Cold Injury
Definition
Cold injuries are damages caused by exposure to low environmental temperatures, leading to systemic hypothermia or localized soft tissue injury. They are classified into:
- Freezing injuries (e.g., frostbite )
- Non-freezing injuries (e.g., frostnip, chilblains, immersion foot, trench foot)
Classification of Cold Injury
- Freezing Injuries
- Frostbite – results from tissue freezing, leading to ice crystal formation, microvascular thrombosis, and cell death. Can be first-fourth degree, with fourth being the most severe.
- Non- Freezing Injuries
- Frostnip – superficial, reversible injury without permanent damage.
- Chilblains (Pernio) – inflammatory skin lesions after repeated cold exposure, especially on extremities.
- Trench Foot / Immersion Foot – prolonged exposure to cold, wet conditions; skin appears pale or black.
- Ombredanne Syndrome – a systemic response seen in severe cold injuries, affecting thermoregulation (from PPT).
Injuries Related to Cold Exposure
- Hypothermia
- Dehydration
- Sunburn (UV exposure on snow)
- Snow blindness (UV- induced keratitis)
- Carbon monoxide poisoning (due to closed heating systems)
Severity and Staging of Frostbite
- Severity Grading
Pathophysiology: Cold → vasoconstriction → ↓ perfusion → thrombosis → ischemia → necrosis.
Systemic Hypothermia
- Clinical Stages:
- Clinical Signs:
- Shivering
- Pale, cyanotic skin
- Tachypnea, tachycardia, atrial fibrillation
- Loss of consciousness below 30°C
Management of Frostbite and Cold Injuries
First Aid (ABCDE protocol)
- Airway, Breathing, Circulation, Disability, Exposure
- Remove wet clothes, protect from further exposure
Rewarming Therapy
- Gentle rewarming of whole body (not just frostbitten part)
- Use lukewarm water (~37–39°C) — avoid dry heat (can worsen injury)
- Hot fluids orally, if conscious
- Analgesia – rewarming is very painful
- IV fluids if hypovolemic
- Cardiac monitoring is essential during rewarming (risk of arrhythmias)
Advanced Care
- Hyperbaric oxygen therapy in severe cases
- Surgical treatment:
- Debridement of necrotic tissue
- Amputation if gangrene develops
- Antibiotics if infection occurs
- Treat associated hypoglycemia or vascular disease
Prevention of Cold Injuries
- Adequate clothing in layers
- Avoid prolonged exposure
- Careful protection for elderly, children, and patients with PVD
- Ensure good circulation and nutrition
Risk Factors (from your notes):
- Low ambient temperature
- Extremes of age
- Immobilization
- Peripheral vascular disease
- Prolonged exposure
- Open wounds
- Hypoglycemia