Idiopathic (approximately 50 percent)
GI (most common, up to 50 percent of diagnosed cases)
	Gastroesophageal reflux
	Gastric volvulus
	Intussusception
	Swallowing abnormalities
	Other GI abnormalities
Neurologic (approximately 30 percent)
	Seizure disorder
	Febrile seizure
	CNS bleeding
	Neurologic conditions affecting respiration (Budd-Chiari syndrome, hindbrain malformation, brainstem malformation)
	Vasovagal reflexes
	Hydrocephalus
	CNS infection
	Ventriculoperitoneal shunt malfunction
	Malignancy
Respiratory (approximately 20 percent)
	Respiratory compromise from infection, respiratory syncytial virus, pertussis, mycoplasma, croup, other pneumonias
	Obstructive sleep apnea
	Breath-holding spells
	Conditions affecting respiratory control (prematurity, central hypoventilation)
Respiratory
	Vocal cord abnormalities, adenoid vegetations
	Laryngotracheomalacia
	Airway obstruction resulting from congenital abnormalities
	Foreign-body aspiration
Cardiac (up to 5 percent)
	Arrhythmia
		Long QT syndrome
		Wolff-Parkinson-White syndrome
	Congenital heart disease
	Myocarditis
	Cardiomyopathy
Metabolic abnormalities (less than 5 percent)
	Inborn errors of metabolism
	Endocrine, electrolyte disorders
	Other infections
	Urinary tract infection
	Sepsis
Child abuse (less than 5 percent)
	Munchausen syndrome by proxy (suffocation, intentional salt poisoning, medication overdose, physical abuse, head injury)
	Smothering (unintentional or intentional)
Other
	Food allergy (uncommon)
	Anaphylaxis
	Medication (prescription, over the counter, herbal remedies)