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Latrodectus venom should be distributed in the subcutaneous or dermal tissue and eventually absorbed systemically either through the lymphatics or cutaneous blood vessels. Diffusion through the fascia into the compartment should be minimal. Finally, alpha-latrotoxin, the most important component in black widow venom, is minimally cytotoxic. Instead, as a potent neurotoxin, it acts at nerve terminals by forming cation pores in the cell membrane. This allows calcium influx, resulting in depolarization of nerve cells and release of neurotransmitters, leading to muscular contraction and the symptoms seen in Latrodectism. 3 Even if some localized underlying muscle con- traction would have occurred in this case, it is most often intermittent 2 and should not lead to compartment syndrome. In addition, since alpha-latrotoxin has not been associated with coagulopathy or bleeding, the presence of the intracompartmental hematoma found on magnetic resonance imaging is unexplained. Latrodectus antivenom can be highly effective and functions by binding and neutralizing alpha-latrotoxin. As was done in this case, patients presenting with suspected or documented Latrodectus bite and severe symptoms should be considered for antivenom. Unfortunately, the reader is not informed in this case about other therapies besides morphine that may have occurred either before or simultaneously with the admin- istration of antivenom that may have contributed to this patient’s improvement. Elevation of the extremity, ice, and administration of vasoactive agents such as morphine can influence compartment pressures independently in some cases. 4 Although the sighting of a black spider and the patient’s clinical improvement temporally related to the administration of Latrodectus antivenom in this case support the possibility of Latrodectus-induced compartment pressure elevations, the reader should carefully consider pharmacologic and pathophysiologic mechanisms before adding alpha-latrotoxin to the list of etiologies for compartment syndrome. The presence of an intracompart- mental hematoma on magnetic resonance imaging suggests a different mechanism of injury, such as unreported trauma. Michael J. Matteucci, MD Saralyn R. Williams, MD Richard F. Clark, MD Division of Medical Toxicology, University of California San Diego Medical Center, San Diego, CA doi:10.1016/j.annemergmed.2004.12.033 This correspondence was co-written by LCDR Michael J. Matteucci, MC, USNR while a fellow at UCSD Medical Center training in Medical Toxicology. The views expressed in the correspondence are those of the authors and do not reflect the official policy or position of the Department of the Navy, Department of Defense, nor the U.S. Government. 1. Cohen J, Bush S. Case report: compartment syndrome after a suspected black widow spider bite. Ann Emerg Med. 10.1016/ j.annemergmed.2004.06.018. 2. Clark RF, Wethern-Kestner S, Vance MV, et al. Clinical presentation and treatment of black widow spider envenomation: a review of 163 cases. Ann Emerg Med. 1992;21:782-787. 3. Ushakaryov YA, Volynski KE, Ashton AC. The multiple actions of black widow spider toxins and their selective use in neurosecretion studies. Toxicon. 2004;43:527-542. 4. Robinson D, On E, Halperin N. Anterior compartment syndrome of the thigh in athletesdindications for conservative treatment. J Trauma. 1992;32:183-186. In reply: We thank Matteucci et al for their interest in our case report, and we appreciate the opportunity to respond to their letter. We disagree with their assertion that ‘‘Latrodectus bites are almost always immediately painful.’’ Other authors attest that ‘‘many bites are not recognized initially’’ 1 and ‘‘often the victim does not notice he has been bitten.’’ 2 These observations are corroborated by other literature, as well as by our own clinical experience treating many patients with black widow spider bites. Similarly, local skin changes may be noted but often are not. For example, in Clark et al, 3 a ‘‘target lesion’’ was noted in less than half the patients. In a series from our own institution, there was no discernable envenomation site found in more than one third of patients with black widow spider bites. 4 In another series, only 6% manifested puncture marks, and only 34% had local or regional diaphoresis. 5 Local findings after black widow spider bites are often very subtle. The authors of this correspondence are mistaken in their contention that symptoms in our case were delayed (45 minutes). In fact, the average time from envenomation until onset of symptoms was over an hour and up to 12 hours in one series 3 and up to 6 hours in another. 5 It is likely that widow spider fangs are too small to penetrate muscle compartments. However, the effects of widow spider venom are often observed to affect local musculature as well as muscles remote from the bite site. Local or extremity pain around the site of the bite was noted in 38% of patients in 2 series. 3,5 Therefore, we were not surprised that the muscles of our patient’s arm were severely affected. However, we never attributed the compartment syndrome to local ‘‘cytotoxic’’ venom activity. Instead, we hypothesized that repeated, sustained muscle contractions induced by widow spider envenomation led to this patient’s injuries. Similarly, com- partment syndrome has been reported after strenuous exercise, such as weight lifting. This form of trauma could have caused the hemorrhage observed on ultrasonography as well. We never implied or suggested that widow spider envenomation leads to coagulopathy. We disclosed all therapeutics given to the patient. His extremity was not elevated, and ice was not applied. We could not find any evidence in the literature to support that morphine reduced compartment pressures, although we are aware of many cases where it did not prevent fasciotomy. In contrast, this patient’s compartment pressures decreased from a surgical to a nonsurgical range after black widow spider antivenom. We think Correspondence 680 Annals of Emergency Medicine Volume 45, no. 6 : June 2005
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Latrodectus venom should be distributed in the subcutaneousor dermal tissue and eventually absorbed systemically eitherthrough the lymphatics or cutaneous blood vessels. Diffusionthrough the fascia into the compartment should be minimal.
Finally, alpha-latrotoxin, the most important componentin black widow venom, is minimally cytotoxic. Instead, as apotent neurotoxin, it acts at nerve terminals by forming cationpores in the cell membrane. This allows calcium influx, resultingin depolarization of nerve cells and release of neurotransmitters,leading to muscular contraction and the symptoms seen inLatrodectism.3 Even if some localized underlying muscle con-traction would have occurred in this case, it is most oftenintermittent2 and should not lead to compartment syndrome. Inaddition, since alpha-latrotoxin has not been associated withcoagulopathy or bleeding, the presence of the intracompartmentalhematoma found on magnetic resonance imaging is unexplained.
Latrodectus antivenom can be highly effective and functions bybinding and neutralizing alpha-latrotoxin. As was done in thiscase, patients presenting with suspected or documentedLatrodectus bite and severe symptoms should be consideredfor antivenom. Unfortunately, the reader is not informed inthis case about other therapies besides morphine that mayhave occurred either before or simultaneously with the admin-istration of antivenom that may have contributed to this patient’simprovement. Elevation of the extremity, ice, and administrationof vasoactive agents such asmorphine can influence compartmentpressures independently in some cases.4
Although the sighting of a black spider and the patient’sclinical improvement temporally related to the administration ofLatrodectus antivenom in this case support the possibility ofLatrodectus-induced compartment pressure elevations, the readershould carefully consider pharmacologic and pathophysiologicmechanisms before adding alpha-latrotoxin to the list of etiologiesfor compartment syndrome. The presence of an intracompart-mental hematoma on magnetic resonance imaging suggests adifferent mechanism of injury, such as unreported trauma.
Michael J. Matteucci, MDSaralyn R. Williams, MDRichard F. Clark, MDDivision of Medical Toxicology, University of California SanDiego Medical Center, San Diego, CA
doi:10.1016/j.annemergmed.2004.12.033
This correspondence was co-written by LCDR Michael J.Matteucci, MC, USNR while a fellow at UCSD Medical Centertraining in Medical Toxicology. The views expressed in thecorrespondence are those of the authors and do not reflect theofficial policy or position of the Department of the Navy,Department of Defense, nor the U.S. Government.
1. Cohen J, Bush S. Case report: compartment syndrome after asuspected black widow spider bite. Ann Emerg Med. 10.1016/j.annemergmed.2004.06.018.
2. Clark RF, Wethern-Kestner S, Vance MV, et al. Clinical presentationand treatment of black widow spider envenomation: a review of 163cases. Ann Emerg Med. 1992;21:782-787.
3. Ushakaryov YA, Volynski KE, Ashton AC. The multiple actions of blackwidow spider toxins and their selective use in neurosecretionstudies. Toxicon. 2004;43:527-542.
4. Robinson D, On E, Halperin N. Anterior compartment syndrome of thethigh in athletesdindications for conservative treatment. J Trauma.1992;32:183-186.
Correspondence
680 Annals of Emergency Medicine
In reply:We thank Matteucci et al for their interest in our case report,
and we appreciate the opportunity to respond to their letter. Wedisagree with their assertion that ‘‘Latrodectus bites are almostalways immediately painful.’’ Other authors attest that ‘‘manybites are not recognized initially’’1 and ‘‘often the victim doesnot notice he has been bitten.’’2 These observations arecorroborated by other literature, as well as by our own clinicalexperience treating many patients with black widow spider bites.Similarly, local skin changes may be noted but often are not.For example, in Clark et al,3 a ‘‘target lesion’’ was noted in lessthan half the patients. In a series from our own institution, therewas no discernable envenomation site found in more than onethird of patients with black widow spider bites.4 In anotherseries, only 6% manifested puncture marks, and only 34% hadlocal or regional diaphoresis.5 Local findings after black widowspider bites are often very subtle.
The authors of this correspondence are mistaken in theircontention that symptoms in our case were delayed (45minutes). In fact, the average time from envenomation untilonset of symptoms was over an hour and up to 12 hours in oneseries3 and up to 6 hours in another.5
It is likely that widow spider fangs are too small to penetratemuscle compartments. However, the effects of widow spidervenom are often observed to affect local musculature as well asmuscles remote from the bite site. Local or extremity painaround the site of the bite was noted in 38% of patients in 2series.3,5 Therefore, we were not surprised that the muscles ofour patient’s arm were severely affected. However, we neverattributed the compartment syndrome to local ‘‘cytotoxic’’venom activity. Instead, we hypothesized that repeated,sustained muscle contractions induced by widow spiderenvenomation led to this patient’s injuries. Similarly, com-partment syndrome has been reported after strenuous exercise,such as weight lifting. This form of trauma could have causedthe hemorrhage observed on ultrasonography as well. We neverimplied or suggested that widow spider envenomation leads tocoagulopathy.
We disclosed all therapeutics given to the patient. Hisextremity was not elevated, and ice was not applied. We couldnot find any evidence in the literature to support that morphinereduced compartment pressures, although we are aware of manycases where it did not prevent fasciotomy. In contrast, thispatient’s compartment pressures decreased from a surgical to anonsurgical range after black widow spider antivenom. We think
Volume 45, no. 6 : June 2005
Correspondence
that a response to antivenom (rather than morphine) is a moreplausible explanation for the decrease in compartment pressure.
Trauma can certainly cause compartment syndrome, but ourpatient did not recall any trauma. We would suspect that hewould recall trauma significant enough to cause compartmentsyndrome. However, he did recall a spider fitting the descriptionof a black widow crawling on the affected arm. All thingsconsidered, we maintain that the most likely cause of ourpatient’s compartment syndrome was black widow spiderenvenomation.
Jennifer Cohen, MDDepartment of Emergency MedicineLoma Linda University Medical CenterLoma Linda, CA
Sean Bush, MDDepartment of Emergency Medicine
IMAGES IN EMERG(continued fro
DIAGNOSIS:Transabdominal ultrasonographic examination reveale
the uterus with a heart rate of 147 beats/min (Figures 1 anPathology of the surgical specimen showed evidence of orirupture and subsequent re-establishment in the abdominalocated in the fallopian tube, with the incidence of abdopregnancies. Abdominal pregnancies can progress furtherof up to 11%.
Ectopic pregnancy is a life-threatening condition. Whenproducts of conception must be visualized inside of the uthey are truly intrauterine and an ectopic pregnancy is notassessing pregnant patients in their second trimester or band that no ultrasonography is required because normal
Volume 45, no. 6 : June 2005
Loma Linda University School of MedicineMedical Center and Children’s HospitalLoma Linda, CA
doi:10.1016/j.annemergmed.2005.01.036
1. Boyer Hassen L, McNally J. Spider bites. In: Auerbach P, ed.Wilderness Medicine: Management of Wilderness and EnvironmentalEmergencies. St. Louis, MO: Mosby Year Book; 2001:829-833.
2. Kobernick M. Black widow spider bite. Am Fam Physician. 1984;29:241-245.
3. Clark RF, Whethern-Kestner S, Vance MV. Clinical presentation andtreatment of black widow spider envenomation: a review of 163cases. Ann Emerg Med. 1992;21:782-787.
4. Woestman R, Perkin R, Van Stralen D. The black widow: is she deadlyto children? Pediatric Emerg Care. 1996;12:360-364.
5. Isbister GK, Gray MR. Latrodectism: a prospective cohort studyof bites by formally identified redback spiders. Med J Aust. 2003;179:88-91.
ENCY MEDICINEm p. 676)
d a 13-week intraabdominal fetus located posterior tod 2). The patient underwent resection of the pregnancy.ginal implantation in the right fallopian tube with tuball cavity. Approximately 96% of ectopic pregnancies areminal pregnancy estimated at less than 1% of ectopicthan most ectopic pregnancies, with fetal survival rates
performing a pelvic ultrasonographic examination, theterus and in between the endometrium to ensure thatmissed. Emergency physicians should be cautious wheneyond and assuming that the pregnancy is intrauterinefetal heart tones are obtained.
Annals of Emergency Medicine 681
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