Black Widow Spider Antivenin

Antivenin (Latrodectus mactans) is used to treat patients with symptoms due to bites by the black widow spider (Latrodectus mactans). Early use of the Antivenin is emphasized for prompt relief. Local muscular cramps begin from 15 minutes to several hours after the bite which usually produces a sharp pain similar to that caused by puncture with a needle. The exact sequence of symptoms depends somewhat on the location of the bite. The venom acts on the myoneural junctions or on the nerve endings, causing an ascending motor paralysis or destruction of the peripheral nerve endings. The groups of muscles most frequently affected at first are those of the thigh, shoulder, and back. After a varying length of time, the pain becomes more severe, spreading to the abdomen, and weakness and tremor usually develop. The abdominal muscles assume a boardlike rigidity, but tenderness is slight. Respiration is thoracic. The patient is restless and anxious. Feeble pulse, cold, clammy skin, labored breathing and speech, light stupor, and delirium may occur. Convulsions also may occur, particularly in small children. The temperature may be normal or slightly elevated. Urinary retention, shock, cyanosis, nausea and vomiting, insomnia, and cold sweats also have been reported. The syndrome following the bite of the black widow spider may be confused easily with any medical or surgical condition with acute abdominal symptoms.

The symptoms of black widow spider bite increase in severity for several hours, perhaps a day, and then very slowly become less severe, gradually passing off in the course of two or three days except in fatal cases. Residual symptoms such as general weakness, tingling, nervousness, and transient muscle spasm may persist for weeks or months after recovery from the acute stage.

If possible, the patient should be hospitalized. Other additional measures giving greatest relief are prolonged warm baths and intravenous injection of 10 mL of 10 percent solution of calcium gluconate repeated as necessary to control muscle pain. Morphine also may be required to control pain. Barbiturates may be used for extreme restlessness. However, as the venom is a neurotoxin, it can cause respiratory paralysis. This must be borne in mind when considering use of morphine or a barbiturate. Adrenocorticosteroids have been used with varying degrees of success. Supportive therapy is indicated by the condition of the patient. Local treatment of the site of the bite is of no value. Nothing is gained by applying a tourniquet or by attempting to remove venom from the site of the bite by incision and suction.

In otherwise healthy individuals between the ages of 16 and 60, the use of Antivenin may be deferred and treatment with muscle relaxants may be considered.

The following adverse reactions have been reported following the use of Antivenin: Hypersensitivity reactions including anaphylaxis and serum sickness. Muscle cramps have also been reported.

No information provided.