Episodes of transient hypoxia with crying

Specialty: Pediatrics.

• Cyanotic sob spasm
• hypoxia crisis in the infant
• glottis spasm

Why it occurs

• Cyanotic or pale type sobbing spasm (benign non-epileptic paroxysmal event initiated by crying, pain, anger or frustration, mediated by an autonomic reflex that generates expiratory apnea and vagal hypertonia)
• Tetralogy of Fallot hypoxia crisis or "spells" (spasm of the pulmonary infundibulum that massively diverts deoxygenated blood from right to left through the VSD, typical after crying, defecation or feeding)
• Primary or secondary pulmonary hypertension (acute pulmonary vasospasm attacks triggered by the stress of crying)
• Severe tracheobronchomalacia (dynamic collapse of the major airway during the expiratory effort of crying that prevents ventilation)
• Congenital long QT syndrome (arrhythmias triggered by vigorous crying or startle with secondary syncope, confused with spasms)

Initial workup

Detailed clinical history specifying the exact sequence of the event (trigger $\rightarrow$ crying $\rightarrow$ silence/apnea during expiration $\rightarrow$ cyanosis/paleness $\rightarrow$ brief loss of consciousness $\rightarrow$ rapid complete recovery). 12-lead electrocardiogram (ECG) in all cases to measure the corrected QTc interval (rule out malignant arrhythmias). Complete blood count, serum ferritin, and serum iron (iron deficiency anemia is closely associated with increased frequency and severity of sob spasms). Color Doppler echocardiogram if there is suspicion of congenital heart disease (Tetralogy of Fallot) or pulmonary hypertension. Electroencephalogram (EEG) only if the episodes suggest primary epileptic seizures.

Standard management

• Preventive pharmacological treatment is not required for benign sob spasms, and parental education and reassurance are essential. Ferrous sulfate or aminochelated iron — indicated of choice if iron deficiency is confirmed, even without frank anemia, since it significantly reduces the frequency of sobbing spasm attacks; dose of 3 to 6 mg/kg/day of elemental iron orally for 3 months
• Propranolol — beta-blocker indicated of choice for the prevention of hypoxia crises in Tetralogy of Fallot by relaxing infundibular spasm; dose of 1 to 3 mg/kg/day orally divided into 3 doses
• Supplementary oxygen therapy and sedation (morphine at a dose of 0.1 mg/kg SC or IV) in the acute in-hospital management of hypoxic crises due to Fallot.