Cause:ASA ingestion of >10 gm (120 mg/kg), >500 mg/kg usually fatal, acutely or chronically build level up
Pathophys:Respiratory stimulation via respiration centers and chemoreceptors; oxidative metabolism uncoupling. Direct CNS stimulation; gastric irritant
Common in children, adult suicides, and the elderly treating various medical illnesses with ASA (insidious, high morbidity, and mortality)
Sx:Dizziness; can be precipitated by steroid withdrawal; nausea, tinnitus, emesis
Si:Fever and hypermetabolism; respiratory alkalosis then metabolic acidosis; confusion evolving into convulsions
CNS damage with seizures, from anoxia; coma; shock
Pulmonary edema even as ASA level decreasing due to increased capillary permeability, especially in smokers (Ann IM 1981;95:405)
Lab:
Chem:Salicylate level initially and 6 h postingestion; >70 mg % (indicates 10-30 gm ingested); therapeutic levels in RA 
30 mg %; lytes show respiratory alkalosis evolving into metabolic acidosis or a combination of both
Hem:Protime increased
Urine:10% FeCl3 to 1 mL of urine shows a purple color
Xray:KUB may show size of pill bolus in gi tract
Rx:
Respiratory alkalosis alone usually requires no rx
Glucose iv to avoid ASA-induced hypoglycemia (Nejm 1973;288:1110) of metabolic acidosis: supportive care and respirator; correct lyte imbalances, eg, acidosis; dialyze soon; NaHCO3 1 mM/kg w 20 mEq KCL diluted in 500 D51/2S at 2-3 mL/kg/h iv to alkalinize urine or as iv push without increasing fluids probably best (BMJ 1982;285:1383)
Vit K for protime prolongation
Hemodialysis if initial salicylate level >120 mg % or 6-h level >100 mg %, or renal failure, or hypoxia, CHF, pulmonary edema, or persistent CNS changes (seizures, coma, confusion)