Salicylate toxicity

2014-05-28T15:45:50Z

Amabdali: add in the airway

== 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 60hr if enteric-coated or extended release)
*Unit Conversion
**100 mg/dL = 1000 mg/L = 7.24 mmol/L

== Pathophysiology ==
*As level rises, switches from hepatic to renal clearance (slower)
*N/V
**Stimulates chemoreceptor trigger zone
*Respiratory alkalosis
**Activates respiratory center of medulla
**If have resp acidosis consider pulm edema, resp depressing co-ingestant, or fatigue
*Anion gap metabolic acidosis
**Interferes w/ cellular metabolism
**Normal AG does not exclude ASA toxicity in pt w/ an unknown ingestion (mixed picture)
*Hyperthermia
**Uncouples oxidative phosphorylation
**As pH drops more ASA is uncharged; able to cross BBB
*Altered mental status
**1. Direct toxicity of salicylate species in the CNS
**2. Cerebral edema
**3. Neuroglycopenia
*** Salicylate toxicity increases CNS utilization of glucose, serum glucose levels may not reflect CNS levels.
*Pulmonary Edema
**Usually occurs in elderly
**Due to increased pulmonary vascular permeability

== Clinical Features ==
#Mild (<150mg/kg)
##Tinnitus
##Hearing loss
##Dizziness
##N/V
#Moderate (150-300mg/kg)
##Tachypnea
##Hyperpyrexia
##Diaphoresis
##Ataxia
##Anxiety
#Severe (>300mg/kg)
##AMS
##Seizure
##Acute lung injury
##N/V
##Renal failure
##Cardiac arrhythmias
##Shock

==Diagnosis==
*Triple-mixed acid-base disturbance
**Respiratory alkalosis (earliest sign), AG metabolic acidosis, metabolic alkalosis (contraction)
**Only other entity that produces this pattern is sepsis
*Elevated ASA level
**Obtain levels q1-2hr until levels decline and pt's clinical status stabilizes
**May be deceptively low early after ingestion and with chronic toxicity

== Work-Up ==
*ASA level
*Chem
**Renal failure prevents ASA clearance
**Hypokalemia requires aggressive repletion
***Urinary alkalinization inhibited by excretion of H+ in order to reabsorb K+
*Utox
*UA
**Proteinuria
*VBG
*CBC
*ECG

== Treatment ==
=== Airway ===
*Avoid intubation unless absolutely necessary!
**Very difficult to achieve adequate minute ventilation on vent
***Sedation/paralysis -> decreased RR -> resp acidosis -> incr ASA crossing BBB
*Indications: hypoxemia or hypoventilation
*If mechnically ventilate must set increased RR to to maintain pH 7.50 - 7.59
* give Na bicarb 50-100 meq prior intubation

=== Breathing ===
*Acute lung injury may lead to high O2 requirements

=== Circulation ===
*Hypotension is common due to systemic vasodilation
*IVF +/- K+ (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
*Whole-bowel irrigation
**Consider for ingestion of large amount of enteric-coated or extended-release forms

=== Glucose ===
*Give D50 to altered pts regardless of serum glucose concentration
*Except for fluids used for initial resuscitation, all IVF should be D5W
**ASA toxicity impairs glucose metabolism

=== Alkalinization of plasma and urine ===
*Not a substitute for dialysis in severe salicylism
*Continuous IV infusion of sodium bicarbonate is indicated even in the presence of mild alkalemia from the early respiratory alkalosis per 2013 ACMT guidelines
*Alkalemia from resp alkalosis is NOT a contraindication to NaHCO3 tx
*Mechanism
**Traps ASA in blood and in renal tubules
***Increases elimination; prevents diffusion across BBB
*Indications
**ASA>35 or suspect serious toxicity
*Goals
**Blood pH goal: = >7.5, <7.6
**Urine pH goal: 7.5-8
*Dosing
**NaHCO3 1-2mEq/kg IV bolus; then 3amp bicarb in 1L D5W @ 2-3mL/kg/hr
***Maintain urine pH >7.5

*Bolus during intubation
**If intubation is required, consider administration of sodium bicarbonate by IV bolus at the time of intubation ito maintain a blood pH of 7.45-7.5 over the next 30 minutes

=== Dialysis ===
Indicated for:
*[[AMS]]
*[[Seizure]]
*Refractory acidosis
*Pulmonary edema
*Acute/chronic [[Renal Failure]]
**Will not be able to clear ASA
*6hr level >100

==Disposition==
*Admit all pts who have ingested enteric-coated or extended-release preprarations

== See Also ==
*[[Toxicology (Main)]]
*[[General Psych Workup]]
*[[Acetaminophen (Tylenol)]]
*[[Antidotes]]

== Source ==
*UpToDate
*Tintinalli
*ACMT 2013 Guidance doc Salicylate toxicity

[[Category:Tox]]

Strychnine

2014-05-28T15:40:08Z

Amabdali: add catageory

==Background==
Strychnine is a highly toxic sabustance, it mimics generalized tetanus.It antagonizes glycine release, but unlike TS, it has no effect on GABA release.

==Clinical Features==
*nausea and vomiting
*opisthotonus while Pt. remaining alert
*convulsions
*eventually death through asphyxia

==Differential Diagnosis==
*generalized tetanus
*Black widow spider bite
*Dystonic reaction
*stiff-man syndrome

==Workup==
serum and urine tests for strychnine

==Management==
*supportive management
*benzo for [[seizure]]

==Disposition==
*all patients should be admitted

==See Also==
*[[Tetanus]]

==Sources==
rosen, 7th edition p1684
<references/>
http://en.wikipedia.org/wiki/Strychnine#Symptoms
== category==tox

Strychnine

2014-05-24T11:46:20Z

Amabdali: first edition

==Background==
Strychnine is a highly toxic sabustance, it mimics generalized tetanus.It antagonizes glycine release, but unlike TS, it has no effect on GABA release.
==Clinical Features==
-nausea and vomiting
-opisthotonus while Pt. remaining alert
-convulsions
-eventually death through asphyxia
==Differential Diagnosis==
-generalized tetanus
-Black widow spider bite
-Dystonic reaction
-stiff-man syndrome
==Workup==
serum and urine tests for strychnine
==Management==
-supportive management
-benzo for seizure
==Disposition==
-all patients shoud be admitted

==See Also==
-tetanus
==Sources==
<references/>
rosen, 7th edition p1684
http://en.wikipedia.org/wiki/Strychnine#Symptoms

WikEM - User contributions [en]

Salicylate toxicity

Strychnine

Strychnine