Review of Scuba Diving Injuries
Scuba diving injuries range from benign to life threatening and can occur during descent, at depth or during ascent. Sports medicine physicians, athletes and other members of the dive team should be prepared to rapidly identify and treat divers with these injuries. In some cases, they are self limited and in others, require significant interventions such as hyperbaric oxygen therapy. In this post, we review some of the more well described diving-related pathology. Please note that there are some conditions not covered in this post.
Barotrauma of Descent
Illustration of the eustachian tube which helps maintain equal air pressure on both sides of the tympanic membrane. When there is a mismatch, otic barotrauma can occur.Image courtesy of merckmanuals.com, “Barotrauma of the Ear”
Otic barotrauma, sometimes termed ear squeeze, can affect the external, middle or inner ear and is seen during descent. The middle ear is most commonly affected. It occurs when the middle ear pressure is not equalized with the ambient pressure which is why divers are taught to equalize their ears at surface and throughout the dive. Divers generally complain of ear pain, fullness, vertigo and hearing loss. On exam, they may have edema, hemorrhage or a ruptured tympanic membrane. External and middle ear disease can typically be treated with ear drops, decongestants and vasoconstrictors. If a TM rupture is present, consider antibiotics. Patients with inner ear barotrauma may need advanced imaging and should be referred to an ENT.
In sinus barotrauma, a decrease in gaseous volume within the nasal cavity and sinuses themselves creates a decompression or squeeze effect. This can lead to mucosal edema, submucosal hematoma, and serosanguinous exudation. Acute barosinusitis is most common, however there are recurrent and chronic forms of the disease as well. Patients typically report sinus pain, headache, epistaxis and dental pain. Periorbital emphysema may occur through the ethmoid sinus. It is primarily a clinical diagnosis, however CT or MRI may be indicated in more subacute or chronic cases. Most cases can be managed with decongestants and saline irritants. The role of antibiotics and steroids are not clear. In some cases, surgical management is indicated when there are complications or anatomic variants.
Mask squeeze is a form of barotrauma resulting from a failure to equalize the air space created between your mask and face. This creates a negative pressure on the area of the face covered by the mask like a suction cup. This is typically seen in new divers. On exam, they will have ecchymosis of the periorbital skin and conjunctival hemorrhage. Most cases can be managed expectantly with cold compresses and analgesics. If any concerns such as blurred vision, hyphema, evidence of retrobulbar hemorrhage the patient should be seen in the ED or by ophthalmology.
Barodentalgia refers to barometric pressure induced dental pain seen in divers and pilots. Most commonly it is “direct” from the dentition related to recent dental therapy, dental caries and pulpitis. Upper molars are most commonly affected. Indirect barodentalgia refers to referred pain from the ears or sinuses and represents about 20% of cases. On physical exam, inspection may be normal or reveal dental fractures, pulpitis, caries, etc. Management is symptomatic with definitive care to see a dentist.
Barotrauma at Depth
Oxygen toxicity occurs when the partial pressure of oxygen is at higher partial pressures than normal. It highly correlates with depth and exposure time. Patients have tracheobronchial symptoms (pleuritic chest pain, dyspnea, cough) initially followed by CNS symptoms (tunnel vision, seizure, nausea) in more severe cases. The diagnosis is primarily clinical. Treatment is aimed at reducing partial pressure of oxygen as low as tolerated while still maintaining peripheral perfusion. Hyperbaric oxygen is indicated for more severe cases.
Nitrogen narcosis occurs as a result of inhalation of compressed nitrogen at depth. It generally manifests as intoxication and euphoria which can impair judgement and create dangerous circumstances at depth. Onset is insidious and it is critical to identify the impaired judgement early to ascend the diver. Ascent reduces the partial pressure of dissolved nitrogen within minutes of ascension and symptoms resolve rapidly. There are no long term effects and hospitalization is not typically required.
The multiorgan effects of carbon monoxide toxicityChen, Rong-Jane, et al. “Carbon monoxide-triggered health effects: The important role of the inflammasome and its possible crosstalk with autophagy and exosomes.” Archives of Toxicology … Continue reading
Carbon Monoxide Toxicity
Carbon monoxide toxicity is a colorless odorless gas which occurs due to incomplete combustion of hydrocarbons. The etiology in diving is usually related to a faulty air compressor pumping CO into the tank. Symptoms are non specific including CNS, eyes, GI, pulm, cards and derm. It is often called the great mimicker. Diagnosis requires a high level of suspicion. A carboxyhemoglobin can confirm your diagnosis. These patients may be critically ill requiring hospital admission. Oxygen therapy is the primary treatment of choice as it displaces CO off hemoglobin. Hyperbaric oxygen therapy should be considered in consultation with a specialist.
The closed circuit diving apparatus associated with the ‘caustic cocktail'Minns, Alicia B., Shaun D. Carstairs, and Richard F. Clark. ““Caustic cocktail”: closed-circuit diving apparatus contamination leading to corrosive injury.” The American Journal of … Continue reading
The so-called caustic cocktail is a disease process in which water into a closed-circuit rebreather creates a highly basic and caustic vapor. Most commonly it is soda limb, which is composed of calcium hydroxide (75%), sodium hydroxide (3%), potassium hydroxide (1%). This creates an alkaline product with a pH greater than 12.5. Patients typically have throat and chest pain from swallowing or inhaling the caustic cocktail. Management is often symptomatic but not well delineated in the literature. Patients may require Esophagogastroduodenoscopy or bronchoscopy.
Barotrauma at Ascent
Chest xray of a patient with pulmonary barotrauma notably for patchy, bilateral airspace disease predominantly in the midlung.Image courtesy of brownemblog.com, “Diving Deep: Pulmonary Barotrauma in a Free Diver”
Pulmonary barotrauma occurs when divers breathing compressed air who ascend too rapidly. It is characterized by damage to the lung parenchyma caused by an increase in pulmonary gas volume during a decrease in ambient pressure. It presents with a wide range of symptoms from very mild pneumothorax or pneumomediastinum to life threatening arterial gas embolism. Symptoms tend to occur immediately upon surfacing or within a few minutes. Patients may have substernal chest pain worse with coughing or swallowing, throat pain, hoarseness, shortness of breath, dyspnea or cyanosis. Radiographs are helpful to evaluate for pneumomediastinum, pneumothorax and more. CT may indicated. EKG should be obtained on all patients as fatal arrythmias can occur. The patient should be transferred to the nearest emergency department. Tension pneumothorax requires needle decompression and tube thoracostomy. Moderate or severe cases should be treated with hyperbaric oxygen therapy.
Mottled skin in a patient with decompression sickness. Air in the portal venous system on CT.Sun, Q., & Gao, G. (2017). Decompression Sickness. New England Journal of Medicine, 377(16), 1568–1568. doi:10.1056/nejmicm1615505
Decompression sickness (DCS) is a disease process where dissolved nitrogen comes out of solution and forms bubbles in blood and tissue. Symptoms start shortly after surfacing but can occasionally be delayed up to 24 hours. Type I DCS involves joint pain (shoulder, elbow, knee) and cutaneous findings (pruritis, scarlatiniform rash, cutis marmorata) only. Type II DCS is more serious can can involve the spinal cord (severe neurological deficits), vestibular system (called the “staggers” involving hearing loss and vertigo), and pulmonary (called the “chokes” involving cough, hemoptysis, dyspnea and substernal chest pain). DCS should be considered in any patient with symptoms shortly after ascent. Oxygen therapy accelerates denitrogenation and patients should be placed on a non-rebreather at 100% O2. Severe cases require hyperbaric oxygen therapy. Other adjuncts include hydration, NSAIDS, and lidocaine.
Arterial Gas Embolism
Arterial Gas Embolism (AGE) is the most severe form of decompression sickness in which compressed gases enter the arterial circulation and cause end organ dysfunction. Classically presents with loss of consciousness within minutes of surfacing, leading to stroke-like symptoms. It should be considered the most severe form of DCS but can be difficult to distinguish clinically. The most common arterial entry point is from pulmonary barotrauma and ruptured alveoli. Some patients may have a right-to-left shunt (e.g. patent foramen ovale, atrial septal defect). Symptoms develop rapidly and dramatically following ascent, typically within 5-10 minutes. The history of ascent is often rapid. The most common symptoms include loss of consciousness, confusion, presyncope and hemiplegia although a wide variety of neurological symptoms can occur. The diagnosis is primarily clinical. Imaging can be considered but is not sensitive or specific. Treatment involves rapid recompression in a hyperbaric oxygen chamber. Prior to that, first aid should include supine positioning, oxygen therapy and aggressive hydration.
|↑1||Image courtesy of merckmanuals.com, “Barotrauma of the Ear”|
|↑2||Image courtesy of dan.org, “sinus barotrauma”|
|↑3||Chen, Rong-Jane, et al. “Carbon monoxide-triggered health effects: The important role of the inflammasome and its possible crosstalk with autophagy and exosomes.” Archives of Toxicology 95.4 (2021): 1141-1159.|
|↑4||Minns, Alicia B., Shaun D. Carstairs, and Richard F. Clark. ““Caustic cocktail”: closed-circuit diving apparatus contamination leading to corrosive injury.” The American Journal of Emergency Medicine 28.7 (2010): 843-e3.|
|↑5||Image courtesy of brownemblog.com, “Diving Deep: Pulmonary Barotrauma in a Free Diver”|
|↑6||Sun, Q., & Gao, G. (2017). Decompression Sickness. New England Journal of Medicine, 377(16), 1568–1568. doi:10.1056/nejmicm1615505|
|↑7||Image courtesy of pedilung.com, “Decompression-Sickness-(DCS)-Arterial-Gas-Embolism-(AGE)”|