Endocrine Abstracts

Case History: A 76 year old woman presented to the Accident & Emergency Department with persistent hypokalaemia, hypertension and metabolic alkalosis. She complained of ongoing muscle fatigue and tiredness and denied any headaches or vision problems. On examination, she had evidence of centripetal obesity, proximal myopathy, pink striae and bruises on her abdomen. No visual field deficit on confrontation and neurological examination was normal. She had a past medical history of hypertension on Amlodipine 5 mg, Ramipril 5 mg and Doxazosin 4 mg daily. She reported two months history of hyperkalaemia managed by her general practitioner with regular potassium supplements.

Investigations: Blood tests and CT adrenal glands were requested to exclude adrenal pathology.

Results and treatment: Her potassium level was low at 2.4 mmol/l with a pH of 7.55 on venous blood gas. Early morning cortisol was elevated at 1885 nmol/l. Plasma metanephrine was normal at 21 ng/l. ACTH level was suppressed. Aldosterone to renin ratio was normal at 2 and HbA1c was 41 mmol/mol. CT adrenals with contrast demonstrated a large right adrenal mass likely to be an adrenal cortical adenocarcinoma with local infiltration into the right renal vein, IVC, right lobe of the liver with multiple lesions in the lung bases keeping in with metastatic lung deposits. She was treated with intravenous potassium replacement with cardiac monitoring and Metyrapone 500 mg twice a day. She was discussed at the local Adrenal MDT and an adrenal biopsy was recommended. Because of the risk of seeding, adrenal biopsy isn’t usually recommended but in this case it was thought that a tissue diagnosis would have potentially helped to confirm the diagnosis and guide chemotherapy. She was subsequently discharged with potassium of 3.3 mmol/l and an early morning cortisol of level 657 nmol/l. She was reviewed in the Endocrinology Clinic a week later and Metyrapone was increased to 750 mg three times a day. Adrenal biopsy confirmed adrenocortical carcinoma. She was offered palliative chemotherapy. WHO performance status was 3. Her condition deteriorated very quickly and she died after several weeks.

Conclusions and Points of Discussion: Endocrine causes of persistent hypokalaemia should always be considered when managing potassium disorders. This case highlights the importance of careful physical examination to pick up subtle clinical signs to build up a diagnosis. In the current pandemic, telephone appointments can be challenging and it is easy to misdiagnose rare conditions. In complex cases with difficult diagnoses, face-to-face appointments should be offered to patients.