Hypokalaemic thyrotoxic periodic paralysis in the UK

Sir, I read with interest the article ‘Severe hypokalaemia in a Chinese male’ by Lin et al .1 In Western countries, most cases of hypokalaemic periodic paralysis (HPP) are due to autosomal dominant familial periodic paralysis (FPP), but in an Asian population, thyrotoxic periodic paralysis (TPP) is the most common cause.1–,5 The age of onset, race, family history, medications and underlying disease states can help in identifying the cause of HPP.6 Initial therapy of the patient with HPP includes potassium (K+) replacement and search for underlying aetiology. Further management depends on the aetiology of hypokalaemia.6 TPP is common in Asian and Hispanic individuals, and uncommon in Whites and Afro-Americans.1–5,8,,9 As patients of Oriental ethnicity are now frequently encountered in the Western world, TPP should be included in the differential diagnosis of muscle weakness in the Emergency department, in order to avoid life-threatening complications such as hypokalaemia and thyrotoxicosis, particularly in the UK with its ethnic Chinese population in the big cities. In October 2002, a 30-year old Vietnamese man of Chinese parentage presented to the Emergency department in the early hours of the morning complaining of sudden generalized weakness in all four limbs. The previous day he started work in his ‘take-away’ restaurant at around 11 am and had worked until 8 pm. He then had a substantial meal of carbohydrate-rich food and went to bed at around midnight. He had no significant past or …