Immersion syndrome occurs due to ?
a) Vagal inhibition
b) Vagal Stimulation
c) Sympathetic stimulation
d) Sympathetic inhibition
Correct Answer - A
Ans. is ‘a’ i.e., Vagal inhibition
Types of drowning
Drowning is classified as (1) typical and (2) atypical.
- Typical drowning (wet drowning)
Typical drowning refers to obstruction of air passages and lungs by
inhalation of water or other fluid. Therefore it is also called wet
drowning and findings offluid and froth are present in PM
examination. Typical drowning may be :-
i. Fresh water drowning : In fresh water drowning large quantities of
water cross the alveolar membrane into circulation causing
hypervolaemia and hemodilution. RBCs imbibe water and burst
(hemolysis) with liberation of potossium. Therefore, heart is exposed
to volume overload, potassium excess, sodium deficit
(hyponatremia), and anoxia. Anoxia and hyperkalemia cause
ventricular fibrillation and death in 4-5 minutes.
ii. Salt water drowning : Hypertonicity of inhaled water causes loss of
fluid from circulation into the lungs giving rise fulminating pulmonary
edema with progressive hypovolaemia, circulatary shock, and
eventually cardiac standstill (asystole) with death in 8-12 minutes. - Atypical drowning
It refers to drowning in which even after submersion of body in
water, little or no water anters respiratory passages and lungs
Hence typical findings of wet drowning in the form of froth and
oedema aquosum of lungs are not found. Atypical drowning may be
:-
i. Dry drowning : On contact with water, especially cold water, there
results intense laryngospasm, so that water does not enter the
lungs. Death is due to asphyxia because of laryngospasm.
ii. Immersion syndrome (hydrocution/submersion inhibition/vagal
inhibition) : Sudden death occurs due to vagal inhibition as a result
of (a) sudden impact with cold water, (b) duck diving (falling in water
with feet first), and (c) horizontal entry in water with impact on
epigastrium.
iii. Submersion of unconscious : If person is unconscious since before
submersion in water, little or no water enters respiratory passages. It
may occur in MI, cerebrovascular accident, hypertension, epilepsy,
cerebral aneurysm and in drunk state.
iv. Near drowning (secondary drowning syndrome/post immersion
syndrome) : In this drowning is survived and death occurs at a later
stage after removal from water. Either the person himself comes out
of water or he is recovered alive, but due to complications of
submersion, he dies at a later stage. It is due to hypoxic
encephalopathy and fibrosing alveolitis. The death occurs due to
combined effect of cerebral hypoxia, pulmonary edema, aspiration
pneumonitis, electrolyte disturbances and metabolic acidosis.