Endocrine Abstracts

Section 1: Case history: A 53 year old male of Chinese ethnicity presented to hospital with a fall and a long lie. He had a heavy meal for dinner, and he fell later in the evening after standing from the sofa. He lacked strength in his limbs and could not stand up again. He was on the floor for 7 hours before he could shuffle his way to the phone and call for help. On examination he had MRC grade. power in the proximal arms and MRC grade. hip. flexion. Sensation was normal. He was tachycardic with a heart rate of 130bpm. There were no signs of thyroid eye disease or palpable goitre. He had lost approximately 6 kg of weight unintentionally over the last 3 months. There was no family history of periodic paralysis.

Section 2: Investigations: Blood tests showed a low potassium level of 2.5 mmol/l, an elevated serum thyroxine level of >100 pmol/l, a low serum TSH of <0.01 mu/l. Sodium, magnesium and calcium levels were normal. Serum thyroid peroxidase antibodies were elevated at 138.0 iu/ml and his thyroid receptor antibodies were also elevated 9.4 iu/l. ECG confirmed atrial fibrillation with rapid ventricular response at 130 bpm.

Section 3: Results and treatment: The patient was hospitalised for further treatment and monitoring. He was initially given intravenous and subsequently given oral potassium supplementation. His potassium level improved from 2.5 mmol/l to 4.9 mmol/l within 6 hours. He was also started on propranolol MR 80 mg twice a day for symptomatic relief from thyrotoxicosis and started on 40 mg once a day of carbimazole. His weakness improved with potassium replacement and he was discharged from hospital after 2 days of inpatient care. His thyrotoxicosis is responding to carbimazole therapy and he is being considered for radioiodine treatment.

Section 4: Conclusions and points for discussion: His presentation and investigations were consistent with a first presentation of Graves’ Disease and concurrent hypokalaemic periodic paralysis. Concurrent hypokalaemia and weakness should trigger a clinician to assess a patient’s thyroid status. These patients should be admitted for monitoring of arrhythmias, potassium levels and muscle weakness recovery. Heavy meals are also recognised to trigger thyrotoxic periodic paralysis. The prevalence of thyrotoxic periodic paralysis is up to 10 times higher in people of Chinese descent compared to people of European descent. The prevalence is estimated to be 2% in Chinese people with thyrotoxicosis.