Breathholding

Breathholding is a common cause of loss of consciousness in small children and often raises concerns that a seizure has occured. Older texts implied that breath holding was a voluntary behavior by the child to attract attention, and therefore they should be ignored so they will stop. It is impossible for anyone (especially small children) to hold their breath until they pass out.

Very strong reflexes are triggered by low oxygen and high carbon dioxide levels which develop during voluntary breathholding. There are also very strong reflexes to preserve blood flow to the brain under all conditions. Breathholding seems to be an exaggerated response to a reduction in blood flow to the brain that occurs during exaggerated inspiration or excessive expiration when small children suddenly begin to cry or cry excessively. The small child is prone to breathholding because in inspiration, the chest wall expands excessively, increasing the pressure within the chest. The pressure increases gradually at first but when the chest can no longer expand there is a sudden pressure rise which compresses the young child's very flexible superior vena cava restricting blood flow to the right side of the heart. If the heart does not fill with blood, there is no blood to pump to the brain. This sudden decrease in blood flow triggers the protective fainting reflex and the child passes out. In a similar fashion, excessive expiration lowers the pressure in the chest and empties the lungs of air so that blood overfills the lungs instead of returning to the left side of the heart. Again, with no blood going to the heart there is no blood to pump out. This lack of blood flow is detected by nerves in the carotid artery and the fainting reflex is triggered. These nerves in each carotid artery, known as the carotid body or bodies, are present to sense blood flow to the brain in response to changes in position and posture. The reflexe from the carotid bodies to the brain and then to the heart through the vagal nerves, known as the vagal reflex, helps the heart adjust to lying, sitting and standing.

Breathholding is most common in children within the first year of walking (being upright while active) suggesting that this vagal reflex is still somewhat inefficient. Also, because of the small size of children (shorter distance between the heart and the carotid bodies) this reflex may be excessively sensitive. Breatholding can cause cyanosis (look blue) or pallor (look pale) depending on reduced blood flow or no blood flow from the heart. Children do not die during breathholding spells, and the episodes always cease spontaneously. (Does anyone know an adult who has breathholding spells? No, as the chest wall and blood vessels mature the are unable to respond to the exaggerated stretching and compression and the sensitivity of the fainting reflex matures, breathholding events no longer occur.) The vagal reflex, chest wall compliance and cardiac output are influenced by numerous factors including fever, adrenalin (from excitment, anger, frustration or stress) and fatigue so there may be conditions or situations when a triggering response causes a breathholding spell on one day but the same trigger may not cause a spell on a different day. Likewise, the surrounding environment may influence how severe an episode is based on the child's perception of the stress and anxiety level of the adults. Therefore, if an episode occurs, ignoring the child and letting the spell resolve sounds like good advice. However, a better plan is to stay calm, let the child "think you are ignoring them" and provide some calming reassurance or distract the child in a calming tone. This advice is much better accepted by the family.

CyanoticSyncope / Breathholding

Clinical Features: Cyanotic spells are usually provoked by anger, frustration, or fear. The infant’s sibling takes away a toy; the child cries and then stops breathing in expiration. Cyanosis develops rapidly, followed quickly by limpness and loss of consciousness. Occasionally, cyanotic episodes are provoked by pain and these may not be preceded by crying. If the attack lasts only a few seconds, the infant may resume crying upon awakening. Most spells, especially the ones referred for neurologic evaluation, are longer and are associated with tonic posturing of the body and clonic movements of the hands or arms. The eyes may roll upward as well. These movements are generally regarded as seizures by most observers, but are probably a brainstem release phenomenon not associated with abnormal electrical discharges. After a short spell, there is rapid recovery and the child seems normal immediately; after a prolonged spell, the child first arouses and then goes to sleep. Once an infant begins having breathholding spells, the frequency first increases for several months, then declines, and finally ceases.

Diagnosis: The typical sequence of crying, cyanosis, and loss of consciousness is critical for diagnosis. Many children with cyanotic syncope are misdiagnosed as having epilepsy because of lack of attention to the precipitating event. It is not sufficient to ask, “Did the child hold his breath?” The question conjures up the image of breathholding during inspiration. Instead, questioning should be focused on family history, precipitating events, absence of breathing, and facial color.

EEG: Between attacks, the EEG is always normal. During an episode, the EEG first shows diffuse slowing and then rhythmic slowing during the tonic-clonic activity.

Treatment: Treatment is not available to prevent future breathholding spells or to stop a spell in progress. The major function of the physician is to correctly identify the nature of the spell and explain that it is harmless.

Pallid Syncope / Breathholding

Clinical Features: These are dramatic and frightening episodes usually provoked by a sudden, unexpected, painful event such as a bump on the head. The child rarely cries but, instead, becomes white and limp and loses consciousness. Parents invariably believe the child is dead and begin mouth-to-mouth resuscitation. After the initial limpness, the body may stiffen and be accompanied by clonic movements of the arms. As in cyanotic syncope, these movements represent a brainstem release phenomenon and not seizure activity. The duration of the spell is difficult to determine. It is very frightening to the observer, and seconds seem like hours. Afterwards, the child often falls asleep and is normal upon awakening.

Diagnosis: The pathophysiology of pallid syncope is reflex asystole (Stephenson, 1980). An attack can be provoked by initiating a vagal reflex by pressure on the eyeballs. However, we do not recommend provoking an attack as an office procedure; the diagnosis can be made by history alone.

Treatment: As with cyanotic spells, the major goal is to reassure the family that the child will not die during an attack. One needs to be very convincing. Atropine, 0.01 mg/kg/day, in two divided doses, has been recommended to prevent attacks, but is without experimental evidence of efficacy.