Hypokalemic periodic paralysis and renal tubular acidosis in a patient with hypothyroid and autoimmune disease.

BACKGROUND

Hypokalemic periodic paralysis (HPP) is a rare muscle disorder characterized by episodic muscle weakness that can lead to respiratory failure. This disorder is a common manifestation of renal tubular acidosis. Renal tubular acidosis can occur associated with various systemic disorders such as Sjogren's syndrome and thyroid disorders.

CASE PRESENTATION: A 58-year-old woman complained of weakness in all extremities. In the last 3 years, the patient was diagnosed with hypothyroidism and got recurrent hypokalemia without vomiting or diarrhea. The examination showed blood pressure of 110/70 mmHg, pulse rate of 98 ×/m, temperature of 36.8 °C, and respiratory rate of 20 ×/m. Motor strength 2 in all four extremities. The ECG examination showed 1st degree AV block. Laboratory examination found hypokalemia, metabolic acidosis with a normal anion gap of 13.8 meq/L, urine pH 8.0, urine anion gap 41 mmol/h. FT4 1.89 ng/dL, TSH 1.21 IU/mL. Anti TPO 20.6 IU/mL, ANA profile: strong positive SS-A (Ro), Ro-52, SS-B (La) which indicates Sjogren's syndrome.

DISCUSSION: HPP is a rare case so the accuracy of diagnosis increases the success of treatment.

CONCLUSION

The patient was diagnosed with HPP and renal tubular acidosis based on hypokalemia, metabolic acidosis, alkaline urine, and positive urine anion gap.