Hypokalemic periodic paralysis: an underestimated autosomal-dominant disease with variable phenotypic presentations
Periodic paralysis (PP) diseases are autosomal dominant disorders due to gene-mutations that manifests with episodic muscle weakness and/or paralysis. Their mutations result in faulty ion-leaks that result in sustained muscle depolarization and inexcitability. The group include; hyperkalemic PP, hypokalemic PP (HypoPP type I & II), normokalemic PP, thyrotoxic PP, Paramyotonia congenita and Andersen-Tawil syndrome. The hypoPP is the most common disorder yet is underestimated in prevalence due to missed diagnosis mimicking hysterical disorders and neurological diseases as well as the hypokalemic syndromes (Bartter, Gitelman and renal tubular acidosis). Moreover, and due to their considerable gene-penetrance, their phenotypic spectrum ranges from infrequent attacks to progressive muscular failure. In this case report we present a patient with missed diagnosis for years and describe the algorithm of his diagnosis and management.
Keywords: chanellopathies, diagnosis, hypokalemia, periodic paralysis, treatment.
2- Donaldson MR, Yoon G, Fu YH, Ptacek LJ. Andersen-Tawil syndrome: a model of clinical variability, pleiotropy, and genetic heterogeneity. Ann Med. 2004; 36 Suppl 1:92-97.
3- Statland JM, Fontaine B, Hanna MG, Johnson NE, Kissel JT, Sansone VA, et al. Review of the Diagnosis and Treatment of Periodic Paralysis. Muscle Nerve. 2018; 57:522-530.
4- Francis DG, Rybalchenko V, Struyk A, Cannon SC. Leaky sodium channels from voltage sensor mutations in periodic paralysis, but not paramyotonia. Neurology. 2011; 76:1635-1641.
5- Assadi F. Diagnosis of hypokalemia: a problem-solving approach to clinical cases. Iran J Kidney Dis. 2008; 2:115-122.
6- Carty RP, Pincus MR, Sarafraz-Yazdi E. Clinical enzymology. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 23rd ed. Philadelphia, PA: Elsevier; 2017: chap 20.
7- Streib EW. AAEE minimonograph #27: Differential diagnosis of myotonic syndromes. Muscle Nerve. 1987; 10:603-615.
8- Chalissery AJ, Munteanu T, Langan Y, Brett F, Redmond J. Diverse phenotype of hypokalaemic periodic paralysis within a family. Pract Neurol. 2018; 18:60-65.
9- Matthews E, Portaro S, Ke Q, et al. Acetazolamide efficacy in hypokalemic periodic paralysis and the predictive role of genotype. Neurology. 2011; 77:1960-1964
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0). that allows others to share the work with an acknowledgment of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgment of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).