Black Widow (latrodectus) Spider Bite

Muscle pain and fasciculations caused by binding of the toxin (venom) to membrane receptors can result in excessive stimulation of the motor end plates. Muscle spasms may involve the abdomen and can lead to the erroneous diagnosis of an acute surgical condition.

Causes

The venom of spiders in the genus Latrodectus and in members of the genus Phoneutria is a nonhemolytic, noncytotoxic neurotoxin that produces diffuse central and peripheral nervous excitement, autonomic activity, muscle spasm, High blood pressure, and vasoconstriction in humans. Other symptoms may include abdominal rigidity, intense pain, paresthesia, headache, sweating, nausea, and facial blood vessel congestion.

The venom of spiders of the Loxosceles is a mixture of hemolysin and cytotoxin that causes ischemic necrosis at the site of the bite. The bite often is relatively painless, and the lesion initially is surrounded by a bluish-white halo of vasoconstriction that may later develop extensive gangrene. Tarantulas, or wolf spiders, of various genera, including Lycosa and Phidippus , also may cause necrosis and ulceration in humans.

Symptoms

• Severe muscle pain and muscle spasms of the involved area, which may progress to the abdomen, back, and other areas
• Pain usually begins within 30 minutes to 2 hours at the site of the bite and is followed by painful muscle cramping in 3 to 4 hours.

Signs

• Muscle fasciculations

Treatment

It is usually used if you have difficulty breathing, seizures, or high blood pressure, or are pregnant.

Treatment also includes:

• Medication for pain and spasms. Pain and spasms may be severe enough to require benzodiazepines, such as lorazepam or diazepam, or narcotics, such as meperidine (Demerol).
• Antihypertension medications for high blood pressure.
• Support the airway, breathing, and circulation per ACLS protocols with oxygen, monitors, and intravenous line.
• Electric shock and various folk and herbal remedies lack therapeutic value and are potentially harmful.
• Wash the bite with soap and water and remove all jewelry.
• Apply cool compresses.