258 Emergency Medicine
alcoholingestion. However, a normal or even negative osmol gap does not
exclude the presence of toxic alcohols.
The patient’s clinical presentation of altered mental status, anion gap
metabolic acidosis, and osmol gap is consistent with a toxic alcoholinges-
tion. In this case, the ingested substance was methanol.
232.The answer is b.(Goldfrank et al, pp 847-860. Rosen, pp 2087-2093.)
For young patients with altered mental status, toxic ingestion should be
high on the differential. This clinical scenario is most consistent with toxic
ingestion of a TCA.Treatment of all toxic ingestions should begin with
assessment of airway, breathing, and circulation. As a result this patient’s
obtunded mental status and loss of gag reflex, orotracheal intubationis
indicated for airway protection. Subsequently, activated charcoalcan be
administered. Because of the anticholinergic effects of TCAs, absorption is
prolonged and GI motility is delayed leading to greater toxicity. Therefore,
an additional dose of charcoal should be administered several hours later.
In an obtunded patient, it is important to first secure an airway prior to
administering charcoal to prevent aspiration in the event of vomiting.
Acute cardiovascular toxicity is responsible for most of the mortalities
from TCA overdose. The characteristic features are conduction delays, dys-
rhythmias, and hypotension. The sodium-blocking activity of TCAs leads to
a widened QRS and rightward axis. It is believed that there is an increased
chance of cardiac dysrhythmias if the QRS is greater than 100 msec. It is rec-
ommended that you treat this condition with IV sodium bicarbonateuntil
the QRS narrows to 100 msec or the serum pH increases to 7.55. In addi-
tion, the patient is hypotensive and should receive a fluid bolus of normal
saline and be placed in Trendelenburg position. If the hypotension does
not resolve after these maneuvers and administration of bicarbonate, the
patient should receive norepinephrine. TCA overdose may progress rapidly
and is frequently unpredictable. It is common for a patient to present to the
ED awake and alert and then develop life-threatening cardiovascular and
CNS toxicity within a couple of hours.
(a)Narcan is the antidote for opioid toxicity; this patient requires
sodium bicarbonate for a TCA overdose. (c)NAC is the antidote for aceta-
minophen overdose. (d)Syrup of ipecac cannot be administered to a patient
who is intubated. It must be given to patients with a normal mental status
with nothing impeding their oropharynx. (e)Inducing vomiting is con-
traindicated given the potential for precipitous neurologic and hemody-
namic deterioration.