The Critical Care Phenotype of Hypokalemic Paralysis: Etiology, Outcomes, and Predictors of Respiratory Failure in a Retrospective Cohort Study

TL;DR

This study examines a severe form of hypokalemic paralysis in ICU patients, finding that respiratory failure risk isn't linked to potassium levels and requires close monitoring.

Contribution

The paper identifies a distinct ICU phenotype of hypokalemic paralysis with respiratory failure not predicted by potassium levels.

Findings

41.7% of patients required mechanical ventilation, defining a severe critical care phenotype.

The need for mechanical ventilation was not associated with the degree of hypokalemia or baseline characteristics.

Most patients achieved full neurological recovery with potassium supplementation and targeted therapy.

Abstract

Background: Hypokalemic periodic paralysis (HPP) presenting as acute quadriparesis is a neuromuscular emergency. While its etiology is described in general wards, its severe "critical care phenotype" in the intensive care unit (ICU) remains poorly characterized. We aimed to define this phenotype by analyzing the clinical profile, etiological spectrum, and predictors of life-threatening severity.

Methods: A retrospective study was conducted of 12 patients (nine male, three female; median age: 31.5 years) admitted to a tertiary ICU (2015-2021) with acute quadriparesis and hypokalemia (median potassium: 1.75 mmol/L). We analyzed management and
outcomes and compared patients requiring mechanical ventilation (MV+) with those who did not (MV−) using distribution-appropriate
statistical methods to identify factors associated with respiratory failure.

Results: All patients presented with acute flaccid quadriparesis and areflexia. Five (41.7%) required invasive mechanical ventilation, defining a severe "critical care phenotype." A secondary cause was identified in eight patients (66.7%), including thyrotoxicosis (n=2), distal renal tubular acidosis (n=2), primary hyperaldosteronism, sepsis, dengue fever, and gastroenteritis. Critically, the need for mechanical ventilation was not associated with the degree of hypokalemia (MV+ 1.7 mmol/L vs. MV- 1.7 mmol/L, p=0.87) or other baseline characteristics. With potassium supplementation and targeted therapy, 11 patients (91.7%) achieved complete neurological recovery; one death occurred in a patient with sepsis.

Conclusion: HPP in the ICU represents a distinct critical care phenotype with a high risk of respiratory failure. As the requirement for
mechanical ventilation was not predicted by admission potassium levels, vigilant monitoring for respiratory muscle fatigue is warranted in all cases. Favorable outcomes are achievable with prompt correction and treatment of the underlying cause, reinforcing that HPP is a reversible ICU emergency.