A pediatric patient with tetralogy of Fallot may have paroxysmal hypercyanotic attacks with hypoxia.
Synonym: blue spell, "tet" (for tetralogy) spell, hypoxic spell
Triggers may include:
(1) crying
(2) waking up in the morning
Clinical features:
(1) hyperpnea (rapid or labored breathing) and/or gasping respirations
(2) restlessness
(3) cyanosis
(4) syncope
Laboratory features:
(1) metabolic acidosis
(2) reduced PaO2, often < 40 mm Hg
Sequelae:
(1) weakness and exhaustion
(2) seizures
(3) unconsciousness
(4) occasionally death
Tet spells tend to occur in the pediatric age group, being absent in adolescents and adults.
