Thyrotoxic periodic paralysis in the Chinese population: clinical features in 45 cases

Thyrotoxic periodic paralysis (TPP) occurs predominantly in Asian males, but there are few reports about TPP in the mainland of the People's Republic of China. The purpose of this study was to report the clinical features of cases of TPP in mainland China.

Forty-five cases of TPP, admitted to Zhongnan Hospital of Wuhan University during a 5-year period, were retrospectively reviewed.

Patients typically presented with acute paralysis of the limbs, almost half (48.6%) initiated with legs, while the rest (51.4%) with both arms and legs. Twenty of 45 patients (44.4%) who had been diagnosed with hyperthyroidism suffered sudden attacks, while the remaining 25 patients were newly diagnosed with TPP. 16 patients had low potassium serum concentrations (1.44-3.00 mmol/L). There was a correlation between the lowest muscle strengths of the proximal and distal legs and serum potassium concentrations (Spearman correlation, r=0.556, P=0.049).

TPP is not an uncommon disease in mainland China. Thyrotoxic patients need to improve medication compliance and follow-up. At the time of the TPP attack, a detailed interview and inquiry with a thorough physical examination usually provide clues to the diagnosis. Leg muscle strength evaluation may be useful to assess the severity of hypokalemia.