Diagnosing Decompression Illness

A 49-year-old female certified recreational scuba diver called the DAN Emergency Hotline from George Town, Grand Cayman, around noon on a February day.

She was experi- encing a sudden, intense and sharp abdominal and back pain that had started 12 hours after her last dive the previous day. That dive had been the thirdon a single-day series of mild, recreational, repetitive scuba dives on air with no manda- tory decompression stops. She had had proper safety stops with the first two dives and maintained adequate surface intervals between all three dives.

Her dives had been uneventful until the last one when she ran out of air after being at 10 metres for approximately30 minutes. She had not been paying close attention to her air gauge and had to perform an emergency controlled ascent to the surface. Her buddy was too far away, so she ascended without assistance. The diver had likely started the dive with a half-empty cylinder by mistake.

No symptoms

She denied having any other symptoms, including skin discolouration, limb or joint pain, or any perceivable neurological deficit. She had no relevant past medical history, hypertension or other cardio- logical or vascular diseases.

Regarding the sudden onset of a severe pain 12 hours post dive, and a relatively long stay at a shallow depth before the last ascent, the diagnosis of decompression illness (DCI) was not the first choice, although it couldn’t be excluded. With limited information available, the acute abdomen and possible acute cardiac condition (heart attack) had to be excluded.

The acute pain in the abdomen could be caused by the following:

• An abdominal aortic aneurysm, which is an abnormal and dangerous dilatation of the main artery that takes blood to the entire lower half of the body and puts the person at risk of fatal internal bleeding if this artery ruptures
  
• A gynaecological or urinary event such as a miscarriage or a severe urinary infection
  

The DAN medic who took the call explained the possibility of DCI as well as the other conditions.

The general recommendations for this diver were to seek further care at the closest hospital emergency room, and to hydrate and get oxygen in the meantime.

Diagnosis?

At the local hospital she received an initial assess- ment, laboratory tests and a physical examination, with particular attention to neuro- logical function. We do not know the extent of her abdom- inal examination. She had no positive findings except for the nonspecific abdominal pain. While not producing any new conclusive information, the examination and test results led the medical team to a clinical diagnosis of possible DCI. The hospital staff quickly moved her to the hospital’s hyperbaric chamber to start immediate treatment with a US Navy Treatment Table 6 recompression protocol.

Her pain lessened during the chamber treatment but worsened immediately after- ward. The hospital team reassessed the diver and found an abdominal rigidity upon palpation; imaging showed an intestinal obstruction.

Surgery

The diver had surgery to remove the small damaged part of her intestine. She recovered well and returned home a few days later. She had no significant repercussions that interfered with her general health or her return to scuba diving after an extended recovery period.

In most cases, DCI has no specific and exclusive symptom and can be a diagnosis of exclusion. We first must rule out all other possible causes, especially serious conditions that need other immediate intervention, before deciding to treat the diver with recompression in a hyperbaric chamber. The findings of a serious medical condition will change from its initial presentation, and symptoms and clinical conditions can change in a matter of hours, demanding a reassessment of the possible diagnoses and recommended treatments.

Head to hospital first

That’s why, in the event of a suspected dive accident, divers should always go to the nearest medical facility and not directly to a hyperbaric chamber.Divers and hospital staff should keep in mind that divers can have other health problems not directly related to diving, as this case illustrates.

The examination should be directed with usual clinical leads like symptoms, signs, and previous medical history. In the case of abdominal pain, an acute abdomen should always be excluded. This diver could have experienced this same obstruction and pain while hiking in the woods or working in an office. Fixating only on a dive-related diagnosis can, and has resulted in delays in obtaining a correct diagnosis and proper treatment.

DAN comments

It is difficult to diagnose a patient over the phone, especially in cases of something that requires an evaluation to exclude a life-threatening possibility.
If you call the DAN Emergency Hotline +1 919 684-9111 (or 1800 088 200 in Australia), our medics can help you understand what is
happening and assist you get the help that you need, wherever you are.

For more diving health and safety articles DANinsider.org for weekly posts discussing recent incidents, and diving health and safety content.
Visit: daninsider.org and follow us on Facebook by searching DAN World.

Need more information? Send DAN World an email info@danap.org or call +61-3-9886 9166

DANAP.org