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4. Black Widow Spider Bite: “Can’t We Just Get a Divorce?”
Keywords
Black widowSpiderBiteEnvenomationAlpha-latrotoxinLatrodectusLatrodectismCase
Pertinent History
This patient is a 7-year-old male who presented after falling from a tree. The child was climbing the tree and lost his balance falling approximately 7 feet, landing on a pile of broken branches. He suffered an injury to his left arm, resulting in a deformity. He was initially seen in the emergency department without a trauma activation. He denied loss of consciousness, neck pain, or back pain. His primary concern was the pain in his arm. Over the course of next 20 minutes, patient developed abdominal rigidity, tachycardia, and mild hypertension. He was then converted to a trauma activation.
Pertinent Physical Exam
Vital signs: Blood pressure 160/95, heart rate 120, respiratory rate 18, temperature 99.4 °F
HEENT: Atraumatic, pupils equal round and reactive to light (7 mm bilaterally), mild ptosis is noted.
Neck: No cervical spine tenderness or bruising noted.
Heart: S1-S2, regular rhythm and tachycardia.
Lungs: Clear bilaterally to auscultation.
Chest wall: No significant bruising or deformity.
Abdomen: Rigid with involuntary guarding and no rebound. Bowel sounds are present.
Extremities: Left upper extremity has a silver fork deformity with swelling noted around the wrist. All other extremities appear intact.
Neuro: Patient moves all extremities and appears to have normal sensation and strength bilaterally.
Skin: Warm and dry.
Pertinent Test Results
Lab Results | |||
|---|---|---|---|
Test | Results | Units | Normal range |
WBC | 14.9 | K/uL | 3.8–11.0 103/mm3 |
Hgb | 14.2 | g/dL | (Male) 14–18 g/dL (Female) 11–16 g/dL |
Platelets | 190 | K/uL | 140–450 K/uL |
CT abdomen: Poor-quality study, motion artifact. No evidence of obvious intra-abdominal injury.
ED Management
After the development of abdominal rigidity, he was converted to a level II trauma and was seen by the trauma team. He had an IV established and was given 25 μg of fentanyl for pain. His arm was splinted. A FAST exam was performed, showing no intraperitoneal fluid. The decision was made to send him for an abdominal CT scan.
Updates on ED Course
Update 1
During the CT scan, the technician called back to say that the patient continues to move and appears to be in substantial discomfort. He was given additional 25 μg of fentanyl. A second call was received, and the team went in to examine the patient. He appeared to have fasciculations and muscle spasms in his abdomen, chest, arms, and legs. His blood pressure was 170/100 mmHg with a heart rate of 140 bpm. The patient was diaphoretic and appeared uncomfortable. He received 1 mg of lorazepam IV, which did not help with the muscle spasms. A second 1 mg of lorazepam was given with little effect.
Update 2
The patient had worsening muscle spasms and now developed labored respirations. At this time, ED and trauma teams were perplexed as to what was causing the patient’s symptoms. Bedside pulmonary function test was performed showing a negative inspiratory force of negative 15 mmHg. End-tidal CO2 was measured at 52 mmHg. He was electively intubated using rocuronium and etomidate. Hypersalivation was noted during the procedure. His sedation was maintained with propofol. His postintubation BP was 200/110 mmHg. He was started on a titratable nicardipine drip with SBP goal of less than 140 mmHg. He was taken for head and cervical spine CT, which were interpreted as normal.
The providers re-examined the patient from head to toe and found a small red patch on his right flank with what appeared to be two small puncture marks. The emergency medicine attending postulated that this might be a black widow envenomation given his symptomatology, including hypertension, muscle rigidity, increased secretions, and respiratory compromise along with the noted wound. The surgery attending was skeptical at first but became more convinced when the emergency physician contacted a toxicology fellow that had a particular interest in envenomation. The fellow confirmed that these findings were in fact indicative of a black widow spider envenomation, although worse than most. The fellow himself admitted to having been bitten by a widow spider on a camping trip when he was in the boy scouts and could attest to the very real nature of the abdominal muscle spasms. Toxicology was formally consulted, and the patient was admitted to the Pediatric ICU after being cleared by the trauma team.
Learning Points
Priming Questions
- 1.
What is the classic presentation of a black widow envenomation?
- 2.
What important features of the history and physical exam point to envenomation?
- 3.
What diagnostic findings may mislead black widow spider bites as a surgical emergency?
- 4.
What is the treatment of black widow spider bites?
Introduction/Background
- 1.
The black widow spider is a member of the genus Latrodectus, which roughly translates into the “bandit biter.” There are 31 species of widow spider but only three are found in North America. These are L. mactans (the Southern widow), L. hesperus (Western widow) and L. variolus (the Northern widow). They are all called black widow spiders.
- 2.
Black widow spiders are found across the United States, and are considered the most clinically significant spider envenomation [1]. Building webs in uninhabited dark places such as barns, garages, outhouses, fences, and woodpiles, they only bite when unexpectedly disrupted or their web is disturbed. Both males and females have the typical red hourglass-shaped marking on the underside of these otherwise black or brown spiders. Females are larger, have longer fangs, and are typically more capable of causing systemic toxic responses in humans. Mild black widow spider bites may cause local pain with minimal swelling, but severe bites may present with greater systemic severity such as autonomic dysfunction. Classically seen in the hospital with impressive abdominal rigidity, the pain may be severe, but the prognosis is good and mortality is rare. Treatment is generally supportive and focuses on pain control, but the clinical presentation warrants ruling out other concerning differential diagnoses (Figs. 4.1, 4.2, 4.3, and 4.4).
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