title: Short-term severe thyroid hormone deficiency does not influence sleep parameters.
abstract: OBJECTIVE
  The influence of short-term severe thyroid hormone deficiency on sleep is currently still unknown. Several studies have demonstrated an effect of long-term hypothyroidism on sleep disorders due to anatomical changes of the pharynx or body mass. The aim of this preliminary study, however, is to evaluate the changes in sleep patterns of patients with short-term hypothyroidism to elucidate the isolated effect of thyroid hormone withdrawal before anatomical changes can potentially occur.
  
  
  METHODS
  Ten patients with differentiated thyroid carcinoma were enrolled in this study. Two patients discontinued the study and one patient was finally excluded due to obesity, so that the datasets of seven patients were available for study analysis. During the course of carcinoma treatment, each patient had previously undergone total thyroidectomy and I-131 remnant ablation. Polysomnographic measurements were performed twice: (1) over the course of two consecutive nights during severe thyroid hormone deficiency after levothyroxine withdrawal and prior to further diagnostics and therapy and (2) during euthyroidism after substitution with levothyroxine.
  
  
  RESULTS
  Comparison of the Epworth Sleepiness Scale during hypo- and euthyroidism for each patient revealed no statistically significant difference. Furthermore, the comparison of polysomnographic parameters like (1) apnea-hypopnea index, (2) the duration of various sleep stages, (3) duration of rapid eye movement sleep, (4) latency until rapid eye movement sleep, (5) total sleep time, (6) periodic leg movements, and (7) arousal index showed no statistically significant differences between the hypothyroid or euthyroid state.
  
  
  CONCLUSIONS
  We conclude that, in this preliminary experimental setting, short-term severe thyroid hormone deficiency per se does not cause sleep disturbances and a feeling of fatigue as described in other studies may be due to changes in perception or brain metabolism during hypothyroidism.
authors.affiliation: Department of Oto-Rhino-Laryngology, University of Wuerzburg, Wuerzburg, Germany. Koehler_C@klinik.uni-wuerzburg.de
authors.forename: C
authors.initials: C
authors.lastname: Koehler
authors.forename: C
authors.initials: C
authors.lastname: Ginzkey
authors.forename: N H
authors.initials: NH
authors.lastname: Kleinsasser
authors.forename: R
authors.initials: R
authors.lastname: Hagen
authors.forename: C
authors.initials: C
authors.lastname: Reiners
authors.forename: F A
authors.initials: FA
authors.lastname: Verburg
mesh_terms: D000328:Adult; D000368:Aged; D001143:Arousal / Q000502:physiology; D006970:Disorders of Excessive Somnolence / Q000188:drug therapy / Q000503:physiopathology; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy / Q000503:physiopathology*; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011183:Postoperative Complications / Q000188:drug therapy / Q000503:physiopathology*; D020181:Sleep Apnea, Obstructive / Q000188:drug therapy / Q000503:physiopathology*; D012894:Sleep Stages / Q000502:physiology*; D011795:Surveys and Questionnaires; D013964:Thyroid Neoplasms / Q000532:radiotherapy* / Q000601:surgery*; D013965:Thyroidectomy; D013974:Thyroxine / Q000627:therapeutic use
chemical_list: D007457:Iodine Radioisotopes; D013974:Thyroxine