What is the intermediate phase in a snake bite (ophidism)?

From the Guidelines

The intermediate phase of snake bite is a critical period that requires close monitoring and supportive care, typically lasting 1-2 hours after the bite, during which patients may experience progressive local swelling, pain, and early systemic symptoms, and antivenom administration should be considered if there are signs of envenomation progression.

Key Characteristics of the Intermediate Phase

• Progressive local swelling and pain extending beyond the bite site
• Early systemic symptoms like nausea, vomiting, headache, and dizziness
• Mild coagulopathy with prolonged clotting times
• Early neurotoxic symptoms such as ptosis or paresthesias
• Cardiovascular changes including tachycardia and mild hypotension

Management of the Intermediate Phase

• Close monitoring in a medical setting with vital signs checked every 15-30 minutes
• Serial neurological examinations
• Laboratory tests including complete blood count, coagulation studies, and renal function tests
• Antivenom administration should be considered if there are signs of envenomation progression 1
• Supportive care includes intravenous access with crystalloid fluids, pain management with acetaminophen or opioids if needed, and tetanus prophylaxis

First Aid Measures

• Emergency services should be activated for any person bitten by a venomous or possibly venomous snake 1
• Rest and immobilize the bitten extremity and minimize exertion by the person who was bitten if it does not delay access to emergency medical care 1
• Remove rings and other constricting objects from the bitten extremity 1
• Avoid application of ice, suction, electric shock, tourniquets, and pressure immobilization bandaging as they are potentially harmful or of unproven benefit 1

From the Research

Intermediate Phase in Snake Bite (Ophidism)

There is limited information available on the specific intermediate phase in snake bite (ophidism) in the provided studies. However, the following points can be noted:

• The clinical features and severity of snake envenomation can vary depending on several factors, including the type of snake, the amount of venom injected, and the time elapsed since the bite 2.
• The studies provided focus on the diagnosis, treatment, and management of snake envenomation, but do not specifically mention an intermediate phase 3, 2, 4, 5, 6.
• The management of snake bite involves close clinical monitoring and consultation with a physician specialist, as the envenomation syndrome can be erratic and affect multiple organ systems 5.
• Antivenom can reverse systemic poisoning if used correctly, but it is recommended to wait for the appearance of signs of systemic poisoning before administering it 6.

Clinical Features and Severity

The following clinical features can indicate severe snake envenomation:

• Time from bite to care of 6 or more hours 2
• Patient younger than 12 years 2
• Large snake size 2
• Ptosis 2
• Initial hypofibrinogenemia 2
• Thrombocytopenia 2
• Microangiopathic haemolytic anaemia 4
• Thrombocytopenia 4
• Acute kidney injury (AKI) 4

Diagnosis and Treatment

The diagnosis of snake envenomation involves clinical evaluation and laboratory testing, including blood film examination and platelet count 4. The treatment of snake envenomation involves the use of antivenom, which can reverse systemic poisoning if used correctly 6. Therapeutic plasma-exchange is not recommended, as there is no evidence of its effectiveness in treating snakebite-associated TMA 4.