History
If aspirin usage is suspected, direct questioning is useful. Many patients do not list aspirin or other over-the-counter (OTC) aspirin-containing products because they may not consider such products as medications. When possible, elicit the following information:
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Type of salicylate
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Amount
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Approximate time of ingestion
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Possibility of long-term ingestion
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Potential co-ingestants
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Presence of other medical conditions (eg, cardiac, renal diseases)
The presence of tinnitus is a clue for salicylate ingestion. Tachypnea, tachycardia, and elevated temperature can be detected by evaluating vital signs. Treatment should not be withheld in symptomatic patients because of pending serum level tests.
The patient who presents with an acute, witnessed, or intentional overdose usually has a history that the physician can directly obtain. Eliciting a history of a chronic overdose in geriatric or psychiatric patients often is harder to accomplish. Thus, diagnosis can be more difficult in these patient populations.
Long-term ingestion of salicylates may produce the appearance of anxiety with its associated tachypnea, diaphoresis, difficulty concentrating, and hallucinations; agitated delirium also may be observed. Elderly individuals may present with deterioration in functional status or with concerns of pneumonia, owing to the presence of tachypnea and fever.
Patients with underlying psychiatric illness may present with symptoms suggestive of an exacerbation of their underlying psychiatric illness (eg, mania, psychosis).
Physical Examination
Pulmonary
Pulmonary symptoms and signs of salicylate poisoning include the following:
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Hyperventilation (common)
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Hyperpnea
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Severe dyspnea due to noncardiogenic pulmonary edema
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Respiratory arrest
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Apnea
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Fever and dyspnea due to aspiration pneumonitis
Auditory
Auditory symptoms caused by the ototoxicity of salicylate poisoning include the following:
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Decreased hearing
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Deafness
Tinnitus is commonly encountered when serum salicylate concentrations exceed 30 mg/dL. Although the presence of tinnitus is not a very specific or sensitive clinical effect of salicylate poisoning., it can be a very useful early sign of salicylate toxicity given the right clinical setting.
Cardiovascular
Cardiovascular symptoms of salicylate poisoning include the following:
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Tachycardia, generally with minimal hemodynamic or clinical significance
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Hypotension
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Dysrhythmias - Eg, ventricular tachycardia, ventricular fibrillation, multiple premature ventricular contractions
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Asystole - With severe intoxication
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Electrocardiogram (ECG) abnormalities - Eg, U waves, flattened T waves, QT prolongation may reflect hypokalemia
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Sudden hemodynamic deterioration secondary to respiratory depression
Respiratory depression limits the respiratory alkalosis and causes an increase in the nonionized portion of salicylate. The nonionized salicylate enters cells and crosses the blood-brain barrier much more readily, causing much higher levels of salicylate in brain tissue, leading to severe CNS toxicity.
Neurologic
Neurologic symptoms, signs, and manifestations of salicylate poisoning include the following:
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CNS depression, with manifestations ranging from somnolence and lethargy to seizures and coma
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Tremor
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Blurring of vision
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Seizures
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Cerebral edema - With severe intoxication
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Encephalopathy
Encephalopathic changes may include irritability, confusion, hyperactivity, and hallucinations. These clinical effects are usually associated with severe cases.
Gastrointestinal
GI symptoms, signs, and manifestations of salicylate poisoning include the following:
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Nausea and vomiting, which are very common with acute toxicity
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Epigastric pain
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GI hemorrhage - More common with chronic intoxication
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Intestinal perforation
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Pancreatitis
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Hepatitis - Generally in chronic toxicity; rare in acute toxicity
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Esophageal strictures - Reported as a very rare delayed complication [18]
Genitourinary
Genitourinary symptoms, signs, and manifestations of salicylate poisoning include the following:
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Acute kidney injury is an uncommon complication of salicylate toxicity
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Kidney failure may be secondary to multisystem organ failure
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Case reports have documented the presence of albuminuria
Hematologic
Hematologic effects may include prolongation of the prothrombin and bleeding times and decreased platelet adhesiveness. Disseminated intravascular coagulation (DIC) may be noted with multisystem organ failure in association with chronic salicylate toxicity. Coagulopathy and major bleeding has also been reported in patients with salicylate toxicity. [19]
Dermatologic
Contact dermatitis may develop from topical application. Diaphoresis is a common sign in patients with salicylate toxicity. [2]
Electrolytic
Electrolyte-associated symptoms, signs, and manifestations of salicylate poisoning include the following:
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Dehydration
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Hypocalcemia
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Acidemia
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Syndrome of inappropriate antidiuretic hormone secretion (SIADH)
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Hypokalemia
Hypokalemia may be a severe iatrogenic complication in patients treated with urinary alkalization if sufficient potassium supplementation is not provided.
