Diagnostic dilemma: A woman injected herself with venom from a black widow spider

The patient: A 37-year-old woman in California

The symptoms: The woman visited the emergency room with severe cramps and muscle pain, primarily in her back, abdomen and thighs. She also reported having a headache and feeling anxious. Her pulse, respiratory rate and blood pressure were elevated, and she had a temperature of 99.5 degrees Fahrenheit (37.5 degrees Celsius), a little below the typical threshold for a fever.

What happened next: Upon admission to the ER, the patient — who had a history of heroin use — told her doctors that she had tried to get high by grinding up a black widow spider (Latrodectus genus), mixing it with 0.35 fluid ounces (10 milliliters) of distilled water, and then injecting it intravenously. Her symptoms appeared one hour later. Several hours after arriving at the hospital, the woman began to have trouble breathing. Her wheezing became so severe that she was moved to the intensive care unit (ICU).

The diagnosis: Doctors determined that the patient's symptoms were triggered by the black widow's toxic venom, they wrote in a report. Black widow venom is known to disrupt signals in the nervous system, thus causing muscle pain and spasms, rapid heartbeat and high blood pressure. In some cases, it leads to inflammation that can ultimately restrict breathing, according to Harvard Medical School. The patient had asthma, and the physicians suspected that her breathing difficulties may have been worsened by an allergic reaction to a protein found in the venom.

Notably, when a black widow bites, it injects a very low volume of venom. Because the woman ground up the whole spider, she may have exposed herself to a dose orders of magnitude higher than is typical. A black widow's venom glands hold about 0.2 milligrams of venom, on average.

The treatment: Doctors gave the woman an IV solution of calcium gluconate, a medication that can help relieve muscle cramps, but her symptoms did not improve significantly. Next, she received morphine for pain relief. The ICU doctors attempted to reduce her wheezing with three treatments of albuterol, a drug that relaxes airway muscles and is a common remedy for asthma. When those treatments were ineffective, they switched to methylprednisolone, a steroid medication. But her labored breathing continued, and the next day, she required a nebulizer. Doctors then gave her morphine and lorazepam — a type of depressant — to ease her muscle spasms and cramping.

Antivenin, or antivenom, for black widow bites carries a risk of anaphylaxis, a severe and immediate allergic reaction. Since the patient was already having trouble breathing, and the doctors suspected that antivenin would worsen her respiratory distress, they did not include it in her treatment.

By the second day of treatment, the patient's breathing had returned to normal, her lungs were unobstructed and her muscle pain was gone. The doctors transferred her to a general ward and discharged her a day later. They instructed her to follow her standard regimen for controlling her asthma and suggested that she take oral steroids to control any lingering inflammation.

What makes the case unique: Most exposures to black widow venom are accidental.

Approximately 2,600 bites from black widow spiders are reported annually in the United States, and these bites typically happen when people inadvertently disturb the spiders in or near their webs, according to Cleveland Clinic. Deliberately injecting spider venom into the body or inducing a bite for recreational reasons is rare but not unheard of.

For instance, in 2023, an 8-year-old boy in Bolivia placed a black widow on his hand and allowed it to bite him. He believed that the bite would grant him superpowers like Spider-Man, Newsweek reported at the time.