SUN-312 - Clinical Characteristics, Precipitating Factors, and Predictors of Severe Paralytic Attacks in Filipino Patients With Hypokalemic Periodic Paralysis: A 10-Year Retrospective Cohort Study

Hypokalemic periodic paralysis (HPP) is a reversible yet potentially life-threatening cause of acute flaccid paralysis due to primary or secondary etiologies such as thyrotoxicosis. Despite the higher incidence of thyrotoxic periodic paralysis (TPP) in Asian populations, contemporary Philippine data remain limited. This study aimed to describe the clinical profile, and outcomes of Filipino patients with HPP; compare thyroid-related and non–thyroid-related cases; and identify predictors of severe attacks in TPP.

We performed a 10-year retrospective cohort study of adult Filipino patients with HPP admitted to a tertiary center in Metro Manila from 2015 to 2025. Clinical, biochemical, management, and outcome data were reviewed. Cases were classified as non-thyrotoxic (idiopathic or secondary causes) or thyrotoxic (biochemical evidence of overt or subclinical hyperthyroidism). Severe paralysis was defined as an MRC score ≤2 in at least one extremity. Multivariate logistic regression was used to identify predictors of severity.

Among 205 patients (mean age 33.3±9.6 years; 75.6% male), most had non-thyrotoxic HPP (71.2%), predominantly idiopathic (60.5%). TPP was the most common secondary cause (28.8%). Majority of the cases had no identifiable triggers (50-60%), but high carbohydrate intake, acute illness, and strenuous activity preceded 8-14% of cases. Compared with non-TPP, patients with TPP were more often male, smokers, and had a family history of HPP. They also presented with more severe hypokalemia (2.2±0.5 vs 2.4±0.4 mmol/L, p=0.027). Graves’ disease accounted for 81.1% of TPP cases. Notably, 91% of newly diagnosed TPP patients had no overt hyperthyroid symptoms, with some showing only biochemical or subclinical thyrotoxicosis. Severe paralysis occurred in 55% of cases. In TPP, lower serum potassium (adjusted OR 0.22, p=0.032) and newly diagnosed hyperthyroidism (adjusted OR 5.17, p=0.017) independently predicted severity. Recovery was rapid with potassium replacement, and recurrence was uncommon, occurring mainly in patients with poor adherence.

In this largest cohort of Filipino patients with HPP, non-thyrotoxic HPP predominated, while TPP remained the leading secondary cause. TPP often presents as “silent” thyrotoxicosis, with paralysis as the initial manifestation. Attack severity appears driven by the degree of hypokalemia and newly diagnosed thyrotoxicosis rather than absolute thyroid hormone levels. Routine thyroid evaluation in all HPP cases is essential to ensure timely diagnosis and appropriate management.

*Unless otherwise noted, all abstracts presented at ENDO must not be released to the press or the public until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.*