Autopsy & forensics

• Stage 1: surprise / reflective inspiration
  • Victim recognizes risk and inhales deeply to fill lungs with as much air as possible
  • Usually lasts a few seconds
• Stage 2: apnea
  • Victim holds breath in attempt to not allow water to enter airways
  • Usually lasts less than 1 minute
• Stage 3: deep breathing / expiratory dyspnea
  • Increasing hypoxia and hypercapnia as a result of apnea lead to respiratory stimulation with expiratory dyspnea and rapid swallowing, resulting in entry of water into airway and gastrointestinal (GI) tract
• Stage 4: convulsive
  • Anoxic brain injury results in bradycardia, arrhythmia and convulsion
• Stage 5: terminal apnea / death
  • Anoxic brain injury becomes irreversible and breathing and circulation cease
    • Dependent on person's age and temperature of water
    • Case reports of survival following prolonged submersion in cold water versus retrospective analysis of near drownings (JAMA 1988;260:377, Resuscitation 2002;52:247)
    • Submersion time thought to be best prognostic factor
• References: Int J Legal Med 2021;135:281, Med J Aust 1985;142:586

Contributed by Lorenzo Gitto, M.D.

• Differences in survivability after inhalation of fresh versus salt water unproven
• Freshwater denatures alveolar surfactant and passes to bloodstream → hemodilution → disruption of osmotic gradient → hemolysis (Pediatr Clin North Am 2001;48:627)
  • Freshwater frequently defined as salinity < 1% (e.g., most rivers, lakes, ponds, pools, bathtubs, etc.)
• Saltwater dilutes surfactant → intravascular water is drawn into alveoli → hemoconcentration → electrolyte disturbances (Exp Ther Med 2017;13:2591)
  • Saltwater most commonly refers to ocean water and includes some lakes
• Reference: Eur Radiol 2016;26:1186

Contributed by Allecia M. Wilson, M.D.

Contributed by Allecia M. Wilson, M.D.

A 51 year old man is discovered deceased, floating face down in a lake where he is known by friends to swim recreationally. He is wearing only swim trunks. He was observed by a passing jogger to be swimming back and forth in regular laps from one side of the lake to the other. This observation was made about 30 minutes before he was discovered floating face down. He also spoke to his sister on the phone the day before and is reported by her to have been in good spirits. The decedent's medical history includes hypertension, depression and seizure disorder. He is known to struggle with medication compliance but is prescribed medications for each of these conditions. He is not married and has one adult child in good health. He is a former smoker. The lake water is found to be clear, still and 77 °F (25 °C). The lake is within walking distance to the decedent's home in northern Florida and only the jogging path is nearby. A pair of tennis shoes are found neatly placed on the shore. Investigators have found no signs of foul play. The above examination finding was discovered at autopsy. Drug and alcohol toxicity panels are negative. What is the most likely cause and manner of death?

1. Cardiac arrhythmia, natural
2. Drowning, accidental
3. Drowning, suicide
4. Myocardial infarction, natural
5. Myocardial infarction with rupture, natural

B. Drowning, accidental. The decedent is known to swim in the lake and was observed doing so 30 minutes before he was found dead. Since he is known to swim there and his shoes were placed neatly at the shore, it is likely that he decided to swim that day as he does regularly for recreation. Answer C is incorrect because there were no scene findings and no situational information to suggest suicide. In addition, although he has a history of depression and may be noncompliant with medication, the decedent was witnessed doing his normal laps at the time in question and is reported by his sister to have been in good spirits the day before. The decedent has a history of noncompliance with medication for a seizure disorder and has several risk factors for cardiac disease (smoking, hypertension, age, sex). It is possible he had a seizure event or a cardiac event while swimming recreationally, leading to accidental drowning. Answers A, D and E are incorrect because if the decedent were not in the water while the event occurred, it is possible that he would have been able to receive medical attention that would have been lifesaving; however, he was in the water at the time of the event and therefore the death should be classified as an accidental drowning (as opposed to natural causes of death).

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Reference: Drowning

A 6 year old boy is determined at autopsy to have died of drowning. Of the locations listed, what is the most likely to been involved in this child's death?

1. Bathtub
2. Lake
3. Ocean
4. Standing outdoor water (e.g., bucket of water near a home or school)
5. Swimming pool

E. Swimming pool. The most likely location of a drowning death in this age group (i.e., preschool or early elementary school aged children) is a swimming pool. Oftentimes the pool is at a community park or in the backyard of a home. Answer A is incorrect because a bathtub is the most common site of drowning in infants (i.e., children less than 1 year of age). Answer D is incorrect because it describes a scenario in which children in the toddler age range (i.e., 1 - 3 years) may get trapped in areas with standing water, such as when they may be playing near a bucket or other basin with water. It is less likely for a child 6 years of age to get trapped in such a scenario. Answers B and C are incorrect because drownings associated with larger outdoor bodies of water (e.g., lakes, ponds or oceans) are more likely to be associated with the teenage and young adult populations.

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Reference: Drowning