Crotalus morulus (Viperidae: Crotalinae) envenoming and treatment with F(ab')2 antivenom.

We present the first published case of Tamaulipan Rock Rattlesnake (Crotalus morulus) envenoming. A 54-year-old male professional herpetologist was bitten on the left thumb by a captive C. morulus. Pain, swelling, bruising, and pressure in the thumb were experienced within minutes. On presentation, he reported 7/10 pain and had firm edema in his thumb and thenar eminence. Initial laboratory studies showed normal platelet count, PT, PTT, and creatine kinase. He was treated with pain medication and 10 vials of crotalidae immune F(ab')2 (equine) antivenom approximately 3 h post envenoming. Lymphangitic streaking and axillary lymphadenopathy developed, followed by progression of edema, emergence of a hemorrhagic bulla, and declining platelets, prompting treatment with two additional 10-vial antivenom doses. His platelet count declined to 125 × 103/µL 24 hours post envenoming and he developed numbness in his thumb. Following antivenom therapy completion no further decline in platelets occurred and thrombocytopenia improved to 131 × 103/µL prior to discharge 46 hours post envenoming; fibrinogen, PT, PTT, and CK remained normal. He had no residual signs or symptoms 5 months later. C. morulus venom includes proteolytic venom enzymes that induce local soft tissue destruction, pain, and edema with ecchymosis and blister formation. Although C. morulus venom contains a unique disintegrin, morulustatin, no fibrinogenolytic activity was observed.

Metabolic effects of metaproterenol overdose: hypokalemia, hyperglycemia and hyperlactatemia.

This case report of metaproterenol toxicity was associated with hypokalemia, hyperglycemia and hyperlactatemia. A similar triad has been reported in acute theophylline poisoning. Hypokalemia and hyperglycemia have been reported with other beta-agonists, but not metaproterenol. Patients presenting with the metabolic triad of hypokalemia, hyperglycemia, and hyperlactatemia should have theophylline and beta-agonist toxicity included in their differential diagnosis because the prognosis and therapy of these 2 intoxications is markedly different.

Continuous intravenous flumazenil infusion for benzodiazepine poisoning.

This is the first US report of continuous iv flumazenil infusion for benzodiazepine poisoning. A MEDLINE search from 1966 to 1999 revealed no similar reports in the US literature. A 24-y-o woman ingested 50, 2 mg (=100 mg) flunitrazepam tablets in a suicide attempt. She presented 30 min after ingestion with a temperature of 36.5 C, blood pressure of 90/36 mmHg, pulse of 84/min, and shallow respirations of 8/min. Her Glasgow coma scale (GCS) was 8. Her ECG showed sinus rhythm at 80/min, a QRS axis of 30 with no terminal 40 msec deviation, and a QRS interval of 84 msec. She received 0.2 mg flumazenil iv and her GCS improved to 15. She was orogastrically lavaged and given 50 g of activated charcoal. Resedation to a GCS of 8 recurred twice, requiring additional 0.3 mg and 0.5 mg boluses of flumazenil iv, totaling 1.0 mg over 1 h. Then, a continuous flumazenil infusion was started at 1.0 mg/h, maintaining her GCS at 15. Fourteen h later, the continuous flumazenil infusion was terminated, resulting in resedation and clinical hypoventilation. Flumazenil infusion was restarted at 1.0 mg/h with resolution of sedation and hypoventilation. Thirty h after overdose flumazenil infusion was terminated without resedation or hypoventilation. Continuous iv flumazenil infusion is not US Food and Drug Administration approved, and further study is necessary in carefully selected patients to determine its safety and efficacy.

Continuous intravenous midazolam infusion for Centruroides exilicauda scorpion envenomation.

STUDY OBJECTIVE: We sought to describe the effects of continuous intravenous midazolam infusion as therapy for severe bark scorpion (Centruroides exilicauda) envenomation. METHODS: A retrospective chart review from July 1, 1993, through January 1, 1998, identified all patients treated at a university hospital with International Classification of Diseases, Ninth Revision, codes 989.5 (toxic effect of venom) or E905.2 (scorpion sting causing poisoning). By using standardized collection forms, data were extracted from the medical record of every patient who had a grade III or IV envenomation and was treated with a continuous intravenous midazolam infusion. RESULTS: Our search identified 104 patients; 34 had grade III or IV envenomation. Of these, 33 were treated in the ICU with continuous intravenous midazolam infusion. Median patient age was 4 years (range, 1 to 68 years). Midazolam dosage was adjusted to induce a light sleep state to control agitation and involuntary motor activity. The median amount of midazolam resulting in the first recorded decrease in agitation and involuntary motor activity was 0.30 mg/kg (range, 0.03 to 1.76 mg/kg). This first evidence of clinical improvement was recorded as 1.00 hour (median), with a range of 0.00 to 3.75 hours. The initial midazolam infusion rate was 0.10 mg x kg(-1) x h(-1) (median), with a range of 0.01 to 0.31 mg x kg(-1) x h(-1). The maximal midazolam infusion rate was 0.30 mg x kg(-1) x h(-1) (median), with a range of 0.06 to 1.29 mg x kg(-1) x h(-1). The median time until the maximal midazolam infusion rate was 2.5 hours (range, 0.00 to 8.50 hours). The median duration of infusion was 9. 50 hours (range, 4.25 to 20.50 hours). The median length of stay in the ICU was 15.17 hours (range, 6.0 to 28.0 hours), and 85% of patients were discharged directly home. All patients had resolution of abnormal motor activity and agitation during their midazolam infusion. Transient hypoxemia without evidence of end-organ dysfunction was documented in 4 patients during midazolam therapy. CONCLUSION: A continuous intravenous midazolam infusion can be a safe, effective, and readily available treatment option for patients with grade III or IV C exilicauda envenomation.

Envenomations.

Envenomations are uncommon, challenging causes of critical care admissions. This article describes the diagnosis and treatment of envenomations that cause the most critical care admissions in the United States. Most are caused by the following animals: rattlesnakes, copperheads, cottonmouths, coral snakes, brown recluse spiders, and bark scorpions.

Recurrent and persistent coagulopathy following pit viper envenomation.

BACKGROUND: Coagulation abnormalities following crotaline (pit viper) snakebite have traditionally been considered short-lived, but laboratory studies have rarely been reported beyond the first few days of treatment for envenomation. During the course of an antivenom clinical trial, we observed coagulation defects as late as 2 weeks following envenomation. OBJECTIVES: To document and characterize the recurrence or persistence of coagulopathy among patients envenomed by pit vipers and treated with a Fab antivenom. METHODS: Patients with moderate pit viper envenomation were enrolled in a multicenter, prospective clinical trial. A Fab-based antivenom preparation, antivenom polyvalent crotalid (ovine) Fab, was administered in all cases. Platelet count, fibrinogen level, presence of fibrin split products, prothrombin time, and partial thromboplastin time were determined before treatment and at standard intervals during the following 2 weeks. RESULTS: Of 38 patients completing the study, 20 (53%) had recurrent, persistent, or late coagulopathy 2 to 14 days after envenomation. Thrombocytopenia occurred in patients with prior thrombocytopenia; hypofibrinogenemia occurred only in those with prior hypofibrinogenemia or positive fibrin split products. No patient experienced significant spontaneous bleeding. One patient with coagulopathy developed minor bleeding following minor surgery 12 days after envenomation. CONCLUSIONS: Prolonged or recurrent coagulopathy may occur after envenomation by North American pit vipers. Patients treated with Fab-based antivenom may benefit from periodic rather than single-bolus dosing. Patients with coagulopathy should undergo close monitoring during the first 2 weeks after snakebite.

Intravascular hemolysis associated with North American crotalid envenomation.

CASE REPORT: This is a case of severe intravascular hemolysis, without significant coagulopathy, following envenomation by a North American crotalid. A MEDLINE search from 1966-1997, and a review of older literature, revealed no similar cases. A 4-year-old girl was envenomated in her right foot by a 2.5 foot-long rattlesnake whose description matched that of the Hopi rattlesnake (Crotalus viridis nuntius). The snake was not captured. Her initial hematocrit was 45%. In spite of treatment with antivenin and improvement in her lower extremity pain and swelling, her hematocrit decreased to 20.4%. Laboratory tests and clinical exam showed a Coombs positive hemolytic anemia without significant signs of coagulopathy.

Squamous cells as predictors of bacterial contamination in urine samples.

STUDY OBJECTIVE: To determine whether squamous cells in urine indicate bacterial contamination. METHODS: We prospectively studied 105 consecutive women who presented to the emergency department with symptoms suggestive of a urinary tract infection. Two urine samples were collected from each woman, a midstream clean-catch (MSCC) sample and a catheterized (CATH) sample. Microscopic urinalyses to assess for squamous cells and urine cultures to assess for bacterial contamination were performed on all samples. Bacterial contamination was defined as growth of fewer than 10,000 colonies of a single species per milliliter or growth of three or more species of commensal bacteria (mixed flora) in a urine sample. RESULTS: Squamous cells were found in 99 of 105 CATH samples (94%); however, no CATH samples had bacterial contamination. Squamous cells were found in 101 of 105 MSCC samples (96%); however, only 22 MSCC samples (21%) had bacterial contamination. CONCLUSION: The presence of squamous cells in CATH urine samples obtained from women is not indicative of bacterial contamination. The presence of squamous cells in MSCC urine samples obtained from women also is not a good indicator, with an overall predictive value for bacterial contamination of 21%.

Spinal cord injury with a narrow spinal canal: utilizing Torg's ratio method of analyzing cervical spine radiographs.

A 65-year-old inebriated man crashed his car and presented with spinal shock and neurogenic shock from a cervical spinal cord injury without cervical spine fracture or dislocation. The lateral cervical spine radiography was initially read as normal, except for degenerative disk disease; however, Torg's ratio method of analyzing cervical spinal canal sagittal width indicated the spinal canal was congenitally narrow. Magnetic resonance imaging confirmed this and showed bulging and herniation of multiple invertebral disks between C2 and C7. This case illustrates the value of using Torg's ratio method of analyzing lateral cervical spine radiographs. Although Torg's method has not been prospectively validated, it may be useful to identify patients at risk for cervical spinal cord injuries without fractures or dislocations. An abnormal Torg's ratio may be the only clue to the fact that the patient is at higher risk of spinal cord injury when the patient's history or examination is questionable because of head injury, drug intoxication, or therapeutic sedation and paralysis.

Exotic snakebite: envenomation by an African puff adder (Bitis arietans).

We report an envenomation by the African puff adder (Bitis arietans), an exotic snake in the United States. The patient developed swelling and ecchymoses in the affected extremity, and cutaneous necrosis of the envenomated fingertip. There was no significant coagulopathy. He received 20 vials of specific antivenin (Schlangengift-Immunserum Behring Zentralafrika, Behringwerke, Marburg, Germany) and debridement of devitalized finger tissue. The only permanent sequelae were cutaneous scarring and permanent loss of the fingernail on the envenomated finger. Exotic snakebite is a rare presenting problem in emergency departments. The initial approach to a patient envenomated by an exotic venomous snake is discussed. Use of antivenin and supportive care are emphasized.

Loxosceles arizonica bite associated with shock.

Envenomation by the brown recluse spider (Loxosceles reclusa) is associated with shock, significant hemolysis, renal insufficiency, and disseminated intravascular coagulation (DIC). Shock has never been associated with envenomation by L arizonica, a related species indigenous to Arizona, southern California, and northwestern Mexico. We report the case of a 13-year-old girl, bitten by a specimen of L arizonica (the spider was identified by an entomologist), in whom shock and a typical cutaneous lesion developed. She did not experience renal insufficiency or disseminated intravascular coagulation. Infectious causes of shock were excluded. She recovered completely with supportive care.

Cisapride poisoning.

A MEDLINE search from 1966-1996 revealed no reports of cisapride poisoning. An 8-mo-old, 8.9 kg girl received 8 mL of cisapride (Propulsid Suspension, 1 mg/mL, Janssen Pharmaceutica, Titusville, NJ) rather than the usual dose of 0.8 mL, resulting in an inadvertent, 10-fold, iatrogenic, dosing error. She developed emesis, hyperactive bowel sounds, abnormal behavior, mild hyperthermia, tachycardia, hypertension, and thrombocytosis. This is the first published report of poisoning with cisapride.

Snakes and snakebite in Central America.

This review treats the general biology, taxonomy, distribution and venom apparatus of the venomous snakes of Central America. Consideration has been given to the chemistry, pharmacology and immunology of the venom, and particular attention is dispensed to the clinical problem, including the treatment, of envenomations by these reptiles.

Hemodialysis and hemoperfusion for treatment of valproic acid and gabapentin poisoning.

A 31-y-old epileptic man developed coma and shock after suicidally ingesting large amounts of valproic acid and gabapentin. His peak valproic acid, level was 1306.9 micrograms/mL (therapeutic range = 30-100 micrograms/mL). His peak gabapentin level was 60.0 micrograms/mL (therapeutic range = 2.0-8.0 micrograms/mL). His hypotension was refractory to crystalloid and pressor infusions, but resolved during concurrent hemoperfusion and hemodialysis to enhance elimination of valproic acid. Concurrent hemoperfusion and hemodialysis, in series, produced a maximum valproic acid plasma clearance of 55.4 mL/min versus a maximum reported intrinsic valproic acid plasma clearance of 10.6 mL/min. concurrent hemoperfusion and hemodialysis, in series, should be considered in hemodynamically unstable patients with valproic acid poisoning whose clinical condition is worsening in spite of aggressive supportive care.

Gabapentin, valproic acid, and ethanol intoxication: elevated blood levels with mild clinical effects.

CASE REPORT: A suicidal, epileptic patient ingested ethanol, valproic acid, and gabapentin, a new antiepileptic drug. He did well clinically despite elevated blood gabapentin, valproic acid, and ethanol. CONCLUSIONS: Preliminary data from this case and one previous report indicate relatively mild clinical signs and symptoms with gabapentin poisoning.

Marijuana and hyperthermia.

BACKGROUND: Animal and human laboratory studies suggest marijuana may cause hyperthermia. However, there are no clinical case reports of life-threatening hyperthermia associated with use of marijuana alone. CASE REPORT: We report a patient who developed severe hyperthermia after smoking a marijuana cigarette and jogging on a warm day. He presented with delirium; hot, red, dry skin; and a rectal temperature of 41.7 degrees C. Historical and laboratory data indicated he had used cannabinoids and no other drugs. This is the first report of life-threatening hyperthermia temporally associated with use of marijuana alone.

Wound botulism.

Wound botulism is a rare infectious and toxicologic complication of trauma and i.v. drug abuse. Only 39 cases have been reported in detail in the English literature. This case report describes a patient with wound botulism who presented to four medical facilities before receiving definitive diagnosis and treatment. Although his history and physical examination were consistent with wound botulism, diagnosis and therapy were delayed because this rare disease was not considered initially in the differential diagnosis. Wound botulism should be considered in trauma patients and i.v. drug abusers who present with cranial nerve palsies and descending paresis.