title: Hypokalemic periodic paralysis in a patient with acquired growth hormone deficiency.
abstract: BACKGROUND
  Hypokalemic periodic paralysis (HypoPP) is a rare disorder consisting of sudden episodes of muscle weakness with areflexia involving all four limbs, which spontaneously resolve within several hours or days. Primary HypoPP is genetically determined, while secondary acquired HypoPP has been described in association with thyreotoxycosis, hyperaldosteronism, kidney diseases, diuretics and liquorice abuse, gastrointestinal potassium loss, or cysplatinum therapy.
  
  
  OBJECTIVE
  To report a case of HypoPP associated with GH deficiency.
  
  
  METHODS
  A 33 yr-old man with hypopituitarism and diabetes insipidus secondary to pituitary stalk-localized sarcoidosis, and documented HypoPP episodes.
  
  
  METHODS
  Neurologic exam outside HypoPP episodes was normal. Needle electromyography was normal without myotonia or other spontaneous electric activity. Muscle biopsy documented a vacuolar myopathy with tubular aggregates. However, genetic analysis ruled out common mutations of the voltage-gated calcium channel observed in primary HypoPP. Common causes of secondary HypoPP were also ruled out. The patient was diagnosed with severe GH deficiency with modest fasting hyperinsulinemia and insulin resistance and started on GH replacement therapy, an alpha-glucosidase inhibitor (acarbose) and a diet low in simple carbohydrates.
  
  
  CONCLUSIONS
  GH replacement therapy, acarbose and a diet low in simple carbohydrates resulted in the complete long-term (>2 yr) remission of HypoPP episodes. This is consistent with the hypothesis that the hyperinsulinemia associated to GH deficiency may trigger HypoPP episodes by increasing Na+/K+ ATPase activity and K+ transport into the intracellular compartment with subsequent hypokalemia.
authors.affiliation: Endocrinology Unit, Department of Internal Medicine, San Raffaele Scientific Institute and Università Vita-Salute San Raffaele, Milan, Italy. lanzi.roberto@hsr.it
authors.forename: R
authors.initials: R
authors.lastname: Lanzi
authors.forename: S C
authors.initials: SC
authors.lastname: Previtali
authors.forename: V
authors.initials: V
authors.lastname: Sansone
authors.forename: M
authors.initials: M
authors.lastname: Scavini
authors.forename: M
authors.initials: M
authors.lastname: Fortunato
authors.forename: E
authors.initials: E
authors.lastname: Gatti
authors.forename: G
authors.initials: G
authors.lastname: Meola
authors.forename: E
authors.initials: E
authors.lastname: Bosi
authors.forename: M
authors.initials: M
authors.lastname: Losa
mesh_terms: D000328:Adult; D004393:Dwarfism, Pituitary / Q000150:complications* / Q000188:drug therapy / Q000473:pathology; D020249:Hormone Replacement Therapy; D019382:Human Growth Hormone / Q000627:therapeutic use; D006801:Humans; D020514:Hypokalemic Periodic Paralysis / Q000188:drug therapy / Q000209:etiology* / Q000473:pathology; D008297:Male; D009132:Muscles / Q000473:pathology
chemical_list: D019382:Human Growth Hormone