Case files of the medical toxicology fellowship at Drexel University. Rhabdomyolysis and compartment syndrome following acute diphenhydramine overdose

QT interval prolongation and rhabdomyolysis associated with diphenhydramine toxicity: a case report

Diphenhydramine is a widely available, over-the-counter medication used for allergies and as a sleeping aid. When used in prescription doses, it is generally safe.

Overdose of the medication has been associated with dangerous and life-threatening outcomes. Our case describes diphenhydramine toxicity manifesting with two rare but potentially

life-threatening complications, rhabdomyolysis, and QT prolongation. Laboratory testing for diphenhydramine levels are not widely available. We recommend a high degree of suspicion for these complications when evaluating patients with diphenhydramine overdose, to adequately manage and prevent untoward outcomes.

IV Lipid Emulsion Infusion in the Treatment of Severe Diphenhydramine Overdose

BACKGROUND Diphenhydramine is a commonly available over-the-counter antihistamine; however, there are few documented cases of treatment when ingested in toxic quantities, where it can cause a sodium channel blockade leading to wide-complex tachycardia, seizures, and death. Conventional treatment includes sodium bicarbonate infusion, but few cases have documented the addition of lipid emulsion therapy. CASE REPORT A 24-year-old African American female ingested 18 g (360 pills of 50 mg) over-the-counter diphenhydramine. She presented comatose, with hemodynamic instability and hypotension, intubated with pupil dilation to 6 to 7 mm, and initial electrocardiography findings showing a type 1 AV block with a QT/QTc of 360/402 ms which progressed into sinus tachycardia with widened QRS intervals of 134 ms and prolonged QT/QTc intervals of up to 638/759 ms. Treatment using sodium bicarbonate and magnesium was initiated; however, the intraventricular conduction delay persisted. Infusion of 20% intravenous lipid emulsion was administered; following this, the patient developed narrow complex QRS with sinus rhythm and shortened the QT/QTc interval to 448/516 ms. She recovered quickly and was transferred to inpatient psychiatric unit for further evaluation, and discharged 1 month later. CONCLUSIONS Lipid emulsion therapy has been utilized in treatment of various medication overdoses, but there are few documented cases in the treatment of diphenhydramine overdose. With the amount of diphenhydramine ingested by the patient in this case report, the use of combined conventional and lipid emulsion therapy was utilized in the stabilization and management of the patient, and should be considered in scenarios where conventional treatments have not improved the clinical outcome.

Cardiac arrest caused by diphenhydramine overdose

Case

A 45‐year‐old man presented to our emergency department with disturbance of consciousness; he had mentioned to his family earlier about a drug overdose. When first responders arrived, he suffered cardiac arrest. Cardiac arrest due to drug overdose was diagnosed.The patient was supported with venoarterial extracorporeal membrane oxygenation. Arterial blood gas showed mixed acidosis, and electrocardiogram showed junctional rhythm and complete right bundle branch block.

Outcome

The patient's blood pressure gradually decreased, and he died on the third day of hospitalization. After death, his serum diphenhydramine concentration at the time of arrival was found to be 18.7 μg/mL.

Conclusion

Although diphenhydramine is regarded as a safe medication, it shows dose‐dependent toxicity. High intake is associated with death; therefore, caution should be exercised in cases of drug overdose. Developing a procedure for rapid measurement in the emergency department should be a priority.

Compartment and Crush Syndromes After Sleep Deprivation and a Therapeutic Dose of Zolpidem

Despite extensive review in the literature, compartment syndrome and crush syndrome remain difficult to diagnose. Trauma, toxins and reperfusion have been associated with these syndromes. Cases involving alcohol and drug abuse have described patients “found down” compressing an extremity. We present a case of a registered nurse who developed compartment syndrome in multiple limbs due to prolonged sleep after sleep deprivation and zolpidem use. To our knowledge, this is the first case of compartment syndrome or crush syndrome to have occurred in the setting of zolpidem use. Sleep disruption in healthcare workers represents a public health issue with dangerous sequelae, both acute and chronic.

Diphenhydramine exposure in dogs: 621 cases (2008-2013)

OBJECTIVE To characterize the signalment, dose response, and clinical signs of diphenhydramine toxicosis in dogs. DESIGN Retrospective case series. ANIMALS 621 dogs with diphenhydramine exposure. PROCEDURES The electronic medical record database for an animal poison control center was reviewed from January 2008 through December 2013 to identify dogs that had ingested or been injected with diphenhydramine. Information extracted from the records and evaluated included the signalment, clinical signs observed, and estimated exposure dose of diphenhydramine. Clinical signs were categorized as none, mild, moderate, and severe. RESULTS The mean ± SEM age of dogs was 3.6 ± 0.1 years (range, 0.1 to 16 years). Diphenhydramine exposure was by ingestion for 581 (93.6%) dogs and injection for 40 (6.4%) dogs. Only 146 (23.5%) dogs developed ≥ 1 clinical signs of toxicosis, the most common of which were associated with the nervous (lethargy, hyperactivity, agitation, hyperthermia, ataxia, tremors, and fasciculations) or cardiovascular (tachycardia) systems, and 3 dogs died. Although the presence and extent of clinical signs varied greatly among dogs, the exposure dose of diphenhydramine was positively associated with the severity of clinical signs in a dose-dependent manner regardless of the route of exposure (ingestion or injection). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that dogs exposed to diphenhydramine developed clinical signs of toxicosis fairly infrequently, and those clinical signs were generally mild and primarily affected the neurologic and cardiovascular systems. Supportive treatment for diphenhydramine toxicosis should be administered on the basis of the clinical signs observed.

A sneaky surgical emergency: Acute compartment syndrome. Retrospective analysis of 66 closed claims, medico-legal pitfalls and damages evaluation

BACKGROUND

Acute compartment syndrome (ACS) is a clinical condition with potentially dramatic consequences, therefore, it is important to recognise and treat it early. Good management of ACS minimises or avoids the sequelae associated with a late diagnosis, and may also reduce the risk of malpractice claims. The aim of this article was to evaluate different errors ascribed to the surgeon and to identify how the damage was evaluated.

MATERIALS AND METHODS

A total of 66 completed and closed ACS cases were selected. The following were analysed for each case: clinical management before and after diagnosis of ACS, imputed errors, professional fault, damage evaluation and quantification. Particular attention was paid to distinguishing between impairment because of primary injury and iatrogenic impairment. Statistical analyses were performed using Fisher's exact test and Pearson's correlation.

RESULTS

The most common presenting symptom was pain. Delay in the diagnosis, and hence delay in decompression, was common in the study. A total of 48 out of 66 cases resolved with the verdict of iatrogenic damage, which varied from 12% to 75% of global capability of the person. A total of $394,780 out of $574,680 (average payment) derived from a medical error.

CONCLUSIONS

ACS is a clinical emergency that requires continuous clinical surveillance from both medical and nursing staff. The related damage should be evaluated in two parts: damage deriving from the trauma, so that it is considered inevitable and independent from the surgeon's conduct, and damage deriving from a surgeon's error, which is eligible for an indemnity payment.

Diphenhydramine overdose with intraventricular conduction delay treated with hypertonic sodium bicarbonate and i.v. lipid emulsion

Diphenhydramine toxicity commonly manifests with antimuscarinic features, including dry mucous membranes, tachycardia, urinary retention, mydriasis, tachycardia, and encephalopathy. Severe toxicity can include seizures and intraventricular conduction delay. We present here a case of a 23-year-old male presenting with recurrent seizures, hypotension and wide complex tachycardia who had worsening toxicity despite treatment with sodium bicarbonate. The patient was ultimately treated with intravenous lipid emulsion therapy that was temporally associated with improvement in the QRS duration. We also review the current literature that supports lipid use in refractory diphenhydramine toxicity.

Compartment syndrome after "bath salts" use: a case series

In recent years, synthetic cathinones, often labeled as "bath salts" in an attempt to evade drug laws, have emerged as substances of abuse. Sympathomimetic drugs are well known to cause rhabdomyolysis but are rarely associated with acute compartment syndrome. In this case series, we describe 3 patients who presented with sympathomimetic signs or symptoms including hyperthermia and agitation and had confirmed synthetic cathinone use. All 3 patients had severe rhabdomyolysis with delayed development of an acute compartment syndrome. Two patients developed paraspinal compartment syndromes, whereas 1 developed bilateral forearm compartment syndromes. Management included fasciotomy in 2 patients and medical management in the third. Two of the 3 patients made a complete recovery before hospital discharge; the third patient was hemodialysis dependent at 5-month follow-up.