Case of Thyrotoxic Periodic Paralysis in a Caucasian Male and Review of Literature

Table 1

Differences between thyrotoxic periodic paralysis (TPP) and familial hypokalemic periodic paralysis (FHPP).

Characteristic	TPP	FHPP
Age	20–40 years	Usually less than 20 years
Heredity	Sporadic	Autosomal dominant
Ethnicity	Predominantly Asian	Predominantly Caucasians
Sex	Males more than females	Not specific
Hyperthyroidism	Present	Not present
Family history	Thyrotoxicosis	Hypokalemic paralysis
Genetic predisposition	Associated with SNPs of CACN1AS^* in Asians	CACN1AS^*, KCNE3^*, and SCN4A^* genes
Response to epinephrine	No change	Electromyography shows marked decrease in compound muscle action potential amplitude

 ^*SNPs = single nucleotide polymorphisms.
^*CACN1AS = calcium channel alpha-1 subunit.
^*KCNE3 = potassium channel voltage-gated, Isk-related family, member 3.
^*SCN4A = sodium channel alpha-subunit.