Salicylate toxicity: Difference between revisions
(Created page with "==Background== *therapeutic: 15mg/kg, 15-30mg/dL, peak level 2-4 h *large ingestion- peak levels 18-24h (2/2 bezoar/pylorospasm), enteric or SR peak lev up to 60hr *1/2 life ...") |
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==Background== | ==Background== | ||
*Fatal dose: | |||
**~10-30g by adult | |||
**~3g by child | |||
*Levels: | |||
**Therapeutic: 10-30mg/dL | |||
**Intoxication: >40-50 mg/dL | |||
**Peak occurs ~6hr after absorption | |||
***Up to 24hr if enteric-coated or extended release | |||
==Pathophysiology== | |||
*As level rises, hepatic detox is saturated, switches to renal clearance (slower) | |||
*As pH drops more ASA is uncharged > crosses BBB | |||
*AMS | |||
**Causes: | |||
***1. Direct toxicity of salicylate species in the CNS | |||
***2. Cerebral edema | |||
***3. Neuroglycopenia | |||
****May occur despite normal serum glucose levels | |||
* | *Pulmonary Edema | ||
**Usually occurs in elderly | |||
** | |||
* | *Anion gap metabolic acidosis (interferes w/ cellular metabolism) | ||
*Nausea/vomiting (stimulates chemoreceptor trigger zone) | |||
*Respiratory alkalosis (activates respiratory center of medulla) | |||
**If have resp acidosis consider pulm edema, resp depressing co-ingestant, or fatigue | |||
2. fluid loss, lytes off: emesis, tachypnea, kidneys excrete bicarb/K,nonolig RF vs oligur (SIADH) | 2. fluid loss, lytes off: emesis, tachypnea, kidneys excrete bicarb/K,nonolig RF vs oligur (SIADH) | ||
Line 26: | Line 40: | ||
6. n/v/gastritis/decr gastric motility | 6. n/v/gastritis/decr gastric motility | ||
==Signs/Symptoms== | |||
*Tinnitus | |||
**May occur within therapeutic range | |||
*Fever | |||
*Vertigo | |||
*N/V | |||
*Diarrhea | |||
*AMS | |||
*Coma | |||
*Noncardiac pulmonary edema | |||
*Death | |||
**Correlated with CNS salicylate levels | |||
* | ==Vital signs== | ||
*Tachypnea | |||
*Increase body temperature | |||
**Lack of hyperthermia does not rule out toxicity! | |||
*Tachycardia (due to hypovolemia, agitation, or general distress) | |||
==Work-Up== | |||
*ASA level | |||
**Check q2hr until two consec levels show a decrease | |||
*Tylenol level | |||
*ETOH level | |||
*Utox | |||
*UA | |||
*VBG | |||
*CBC | |||
*Chem | |||
**If renal failure unable to clear ASA | |||
**Hypokalemia requires aggressive repletion | |||
***K+/H+ pump in distal tubule > decr ur. alkalinization | |||
*LFT | |||
*Coags | |||
**Rarely may cause hepatotoxicity | |||
*hCG | |||
*ekg | *ekg | ||
**level >30mg/dL s/s of tox or >35 at any time | |||
*level >30mg/dL s/s of tox | |||
or | |||
==Treatment== | ==Treatment== | ||
Airway | |||
*Avoid intubation unless absolutely necessary! | |||
**1. Very difficult to achieve adequate minute ventilation on vent | |||
***Leads to resp acidosis > incr ASA crossing BBB | |||
**2. Sedation/paralysis > incr ASA crossing BBB | |||
**Indications = Hypoxemia or hypoventilation | |||
**If intubate maintain pH 7.50 - 7.59 | |||
Breathing | |||
*Acute lung injury may lead to high O2 requirements | |||
Circulation | |||
*Hypotension is common due to systemic vasodilation | |||
**Give fluids if no cerebral edema, no pulmonary edema | |||
***If these are present consider pressors | |||
Decontamination | |||
*Charcoal 1g/kg up to 50g PO | |||
**Effectively absorbs ASA | |||
**Give multiple doses if tolerated | |||
***25g PO q2hr x 3 doses OR 50g q4hr x 2 doses after initial dose | |||
Glucose | |||
*Give D50 to pts with AMS regardless of serum glucose concentration | |||
Alkalinization of plasma and urine | |||
- | *lytes: consider 40mEq KCl/L, hypoK will prevent urine alkaliniz | ||
*Alkalinization | |||
**Traps ASA in blood and in rental tubules (so can't diffuse across BBB) | |||
**fxn of flow & pH | |||
***consider bicarb if ASA>35 or suspect serious toxicity | |||
***1-2mEq/kg IV bolus then D5W c 3amps bicarb/L @1.5-2x maintenance adjust for goal urine pH>7.5 | |||
**maintain hypervent if intubated | **maintain hypervent if intubated | ||
Line 81: | Line 123: | ||
==Dialysis== | ==Dialysis== | ||
*Indicated for: | |||
**AMS | |||
**Coma | |||
**Seizure | |||
**Refractory acidosis | |||
**Pulmonary edema | |||
**Acute/chronic renal failure | |||
***Pts will not be able to clear ASA | |||
**6hr level > 100 | |||
==Source== | ==Source== | ||
UpToDate | |||
[[Category:Tox]] | [[Category:Tox]] |
Revision as of 20:42, 10 April 2011
Background
- Fatal dose:
- ~10-30g by adult
- ~3g by child
- Levels:
- Therapeutic: 10-30mg/dL
- Intoxication: >40-50 mg/dL
- Peak occurs ~6hr after absorption
- Up to 24hr if enteric-coated or extended release
Pathophysiology
- As level rises, hepatic detox is saturated, switches to renal clearance (slower)
- As pH drops more ASA is uncharged > crosses BBB
- AMS
- Causes:
- 1. Direct toxicity of salicylate species in the CNS
- 2. Cerebral edema
- 3. Neuroglycopenia
- May occur despite normal serum glucose levels
- Causes:
- Pulmonary Edema
- Usually occurs in elderly
- Anion gap metabolic acidosis (interferes w/ cellular metabolism)
- Nausea/vomiting (stimulates chemoreceptor trigger zone)
- Respiratory alkalosis (activates respiratory center of medulla)
- If have resp acidosis consider pulm edema, resp depressing co-ingestant, or fatigue
2. fluid loss, lytes off: emesis, tachypnea, kidneys excrete bicarb/K,nonolig RF vs oligur (SIADH)
3. abnml gluc metabolism
4. non-cards pulm & cerebral edema
5. plt dysfxn, anemia (chronic tox)
6. n/v/gastritis/decr gastric motility
Signs/Symptoms
- Tinnitus
- May occur within therapeutic range
- Fever
- Vertigo
- N/V
- Diarrhea
- AMS
- Coma
- Noncardiac pulmonary edema
- Death
- Correlated with CNS salicylate levels
Vital signs
- Tachypnea
- Increase body temperature
- Lack of hyperthermia does not rule out toxicity!
- Tachycardia (due to hypovolemia, agitation, or general distress)
Work-Up
- ASA level
- Check q2hr until two consec levels show a decrease
- Tylenol level
- ETOH level
- Utox
- UA
- VBG
- CBC
- Chem
- If renal failure unable to clear ASA
- Hypokalemia requires aggressive repletion
- K+/H+ pump in distal tubule > decr ur. alkalinization
- LFT
- Coags
- Rarely may cause hepatotoxicity
- hCG
- ekg
- level >30mg/dL s/s of tox or >35 at any time
Treatment
Airway
- Avoid intubation unless absolutely necessary!
- 1. Very difficult to achieve adequate minute ventilation on vent
- Leads to resp acidosis > incr ASA crossing BBB
- 2. Sedation/paralysis > incr ASA crossing BBB
- Indications = Hypoxemia or hypoventilation
- If intubate maintain pH 7.50 - 7.59
- 1. Very difficult to achieve adequate minute ventilation on vent
Breathing
- Acute lung injury may lead to high O2 requirements
Circulation
- Hypotension is common due to systemic vasodilation
- Give fluids if no cerebral edema, no pulmonary edema
- If these are present consider pressors
- Give fluids if no cerebral edema, no pulmonary edema
Decontamination
- Charcoal 1g/kg up to 50g PO
- Effectively absorbs ASA
- Give multiple doses if tolerated
- 25g PO q2hr x 3 doses OR 50g q4hr x 2 doses after initial dose
Glucose
- Give D50 to pts with AMS regardless of serum glucose concentration
Alkalinization of plasma and urine
- lytes: consider 40mEq KCl/L, hypoK will prevent urine alkaliniz
- Alkalinization
- Traps ASA in blood and in rental tubules (so can't diffuse across BBB)
- fxn of flow & pH
- consider bicarb if ASA>35 or suspect serious toxicity
- 1-2mEq/kg IV bolus then D5W c 3amps bicarb/L @1.5-2x maintenance adjust for goal urine pH>7.5
- maintain hypervent if intubated
Dialysis
- Indicated for:
- AMS
- Coma
- Seizure
- Refractory acidosis
- Pulmonary edema
- Acute/chronic renal failure
- Pts will not be able to clear ASA
- 6hr level > 100
Source
UpToDate