Salt water aspiration syndrome
| Salt water aspiration syndrome | |
|---|---|
| Other names | Saltwater aspiration syndrome |
| Specialty | Undersea medicine |
| Symptoms | Cough, shortness of breath, chest discomfort, fever, malaise, shivering, headache, nausea |
| Usual onset | Immediately after an underwater dive |
| Duration | ~ 24 hours |
| Causes | Lung inflammation caused by inhalation of salt water |
| Diagnostic method | Clinical |
| Treatment | Normobaric oxygen therapy |
Salt water aspiration syndrome or saltwater aspiration syndrome is a medical condition caused by the inhalation or aspiration of small amounts of salt water, leading to lung irritation and inflammation. Unlike drowning or near-drowning, it does not involve ingestion of large volumes of water. It often results from faulty diving equipment or improper breathing techniques, allowing fine water droplets to reach the lower respiratory tract.
The condition often begins with cough and shortness of breath, followed by shivering, fever, and other systemic symptoms. It can resemble a viral infection but improves within hours, especially with normobaric oxygen therapy. While most cases resolve on their own, severe instances may require intensive care. Diagnosis is based on clinical history and symptom progression. Salt water aspiration syndrome was first described in 1970.
Cause and mechanism
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Salt water aspiration syndrome occurs when small amounts of salt water is inhaled or aspirated over time.[1] Hypertonic salt water, being more concentrated than human blood, creates an osmotic gradient when it enters the lungs. This gradient draws water out of surrounding lung tissues into the alveoli and bronchioles, leading to irritation and inflammation. Salt water can also cause oxidative stress, dilution of pulmonary surfactant, breakdown of the blood-air barrier, cellular degradation and cell death.[2] Marine microorganisms and particulates can further contribute to inflammatory processes, which may explain systemic symptoms associated with the syndrome.[3]
Unlike drowning or near-drowning which involves sudden intake of large quantities of liquid, this condition can develop subtly over a prolonged period. Faulty diving equipment such as diving regulators, improper breathing techniques, or buddy breathing lead to the inhalation of fine salt water droplets. The small size of the droplets allows them to reach the lower respiratory tract without significantly triggering the upper airway's cough reflex, hence getting aspirated without causing immediate symptoms.[1]
Signs and symptoms
[edit]Salt water aspiration syndrome often begins with an aspiration event. After completing an underwater dive, the first symptom is usually a cough, sometimes producing sputum that may be excessive or blood-tinged. Within the next two hours, divers may develop bluish skin, shortness of breath, increased respiratory rate, increased heart rate, chest discomfort and pain.[1] In rare but severe cases, low oxygen levels in blood and inflammation of lungs can occur.[4] Lungs auscultation may reveal abnormal breath sounds such as rhonchi,[1] and chest imaging can show prominent lung markings or opacities.[4] Blood work usually does not show specific abnormalities, but slightly elevated white blood cell count and lactate dehydrogenase levels may be seen.[1]
Salt water aspiration syndrome generally mimics symptoms of an acute viral infection. Fever, malaise and chills are most commonly reported, and usually the first systemic symptoms to appear. Most individuals experience tremors and shivering[5][3] – the latter is often worse with reduced oxygen levels in blood.[6] Headaches are reported in about two-thirds of cases, while about one-third experience body aches. Gastrointestinal involvement can result in loss of appetite, nausea and vomiting. Less commonly, affected individuals experience fainting, temporary loss of consciousness and mild confusion.[1]
Diagnosis
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The diagnosis of salt water aspiration syndrome is based on medical history and physical examination. Its initial symptoms of cough and difficulty breathing are similar to near-drowning, however near-drowning does not cause viral infection-like symptoms. Furthermore it can be difficult to distinguish the condition from an acute viral infection at first; unlike viral illnesses however, salt water aspiration syndrome tends to improve within a few hours.[3]
The condition shares features with decompression sickness; a review of the dive profile and the absence of other symptoms associated with decompression can help distinguish between the two. Significant improvement after supplementation with normobaric oxygen therapy further supports the diagnosis of salt water aspiration syndrome.[A] Other diving conditions like pulmonary barotrauma, immersion pulmonary edema and low body temperatures can produce similar symptoms or occur alongside this syndrome; these can be distinguished through the clinical course and imaging results.[1]
Treatment
[edit]Treatment involves supportive care with normobaric oxygen therapy, observation and rest. Most cases resolve within the first 24 hours,[1] often spontaneously without treatment.[3] Intensive care unit (ICU) care may be necessary for severe cases or cases complicated with other diving and respiratory disorders.[4]
Research
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The condition was first described in 1970 by Carl Edmonds, who documented 30 cases at the Royal Australian Navy School of Underwater Medicine.[3] A 1989 study estimated that 37 percent of deaths that occurred during recreational scuba diving in Australia and New Zealand in the 1980s involved salt water aspiration syndrome. The study hypothesized—based on reports of the victims symptoms and an analysis of their equipments—that the syndrome acted as an intermediate factor, exacerbating panic and exhaustion, which ultimately led to loss of consciousness.[9] In 2019, a case study described severe salt water aspiration syndrome in an individual requiring ICU admission caused by a beluga whale splash during a show at Georgia Aquarium.[4]
Notes
[edit]- ^ Decompression sickness will improve significantly with hyperbaric oxygen therapy, not normobaric.[8]
References
[edit]- ^ a b c d e f g h Edmonds, Carl; Bennett, Michael; Lippmann, John; Mitchell, Simon (2015). Diving and Subaquatic Medicine (5th ed.). Boca Raton, Florida: CRC Press. pp. 303–307. ISBN 978-1-4822-6013-7.
- ^ Jin, Faguang; Li, Congcong (June 2017). "Seawater-drowning-induced acute lung injury: From molecular mechanisms to potential treatments". Experimental and Therapeutic Medicine. 13 (6). Athens, Greece: Spandidos Publications: 2591–2598. doi:10.3892/etm.2017.4302. ISSN 1792-0981. PMC 5450642. PMID 28587319.
- ^ a b c d e Mitchell, Simon (2002). "Salt water aspiration syndrome". South Pacific Underwater Medicine Society Journal. 32 (4). Melbourne, Australia: South Pacific Underwater Medicine Society: 205–206. ISSN 0813-1988.
- ^ a b c d Rabih, Fadi; Velasquez, Alvaro (October 2019). "Splash by a beluga whale: an unusual case of salt water aspiration syndrome". Unusual Cases and Treatments in the ICU. Chest. 156 (4). Glenview, Illinois: American College of Chest Physicians: A1573. doi:10.1016/j.chest.2019.08.1387. ISSN 1931-3543.
- ^ Edmonds, Carl (1970-09-01). "A salt water aspiration syndrome". Military Medicine. 135 (9). Gaithersburg, Maryland: Association of Military Surgeons of the United States: 779–785. doi:10.1093/milmed/135.9.779. ISSN 0026-4075. PMID 4991232.
- ^ Bullard, Robert (December 1961). "Effects of hypoxia on shivering in man". Aerospace Medicine. 32. Alexandria, Virginia: Aerospace Medical Association: 1143–1147. ISSN 0001-9402. PMID 13874609.
- ^ Richard, Moon; Mitchell, Simon (2019). "Hyperbaric treatment for decompression sickness: current recommendations". In Moon, Richard (ed.). Hyperbaric Oxygen Therapy Indications (14th ed.). North Palm Beach, Florida: Best Publishing Company. p. 686. ISBN 978-1-947239-17-3.
- ^ Edmonds, Carl; Walker, Douglas (1989). "Scuba diving fatalities in Australia and New Zealand: 1. The human factor". South Pacific Underwater Medicine Society Journal. 19 (3). Melbourne, Australia: South Pacific Underwater Medicine Society: 94–104. ISSN 0813-1988.
