Stroke Mimic: A Case of Unilateral Thyrotoxic Hypokalemic Periodic Paralysis

Abstract

Thyrotoxic hypokalemic periodic paralysis (THPP) is a condition that results in transient skeletal muscle paralysis secondary to intracellular potassium sequestration. Susceptible individuals often have an underlying channelopathy, which may be exacerbated by lifestyle factors or underlying medical comorbidities such as hyperthyroidism or diarrheal illness. Classically, THPP presents with paralysis of proximal extremity musculature. In this case, we present a rare case of unilateral THPP. Such a presentation is relevant to emergency physicians as it mimics a stroke or transient ischemic attack and should be considered on the differential for unilateral neurologic deficits.

An unusual stroke mimic: A case report

“…In three of the case reports, the patients had sudden-onset right-sided weakness. 11 – 13 Another patient also developed sudden onset of right-sided weakness which was associated with right facial droop and dysarthria. 14 This atypical manifestation of hypokalaemic paralysis can be misdiagnosed as acute stroke especially in individuals who have comorbid cardiovascular risk factors just as our patient did.…”

“…As shown in Table 2 , one patient presenting with right-sided weakness had CT scan of the brain to exclude a stroke 12 just like in our case. One had both CT scan and CT angiography, 13 while another underwent both magnetic resonance imaging and CT scanning of the brain. 15 …”

Stroke mimics: A review

“…Some neurologic symptoms caused by many diseases such as thyrotoxic hypokalemic periodic paralysis, hepatic encephalopathy, paraneoplastic cerebellar degeneration, and transient headache, neurological deficits and lymphocytic pleocytosis in the cerebrospinal fluid can mimic stroke sometimes [105][106][107][108].…”

A Literature Review on Thyrotoxic Periodic Paralysis

“…The deep tendon reflexes in these patients can be diminished to absent. There are some case reports where patients would present acutely with monoplegia highly mimicking a stroke [19]. Cognitive and sensory functions usually remain normal.…”