Prevalence of patent foramen ovale (PFO) and MRI-lesions in mild neurological decompression sickness (type B-DCS/AGE)

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Closure of a Patent Foramen Ovale (PFO): An Intervention Sequence
10:52

Closure of a Patent Foramen Ovale (PFO): An Intervention Sequence

Published on: December 23, 2022

A E Koch1, H Kirsch, M Reuter

  • 1German Naval Medical Institute, Kiel-Kronshagen, Germany.

Undersea & Hyperbaric Medicine : Journal of the Undersea and Hyperbaric Medical Society, Inc
|July 16, 2008
PubMed
Abstract

Insights

Type B neurological decompression sickness (DCS/AGE) and patent foramen ovale (PFO) prevalence were similar in patients and controls. This suggests different underlying causes for Type A and Type B DCS/AGE, with Type B potentially not being embolic.

Area of Science:

  • Neurology
  • Diving Medicine
  • Cardiology

Background:

  • Neurological decompression sickness (DCS/AGE) presents in two types: Type A with severe central nervous system symptoms and Type B with milder symptoms.
  • Type A DCS/AGE is often linked to patent foramen ovale (PFO), suggesting an embolic origin.
  • The pathophysiology of Type B DCS/AGE may differ, potentially involving micro-embolic or non-embolic mechanisms.

Purpose of the Study:

  • To investigate the prevalence of PFO and brain lesions in patients with Type B DCS/AGE compared to matched controls.
  • To explore potential differences in pathophysiology between Type A and Type B DCS/AGE.

Main Methods:

  • 18 patients with Type B DCS/AGE underwent echocardiography and transcranial ultrasound with echo-contrast to assess PFO.
  • Cranial MRI was used to visualize Type A-brain lesions (ACFs) as potential sequelae of gas-embolic events.
  • Patients were compared with matched controls.

Main Results:

  • PFO prevalence was similar in Type B DCS/AGE patients (5/18) and controls (7/18), aligning with general population PFO rates (p = 0.725).
  • The number of MRI-identified brain lesions (ACFs) was comparable between Type B DCS/AGE cases (15 ACFs in 5 patients) and controls (37 ACFs in 8 divers).

Conclusions:

  • Findings suggest that indirect evidence of embolic brain injuries occurs with similar frequency in Type B DCS/AGE patients and controls.
  • This contrasts with findings in Type A DCS/AGE, supporting distinct pathophysiological mechanisms for Type A and Type B DCS/AGE.

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