History and exam

Key diagnostic factors

common

ingestion of 150 mg/kg or more, or 6.5 g or more, of aspirin or aspirin equivalent

An expert panel consensus statement recognizes that a definite threshold dose for toxicity has not been established, and that many exposures are not single-dose exposures.[2] The panel concluded that the acute ingestion of 150 mg/kg or 6.5 g, whichever is less, of aspirin or aspirin equivalent warrants evaluation in an ER due to the risk of salicylate poisoning.

ingestion of methyl salicylate (oil of wintergreen)

Particularly ingestion of more than a lick or taste by children <6 years old, or >4 mL by patients ages 6 years or older.

Oil of wintergreen is 98% methyl salicylate, and its ingestion carries a substantial risk of salicylate poisoning.[1][2] It is sold by itself as an essential oil, and is also found in some topical liniments. One teaspoon (5 mL) of concentrated oil of wintergreen is approximately equivalent to 7 g of aspirin.[1][6]​​

ingestion of bismuth subsalicylate

Although rare, cases of salicylate poisoning have been reported in patients who ingest large amounts of bismuth subsalicylate, which is found in some gastrointestinal medications.[15][16][17]​​​​

self-harm or suicide attempt

Among adolescents and adults, should arouse suspicion of undisclosed toxin ingestion, including salicylates.[1]

children ages 3 years or younger and adults 70 years or older

Incorrect salicylate dosing in children and older people can result in toxic salicylate exposure. Accidental ingestion is also of particular concern at extremes of age. Of 31 deaths primarily attributed to salicylate poisoning in the 2021 report of the US National Poison Data System, 14 deaths occurred in people ages 65 years or more, while none involved children ages less than 18 years.[1]

unknown toxin ingestion or exposure

Diagnosis of salicylate poisoning should be considered in patients with a history of toxin ingestion or exposure of any kind, particularly in the presence of an unexplained metabolic acidosis.

abnormal behavior

Unexplained delirium should initiate workup for poisoning, including salicylate toxicity, particularly if respiratory alkalosis or anion gap metabolic acidosis are present.[1]

nausea, vomiting, hematemesis, epigastric pain

Gastrointestinal symptoms in association with toxin ingestion should arouse suspicion of possible salicylate poisoning.[1]​ 

fever and diaphoresis

Impaired production of energy and its release as heat may result in fever (hyperpyrexia may occur) and diaphoresis.[1]​ In association with toxin ingestion, these symptoms should arouse suspicion of possible salicylate poisoning.

shortness of breath

A chief complaint of shortness of breath associated with a history of suspected poisoning should alert the physician to the possibility of an underlying metabolic acidosis and/or respiratory alkalosis.[1]

May also reflect onset of acute respiratory distress syndrome (ARDS), which, although not common, is regarded as life-threatening and can develop in both subacute and chronic poisoning.[1][2]

Shortness of breath may be the only presenting symptom.

tachypnea, Kussmaul respirations

Salicylates directly stimulate the respiratory center and cause tachypnea.[1]​ Respiratory alkalosis is, therefore, a feature of early salicylate poisoning. Metabolic acidosis, when it develops, also stimulates a compensatory respiratory response. 

Respiratory signs may be the only presenting features.

tinnitus and/or deafness

Mild central nervous system effects usually present in early stages of acute ingestion.[1]​ Tinnitus is commonly present as a clinical symptom indicating onset of potential salicylate toxicity. Tinnitus is so common at salicylate levels of 20 mg/dL or more that it can be used to gauge presence of excess intake.[1]​ Tinnitus and deafness resolve as salicylate levels fall.

malaise and/or dizziness

Mild central nervous system effects usually present in early stages of acute ingestion.[1]

movement disorders, asterixis, stupor

Neurologic toxicity may be the only presenting sign or symptom. Substantial neurologic toxicity indicates severe poisoning.[1]

confusion and/or delirium (irritability, hallucinations)

Neurologic toxicity may be the only presenting sign or symptom, with confusion and delirium occurring particularly in chronic or subacute ingestions.[1]​ Substantial neurologic toxicity indicates severe poisoning.

coma and/or papilledema

Neurologic toxicity may be the only presenting sign or symptom. It can extend beyond tinnitus and mild confusion to life-threatening manifestations such as coma and cerebral edema (papilledema is suggestive but neither a sensitive nor a specific finding).[1]

seizures

High probability of seizures in patients with salicylate levels 75 mg/dL or higher.[1]​ 

uncommon

rales plus low oxygen saturation

Indicates life-threatening noncardiogenic pulmonary edema, which can develop in both subacute and chronic poisoning.[1][2]​​

Pulmonary edema marks the poisoning as severe and is an indication for urgent hemodialysis.[13]

Other diagnostic factors

common

volume depletion

Common though nonspecific sign, including dry mucous membranes and poor skin turgor.

Central volume depletion may not be obvious in a patient with diaphoresis.

uncommon

skin rash

Contact dermatitis may suggest topical salicylate exposure.

Risk factors

strong

ingestion of 150 mg/kg or more, or 6.5 g or more, of aspirin or aspirin equivalent

An expert panel consensus statement recognizes that a definite threshold dose for toxicity has not been established, and that many exposures are not single-dose exposures.[2] The panel concluded that the acute ingestion of 150 mg/kg or 6.5 g, whichever is less, of aspirin or aspirin-equivalent warrants evaluation in an emergency department because of the risk of salicylate poisoning.

ingestion of methyl salicylate (oil of wintergreen)

Oil of wintergreen is 98% methyl salicylate, and its ingestion carries a substantial risk of salicylate poisoning.[1][2] It is found in some topical liniments. One teaspoon of concentrated oil of wintergreen is approximately equivalent to 7 g of aspirin.[1][6]​ Ingestion of more than a lick or taste by children <6 years old, or >4 mL by patients ages 6 years or older may be medically significant.

ingestion of bismuth subsalicylate

Many nonprescription antidiarrheal medications contain bismuth subsalicylate, a 50% aspirin equivalent.[1]​ Salicylate overdosage from these products is rare.

history of self-harm or suicide attempt

Salicylate-containing products may be ingested in overdose as a means of self-harm or suicide attempt.[1][2]

children ages 3 years or younger and adults 70 years or older

Incorrect salicylate dosing in children and older people can result in toxic salicylate exposure. Accidental ingestion is also of particular concern at extremes of age. Of 31 deaths primarily attributed to salicylate poisoning in the 2021 report of the US National Poison Data System, 14 deaths occurred in people ages 65 years or more, while none involved children ages less than 18 years.[1]

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