A 10-year old 24kg female is seen in the Emergency Department accompanied by her parents. You are informed that the child arrived home after school 20 minutes ago. She appeared hyperactive and her pulse was 190. The child denies any discomfort. When asked about recent activities, she states: “nothing.” Physical exam reveals a well-nourished 10-year old female with stable perfusion status and respiratory function. She seems unsettled and has unusual hand movements and changes her body position frequently. Blood pressure is 158/90 with a pulse of 194/minute. The ECG monitor shows sustained sinus tachycardia. The patient denies pain or discomfort. Her oral temperature is 37.2 degrees C.
Differential diagnosis? Sinus tachycardia vs. a supra-ventricular arrhythmia.
Sinus tachycardia is most commonly caused by high-levels of anxiety; pain; febrile states; and dehydration. None of these seem to apply to this patient.
Arrhythmias frequently have a sudden-onset/sudden termination history. The electrophysiology is accessory pathway, or re-enterent pathway conduction. There may be a previous cardiac or family history of paroxysmal palpations, etc. None of these seem to apply to this patient.
Other possibilities?
30 minutes after admission, information is received from the school that another child has developed similar symptoms and has admitted she and the patient ingested “coke” acquired from an older sibling.
COURSE OF ACTION:
One of the ED staff performed a Valsalva maneuver and during stimulation the heart rate slowed 10%. It immediately returned to pre-intervention rate when vagal stimulation ceased. One staff member suggested Adenosine, however, the attending physician felt it unnecessary at this time as an assumptive diagnosis of sinus tachycardia seemed likely.
I.V. access was established and a basic lab panel and toxicology study drawn and forwarded to the lab. Because of the child’s hyperactive behavior, 3.0 mg of diazepam was administered by I.V. Within several minutes, the child appeared calmer and the sinus tachycardia slowed to 172/minute and the blood pressure dropped to 128/82.
PLAN:
1. Continue to monitor patient for:
2. Follow-up with Social Services/School as needed or required and provide patient education
1. Paroxysmal behavior (sudden start/end) is associated with:
a. sinus tachycardia
b. arrhythmia (i.e. SVT)
c. ventricular fibrillation
d. none of the above
2. Which of the following is NOT appropriate to use in differentiating narrow QRS tachycardias?
a. adenosine IV push
b. Valsalva maneuvers
c. electrical cardioversion
d. careful patient history
3. Ingestion/inhalation of cocaine can induce organic cardiac damage in patients.
a. true
b. false
4. Cocaine may induce seizure activity.
a. true
b. false
5. Benzodiazepam drugs (diazepam, midazolam, etc.) may be used to:
a. (1,2)
b. (2,3)
c. (1,2,3)
d. (4 only)
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