99  Snake Bites

Published

July 2, 2025

99.1 Introduction

Snake bites are a significant public health concern in many parts of the world, particularly in rural, tropical, and subtropical regions. Ghana, with its mix of rural populations and agriculture-based livelihoods, is home to both venomous and non-venomous snakes. Children are particularly vulnerable due to their small body size, curious nature, and increased exposure during play or farm-related activities. In children, envenomation may have more severe effects compared to adults, necessitating prompt and effective clinical management.

This note aims to provide medical students in Ghana with a comprehensive overview of snake bites in children, covering epidemiology, pathophysiology, clinical features, diagnosis, management, complications, and preventive strategies.

99.2 Epidemiology

  • Global Burden: The World Health Organization (WHO) estimates over 5 million snake bites per year globally, leading to over 100,000 deaths and 400,000 amputations or other permanent disabilities.
  • Africa and Ghana: Sub-Saharan Africa accounts for a significant portion of these bites. In Ghana, rural areas, including the Northern, Upper East, Volta, Ashanti, and Brong-Ahafo regions, report high incidences of snakebites.
  • Age Distribution: Children under 15 years are at high risk, especially boys who may assist in farming or play outdoors.

99.3 Common Venomous Snakes in Ghana

In Ghana, the major venomous snakes include:

Snake Family Example Type of Venom Effects
Elapidae Cobra (e.g., Naja nigricollis) Neurotoxic Paralysis, respiratory failure
Mamba (Dendroaspis spp.) Neurotoxic Rapid-onset paralysis
Viperidae Puff Adder (Bitis arietans) Cytotoxic and Hemotoxic Swelling, bleeding, necrosis
Gaboon Viper (Bitis gabonica) Hemotoxi Severe local effects, shock

Non-venomous snakes also exist and are often mistaken for dangerous species, leading to unnecessary anxiety and medical attention.

99.4 Pathophysiology of Snake Envenomation

Types of Venom

  1. Neurotoxic Venom (e.g., mambas, cobras):
    • Acts on neuromuscular junctions
    • Leads to paralysis and respiratory arrest
  2. Cytotoxic Venom (e.g., puff adder):
    • Causes tissue destruction and necrosis
    • Leads to local swelling, blistering, and potential amputation
  3. Hemotoxic Venom (e.g., vipers)
    • Disrupts blood clotting
    • Causes internal bleeding, hypotension, and shoc

Factors Influencing Severity in Children

  • Smaller body mass increases the venom-to-weight ratio
  • Delayed presentation to healthcare
  • Inappropriate first aid (e.g., tourniquets)

99.5 Clinical Features

Local Effects

  • Pain and swelling at the bite site
  • Bruising and blister formation
  • Tissue necrosis (especially with cytotoxic venom)
  • Fang marks (may be single or double puncture wounds)

Systemic Effects

Neurotoxic Bites:

  • Ptosis (drooping eyelids)
  • Dysphagia (difficulty swallowing)
  • Respiratory distress
  • Flaccid paralysis

Hemotoxic Bites:

  • Bleeding from gums, nose, or bite site
  • Hematuria
  • Hypotension and shock
  • Disseminated intravascular coagulation (DIC)

Other Signs:

  • Fever
  • Vomiting
  • Abdominal pain
  • Shock

99.6 First Aid and Pre-Hospital Management

Do’s:

  • Keep the child calm and still (to slow the venom spread)
  • Immobilize the bitten limb using a splint
  • Remove any tight clothing or jewelry near the bite
  • Transport to a healthcare facility quickly

Don’ts

  • Do not apply a tourniquet
  • Do not suck the venom
  • Do not cut the wound
  • Do not apply traditional medicines

99.7 Hospital Evaluation and Diagnosis

History:

  • Time and place of bite
  • Activity at the time of bite
  • Description or photo of the snake (if available)
  • Symptoms since the bite

Physical Examination:

  • Vital signs: hypotension, tachypnea, hypoxia
  • Site inspection: swelling, necrosis, fang marks
  • Neurologic assessment: cranial nerves, motor strength
  • Bleeding manifestations

Laboratory Investigations:

  • Full blood count (for anemia, leukocytosis, thrombocytopenia)
  • Clotting profile (PT, aPTT, 20-minute whole blood clotting test)
  • Renal function tests (serum urea, creatinine)
  • Urinalysis (hematuria, myoglobinuria)
  • Crossmatch for transfusion if necessary

20-Minute Whole Blood Clotting Test (20WBCT):

  • Simple bedside test using a clean, dry glass tube
  • Failure to clot within 20 minutes suggests coagulopathy (common in viper bites)

99.8 Antivenom Therapy

Indications:

  • Rapidly progressive swelling
  • Systemic signs: neurotoxicity, coagulopathy, hypotension
  • Evidence of hemolysis or bleeding
  • Children with severe pain or systemic deterioration

Types of Antivenom:

  • Polyvalent antivenoms are commonly used in Ghana and are effective against several species.
  • Supplied by institutions like the Ministry of Health and the WHO.

Administrations

  • Test for hypersensitivity (some centers do not recommend skin testing)
  • Administer IV over 30-60 minutes
  • Monitor for anaphylaxis (rash, bronchospasm, hypotension)

Side Effects:

  • Early reactions: urticaria, itching, anaphylaxis
  • Late reactions: serum sickness (fever, rash, arthritis)

99.9 Supportive Management

  • Airway and Breathing: Intubation and ventilation if neurotoxic paralysis occurs
  • Circulation: IV fluids for shock, blood transfusions for anemia or coagulopathy
  • Pain Control: Paracetamol; avoid NSAIDs due to bleeding risk
  • Tetanus Prophylaxis
  • Antibiotics: Only if signs of secondary infection; snakebite wounds are generally not sterile
  • Wound Care: Debridement if necrosis develops; monitor for compartment syndrome

99.10 Complications

  • Acute Kidney Injury (AKI): Hemoglobinuria or hypotension may lead to renal damage
  • Compartment Syndrome: Due to excessive swelling; requires surgical fasciotomy
  • Limb Loss: From severe necrosis or gangrene
  • Shock: From venom or sepsis
  • Chronic Sequelae:
    • Disfigurement
    • Reduced limb function
    • Psychosocial issues

99.11 Prognosis

  • Prognosis depends on:
    • Type of snake
    • Time to hospital presentation
    • Child’s nutritional status and comorbidities
  • Early intervention greatly improves outcomes.
  • Mortality rates can be significantly reduced with appropriate antivenom and supportive care.

99.12 Prevention Strategies

Community Education:

  • Teach children to avoid snake-infested areas
  • Use of protective clothing (boots, gloves)
  • Awareness about seeking early medical care

Environmental Measures:

  • Keep surroundings clear of bushes and rodents (which attract snakes)
  • Use of mosquito nets (many bites occur at night)

Government and Health Policy

  • Ensure a consistent supply of antivenoms
  • Train rural healthcare workers in snakebite management
  • Integrate snakebite education in school curricula

99.13 Special Considerations in Ghana

  • Traditional beliefs often delay hospital treatment.
  • Transportation difficulties in rural areas
  • Cost of antivenom, though often subsidised, remains a barrier.
  • Lack of access to ventilators in some facilities hinders care for neurotoxic bites

99.14 Case Study (Example)

Patient: 7-year-old boy from Brong-Ahafo
Presentation: Bitten on the left foot while walking through the grass to school
Symptoms: Pain, swelling up to the knee, bleeding from the gums
Findings: Fang marks present, 20WBCT abnormal, hematuria
Management:

  • IV fluids

  • Polyvalent antivenom (2 vials)

  • Paracetamol for pain

  • Close monitoring in the pediatric ward

    Outcome: Swelling reduced by day 3, discharged on day 5 with normal clotting time

99.15 Summary

  • Snake bites are a medical emergency in children, especially in rural Ghana.
  • Prompt immobilization and transportation to a health facility are critical.
  • Antivenom is the cornerstone of treatment for venomous bites.
  • Supportive care and complication management improve survival and reduce the risk of disability.
  • Preventive education and community engagement are essential.

99.16 Key Points

  1. Always suspect a venomous bite in a symptomatic child from an endemic area.
  2. Do not delay administering antivenom if systemic signs or rapid local progression are present.
  3. Monitor vital signs and watch for early and late antivenom reactions.
  4. Avoid outdated or potentially harmful first-aid practices, such as using tourniquets or making incisions.
  5. Educate families and communities about snakebite prevention, early care, and treatment.