Snakebite envenomation

What it is

From: Orphanet

A rare disorder due to poisoning caused by toxins in the bite of a venomous snake. Envenoming can also be caused by spraying of venom into the eyes. Depending on venom composition and other factors, consequences range from local tissue damage to potentially life-threatening systemic effects. Severe manifestations include paralysis, bleeding disorders, kidney failure, or permanent disability and limb amputation due to severe local tissue destruction. Children may suffer more severe effects because of their lower body mass. Immediate medical attention, in particular administration of antivenom, is critical.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Edema · Very frequent (99-80%)

An abnormal accumulation of fluid beneath the skin, or in one or more cavities of the body.

Ecchymosis · Frequent (79-30%)

A purpuric lesion that is larger than 1 cm in diameter.

Erythema · Frequent (79-30%)

Redness of the skin, caused by hyperemia of the capillaries in the lower layers of the skin.

Localized skin lesion · Frequent (79-30%)

A lesion of the skin that is located in a specific region rather than being generalized.

Pain · Frequent (79-30%)

An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.

Abnormal bleeding · Occasional (29-5%)

An abnormal susceptibility to bleeding, often referred to as a bleeding diathesis. A bleeding diathesis may be related to vascular, platelet and coagulation defects.

Abnormality of coagulation · Occasional (29-5%)

An abnormality of the process of blood coagulation. That is, altered ability or inability of the blood to clot.

Abnormality of the nervous system · Occasional (29-5%)

An abnormality of the nervous system.

Cerebral ischemia · Occasional (29-5%)

Restriction of arterial blood supply to the brain associated with insufficient oxygenation to support the metabolic requirements of the tissue.

Hypofibrinogenemia · Occasional (29-5%)

Decreased concentration of fibrinogen in the blood.

Intracranial hemorrhage · Occasional (29-5%)

Hemorrhage occurring within the skull.

Muscle fiber necrosis · Occasional (29-5%)

Abnormal cell death involving muscle fibers usually associated with break in, or absence of, muscle surface fiber membrane and resulting in irreversible damage to muscle fibers.

Paralysis · Occasional (29-5%)

Paralysis of voluntary muscles means loss of contraction due to interruption of one or more motor pathways from the brain to the muscle fibers. Although the word paralysis is often used interchangeably to mean either complete or partial loss of muscle strength, it is preferable to use paralysis or plegia for complete or severe loss of muscle strength, and paresis for partial or slight loss. Motor paralysis results from deficits of the upper motor neurons (corticospinal, corticobulbar, or subcorticospinal). Motor paralysis is often accompanied by an impairment in the facility of movement.

Pseudobulbar paralysis · Occasional (29-5%)

Bilateral impairment of the function of the cranial nerves 9-12, which control musculature involved in eating, swallowing, and speech. Pseudobulbar paralysis is characterized clinically by dysarthria, dysphonia, and dysphagia with bifacial paralysis, and may be accompanied by Pseudobulbar behavioral symptoms such as enforced crying and laughing.

Other findings in the same source

From: Orphanet

Additional reported features include Rhabdomyolysis (Occasional (29-5%)); Speech articulation difficulties (Occasional (29-5%)); Stroke (Occasional (29-5%)); Tachycardia (Occasional (29-5%)); Thrombocytopenia (Occasional (29-5%)); Vomiting (Occasional (29-5%)); Acute kidney injury (Very rare (<4-1%)); Angioedema (Very rare (<4-1%)); Cardiogenic shock (Very rare (<4-1%)); Diarrhea (Very rare (<4-1%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

All ages

Inheritance in the source

From: Orphanet

Not applicable

Frequency and the population described

From: Orphanet

Point prevalence: 1-9 / 100 000; Europe; Class only.

Which doctor should you see?

The suggested department for discussing Snakebite envenomation is Emergency Medicine, with a emergency physician as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• What is the immediate problem that needs stabilisation?
• Which results and discharge instructions should the family keep?
• What follow-up and return precautions are needed after emergency treatment?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Snakebite envenomation. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.