An unusual cause of hypokalaemia

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C.Y. Bruggeman, M.J. Agterof, I.M.M.J. Wakelkamp

Voorzitter(s): prof. dr. J.W. de Fijter, LUMC, Leiden & dr. W.G. Meijer, WestFries Gasthuis, Hoorn

Woensdag 22 april 2015

15:00 - 16:00u in Auditorium 1

Categorieën: parallelsessie (case reports/research)

Parallel sessie: Parallelsessie 1: Case reports/research

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Case:
A 73-year old woman was referred to the Emergency Room because of hypokalaemia (2.5 mmol/L). She had complaints of fatigue, weight loss and she was thirsty. Physical examination showed a blood pressure of 190/90 mmHg, a small buffalo hump and the liver was enlarged. Laboratory investigations showed beside the hypokalaemia, a metabolic alkalosis and increased liver function tests. Because of the combination: hypokalaemia, hypertension and buffalo hump we suspected Cushing syndrome and indeed measured increased cortisol (1833nmol/l) and ACTH (35.5 pmol/l) levels. Treatment with potassium was started.

Ultrasound and computed tomography of chest and abdomen showed liver, bone and lymph node metastasis and a hypodensity of the uterus. Liver biopsy and a cervical PAP smear showed small cell carcinoma. Chemotherapy with carboplatin/etoposide was started. Cortisol levels dropped after chemotherapy commenced and hydrocortisone suppletion was started in a normal Addison suppletion dose of 10-5-5 mg/day. We could abolish potassium treatment after the first chemotherapy cycle and the hypertension decreased rapidly.

After three cycles of chemotherapy there was a good response and the treatment was continued.

Discussion:
Cushing’s syndrome as first presentation of cervical small cell carcinoma due to ectopic adrenocorticotropin hormone production is very rare. Only two percent of cervical cancers are small cell carcinoma, most of which are not neuroendocrine active. Because of its rarity, no clinical trials have been performed. Treatment is based on experience with small cell lung cancer. The prognosis for metastatic disease is very poor. Lastly, management of cortisol levels should be part of treatment.