Acute Renal Failure Common After Poisoning

Norra MacReady

February 29, 2012

February 29, 2012 — Snake bites, insect stings, and poisoning were the causes of acute renal failure (ARF) among patients presenting at a tertiary-care hospital in India, according to results from a study published in the March issue of the Journal of Renal Care.

Although ARF is relatively rare in India, patients have a mean age of 37 years, which is young compared with patients in developed countries. "By affecting those in the productive age group, the toxic nephropathies have serious economic implications on the family as well as the country," lead author Shah Sweni, MD, from Chennai Medical College Hospital and Research Centre, Irungalur, Trichy, and colleagues explain. They conducted this prospective, nested, case–control study to determine the risks, causes, and outcomes of ARF among patients admitted to the Poison Control Training and Research Centre of Government General Hospital in Madras, India, during 12 consecutive months.

From August 2006 to July 2007, 1250 patients were admitted, of whom 32 (2.56%) developed ARF and did not have any exclusion criteria: diabetes or hypertension, known chronic kidney disease, chronic therapy with nonsteroidal anti-inflammatory drugs, use of drugs that increase serum creatinine by inhibiting creatinine secretion, or other comorbid conditions.

Of the 32 cases, 22 (68.75%) were related to snake bites by Russell's viper Daboia russelii. Copper sulfate, a popular means of suicide attempts in India, and rat poison each accounted for 2 cases, followed by 1 case each caused by other poisons such as hair dye swallowed in suicide attempts, indigenous medicine, and dichromate. Wasp and scorpion stings also were responsible for 1 case each.

Snake Bites and Insect Stings vs Chemical Poisoning

Oliguria was the most common symptom of renal dysfunction in all patients. The 22 patients with snake bites all had hemolysis, defined as whole blood clotting times exceeding 20 minutes. Of the 24 patients with ARF resulting from bites or stings, albuminuria occurred in 20 (83%) compared with none of the patients with chemical poisoning. However, none of the patients with snake bites or insect stings experienced hepatic failure compared with 7 (88%) of the patients with chemical poisoning.

Patients with bites or stings required longer hospital stays, ranging on average from 14 to 21 days, whereas patients suffering from chemical poisoning stayed an average of 3 to 4 days. All of the patients with chemical poisoning and 18 (75%) of the patients with bites or stings were placed on dialysis.

ARF from chemical poisoning was associated with 7 deaths (88%) compared with 5 deaths (21%) among the patients with bites or stings (P = .005; odds ratio [OR], .04 - 1.0; 95% confidence interval [CI], .004 - .38). Predisposing factors, such as hemolysis in cases of bites or stings or direct nephropathy in cases of chemical poisoning, were present in 19 patients and associated with 11 deaths, whereas only 1 patient without such factors died (P = .0040; OR, 16.50; 95% CI, 1.63 - 767.7).

Snake Bites: Significant Health Problem in India

Snake bites are a significant public health problem in India, write Dr. Sweni and colleagues. When bitten, most people in rural areas go first to snake charmers or religious men who chant mantras or use herbal medicines, "further contributing to morbidity." In addition, "[t]he combination of poverty, illiteracy, ignorance, easy availability and perception of effectiveness with spiritual belief in indigenous systems of medicine in rural areas make traditional quasi-trained 'doctors' popular amongst the general population." These practitioners prescribe medicines and herbs that may be contaminated with heavy metals, toxic chemicals, or pesticides, or may be poisonous plants picked in error.

Study limitations include the lack of renal biopsies and of complete coagulation profiles to identify disseminated intravascular coagulation, which would have helped identify the exact causes of renal failure in the study patients, the investigators write.

Early treatment with antivenom reverses the symptoms of venom poisoning, including ARF, but a delay in administering the antidote increases the risk for ARF, the authors warn. Similarly, ARF associated with bites and stings has a better prognosis than ARF associated with chemical poisoning, so "vigorous management should be directed in the cases of chemical poisoning to improve the survival." They urge better education of physicians on the management of poisoning cases, including the importance of prompt treatment, and they also recommended that the government provide antivenom at primary healthcare centers, "because most poisonings occur in the rural population."

The authors disclosed no relevant conflicts of interest.

J Renal Care. 2012;38:22-28. Abstract

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