Sudden episodes of cyanosis and apnea triggered by crying

Specialty: Pediatrics.

• Cyanotic type sobbing spasm
• hypoxia crisis in the infant
• benign paroxysmal apnea

Why it occurs

• Cyanotic-type sob spasm (benign non-epileptic event characterized by an involuntary vagal reflex that occurs in healthy infants between 6 months and 4 years of age, triggered by pain, anger, crying or frustration, presenting with prolonged expiratory apnea, rapid cyanosis, brief loss of consciousness and subsequent complete recovery)
• Hypoxia crises or "spells" of Tetralogy of Fallot (spasm of the right ventricular infundibulum that critically increases resistance to pulmonary flow, massively diverting deoxygenated blood to the systemic circulation through the ventricular septal defect, typically triggered by crying or defecation)
• Pulmonary hypertension, primary or secondary to heart disease (episodes of acute pulmonary vasospasm and right ventricular failure reactive to stress or crying)
• Severe tracheobronchomalacia or dynamic collapse of the upper airway (mechanical respiratory obstruction during the expiratory effort of crying with secondary hypoxia)
• Primary cardiac arrhythmias (Congenital long QT syndrome, triggered by adrenergic stimulation of crying or startle).

Initial workup

Detailed medical history that carefully describes the chronology of the event (clear trigger $\rightarrow$ crying $\rightarrow$ sudden silence on expiration $\rightarrow$ cyanosis $\rightarrow$ brief loss of consciousness $\rightarrow$ rapid complete recovery). 12-lead electrocardiogram (ECG) in all cases to measure the corrected QTc interval (rule out serious cardiac arrhythmias such as Long QT Syndrome). Complete blood count, serum ferritin, serum iron and iron binding capacity (iron deficiency anemia and iron deficiency are closely linked to the severity and frequency of sob spasms). Doppler echocardiogram if there is suspicion of underlying congenital heart disease or pulmonary hypertension.

Standard management

• Preventive pharmacological treatment is not required for benign sob spasms, education, tranquility and family demystification being essential. Ferrous sulfate or aminochelated iron — indicated of choice if iron deficiency is confirmed, even without frank anemia, since it very significantly reduces the frequency and severity of sob spasm attacks; doses of 3 to 6 mg/kg/day of elemental iron orally for a minimum cycle of 3 months
• Propranolol — beta-blocker indicated of choice to prevent hypoxia crises in Tetralogy of Fallot by relaxing the infundibular muscle; dose of 1 to 3 mg/kg/day orally divided into 3 doses
• Morphine (indicated in the acute hospital management of hypoxia crisis due to Fallot to depress the respiratory center and relax the spasm; dose of 0.1 mg/kg SC or IV).