Hypothermia - Forensic Medicine

Definition

• Direct effects of cold are prominent on fatty tissue and myelinated nerve fibers
• Indirect effects are mostly ischaemic, due to vascular damage
• The hypothalamus loses its ability to regulate temperature completely below 30°C
• Fat persons and women tolerate cold better than lean persons and men

Local Effects of Cold

1. Stage 1 - Blanching and pallor of skin due to vascular spasm
2. Stage 2 - Erythema, oedema, swelling due to later vascular dilatation and paralysis, and increased capillary permeability
3. Stage 3 - Blister formation involving skin, subcutaneous tissues, muscles, and nerves - either tissues become frozen/hard/necrotic directly, or necrosis follows vascular occlusion, thrombosis, obliterating endarteritis, and secondary infection

Localized Conditions

• Result of prolonged exposure to severe cold (5-8°C) and dampness
• Seen in soldiers during winter warfare (trenches) and persons exposed to prolonged immersion at sea
• Extremities are affected
• Blister formation with ulceration and localized dry gangrene occurs

• Infarction of peripheral digits and other parts (nose, ears, face)
• Necrosis with blister formation and gangrene
• Skin becomes hard and black in about 2 weeks

• Frostnip - no permanent damage; skin color change with numb/irritant feeling
• Superficial frostbite - skin feels warm, appears swollen and blistered (due to osmotic forces from ice crystals)
• Deep frostbite - tissue turns blue-black with loss of function

General (Systemic) Effects - Three Stages

Postmortem Appearances

External

• Pink or brown-pink areas with indistinct, blurred margins - particularly over and around joints (knees, elbows, hips) - this is characteristic
• Pink patches on cheeks, chin, and nose
• Extremities may be cyanosed
• Oedema of feet and lower legs
• PM lividity is bright pink

Internal (not characteristic)

• Subcutaneous tissues are relatively avascular
• Ice crystals in blood vessels, heart, and interstitial tissue spaces
• Blood is often bright red due to retention of oxygen by hemoglobin at low temperatures
• Stomach mucosa - studded with numerous brown-black acute erosions, ulcerations, and hemorrhages (Wischnewski spots/lesions - similar to stress ulcers)
• Pancreas - variable degree of fat necrosis in ~50% cases; areas of stiff, yellow fat necrosis in pancreas and adjacent omentum/mesentery
• Pulmonary oedema and micro-infarcts in many organs
• Perivascular hemorrhages in brain and small infarcts in heart
• Internal organs congested

Medicolegal Importance

• Drunkenness (alcohol causes peripheral vasodilation increasing heat loss)
• Mountaineering
• Persons lost in snow-drifts
• Immersion in ice-cold water

Special Phenomena of Forensic Significance

1. Paradoxical (Reciprocal) Undressing

• A strange phenomenon seen in accidental hypothermia, particularly in old persons
• Cause not fully understood
• Prolonged severe cold causes paralysis of thermal regulatory mechanism
• This leads to failure of arteriolar vasoconstriction in skin, causing a flow of blood from the body core - creating an exaggerated sensation of warmth
• Terminal hallucinations occur
• The person removes some or all clothing despite freezing temperatures
• Found dead in cold environment while undressed - may raise suspicion of sexual offence

2. Hide-and-Die Syndrome (Terminal Burrowing Behavior)

• In rare cases, the disoriented dying hypothermic victim hides in corners, cupboards, or under furniture/household goods
• Typically a naked or partly clothed old person is found amid a scene of utter confusion - furniture pulled over, drawers and cupboards emptied, but disturbance is at a low level (tops of tables undisturbed)
• This may lead to suspicion of homicide and robbery
• Outdoors, victim may burrow into snow, bush, or environment
• Terminal mental confusion, delirium, and hallucinations occur
• Key forensic question: Did hypothermia cause mental confusion leading to strange behavior, or was there pre-existing mental aberration?

Neonatal Cold Injury

• Results from failure of metabolism to maintain temperature in a cold environment
• Symptoms appear usually in the first week of life
• Rectal temperature usually below 32°C
• Features: lethargy, drowsiness, refusal of food
• Outstanding feature: swelling of extremities with pitting oedema (hands, feet, eyelids)
• Localized hardening of skin and subcutaneous tissue
• Face, hands and feet are red - striking and constant finding
• Slow heart rate, absent peripheral pulsations, shallow/slow respirations
• Hemorrhagic tendency: GI bleeding, petechial hemorrhages

Exam Questions from Anil Aggarwal (Forensic Relevance)

• Long Essay: Discuss causes, pathophysiology, clinical features, postmortem findings, and medicolegal importance of thermal deaths (burns, heat stroke, hypothermia, electrocution)
• Short Essay: Explain the medicolegal aspects of death due to hypothermia
• Short Essay: Write short notes on immersion hypothermia (death in cold water)
• Short Answer: List two postmortem findings of hypothermia
• MCQ classic: Wischnewski spots are associated with hypothermia (correct answer: B)

Starvation - Forensic Medicine

Definition

Types of Starvation

Causes of Starvation Death

1. Famine
2. Entrapment - in pits, mines, landslides
3. Neglect by parents or guardians
4. Willful withholding of food (homicidal)
5. Willful refusal to consume food (suicidal/voluntary fasting)

Medicolegal Modes of Starvation

Suicidal / Voluntary Starvation

• Voluntary fasting for exhibition
• Lunatics and hysterical women refusing food
• Fast unto death - to attract public attention, rectification of grievances (legally important in India)

Homicidal Starvation

• Victim is usually an infant, aged, or feeble-minded person starved with evil intention
• Illegitimate children frequently starved to death
• Children starved by parents/guardians = "Baby-farmers"

Accidental Starvation

• During famine, trapped in pits/mines/landslides/shipwreck
• Ignorance leading to failure to provide adequate/appropriate food
• Stricture or cancer of esophagus; ankylosis of jaw
• Drug addicts (desire for drug exceeds desire for food)
• Old persons with paranoid schizophrenia or senile dementia refusing to spend on food

Clinical Features

Acute Starvation

1. Feeling of hunger for first 30-48 hours, followed by epigastric pain relieved by pressure
2. After 4-5 days: general emaciation and absorption of subcutaneous fat
3. Sunken, glistening eyes; dilated pupils; sunken cheeks; bony prominences visible
4. Bichat's buccal pad of fat is among the last subcutaneous adipose tissue to disappear
5. Lips dry and cracked; tongue coated and dirty; intolerable thirst; thick, scanty saliva
6. Weak, whispering voice
7. Skin - dry, rough, thin, inelastic, wrinkled, pigmented
8. Abdomen concave from costal margins to iliac crests; ribs prominent with intercostal concavities; sunken supraclavicular fossae
9. Limbs thin and flaccid; progressive muscular weakness
10. Cardiovascular: pulse slow at rest; paroxysmal tachycardia on exertion; progressive insufficiency
11. Temperature subnormal
12. Constipation usual; near death - diarrhea and dysentery
13. Urine - scanty, turbid, highly concentrated, shows acidosis
14. Death when 40% of original body weight is lost; intellect remains clear till death (sometimes delusions/hallucinations of sight and hearing)

Chronic Starvation (changes are constant and develop in a regular order)

1. Loss of well-being, hunger and hunger-pains
2. Mental and physical lethargy, easy fatigue
3. Progressive loss of weight - rapid in first 6 months
4. Polyuria
5. Increasing cachexia; body weight reduced by ~40% of normal; pigmentation and anemia
6. Hypothermia, peripheral vascular stasis in cold, hypotension
7. Extreme lethargy, gross mental retardation, loss of self-respect
8. Oedema - first in the feet and lower limbs
9. Reduced resistance to infection - diarrhea, dysentery, tuberculosis, etc.

Mechanism of Energy Utilization in Starvation

1. Early phase: Rapid mobilization of protein stores - converted by liver to glucose (primarily for brain energy)
2. Middle phase: Main energy from lipolysis - adipose tissue releases free fatty acids; liver converts them to ketone bodies (fuel for skeletal muscle, heart, brain)
3. Late phase: As fat stores deplete, protein again rapidly used as energy source

Fatal Period

Factors Influencing Fatal Period

1. Age - Very young and old suffer worst
2. Sex - Females withstand starvation for a longer period
3. Condition of body - Fatty, healthy people withstand starvation better
4. Temperature - Exposure to cold or excessive heat hastens death
5. Physical activity - Active physical exertion hastens death

Postmortem Appearances

External

• Rigor mortis sets in and disappears early
• Face pale; skin inelastic and pigmented
• Sometimes follicular hyperkeratosis
• Subcutaneous patches of oedema around ankles and inside thighs
• In wet type: marked oedema of face, trunk and limbs with ascites and pleural effusions
• Trophic skin changes and infections common
• Pressure sores on buttocks, heels and spine
• Hair - dry, luster-less, brittle; nails also brittle
• Characteristic ketone body odor commonly found

Internal

Medicolegal Aspects

1. Exclusion of disease causing weight loss is essential before diagnosing starvation - must rule out: malignant disease, progressive muscular atrophy, Addison's disease, diabetes mellitus, tuberculosis, pernicious anemia, chronic diarrhea
   • Sometimes it may be impossible to determine whether disease was cause or effect of malnutrition (e.g., TB)
2. Diagnosis of starvation at autopsy: If marked loss of weight and especially complete absence of fat are found, and there is no evidence of disease - diagnosis of starvation can be made
3. Death due to starvation must be reported to police (MCQ answer: A)
4. Inquest: Held by police (MCQ answer: C)
5. Article 21, Constitution of India: Right to life does NOT include right to die - arrest and forcible feeding of persons on hunger strike is lawful
6. Criteria for forced feeding: Loss of weight + acidosis with ketone bodies in urine

MCQ Key Points