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| {{SI}}
| | #redirect[[Aluminium phosphide]] |
| {{CMG}}
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| ==Overview==
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| '''Acute aluminium phosphide poisoning''' (AAlPP) is a large, though under-reported, problem in the Indian subcontinent. [[Aluminium phosphide]] (AlP), which is readily available as a [[fumigant]] for stored cereal grains, is highly toxic when consumed from a freshly opened container.<ref name="Pmid">{{cite journal|pmid=1937606|year=1991|last1=Chugh|first1=SN|last3=Ram|first3=S|last4=Arora|first4=B|last5=Malhotra|first5=KC|title=Incidence & outcome of aluminium phosphide poisoning in a hospital study|volume=94|pages=232–5|journal=The Indian journal of medical research}}</ref><ref>{{cite journal|pmid=8941200|journal= J Toxicol Clin Toxicol|year=1996|volume=34|issue=6|pages=703–6|title=Aluminum phosphide ingestion—a clinico-pathologic study|author=Singh S, Singh D, Wig N, Jit I, Sharma BK}}</ref> Death results from profound shock, [[myocarditis]] and multi-organ failure.<ref name="r1"/> Aluminium phosphide has a fatal dose of between {{convert|0.15|and|0.5|g}}.<ref>{{cite journal|url=http://www.hkcem.com/html/publications/Journal/2008-3/p152-155.pdf|title=Acute aluminium phosphide poisoning: an update|author=A Wahab, MS Zaheer, S Wahab, RA Khan|journal=Hong Kong Journal of Emergency Medicine|page=152}}</ref> It has been reported to be the most common cause of suicidal death in [[North India]].<ref name=r4>{{cite journal|pmid=8773034|year=1995|last1=Siwach|first1=SB|last2=Gupta|first2=A|title=The profile of acute poisonings in Harayana-Rohtak Study|volume=43|issue=11|pages=756–9|journal=The Journal of the Association of Physicians of India}}</ref>
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| ==Mechanism of intoxication==
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| Aluminium phosphide is an extremely toxic compound, resulting in a high mortality rate when consumed. The toxicity of aluminium phosphide is attributed to the liberation of phosphine gas, a [[cytotoxicity|cytotoxic]] compound that causes [[free radical]] mediated injury. The [[chemical formula]] for combination with water molecules is:
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| :AlP + 3 H<sub>2</sub>O → Al(OH)<sub>3</sub> + PH<sub>3</sub>, and
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| :AlP + 3 HCl → AlCl<sub>3</sub> + PH<sub>3</sub> (stomach)
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| [[Phosphine]], a [[nucleophile]], acts as a strong reducing agent capable of inhibiting cellular enzymes involved in several metabolic processes. Early studies on phosphine demonstrated specific inhibitory effects on mitochondrial [[cytochrome c]] [[oxidase]].<ref name=r1/> Experimental and observational studies have subsequently demonstrated that the inhibition of cytochrome c oxidase and other enzymes leads to the generation superoxide radicals and cellular peroxides. Cellular injury subsequently occurs through lipid peroxidation and other oxidant mechanisms.
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| The major lethal consequence of aluminium phosphide ingestion i.e., profound circulatory collapse, is reportedly secondary to these toxins generated, which lead to direct effects on [[cardiac myocytes]],<ref>{{cite journal|pmid=9251315|year=1996|last1=Chugh|first1=SN|last2=Pal|first2=R|last3=Singh|first3=V|last4=Seth|first4=S|title=Serial blood phosphine levels in acute aluminium phosphide poisoning|volume=44|issue=3|pages=184–5|journal=The Journal of the Association of Physicians of India}}</ref> fluid loss, and adrenal gland damage. In addition, phosphine also has corrosive effects on tissues.<ref name=r1/>
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| ==Signs and symptoms==
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| The signs and symptoms are non-specific, instantaneous and depend on the dose, route of entry, and time lapse since exposure to the poison. After inhalation exposure, patients commonly exhibit airway irritation and breathlessness.<ref name=r4/> The dominant clinical feature is severe hypotension refractory to [[dopamine]].<ref>[http://www.ncbi.nlm.nih.gov/pubmed/7829435?dopt=AbstractPlus J Assoc Physicians India]</ref> Other features may include dizziness, fatigue, tightness in the chest, headache, [[nausea]], vomiting, [[diarrhoea]], [[ataxia]], numbness, [[paraesthesia]], tremor, muscle weakness, [[diplopia]] and [[jaundice]].<ref name="Pmid_a">{{cite journal|pmid=18085124|year=2007|last1=Goel|first1=A|last2=Aggarwal|first2=P|title=Pesticide poisoning|volume=20|issue=4|pages=182–91|journal=The National medical journal of India}}</ref><ref name="Pmid_b">{{cite journal|pmid=15727053|year=2005|last1=Sudakin|first1=DL|title=Occupational exposure to aluminium phosphide and phosphine gas? A suspected case report and review of the literature|volume=24|issue=1|pages=27–33|journal=Human & Experimental Toxicology}}</ref><ref name="Pmid_c">{{cite journal|pmid=7837309|year=1995|last1=Gupta|first1=S|last2=Ahlawat|first2=SK|title=Aluminum phosphide poisoning—a review|volume=33|issue=1|pages=19–24|journal=Journal of toxicology. Clinical toxicology}}</ref><ref name=r2>{{cite journal|doi=10.4103/0974-2700.83868|title=Managing aluminum phosphide poisonings|year=2011|last1=Gurjar|first1=Mohan|last2=Azim|first2=Afzal|last3=Baronia|first3=Arvindk|last4=Sharma|first4=Kalpana|journal=Journal of Emergencies, Trauma, and Shock|volume=4|issue=3|pages=378–84|pmid=21887030|pmc=3162709}}</ref> If severe inhalation occurs, the patient may develop acute respiratory distress syndrome (ARDS), cardiac failure, cardiac arrhythmias, convulsion and coma, and late manifestation of hepatotoxicity and nephrotoxicity may also occur.<ref name="Pmid_a" /><ref name="Pmid_b" /><ref name="Pmid_c" /><ref name=r2/>
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| After ingestion, toxic features usually develop within a few minutes. Common clinical features in mild poisoning cases are nausea, repeated vomiting, diarrhoea, headache, abdominal discomfort or pain and tachycardia. These patients usually show recovery. On the other hand, in moderate to severe ingestional poisoning, the signs and symptoms of the gastrointestinal, cardiovascular, respiratory and nervous systems appear initially and, later on, features of hepatic and renal failure and disseminated intravascular coagulation may also occur.<ref name="Pmid_a" />
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| The diagnosis of AlP usually depends on the clinical suspicion or history (self-report or by attendants). At some places, tablets of AlP are also referred to as “Rice Tablets” and, if there is a history of rice tablet ingestion, then it should be treated differently than other types of rice tablets that are made up of herbal products.<ref>{{cite journal|pmid=20097728|year=2010|last1=Mehrpour|first1=O|last2=Singh|first2=S|title=Rice tablet poisoning: A major concern in Iranian population|volume=29|issue=8|pages=701–2|doi=10.1177/0960327109359643|journal=Human & Experimental Toxicology}}</ref>
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| ===Tests===
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| For a [[Silver nitrate]] test on gastric aspirate, diluted gastric content is heated in a flask up to 50 °C for 15–20 minutes, keeping silver nitrate paper on the mouth of the flask. If [[phosphine]] is present then the paper will turn black due to silver phosphate. As [[hydrogen sulfide]] also changes the colour, its presence could be differentiated using [[lead acetate paper]], i.e. both papers will turn black in the presence of hydrogen sulfide. Further confirmation of phosphine can be done by putting a drop of ammonium molybdate solution on the black-turned filter paper, and the colour of the paper will change to blue.<ref name=r3/>
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| ==Management==
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| The management of AAlPP remains purely supportive because no specific antidote is known. Aluminium phosphide is an extremely toxic compound with a mortality rate close to 60%. The role of [[magnesium sulfate]] as a potential therapy in AlP poisoning may decrease the likelihood of a fatal outcome, and has been described in many studies.<ref name=r1>{{cite journal|doi=10.4103/0019-5049.68372|title=Acute aluminium phosphide poisoning: Can we predict mortality?|year=2010|last1=Mathai|first1=Ashu|last2=Bhanu|first2=Madhuritasingh|journal=Indian Journal of Anaesthesia|volume=54|issue=4|pages=302–7|pmid=20882171|pmc=2943698}}</ref><ref name=r2/>
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| After ingestion, effectiveness of gut decontamination to reduce the absorption of unabsorbed poison is primarily dependent on the duration of exposure to the poison, if administered within 1–2 hours it can be effective. Gut decontamination should not be performed if the patient has an unprotected airway without endotracheal intubation. Potassium permanganate (1:10,000) is used for gastric lavage through a [[nasogastric tube]] as it oxidises phosphine to non-toxic phosphate. This can be followed by approximately 100 g of activated charcoal to reduce absorption if the patient arrives within 1 hour after ingestion of a large amount of poison.
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| There is insufficient data to support the routine use of activated charcoal in AlP poisoning, as phosphine gas is rapidly absorbed through the gut. Also, a position paper on activated charcoal recommends that it should not be administered routinely in the management of poisoned patients.<ref>{{cite journal|pmid=15822758|year=2005|last1=Chyka|first1=PA|last2=Seger|first2=D|last3=Krenzelok|first3=EP|last4=Vale|first4=JA|author5=American Academy of Clinical Toxicology|author6=European Association of Poisons Centres Clinical Toxicologists|title=Position paper: Single-dose activated charcoal|volume=43|issue=2|pages=61–87|journal=Clinical toxicology (Philadelphia, Pa.)}}</ref>
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| Myocardial injury and hemodynamic instability is one of the most important features, and most of the deaths in ALP poisoning have been reported to be due to cardiovascular failure. All patients of severe AlP poisoning require continuous invasive hemodynamic monitoring and early resuscitation with fluid and vasoactive agents. Phosphine virtually affects all the organs in the body and, therefore, early identification of impending organ failure and appropriate supportive therapy is extremely important until the toxin is excreted from the body.
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| Requirement of endotracheal intubation and mechanical ventilation usually depends on the severity of the acute lung injury, sometimes, due to poor mental status. Hemodialysis is not very effective in removing phosphine but is helpful when renal failure, severe metabolic acidosis or if fluid overload is present.<ref name=r3>{{cite journal|pmc=3162709|title= Managing aluminum phosphide poisonings|author=Mohan Gurjar, Arvind K Baronia, Afzal Azim, and Kalpana Sharma | pmid=21887030|doi=10.4103/0974-2700.83868|volume=4|issue=3|year=2011|month=July|journal=J Emerg Trauma Shock|pages=378–84}}</ref>
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| ==References==
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| {{reflist|2}}
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| [[Category:Toxic metal poisoning]]
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| [[Category:Aluminium]]
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| [[Category:Poisoning and certain other consequences of external causes]]
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| [[Category:Poisoning]]
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| [[Category:Toxins]]
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