her cardiac disease. All these additional blood tests came back normal.
Bobbi was sent home later that evening with oral treatment for her hyperthyroidism. Sadly, heart failure in cats is irreversible and can only be managed symptomatically by ensuring their lungs do not fill with fluid and they are able to breathe properly. With this in mind, Bobbi was sent home with oral diuretics to help with her breathing. Cats in heart failure are also prone to throwing clots, so she was also sent home with a blood thinner to reduce the probability of unwanted clot formation.
Bobbi was seen back monthly for the next 3-4 months to re-check her thyroid levels, kidney function and lungs. So far, she is responding very well to all the treatment given. Her weight is back to normal, she is able to breathe comfortably at home (she is even playing with her other cat siblings) and has an excellent quality of life. Cats in heart failure do have a shorter life expectancy than cats with normal cardiac function. However, their symptoms can sometimes successfully be managed with medical therapy and can have an excellent quality of life for their remaining lifespan. Bobbi is currently living her best life and enjoying all the extra treats she gets to ensure she takes her daily medications!
