The Acromegalic Imposter: a common missed diagnosis

There has been a lot of buzz online about a human diabetes paper suggesting diabetes may be more complex than historically thought. A paper in The Lancet: Diabetes and Endocrinology early this year suggests there may be as many as 5 types of diabetes in humans; instead of 2. This reminded me of a paper I had read in PLoS One regarding feline diabetes induced by hypersomatotropism.

Hypersomatotropism (HS) is an excess in production of growth hormone (GH) from the pituitary gland. Usually as a result of a benign tumour in the pars distalis of this gland. Acromegaly is the name of the resulting condition.

1 in 4 cases of diabetes mellitus in domestic cats are caused by excess secretion of pituitary growth hormone.

 Example of a cat before and after onset of HS-induced changes  (PLoS One)

Example of a cat before and after onset of HS-induced changes (PLoS One)

 A  cat with confirmed acromegaly demonstrating prognathia inferior (PLoS One)

A  cat with confirmed acromegaly demonstrating prognathia inferior (PLoS One)

Diabetes is thought to occur in as many as  1 in 200 cats in the UK. In this PLoS One paper, conducted over 9 years, 1221 diabetic cats were screened for acromegaly with 1 in 4 being diagnosed with this disease. An important note is that only a quarter of referring clinicians suspected acromegaly in diabetic cats they submitted to this study. Suggesting acromegaly is both common and misdiagnosed in feline patients as primary (type 2) diabetes mellitus.

 Cranial abdominal organomegaly in a acromegalic diabetic cat (PLoS One)

Cranial abdominal organomegaly in a acromegalic diabetic cat (PLoS One)

Good glycemic control is more difficult to achieve in acromegalic diabetics. Therefore an early diagnosis is critical for achieving better outcomes in diabetic patients. Features to be aware of include a broadened wide face, enlarged feet, protrusion of the mandible, organomegaly and cardiovascular abnormalities. Serum IGF-1 is a useful test to help diagnose acromegaly.

 

References:

Niessen, S. J., Forcada, Y., Mantis, P., Lamb, C. R., Harrington, N., Fowkes, R., … Church, D. B. (2015). Studying cat (Felis catus) diabetes: beware of the acromegalic imposter. PLoS ONE, 10, e0127794.