Makindo Medical Notes.com

Related Subjects: |Assessing Breathlessness |Respiratory failure |Caisson Disease - Decompression sickness |Altitude sickness / Acute Mountain sickness

Caissons were structures built to allow workers to work below sea level in high-pressure constructions. Leaving them could then result in Caisson disease.

About

• Decompression sickness, Divers' disease, the Bends or Caisson disease

Aetiology

• Person goes from inhaling air under a high-pressure environment to lower pressure
• Nitrogen or Helium bubbles form in the tissues and blood vessels
• These can block vessels causing ischaemia and infarction

High to Low pressure

• Moving from Deep underwater to the surface
• Moving from sea-level to high altitude in unpressurised aircraft
• Moving from spacecraft to outside
• Deep Mine or caisson to sea-level
• Multiple events: having dived and then flying
• Cabin pressures can fail
• Diving at altitude is even worse

other factors

• The magnitude of change of pressures
• The rate of change - quicker is worse
• Duration of exposure, Dehydration, increased obesity
• PFO; makes systemic risks higher - stroke and cord injury

Prevention

• Oxygen pre-breathing reduces the nitrogen loads in body tissues
• Ascent rate < 10 metres/ minute
• Regular Decompression stops
• Using decompression tables

Clinical

• Connective tissue: joint pains, itching, formication
• Neurology: altered neurology, vision, mood, delirium, motor, seizure, coma
• Cardio-Respiratory: cough, SOB, chest pain
• Symptoms present within 48 hours of the event

Investigations

• FBC, U&E, LFTs, ABG, Lactate
• MRI: The white matter tracts of the spinal cord and brain are predominantly affected due to their high myelin content. Cord lesions are more common than brain lesions. In the spinal cord, there is a predilection for the thoracic cord segments to be affected, thought to be secondary to more nitrogen accumulating in the lateral and posterior columns where there is higher fat content and also the relatively low blood flow compared to the cervical and lumbar segments.

Management

• ABC and Immediately commence 100% Oxygen
• Give IV fluids. Analgesia.
• Hyperbaric oxygen in a recompression chamber

References