On the mechanisms underlying poisoning-induced rhabdomyolysis and acute renal failure

Acute Poisoning with Rhabdomyolysis in the Intensive Care Unit: Risk Factors for Acute Kidney Injury and Renal Replacement Therapy Requirement

Acute kidney injury (AKI) is the major complication of rhabdomyolysis. We aimed to identify the predictive factors for AKI and renal replacement therapy (RRT) requirement in poisoning-associated rhabdomyolysis. We conducted a cohort study including 273 successive poisoned patients (median age, 41 years) who developed rhabdomyolysis defined as creatine kinase (CK) >1000 IU/L. Factors associated with AKI and RRT requirement were identified using multivariate analyses. Poisonings mainly involved psychotropic drugs. AKI occurred in 88 patients (37%) including 43 patients (49%) who required RRT. Peak serum creatinine and CK were weakly correlated (R² = 0.17, p < 0.001). Death (13%) was more frequent after AKI onset (32% vs. 2%, p < 0.001). On admission, lithium overdose (OR, 44.4 (5.3–371.5)), serum calcium ≤2.1 mmol/L (OR, 14.3 (2.04–112.4)), female gender (OR, 5.5 (1.8–16.9)), serum phosphate ≥1.5 mmol/L (OR, 2.0 (1.0–4.2)), lactate ≥ 3.3 mmol/L (OR, 1.2 (1.1–1.4)), serum creatinine ≥ 125 µmol/L (OR, 1.05 (1.03–1.06)) and age (OR, 1.04 (1.01–1.07)) independently predicted AKI onset. Calcium-channel blocker overdose (OR, 14.2 (3.8–53.6)), serum phosphate ≥ 2.3 mmol/L (OR, 1.6 (1.1–2.6)), Glasgow score ≤ 5 (OR, 1.12; (1.02–1.25)), prothrombin index ≤ 71% (OR, 1.03; (1.01–1.05)) and serum creatinine ≥ 125 µmol/L (OR, 1.01; (1.00–1.01)) independently predicted RRT requirement. We identified the predictive factors for AKI and RRT requirement on admission to improve management in poisoned patients presenting rhabdomyolysis.

Acute administration of tramadol and tapentadol at effective analgesic and maximum tolerated doses causes hepato- and nephrotoxic effects in Wistar rats

Tramadol and tapentadol are two atypical synthetic opioid analgesics, with monoamine reuptake inhibition properties. Mainly aimed at the treatment of moderate to severe pain, these drugs are extensively prescribed for multiple clinical applications. Along with the increase in their use, there has been an increment in their abuse, and consequently in the reported number of adverse reactions and intoxications. However, little is known about their mechanisms of toxicity. In this study, we have analyzed the in vivo toxicological effects in liver and kidney resulting from an acute exposure of a rodent animal model to both opioids. Male Wistar rats were intraperitoneally administered with 10, 25 and 50mg/kg tramadol and tapentadol, corresponding to a low, effective analgesic dose, an intermediate dose and the maximum recommended daily dose, respectively, for 24h. Toxicological effects were assessed in terms of oxidative stress, biochemical and metabolic parameters and histopathology, using serum and urine samples, liver and kidney homogenates and tissue specimens. The acute exposure to tapentadol caused a dose-dependent increase in protein oxidation in liver and kidney. Additionally, exposure to both opioids led to hepatic commitment, as shown by increased serum lipid levels, decreased urea concentration, increased alanine aminotransferase and decreased butyrylcholinesterase activities. It also led to renal impairment, as reflected by proteinuria and decreased glomerular filtration rate. Histopathological findings included sinusoidal dilatation, microsteatosis, vacuolization, cell infiltrates and cell degeneration, indicating metabolic changes, inflammation and cell damage. In conclusion, a single effective analgesic dose or the maximum recommended daily dose of both opioids leads to hepatotoxicity and nephrotoxicity, with tapentadol inducing comparatively more toxicity. Whether these effects reflect risks during the therapeutic use or human overdoses requires focused attention by the medical community.

Nephrotoxicity of methadone: a systematic review

Background

Methadone is commonly administered for chronic pain relief and treatment of opioid dependence. Concurrent with its increased consumption, toxicities and fatalities have increased. One of the adverse effects of opioid analgesics, including methadone, is that of nephrotoxicity. Opioids can have an effect on renal function through several different mechanisms.

Methods

We searched common bibliographical databases for the terms methadone, toxicity, poisoning, kidney, renal, and nephrotoxicity and summarize our findings in this review.

Results

Methadone can have both direct and indirect effects on the kidney. These effects include rhabdomyolysis (leading to acute kidney injury), volumetric changes, renal lipidosis and amyloidosis, kidney growth during pregnancy, and kidney transplant rejection.

Conclusion

Improved understanding of the effects of methadone on kidney function can promote safer and more confident use of the drug.

Beyond muscle destruction: a systematic review of rhabdomyolysis for clinical practice

Background

Rhabdomyolysis is a clinical syndrome that comprises destruction of skeletal muscle with outflow of intracellular muscle content into the bloodstream. There is a great heterogeneity in the literature regarding definition, epidemiology, and treatment. The aim of this systematic literature review was to summarize the current state of knowledge regarding the epidemiologic data, definition, and management of rhabdomyolysis.

Methods

A systematic search was conducted using the keywords “rhabdomyolysis” and “crush syndrome” covering all articles from January 2006 to December 2015 in three databases (MEDLINE, SCOPUS, and ScienceDirect). The search was divided into two steps: first, all articles that included data regarding definition, pathophysiology, and diagnosis were identified, excluding only case reports; then articles of original research with humans that reported epidemiological data (e.g., risk factors, common etiologies, and mortality) or treatment of rhabdomyolysis were identified. Information was summarized and organized based on these topics.

Results

The search generated 5632 articles. After screening titles and abstracts, 164 articles were retrieved and read: 56 articles met the final inclusion criteria; 23 were reviews (narrative or systematic); 16 were original articles containing epidemiological data; and six contained treatment specifications for patients with rhabdomyolysis.

Conclusion

Most studies defined rhabdomyolysis based on creatine kinase values five times above the upper limit of normal. Etiologies differ among the adult and pediatric populations and no randomized controlled trials have been done to compare intravenous fluid therapy alone versus intravenous fluid therapy with bicarbonate and/or mannitol.

Survey on Hypothermia and Hyperthermia in Poisoned Patients in a Unique Referral Hospital, Tehran, Iran

Background

Body temperature is a critical criterion of health. Drugs and a variety of poisons can affect body temperature in poisoned patients, causing hyperthermia and hyperpyrexia.

Objectives

Our previous study’s findings in patients poisoned with organophosphate led us to the goal of this study: obtaining the initial tympanic temperature in patients poisoned by a variety of toxins.

Materials and Methods

A cross-sectional study reviewed the records of poisoned patients who were admitted to the toxicological intensive care unit (TICU) at Loghman Hakim hospital poison center (LHHPC) from February 2014 to February 2015. The data collected included gender, age, type of poisoning, the season during which poisoning occurred, vital signs, initial tympanic temperature (first four hours), presence of seizures, white blood cell (WBC) count, creatinine phosphokinase (CPK), length of stay and patient outcome. We determined the mean (SD) for normally distributed continuous variables, the median and interquartile range for non-normally distributed continuous variables, and the absolute and relative frequency (%) for categorical variables. All were determined using SPSS version 16.

Results

Data were collected from 310 eligible patients. The mean patient age was 32.65 (with a standard deviation of 14.40). Of the patients in the study, 183 (59%) were male. Intentional poisoning in an attempted suicide was documented in 253 (81.6%) patients. The most prevalent poisoning agent was aluminum phosphate (18.70%), followed by methadone (10%) and opium (10%). Seventy percent of the patients (n = 217) were diagnosed and classified with fever or hyperthermia. A temperature ≥ 40°C was detected in just three cases. The highest mean temperature was found in patients poisoned with amphetamine, organophosphate and tramadol. Patients with alcohol and phenobarbital poisoning were included in the sample, but these patients were not diagnosed with hypothermia. WBC ≥ 10,000 cells/mL and CPK ≥ 975 IU/L were recorded in 57.7% and 13.2% of subjects, respectively.

Conclusions

Body temperature changes in human poisonings are a matter in need of special attention. A literature review did not reveal any controversy over hypothermia, but poisoning cases exhibit a variety of patterns of fever and hyperthermia. If there are no limits to the diagnosis of fever and hyperthermia, all cases with a poor prognosis which fail to respond to treatment could be categorized as drug-induced hyperthermia. Therefore, a different approach is needed for poisoning cases.

Effectiveness of naltrexone in the prevention of delayed respiratory arrest in opioid-naive methadone-intoxicated patients

Acute methadone toxicity is a major public health concern in Iran. Methadone-intoxicated patients are in a great risk of recurrent or delayed respiratory arrest despite the prescription of initial doses of naloxone. This study aimed to evaluate the effectiveness of oral naltrexone in the management of acute methadone overdose in opioid-naive patients and check if it could be a substitute of continuous infusion of naloxone in maintaining adequate ventilation. In a randomized, double-blind, placebo-controlled study, a total of 54 opioid-naive patients with acute methadone toxicity were enrolled. The patients received either oral naltrexone or placebo capsules after awakening by naloxone. All patients underwent close monitoring of respiration. Frequency of respiratory depression or arrest, need for another dose of naloxone, duration of hospital stay, and adverse outcomes compared between the two groups. The incidence of respiratory depression was significantly less in those who had received naltrexone. Our results show that single oral dose of naltrexone is quite efficient in the prevention of recurrent or delayed respiratory arrest in opioid-naive methadone-intoxicated patients. It can shorten the duration of hospitalization and, as a consequence, decreased the risk of complications. Further studies are warranted before the generalization of this approach to other patient populations.

Prevention of kidney injury following rhabdomyolysis: a systematic review

OBJECTIVE

To conduct a systematic literature review to evaluate evidence-based recommendations for the prevention of rhabdomyolysis-associated acute renal failure (ARF).

DATA SOURCES

PubMed (1966-December 2012), International Pharmaceutical Abstracts, Science Citation Index, and Cochrane databases (1970-December 2012) were searched. There were no language restrictions.

STUDY SELECTION AND DATA EXTRACTION

Studies selected dealt with treatment of rhabdomyolysis (crush syndrome) or prevention of ARF in patients with rhabdomyolysis. Articles excluded did not present original data or described only the management of ARF after it developed. Single case reports were excluded. Extracted data included study type; population; definitions of rhabdomyolysis and ARF; fluid, sodium bicarbonate, and mannitol dosages; and study findings.

DATA SYNTHESIS

Twenty-seven studies met the inclusion criteria. No controlled trials compared intravenous fluid administration plus sodium bicarbonate to fluid administration alone. Three concluded that there was no significant difference in the rates of ARF between patients receiving and those not receiving sodium bicarbonate; however, urine alkalinization was not documented. Eight investigations concluded that delayed fluid administration increased the risk of ARF. No controlled study compared volumes of fluid administered or targeted urine output goals. Fluid type, therapy duration, and monitoring parameters varied widely; 4 used a urine output goal in adults of more than 300 mL/h or 300 mL/h or more. No evidence supported a preferred fluid type or that sodium bicarbonate with or without mannitol was superior to fluid therapy alone.

CONCLUSIONS

Intravenous fluids should be initiated as soon as possible, preferably within the first 6 hours after muscle injury, at a rate that maintains a urine output in adults of 300 mL/h or more for at least the first 24 hours. Sodium bicarbonate should be administered only if necessary to correct systemic acidosis and mannitol only to maintain urine output of 300 mL/h or more despite adequate fluid administration.