Characterization of opioid consumption and disposal patterns after total knee arthroplasty.

AIMS: The aim of this study was to determine the general postoperative opioid consumption and rate of appropriate disposal of excess opioid prescriptions in patients undergoing primary unilateral total knee arthroplasty (TKA). PATIENTS AND METHODS: In total, 112 patients undergoing surgery with one of eight arthroplasty surgeons at a single specialty hospital were prospectively enrolled. Three patients were excluded for undergoing secondary procedures within six weeks. Daily pain levels and opioid consumption, quantity, and disposal patterns for leftover medications were collected for six weeks following surgery using a text-messaging platform. RESULTS: Overall, 103 of 109 patients (94.5%) completed the daily short message service (SMS) surveys. The mean oral morphine equivalents (OME) consumed during the six weeks post-surgery were 639.6 mg (sd 323.7; 20 to 1616) corresponding to 85.3 tablets of 5 mg oxycodone per patient. A total of 66 patients (64.1%) had stopped taking opioids within six weeks of surgery and had the mean equivalent of 18 oxycodone 5 mg tablets remaining. Only 17 patients (25.7%) appropriately disposed of leftover medications. CONCLUSION: These prospectively collected data provide a benchmark for general opioid consumption after uncomplicated primary unilateral TKA. Many patients are prescribed more opioids than they require, and leftover medication is infrequently disposed of appropriately, which increases the risk for illicit diversion. Cite this article: Bone Joint J 2019;101-B(7 Supple C):98-103.

Heparin-induced thrombocytopenia.

Abstract A summary of heparin-induced thrombocytopenia (HIT) is presented. HIT is an adverse drug reaction characterized by thrombocytopenia and a high risk for venous or arterial thrombosis. The frequency of HIT ranges from 1 to 5% of patients receiving heparin with exact frequencies ranging between specific agents. Interestingly, this immune-mediated syndrome is ironically associated with thrombosis, not bleeding, with thrombin formation playing a major role. It is caused by heparin-dependent, platelet-activating antibodies that identifies a self-protein, PF4, bound to heparin that results in an antibody formation. The resulting platelet activation is associated with increased thrombin generation. Typically, the platelet count fall begins 5-10 days after starting heparin, although a rapid platelet count fall can occur in a patient who has antibodies from recent heparin use. Typical causes of HIT as well as the best diagnostic studies and treatment are discussed in this review. HIT was reviewed using a pubmed™ search; google scholar™ using key words: "Heparin-induced thrombocytopenia"; "heparin", and "drug AND thrombocytopenia."

Outcomes following abuse of methanol-containing carburetor cleaners.

INTRODUCTION: Carbureter cleaners may contain methanol and are abused via inhalation. Toxicity resulting from the methanol component of these products is poorly described. METHODS: We conducted a retrospective poison center chart review over a four-year period (3/98-3/02) of outcomes following methanol-containing carbureter cleaners (MCC) exposure. Inclusion criteria were: (1) use of MCC, (2) evaluation in health care facility (HCF), (3) no known co-ingestion exposure and (4) at least 12 hour follow-up. RESULTS: 33 cases were reviewed with 11 cases excluded because of significant co-ingestions. Of the remaining 22 cases the mean age was 17 [range: 14-41] years old with 90% of cases between 14 and 17 years old. Six women and 16 men were in the study. Six of 22 cases had acidosis (serum bicarbonate < or =22 mmol/L or pH < or =7.35), 100% of patients had neurological symptoms (ataxia, etc.) and 14/22 had vomiting on presentation. Three patients received treatment with ethanol (1) and fomepizole (2). All others received intravenous fluids (15) or no treatment (4). Mean serum methanol concentration was 28mg/dl [range: 0-341 with 17/22 developing acidosis. Serum methanol was obtained at a mean of 3.5 hours [range 1-7 hours] post use. All metabolic disturbances resolved within 24 hours except in one patient (41 years old) in which her disturbances resolved within 72 hours. No patient developed visual disturbances or neurological sequealae. CONCLUSIONS: Significant toxicity following inhalation of MCC was rare with symptoms improving without aggressive care (dialysis, alcohol dehydrogenase blockade).

Scorpion envenomations in young children in central Arizona.

INTRODUCTION: Centruroides sculpturatus, also known as Centruroides exilicauda or bark scorpion, is the only scorpion native to the United States whose venom produces a potentially life-threatening illness, particularly in children. OBJECTIVES: To describe the distribution of the severity grades following scorpion envenomations, the onset of clinical signs and symptoms, the time to deterioration, and side effects of antivenom treatment in children < or = 2 yrs of age. METHODS: Prospective case-series with the following inclusion criteria of presumed scorpion envenomation, witnessed scorpion or signs and symptoms consistent with envenomation, patient age < or = 2 yrs, and the call was received by the poison center. After data were entered prospectively, a reviewer who was blinded as to the purpose of the study reviewed the charts. A second reviewer examined 10% of the charts for accuracy in coding. Envenomation severity grades were based on a previously described scorpion grading scale and were correlated with admission rates, clinical deterioration, and outcomes. Descriptive statistics (STATA & EXCEL) were used. RESULTS: Of the 491 charts, 483 (98%) had adequate information available. The mean age was 20.8 [range 2-24] months with 133 patients (27.5%) presenting to an emergency department (ED), 86 patients (17.8%) received antivenom, and 25 patients (5.2%) were admitted. The p-value for kappa and the 95% confidence interval (CI) for interobserver reliability kappa score was 0.69 with CI (0.44-0.95). The grade distributions were Grade I = 343 cases (71%), Grade II = 8 cases (1.7%), Grade III = 49 cases (10.1%), and Grade IV = 83 cases (17.2%). The mean time to advancement of grade was 14 min (95% CI [10.97,17.06], 99% CI [10.04,18.03]) and the median time was < 1 min (range 0-140 min). Twenty-five patients (5.2%) were admitted, of which 13 were Grade III and 12 were Grade IV. Three patients (0.6% of total), all Grade IV envenomations, were intubated (95% CI [0.0021-0.0181] or an upper limit of 8.7 patients). Antivenom was administered to 86 patients (17.8%). The mean time of abatement of symptoms following antivenom was 31 [95% CI 10-82] min vs. 22.2 h [95% CI 12-46]. There was one acute reaction (rash) to antivenom administration and 49 cases (57%) of serum sickness. CONCLUSIONS: Clinical progression following scorpion envenomation in children < or = 2 yrs old occurred on average within 14 min of envenomation with onset almost immediately. Serum sickness occurred in 57% of toddlers receiving antivenom and typically lasted less than 3 days. Admissions were less common among patients receiving antivenom.

Snakebite envenomation in children: a 10-year retrospective review.

OBJECTIVE: To describe the epidemiology, short-term outcomes, and clinical characteristics of rattlesnake bites (RSB) in children. METHODS: This was a 10-year retrospective chart review of all patients who were <13 years old admitted to a medical toxicology referral service in a major metropolitan area of the southwestern United States with a diagnosis of RSB. RESULTS: Sixty-six children (mean age, 6.33 years) presented to or were transferred to our center with a diagnosis of RSB. Sixty-three percent were male, and the majority of bites (71.93%) occurred on the lower extremities. Forty-nine children (85.96%) developed coagulopathies, and 50 children (87.72%) received Antivenin (Crotalidae) Polyvalent (ACP) administration. Of the 50 children receiving ACP, 19 developed an immediate hypersensitivity reaction. Five cases of morbidity resulted, but no deaths were recorded. CONCLUSIONS: Serious morbidity is infrequent in children following RSB.

Narcotic analgesia in the acute abdomen--a review of prospective trials.

Withholding administration of narcotic analgesia in patients with acute abdominal pain for fear of masking pathology is still pervasive in current medical practice. We reviewed all the prospective trials that investigated the safety, adverse affects, and ultimate outcome in patients with acute abdominal pain receiving narcotic analgesia within the emergency department (ED). No adverse outcomes or delays in diagnosis could be attributed to the administration of analgesia. Based on this research, we propose that it is safe and humane to administer narcotic pain relief to patients presenting to the ED with acute abdominal pain provided no contraindications exist.

Ventricular fibrillation following inhalation of Glade Air Freshener.

Intentional hydrocarbon inhalation can be fatal. Death can be secondary to hydrocarbon's cardiopulmonary effects. We present a case of a patient who survived ventricular fibrillation after inhalation of Glade Air Freshener, which contains short chain aliphatic hydrocarbons (butane and isobutane). Unlike our case, myocardial sensitization and hypoxia are more commonly described with aromatic, halogenated or longer chain hydrocarbons.

Intravenous pyridoxine-induced metabolic acidosis.

STUDY OBJECTIVE: Pyridoxine hydrochloride, the antidote for isonicotinic acid hydrazide (INH)--induced seizures, is available in solution at a concentration of 100 mg/mL at a pH of less than 3. Pyridoxine is often infused rapidly in large doses for INH-induced seizures. Effects of pyridoxine infusion on base deficit in amounts given for INH poisoning have not been studied in human subjects. We hypothesized that this infusion would result in transient worsening of acidosis. METHODS: We conducted a randomized, controlled crossover trial in human volunteers. Five healthy volunteers (mean age, 35 years; range, 29 to 43 years) were randomized to receive intravenous placebo (50 mL of normal saline solution) or 5 g of pyridoxine (50 mL) over 5 minutes. A peripheral intravenous catheter was established in each arm, and a heparinized venous blood sample was obtained for base deficit at baseline and 3, 6, 10, 20, and 30 minutes after infusion. After at least a 1-week washout period, the volunteers were assigned to the alternate arms of the experiments, thus acting as their own control subjects. Data were analyzed by using the 2-tailed paired t test, controlling for multiple comparisons. RESULTS: No difference was noted between groups at baseline. A statistically significant increased base deficit was noted after the pyridoxine infusion versus control at 3 to 20 minutes but not at 30 minutes (P =.1). Maximal mean increase in base deficit (2.74 mEq/L) was noted at 3 minutes. CONCLUSION: A transient increase in base deficit occurs after the infusion of 5 g of pyridoxine in normal volunteers.

Failure of intravenous N-acetylcysteine to reduce methemoglobin produced by sodium nitrite in human volunteers: A randomized controlled trial.

STUDY OBJECTIVE: To determine whether intravenous N -acetylcysteine (NAC) produces a clinically significant decline in sodium nitrite-induced methemoglobinemia in human volunteers. METHODS: We conducted a randomized, control crossover trial with each subject serving as his own control. Methemoglobinemia was induced with intravenous sodium nitrite (4 mg/kg) administered over 10 minutes starting at time 0. At time 30 minutes, subjects were randomly assigned to treatment with intravenous NAC for 100 minutes (150 mg/kg over 1 hour followed by 14 mg/kg per hour for 40 minutes) or administration of an equal volume of 5% dextrose in water. Each subject received the alternative treatment after an interval of at least 1 week. Blood methemoglobin concentrations were measured by multiwavelength co-oximetry at time 0, 15, 30, 50, 70, 90, 110, and 130 minutes. Area under the methemoglobin concentration-time curve (AUC) between 30 and 130 minutes was compared between groups using a 2-tailed, paired t test. RESULTS: There were no statistically significant differences in the control and treatment groups with respect to baseline hemoglobin or methemoglobin concentrations, as well as nitrite-induced methemoglobin concentrations at the initiation of treatment (0.85+/-0.06 g/dL, 0.88+/-0.04 g/dL; mean+/-SEM; P =.31). Mean AUC for the control group (77.1+/-5.7 g x min/dL) was significantly lower than the mean AUC for the treatment group (84.5+/-4.7 g x min/dL); P =.01). CONCLUSION: Intravenous NAC failed to enhance methemoglobin reduction in this model.

Fatal tetanus in a drug abuser with "protective" antitetanus antibodies.

Tetanus is a rare disease in the United States. From 1995-1997, the average annual incidence of tetanus was 0.15/1,000,000 population. Injecting-drug users, particularly those who use heroin, are among the highest risk population for acquiring tetanus. We present a case of an injecting-drug user who was seen in the emergency department with worsening diffuse midthoracic back pain and spasms. He subsequently developed acute respiratory failure and central nervous system hypoxic injury. Serum obtained before administration of tetanus immune globulin showed a tetanus antibody titer greater than 16 times the level considered protective. Because of limited human data on the minimum protective level of neutralizing antibody, as well as reports of tetanus among individuals with "protective" antibody titers, the diagnosis of tetanus should not be excluded solely on the basis of antitetanus titers.

Incidence of immediate and delayed hypersensitivity to Centruroides antivenom.

STUDY OBJECTIVE: To assess the incidence and course of immediate and delayed hypersensitivity to Centruroides antivenom. METHODS: We performed a 12-month prospective observation study, with telephone follow-up, evaluating the incidence of anaphylaxis or anaphylactoid reactions and serum sickness after Centruroides antivenom administration. The setting for the study was a poison control center and tertiary care toxicology treatment center. Participants included all patients who received Centruroides antivenom, and no interventions were performed. RESULTS: For immediate hypersensitivity reactions, 116 patients with grade III or IV envenomation received Centruroides antivenom; 77 of these patients were younger than 13 years. Three patients completed the infusion despite development of rash. A fourth patient with a history of atopy and asthma received epinephrine infusion and an inhaled beta-agonist for transient wheezing that quickly resolved; she was admitted for observation. Nine patients without hypersensitivity reactions were admitted for social reasons, for inappropriate sedation from drugs used before antivenom, or to rule out aspiration; all were discharged within 24 hours. The remaining 106 patients were discharged from the emergency department after resolution of symptoms. Thus 4 of 116 patients had immediate reactions. For patients with delayed reactions, 17 patients were lost to follow-up. Of 99 remaining patients, serum sickness developed in 61% (n=60), as defined by using liberal criteria. Serum sickness responded to oral steroids, antihistamines, or both; mean duration of symptoms with medication was 2.8 days. CONCLUSION: Anaphylactic reactions are uncommon after Centruroides antivenom infusion. Self-limited serum sickness that is easily controlled with corticosteroids and antihistamines commonly follows the use of Centruroides antivenom.

Serotonin syndrome in a child after a single dose of fluvoxamine.

Serotonin syndrome, a potentially fatal iatrogenic complication of psychopharmacologic therapy, is most commonly reported with combinations of serotonergic medications. Serotonin syndrome is characterized by alterations in cognition, behavior, autonomic, and central nervous system function as a result of increased postsynaptic serotonin receptor agonism. We present the first reported case of serotonin syndrome after a single dose of fluvoxamine in a pediatric patient after ingestion of a single supratherapeutic dose of fluvoxamine.

Effect of magnesium hydroxide on iron absorption following simulated mild iron overdose in human subjects.

OBJECTIVE: To determine the effect of oral magnesium hydroxide [Mg(OH)2] on iron absorption after simulated iron overdose in human subjects. METHODS: A randomized, controlled crossover study was conducted in healthy adult male human volunteers taking no medications. Subjects received an average of 5.0 mg/kg elemental iron orally followed 1 hour later by either oral administration of 4.5 g of Mg(OH)2 per g ingested elemental iron or no treatment. Serial serum specimens were obtained over the 12 hours following iron ingestion and stored at -60 degrees C until standard serum iron assay was performed. After a 2-week washout period, the subjects were enrolled in the alternative trial arm. Individual baseline diurnal variation in serum iron levels was determined over a 12-hour period on the day prior to each trial. Area under time-concentration curves (AUCs) were calculated, and the AUC due to experimental iron ingestion (deltaAUC) was determined by subtracting the baseline diurnal AUC from the experimental AUC for each subject. RESULTS: Thirteen healthy adult male subjects were enrolled. Mean +/- SEM for deltaAUC due to experimental iron ingestion followed by treatment with Mg(OH)2, 78 +/- 23 micromol(hr)/L, was significantly less than that followed by no treatment, 144 +/- 33 micromol(hr)/L (p = 0.03 by signed rank test). CONCLUSIONS: Magnesium hydroxide, administered 1 hour post-iron ingestion at an oral dose of 4.5 g per g elemental iron ingested, significantly reduced iron absorption during a 12-hour period following simulated mild iron overdose in healthy adult human volunteers.

Rapid reversal of life-threatening toluene-induced hypokalemia with hemodialysis.

A case of toluene-induced hypokalemia, respiratory failure, metabolic acidosis, and ventricular tachycardia is presented. Hemodialysis was associated with rapid improvement in our patient.

Dexfenfluramine overdose.

Dexfenfluramine (Redux), the dextro-rotatory (+) steroisomer of fenfluramine, was previously approved for the treatment of weight control in the United States. We report a case of acute dexfenfluramine ingestion characterized by coma, clonus, and respiratory failure.