Abdominal imaging in zinc phosphide poisoning
Hossein Hassanian-Moghaddam, Makhtoom Shahnazi, Nasim Zamani & Hooman Bahrami-Motlagh Emergency Radiology A Journal of Practical Imaging Official Journal of the American Society of Emergency Radiology ISSN 1070-3004 Emerg Radiol DOI 10.1007/s10140-014-1195-3
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Author's personal copy Emerg Radiol DOI 10.1007/s10140-014-1195-3
CASE REPORT
Abdominal imaging in zinc phosphide poisoning Hossein Hassanian-Moghaddam & Makhtoom Shahnazi & Nasim Zamani & Hooman Bahrami-Motlagh
Received: 24 December 2013 / Accepted: 14 January 2014 # Am Soc Emergency Radiol 2014
Abstract Radiography has been proved to be a good diagnostic tool in visualization of many radiopaque xenobiotics in clinical toxicology. Zinc is a potentially radiopaque material which is a constituent of the zinc phosphide (ZN2P3) rodenticide. We report two cases of zinc phosphide poisoning with positive abdominal X-rays in whom the diagnosis was confirmed by abdominal imaging. Positive abdominal imaging was an indication for aggressive management; however, aggressive treatment was not lifesaving in one of them. We aim to emphasize the diagnostic value of abdominal X-rays in zinc phosphide-poisoned patients. We also would like to suggest that zinc phosphide (ZP)-poisoned patients with positive Xrays have more chance to become unstable even if they are symptom free on presentation and should be more aggressively managed. Keywords Abdominal imaging . Zinc phosphide . Poisoning . Diagnosis
Introduction When a poisoned patient refers with decreased level of consciousness, the history given by the relatives is generally not sufficient in determining the overdosed toxin or medication. Even in suicidal-alert patients, the history is unreliable or not sufficient. In such circumstances, diagnostic tools may help in H. Hassanian-Moghaddam : N. Zamani (*) Department of Clinical Toxicology, Loghman-Hakim Hospital, Shahid Beheshti University of Medical Sciences, Karegar Street, Tehran, Iran e-mail:
[email protected] M. Shahnazi : H. Bahrami-Motlagh Department of Radiology, Loghman-Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
the diagnosis of the toxin responsible for the poisoning. Of these diagnostic tools, conventional radiography is available everywhere. In medical toxicology, radiography has been proved to be a good diagnostic tool in visualization of many radiopaque xenobiotics including chloral hydrate, heavy metals, iron, phenotiazines, and enteric-coated and sustained-release preparations [1]. Different factors have been postulated to affect the intrinsic radiopacity of a substance including the physical density and atomic numbers of the constituent atoms in the toxin [2]. Zinc with an atomic number of 30 is a potentially radiopaque material [3] (Fig. 1) which is a constituent of the famous zinc phosphide (ZP) rodenticide, but, as far as we know, there is no report using this characteristic for diagnosis of ZP exposure. The toxin affects the body system through releasing phosphine gas and interrupting the cell respiration [4]. We, hereby, report two cases of ZP poisoning with positive abdominal Xrays in whom the diagnosis was confirmed by abdominal imaging. Positive abdominal imaging was an indication for aggressive management (treatment with polyethylene glycol [PEG]) in these two patients, one of whom survived and the other deteriorated eventually and died. We aim to emphasize the diagnostic value of abdominal X-rays in ZP-poisoned patients. We also would like to suggest that ZP-poisoned patients with positive X-rays may have more chance to become unstable and probably should be more aggressively managed.
Case 1 A 62-year-old male referred to us almost 5.5 h after intentional ingestion of about one table spoon of ZP powder complaining mild nausea and vomiting. His vital signs were stable on presentation. He was admitted to the poisoning ward and received charcoal and sorbitol, metoclopramide, and
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limits. Serial arterial blood gas (ABG) analyses were performed every 12 h. Although the first ABG was normal, the second ABG components changed to pH=7.28, PCO2=44.1 mm Hg, HCO3=20 mEq/L, and base excess=−6.4 mEq/L. The third ABG became even worse; pH=6.8, PCO2=60.8 mm Hg, HCO3=11.7 mEq/L, and base excess=−18 mEq/L. Serum creatinine also rose to 1.5 mg/dL from a baseline of 0.9 mg/dL. Considering the deteriorating situation of the patient, sodium bicarbonate was initiated and PEG was administered. After four times of defecation and continuous infusion of sodium bicarbonate, the patient improved. A control abdominal X-ray was clear. The patient became stable within 3 days and was discharged in good condition and completely symptom free.
Case 2
Fig. 1 Plain radiograph obtained from the ZP (upper) which contains small dense particles of different sizes in comparison with phantom (pure water, lower)
ranitidine. An abdominal X-ray was performed and showed radiopaque material in it (Fig. 2). All lab tests were within normal
Fig. 2 Punctuate and amorphous opacities in the cecal and rectosigmoid regions, respectively, which are due to ingested substance (ZP)
A 47-year-old male referred to our emergency department (ED) after intentional ingestion of an unknown amount of ZP powder complaining abdominal pain. He did not mention when he had consumed the toxin, either. His vital signs were stable on admission. Nasogastric tube was inserted and gastrointestinal washing was performed. An abdominal X-ray was also done showing radiopaque material (Fig. 3). Almost 3 h after admission, he developed dyspnea and respiratory distress and was therefore admitted to medical toxicology intensive care unit (MTICU). He was then intubated due to
Fig. 3 Scattered patchy opacities in the lower abdominal region presumed to be in the colon due to ingested substance (ZP)
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decreased O2 saturation. About 3.5 h after MTICU admission, he experienced sudden cardiorespiratory arrest. Cardiopulmonary resuscitation was performed which was unsuccessful, and the patient died about 6 h after hospital presentation with respiratory failure.
Discussion Abdominal X-rays can help in determining ingestion of many xenobiotics. Arsenic, lead, iodine, iron, barium, potassium, and aluminum are the xenobiotics that can be visualized in Xrays [1, 5]. X-rays are generally applied for the diagnosis of the exposure and further toxicity, but they may also be helpful in determining the treatment protocol. For instance, visualization of the iron tablets in the gastrointestinal tract is an indication for PEG therapy [6]. Zinc is a potentially radiopaque constituent of ZP rodenticides which are a major cause of poisoning and mortality (as high as 20 % of the rodenticide-induced mortalities) in some countries [7]. Review of our two cases emphasizes the diagnostic value of abdominal X-ray in ZP-poisoned patients. They both were asymptomatic on presentation except for a positive abdominal radiography. However, they both deteriorated during hospital admission: one with metabolic acidosis as well as acute renal failure and the second one with respiratory failure. This may suggest that abdominal X-ray may even be useful in determination of the ZP-poisoned patients’ outcome since many of the patients who refer with this poisoning and have negative X-rays remain symptom free (HassanianMoghaddam, Plain abdominal radiography; a powerful tool to prognosticate zinc phosphide-poisoned patients’ outcome, unpublished data). Also, it may be suggested that if a ZPintoxicated patient refers with positive X-ray, more aggressive therapies should be used.
Conclusion Abdominal X-ray should be performed in every single patient who refers to toxicology ED with the history of ZP ingestion or ingestion of an unknown rodenticide. Positive radiography may show a worse prognosis even if the patient refers without signs and symptoms of toxicity and may suggest the need for more aggressive treatments. This needs to be further evaluated in a greater number of ZP-poisoned patients.
Conflict of interest The authors declare that they have no conflict of interest.
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