title: Susceptibility of the inner ear structure to shunt-related decompression sickness.
abstract: BACKGROUND
  Decompression sickness (DCS) is caused by formation and growth of bubbles from excess dissolved gas in body tissues following reduction in ambient pressure. Inner ear decompression sickness (IEDCS) is a complex disorder involving the vestibulo-cochlear apparatus whose pathophysiology remains incompletely understood.
  
  
  METHODS
  The records of 662 consecutive DCS cases treated over a 7-yr period at 2 UK hyperbaric units were examined for symptoms suggesting IEDCS (nausea, vomiting, dizziness, and hearing loss arising within 2 h of surfacing). For IEDCS cases, demographics, dive, treatment, and outcome data were extracted with particular attention to the outcome of testing for a right-to-left shunt.
  
  
  RESULTS
  Included were 31 men and 2 women with a mean age of 46 yr (range 31-61 yr). Of these, 16 patients had isolated IEDCS and 17 patients had associated symptoms ranging from joint pain to tingling and numbness. The depth of the dive leading to the incident ranged from 49-256 ft (15-78 m). As primary treatment, 21 patients received a U.S. Navy Treatment Table 6 (USN TT6) and 11 patients received a Comex 30. No difference in the speed of recovery or number of treatments needed was seen between the two tables. All patients were advised to have a right to left shunt (RLS) check, but only 30 complied with that, with 24 (80%) testing RLS positive.
  
  
  CONCLUSIONS
  Our retrospective study confirms the correlation between IEDCS and the presence of a significant patent foramen ovale (PFO). In our series 48% of patients had an isolated IEDCS. IEDCS responds slowly to treatment irrespective of the initial table used. Recovery is thought to be mainly a central compensation process.
authors: London Hyperbaric and Wound Healing Centre, Whipps Cross University Hospital, London, UK. mihaela.ignatescu@ddrc.org
authors: Mihaela
authors: M
authors: Ignatescu
authors: Philip
authors: P
authors: Bryson
authors: Christoph
authors: C
authors: Klingmann
mesh_terms: D000328:Adult; D003665:Decompression Sickness / Q000150:complications* / Q000503:physiopathology* / Q000628:therapy; D007758:Ear, Inner / Q000293:injuries*; D005260:Female; D054092:Foramen Ovale, Patent / Q000150:complications*; D006801:Humans; D006931:Hyperbaric Oxygenation; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018709:Statistics, Nonparametric