A mother bring her 12 months old baby being more sleepy 2 hours after drinking unknown amount of his older brother's medicine while playing together.
On examination ,child is sleepy but arousable. Vital signs:HR 150 , BP: 120/70, T:37.5, RR:25,SPO2:98% in R.A, blood sugar:
6 mmol/l ,rest of examination is unremarkable
Q1What are the expected toxicity?
Q2 How you will manage this child?
Sleepy Baby Cont'
Thank you all for your excellent comments.
Antihistamine toxicity is variable specially with different generation , with newer generation having more cardiac than CNS manifestations
In general, toxicity occurs after ingestion of 3-5 times the usual daily dose of antihistamine.
Signs and symptoms resemble anticholinergic syndrome and appear within 30 minutes-2 hours after ingestion.
o CNS effects: excitation, psychomotor agitation, convulsions is common in children. Drowsiness,
sedation, delirium, hallucinations, coma are common in adults.
o Anticholinergic effects: hyperthermia, tachycardia, hypertension, fixed and dilated pupils, blurry vision , diplopia, dry mouth and
urinary retention.
o Cardiac effects: myocardial depression, QRS widening (common with diphenhydramine overdose), QT
prolongation-resulting in torsades de pointes (polymorphic VT), cardiac arrythemia
o GI effects: nausea, vomiting, diarrhea, or constipation, decreased bowel sounds
Management:
Mainly supportive and symptomatic patients need admission for observation.
Physostigmine: is used in pure anticholinergic poisoning and not routinely recommended for antihistamine drug overdose/poisoning due to its own toxicity (seizures, bronchoconstriction and asystole).
- It should be considered only in cases of severe toxicity (severe delirium, seizures and supraventricular
tachyarrhythmias unresponsive to other measures) of pure anticholinergic poisoning (not in tricyclic
antidepressant overdose, due to bradydysrhythmias and asystole in such cases).
References:
National management Guidelines of Poisoning.