Frank G. Walter

Establishing causality of CNS depression in breastfed infants following maternal codeine use.

AbstractBackground: We recently reported on a breastfed infant who succumbed to opioid toxicity following exposure to morphine, the active metabolite of codeine, which was prescribed to his mother who was a cytochrome P450 2D6 (CYP2D6) ultrarapid metabolizer. This report is believed to be the first case of neonatal fatality as a direct result of maternal drug excretion into breast milk and, therefore, it is critical to corroborate the causative relationship between maternal codeine use during breastfeeding and neonatal opioid toxicity with other existing evidence. Objective: To establish whether maternal use of codeine can be a cause of CNS depression in breastfed infants. Study design: A systematic review of the medical literature using several databases was conducted. The Naranjo Adverse Drug Reaction Probability Scale (NADRPS) was used to examine causality. Results: In addition to our case report, three abstracts and two full-length studies reported adverse drug reactions (ADRs) in infants exposed to codeine in breast milk. In total, 35 infants were identified. Specifically, ADRs were described as unexplained episodes of drowsiness, apnea, bradycardia, and cyanosis in suckling infants. Using the NADRPS, codeine was found to be a definite cause of CNS depression in breastfed infants. Conclusion: The use of codeine by breastfeeding mothers can cause adverse CNS events in breastfed infants. Physicians should recognize codeine use during breastfeeding as a cause of CNS depression in infants, and breastfeeding mothers should be educated on these adverse events before receiving codeine.

Epidemiology of organophosphate pesticide poisoning in Taiwan.

Introduction. The nationwide epidemiology of organophosphate pesticide (OP) poisoning has never been reported in detail for Taiwan. Methods. This study retrospectively reviewed all human OP exposures reported to Taiwans Poison Control Centers (PCCs) from July 1985 through December 2006. Results. There were 4799 OP exposures. Most OP exposures were acute (98.37%) ingestions (74.50%) of a single OP (80.37%) to attempt suicide (64.72%) in adults (93.25%). Males were the most common gender (64.95%). Most patients (61.97%) received atropine and/or pralidoxime. The mortality rate for all 4799 OP exposures was 12.71%. Exposures to single OPs without co-intoxicants caused 524 deaths; of these, 63.36% were due to dimethyl OPs. Conclusion. Dimethyl OPs cause the majority of deaths in Taiwan.

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.

Amelioration of nifedipine poisoning associated with glucagon therapy

Glucagon relieves calcium channel blocker-induced hypotension in animal studies. There are no published case reports of glucagon relieving hypotension in patients with calcium channel blocker poisoning. We describe a patient who developed hypotension after ingestion of 900 mg nifedipine. Therapy with IV lactated Ringers solution and calcium chloride alone did not relieve his hypotension. However, hypotension rapidly resolved after the addition of IV glucagon therapy. This is the first case report of glucagon therapy at least temporally associated with relief of hypotension in a patient with calcium channel blocker poisoning. More research is needed to determine the appropriate role for glucagon in treating patients with calcium channel blocker poisoning.

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.

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.

Crotalid Envenomation : The Southern Arizona Experience

Objective To review a regional experience with the treatment of snakebites. Setting Five major southern Arizona hospitals, including two Level I trauma centers. Design A review of all snakebite admissions over a five-year period was performed. Results During the period reviewed, 164 patients were admitted for snakebites. Rattlesnakes were responsible for 98 percent of identified envenomations. Thirty-six percent of the patients were transported by air to the admitting facility. Eighty percent of patients were admitted to the intensive care unit for an average of 1.6 days. Total hospital stays averaged 2.8 days. Ninety percent of patients received antivenin, usually only on the day of admission. Of those receiving antivenin, 20 percent had an anaphylactoid reaction, and 1 percent required readmission for serum sickness. Laboratory evaluation indicated abnormalities in platelet count, coagulation parameters, and fibrinogen levels, but these rarely required treatment. Thirteen percent of patients underwent surgical intervention, including a 4 percent fasciotomy rate, and a single amputation. Conclusion The use of field treatment, including “cut and suck,” tourniquets, and cryotherapy, increased the likelihood of surgery. The authors concluded that the intensive care unit and helicopter transport system were overused. They recommend that established objective envenomation severity scores be used to dictate patient treatment, specifically the use of antivenin.

Delayed Toxic Acetaminophen Level after Initial Four Hour Nontoxic Level

Antidotal therapy for acetaminophen poisoning is routinely based on a single acetaminophen level obtained four or more hours after ingestion. Some experts recommend additional acetaminophen levels if there are coingestants. This case report describes a 20-year-old woman who ingested acetaminophen 13 g, propoxyphene napsylate 2 g and naproxen sodium 3.75 g. A 4.5 h acetaminophen level was 83.5 mg/L (nontoxic). A 6.75 h acetaminophen level was 124.6 mg/L (toxic). The patient was treated with N-acetylcysteine and recovered without sequelae. This is the first published report of a delayed toxic acetaminophen level occurring after an initial nontoxic level. Although rare, the possibility of a delayed peak acetaminophen level merits consideration, particularly with coingestions that delay gastric emptying.

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.

Urine sampling in ambulatory women: Midstream clean-catch versus catheterization

We conducted a study to determine if there were any significant differences in urinalyses or urine cultures obtained by midstream clean-catch (MSCC) urine sampling in comparison with in-and-out catheterization (CATH). One hundred five women with symptoms suggestive of a urinary tract infection were studied prospectively. Each woman had a MSCC urine sample obtained initially, followed by a CATH sample. The MSCC and CATH urine samples were analyzed and compared for urine culture, leukocyte esterase, nitrites, microscopic bacteriuria, and pyuria. Of the 105 patients, 42 (40%) had a culture-proven urinary tract infection. The concordance rates between MSCC and CATH urine cultures, nitrites, leukocyte esterase, significant microscopic bacteriuria, and pyuria were 96%, 94%, 93%, 90%, and 90%, respectively. There were no statistically significant differences between MSCC and CATH sensitivities, specificities, or positive or negative predictive values for any urinalysis variable (leukocyte esterase, nitrites, significant microscopic bacteriuria, or pyuria). We conclude that if proper MSCC technique is used, the differences between MSCC and CATH urinalyses or urine cultures do not appear to be significant in the majority of ambulatory women without active vaginal bleeding who present with symptoms suggestive of a urinary tract infection.