SNAKE BITE (عضة الثعبان)
Clinical Assessment & Management Protocols
Overview & Pathophysiology
About 50-70% of bites cause envenomation. Two main families are dangerous to humans:
Hemotoxic Snake: (e.g., Horned Viper) - Causes coagulopathy & tissue necrosis.
Neurotoxic Snake: (e.g., Egyptian Cobra) - Causes muscle paralysis & respiratory failure.
1. Hemotoxic Snake (الطريشة / أم قرون)
Hemotoxic & Cytotoxic
Clinical Syndrome:
- Inflammatory: Local edema (may spread to trunk) ± Blisters.
- Hemorrhagic: Coagulopathy, spontaneous bleeding, skin necrosis, compartment syndrome.
Hemotoxic Antivenom Dosage (Standard):
| Severity | Dose | Instructions |
|---|---|---|
| Minimal | None | Observe 24h |
| Mild | 3 Ampules | In Saline over 1-2h, repeat Q4-6h PRN |
| Moderate | 5 Ampules | In Saline over 1-2h, repeat Q4-6h PRN |
| Severe | 10 Ampules | Repeat as needed. Consider FFP/Platelets if bleeding. |
Saudi MOH Guidelines (Hemotoxic):
- Mild (Local): 5–10 vials.
- Moderate (Bleeding): 10–20 vials + FFP.
- Severe (DIC/Renal): 20–30 vials + ICU + Dialysis.
2. Neurotoxic Snake (الكوبرا المصرية)
Blocks Acetylcholine at NMJ → Descending Muscle Paralysis.
Pathognomonic Sign: Bilateral Ptosis (سقوط الجفن)
Bulbar palsy (Dysarthria, Dysphagia)
Descending paralysis (Eyes → Face → Limbs → Diaphragm)
Autonomic Storm (Sweating, Tachycardia)
Management:
- Antivenom: Initial dose 5-10 ampules over 1-2 hours. Repeat Q4-6h.
- Respiratory: Early intubation if respiratory muscles are involved.
⚠️ Atropine is Contraindicated (Worsens tachycardia).
Clinical Severity Grading (All Bites)
| Grade | Symptoms | Treatment |
|---|---|---|
| 0 (Dry) | No envenomation, minor pain. | Wound care, Observe 6-8h. |
| 1 (Mild) | Local swelling, normal labs. | Consider Antivenom if near airway. |
| 2 (Moderate) | Progressive edema, vomiting, coagulopathy. | Admit + Antivenom. |
| 3 (Severe) | Rapid swelling, shock, neuro signs. | ICU + Antivenom + Airway. |
| 4 (Critical) | Anasarca, internal hemorrhage, paralysis. | ICU + High dose Antivenom. |
Essential Investigations
Coagulation: PT, INR, PTT, Fibrinogen (Repeat Q6h).
CBC: Hemolytic anemia, Thrombocytopenia.
Renal/Liver: BUN, Creatinine, SGPT, SGOT.
Cardiac: ECG, Troponin (Cardiotoxicity).
Urine: Hematuria, Myoglobinuria.
