TPP may be an underrecognized cause of paralysis in young Hispanic men

Thyrotoxic periodic paralysis (TPP), a rare neurological condition causing limbs to go limp, may be an underrecognized cause of paralysis in young Hispanic men, a review of data by UT Southwestern Medical Center endocrinologists shows.

The rare paralysis disorder is found primarily in East Asian men. But a 16-year review of cases in Dallas through a hyperthyroidism registry identified 33 patients with TPP, making this the largest known cohort with the disorder in the U.S. to date. Of those identified, 85% percent were Hispanic males.

Our hope is that our research will raise awareness among clinicians about TPP so that it can be more effectively diagnosed and treated. Furthermore, we hope that our work will help future researchers investigate the underlying genetic and molecular causes of TPP and understand better why it is more common in some ethnic groups than others."

Iram Hussain, M.D., Member of UTSW's Harold C. Simmons Comprehensive Cancer Center and Assistant Professor of Internal Medicine in the Division of Endocrinology

UTSW is ranked 18th among the nation's top hospitals for diabetes and endocrinology care by U.S. News and World Report.

TPP is characterized by excessive levels of thyroid hormones circulating in the body, low potassium levels, and flaccid paralysis. Given the disorder's historic prevalence in the Asian population, however, it is often not considered when diagnosing non-Asian patients who arrive at the hospital emergency department with paralysis.

Researchers reviewed medical records of patients diagnosed with hyperthyroidism and periodic or transient paralysis between January 2006 and February 2022 at Parkland Memorial Hospital and William P. Clements Jr. University Hospital. Of the 33 patients with TPP, all were male with a median age of 28. Although hyperthyroidism is more common in women, TPP occurs more often in men.

The study, published in The Journal of Emergency Medicine, also offers insights into managing TPP. Paralysis associated with TPP is reversible with medication and is thought to be caused in part by genetic predisposition. One frequently reported complication in treating TPP is the administration of too much potassium. Through their analysis, UTSW researchers offer insights on the ideal potassium dosage for avoiding hyperkalemia.

"We believe that as the U.S. grows more diverse, clinicians need to be aware of the evolving understanding of the epidemiology and treatment of this rare disorder," Dr. Hussain said.

The hyperthyroidism registry, which includes data from Parkland, was created by Dr. Hussain and Marconi Abreu, M.D., Associate Professor of Internal Medicine at UTSW and Medical Director of the Parkland General Endocrinology Clinic. Dr. Abreu was not involved in the study.

Other UTSW researchers who contributed to the study are Andrew Gulde, M.D., a third-year Internal Medicine resident, and Shuyao Zhang, M.D., an Endocrinology fellow.