Salicylates poisoning

Aspirin is acetylsalicylic acid and is used as an antiplatelet agent and for pain relief. Its use for anti-inflammatory effects is limited by the occurrence of side-effects, which include tinnitus and deafness, both features of salicylate poisoning. 

The most effective treatment is haemodialysis, which allows the removal of salicylate and the correction of acid-base, fluid, and electrolyte disturbances, and is the preferred treatment for severe or complicated salicylate poisoning. 

Over dose/acute salicylate poisoning is characterized by salicylism which consists of tinnitus, vertigo and deafness, hyperthermia, toxic encephalopathy (agitation, confusion and convulsions followed by coma), dehydration (due to hyperpyrexia, sweating and vomiting), disturbances of acid base balance and petechial haemorrhages. 

Changes in plasma pH may also affect the distribution of toxic compounds by altering the proportion of the substance in the nonionized form, which will cause movement of the compound into or out of tissues. This may be of particular importance in the treatment of salicylate poisoning (see chap. 7) and barbiturate poisoning, for instance. Thus, the distribution of phenobarbital, a weak acid (pKa 7.2), shifts between the brain and other tissues and the plasma, with changes in plasma pH (Fig. 3.22). Consequently, the depth of anesthesia varies depending on the amount of phenobarbital in the brain. Alkalosis, which increases plasma pH, causes plasma phenobarbital to become more ionized, alters the equilibrium between plasma and brain, and causes phenobarbital to diffuse back into the plasma (Fig. 3.22). Acidosis will cause the opposite shift in distribution. Administration of bicarbonate is therefore used to treat overdoses of phenobarbital. This treatment will also cause alkaline diuresis and therefore facilitate excretion of phenobarbital into the urine (see below). 

Other co-substrates possibly limited in supply are inorganic sulfate and glycine for conjugation these may be important factors in paracetamol hepa to toxicity and salicylate poisoning, respectively (chap. 7). 

Figure 7.58 Overview of the biochemical and physiological interrelationships and changes in salicylate poisoning.

The specific treatment for salicylate poisoning, apart from gastric lavage and aspiration to remove the drug from the stomach, is based on a knowledge of the biochemical mechanisms underlying the toxicity. There is no antidote, but treatment may be successful. Thus, treatment involves the following ... 

Diem, E. and P. Fritsch, Salicylate poisoning by percutaneous resorption. Hautarzt, 1973, 24 552-5. 

Chapman, B.J. and A.T. Proudfoot, Adult salicylate poisoning deaths and outcome in patients with high plasma salicylate concentrations. Q. J. Med., 1989, 72 699-707. 

Germann, R., I. Schindera, M. Kuch, U. Seitz, S. Altmeyer, and F. Schindera, Life threatening salicylate poisoning caused by percutaneous absorption in severe ichthyosis vulgaris. Hautarzt, 1996, 47 624-7. 

Methyl Salicylate Dose forms, such as liniments or ointments containing methyl salicylate, should not be dispensed in polystyrene-type containers, as it is not stable. Accidental and deliberate injection causes severe and rapid salicylate poisoning because of its highly concentrated form and rapid absorption.68... 

Brubacher JR, Pursseh R, Kent DA. Salty broth for salicylate poisoning Adequacy of overdose management... 

Respiratory alkalosis and metabolic acidosis are characteristic features of salicylate poisoning, and... 

Acute salicylate poisoning is a major clinical hazard (96), although it is associated with low major morbidity and mortality, in contrast to chronic intoxication (SEDA-17,... 

Pierce RP, Gazewood J, Blake RL Jr. Salicylate poisoning from enteric-coated aspirin. Delayed absorption may complicate management. Postgrad Med 1991 89(5) 61-4. 

Chan TY. The risk of severe salicylate poisoning following the ingestion of topical medicaments or aspirin. Postgrad Med J 1996 72(844) 109-12. 

Howrie DL, Moriarty R, Breit R. Candy flavoring as a source of salicylate poisoning. Pediatrics 1985 75(5) 869-71. 

Chan TH, Wong KC, Chan JC. Severe salicylate poisoning associated with the intake of Chinese medicinal oil ( red flower oil ). Aust NZ J Med 1995 25(1) 57. 

Accidental ingestion of methylsalicylate in young children has resulted in severe salicylate poisoning, in one case with laryngeal edema (7). A suicide attempt by deliberate ingestion of about 100 ml resulted in severe salicylate poisoning (8). 

Chan TY. Ingestion of medicated oils by adults the risk of severe salicylate poisoning is related to the packaging of these products. Hum Exp Toxicol 2002 21(4) 171-4. 

Chyka PA, Erdman AR, Christianson G, et al. Salicylate poisoning an evidence-based consensus guideline for out-of-hospital management. Clin Toxicol (Phila). 2007 45 95-131... 

Salicylic acid (3) is a mild irritant and application of salicylic acid preparations to the skin may cause dermatitis. Symptoms of acute systemic salicylate poisoning have been reported after the application of asalicylic acid to large areas of the body. 

The acid-base aspects to salicylate poisoning are the following ... 

Although salicylic acid is readily absorbed through the skin, salicylate poisoning is highly unlikely to result from application to a small area for the limited period of treatment for athlete s foot. 

Salicylic acid is a mild irritant and similar precautions should be adopted as for benzoyl peroxide. Preparations are applied twice or three times a day. Salicylic acid is readily absorbed through the skin and excreted slowly, and salicylate poisoning can occur if preparations are applied frequently, in large amounts and over large areas. Patients who are sensitive to aspirin should avoid these preparations. 

When apphed to large, inflamed areas of skin, salicyhc acid may induce salicylism, with symptoms of nausea, vomiting, tinnitus, and hyperventilation. Salicylate poisoning in small children is potentially more serious than in older people because they are at higher risk of developing metabolic acidosis. Several fatal cases of percutaneous salicylate intoxication have been reported in children under 3 years of age. ... 

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