Abstract Details

To report a case of acute onset quadriparesis in a young Asian patient with hypokalemia, caused by hyperthyroidism and to identify clues pointing to the correct diagnosis of TPP.

TPP is a disorder of muscle weakness and hypokalemia associated with hyperthyroidism, more common in an Asian population. It often goes unrecognized by emergency physicians and neurologists in the United Sates. It presents more commonly in males as compared to females (20:1), typically in age 20-40 years. Weakness is often symmetric, and proximal greater than distal. Most episodes happen in early morning and can be precipitated by a high carbohydrate load or strenuous exercise.

A 22 year old Chinese student presented with acute quadriparesis upon waking up in the morning. Examination revealed intact sensation to all modalities, brisk reflexes, decreased rectal tone and weakness (Medical Research Council MRC grade 0-2/5 proximally and 2-4/5 distally). He had mild sinus tachycardia. Because of the suddenness of symptom onset, spinal cord infarction was the leading cause in the differential. MRI spine showed possible diffusion restriction in C3-5 segments, which was ultimately determined to be artifactual, although initially spinal cord infarction could not be ruled out. Serum potassium on admission was 1.8 mEq/L. The patient recovered to almost full strength the next day without any intervention and on repeat testing potassium normalized to 4.7 mEq/L spontaneously. Further lab testing showed decreased thyroid stimulating hormone, increased free thyroxine, triiodothyronine levels with increased anti thyroid anti peroxidase antibodies. Patient was treated with methimazole and atenolol and discharged home.

Clues to the correct TPP diagnosis are: Asian origin, male gender, sinus tachycardia and/or systolic hypertension, hypokalemia. Prompt diagnosis is important to prevent potentially fatal arrhythmias. Acutely, a normal sensory examination and normal/brisk reflexes can help distinguish TPP induced quadriparesis from myelopathy avoiding unnecessary and expensive testing.