Scuba Diving–Related Disorders

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Last modified 14/03/2015

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Scuba Diving–Related Disorders

The disorders related to scuba diving include those caused by environmental exposure (see Chapters 3 and 50), dysbarism, nitrogen narcosis, contaminated breathing gas, decompression sickness (DCS), and hazardous marine life (see Chapters 52 and 53) (Box 51-1).

Box 51-1 Medical Problems of Scuba Divers

Environmental Exposure Problems

• Motion sickness

• Near drowning

• Hypothermia

• Heat illness

• Phototoxic and photoallergic reactions

• Irritant and other dermatitides

• Infectious diseases

• Mechanical trauma

Diving-Related Disorders

• Arterial gas embolism

• Decompression sickness

• Dysbaric osteonecrosis

• Dysbaric retinopathy

• Immersion pulmonary edema

• Hyperbaric cephalalgia

Breathing Gas–Related Problems

• Inert gas narcosis

• Oxygen toxicity

• Hypercapnia

• Carbon monoxide poisoning

• Lipoid pneumonitis

Hazardous Marine Life (see Chapters 52 and 53)

• Hyperventilation

• Hearing loss

• Carotid-related blackout

• Panic and other psychologic problems

Dysbarism

Dysbarism encompasses all the pathologic changes caused by altered environmental pressure. At sea level, atmospheric pressure is 760 mm Hg (14.7 psi). Each 10-m (32.8-foot) descent under water increases the pressure by 1 atm. Gas in enclosed spaces obeys Boyle’s law, which states that the pressure of a given quantity of gas when its temperature remains unchanged varies inversely with its volume.

Mask Squeeze

An air space is present between the face and the glass of a scuba (self-contained underwater breathing apparatus) diving mask. If nasal exhalations do not maintain air pressure within this space during descent, the volume of air contracts, creating negative pressure. This leads to capillary rupture, which is potentially dangerous after keratotomy because of the slow healing rate of corneal incisions.

Signs and Symptoms

1. Skin ecchymoses in mask pattern

2. Conjunctival hemorrhage similar to strangulation injury

Treatment

1. No treatment is necessary because the manifestations are self-limited.

2. Orbital hemorrhage is a rare complication and is associated with diplopia, proptosis, and visual loss. Prompt referral should be made for magnetic resonance imaging and ophthalmologic care. Recompression therapy is not indicated.

Ear Canal Squeeze

A tight-fitting wet suit hood, earplugs, exostoses, or cerumen impaction can trap air in the external auditory canal. On descent, this air contracts in the enclosed space between the tympanic membrane and the (occluded) external opening of the ear.

Signs and Symptoms

1. Pain, swelling, erythema, and petechiae or hemorrhagic blebs (bullae) of external ear canal wall

2. Hemorrhage possible

3. In severe cases, tympanic membrane rupturing outward

Treatment

1. If a remediable occlusion exists, correct it.

2. If inflammation of the external canal occurs without tympanic membrane rupture, instill eardrops suitable for the treatment of otitis externa (a fluoroquinolone combined with a steroid component) as directed for 2 to 3 days.

3. If the tympanic membrane is perforated, seek otolaryngologic evaluation. Do not allow further diving until the membrane has healed. Instill fluoroquinolone otic drops.

4. Do not incise bullae.

Middle Ear Squeeze (Barotitis Media)

If air cannot enter the middle ear via the (contracted or blocked) eustachian tube during an underwater descent, the existing air in the middle ear space contracts, creating a relative vacuum and pulling the tympanic membrane inward (Fig. 51-1).

FIGURE 51-1 Middle ear trauma. Symptoms include feeling of “fullness” and pain caused by stretching of tympanic membrane.

Signs and Symptoms

1. Initially, slight pain that progresses to severe pain with further underwater descent

2. Hemorrhage in the tympanic membrane revealed on otoscopy; ranges from erythema over the malleus to gross blood throughout the tympanic membrane; blood around the mouth and nose and hearing loss also possible

3. If the tympanic membrane ruptures:

a. Sudden severe pain, accompanied by vertigo as water rushes into the middle ear

b. Total hearing loss in the affected ear

Treatment

1. Before tympanic membrane rupture, administer an oral decongestant and a long-acting topical decongestant nasal spray such as oxymetazoline. In a severe case, if the tympanic membrane is intact, a short course of prednisone (50 mg PO, tapered over 7 days) may be helpful. An antihistamine may be administered if there is an allergic component.

2. Repeated gentle autoinflation of the middle ear by use of the Frenzel maneuver may help to displace any collection of middle ear fluid through the eustachian tube.

3. For tympanic membrane rupture, administer an antibiotic such as amoxicillin/clavulanate for 7 days. In addition, administer fluoroquinolone otic drops. Suspend all diving activities until the tympanic membrane is fully healed or has been surgically repaired and eustachian tube function allows easy autoinflation.

Barosinusitis

Barosinusitis, or “sinus squeeze,” results from an inability to inflate a paranasal sinus during descent, at which time contraction of the trapped air creates a relative vacuum. This damages the sinus wall mucosa, which ultimately hemorrhages. Less often, a “reverse sinus squeeze” can occur on ascent in the water because the expanding air cannot be vented from the sinus.

Signs and Symptoms

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