Three of the most common neurological paroxysmal disorders in childhood are headache, sleep disorders, and epilepsy. As these subjects are examined thoroughly in other chapters in this book, they will not be covered here. Instead, this chapter will cover non-epileptic neonatal events, breath-holding spells, syncope, paroxysmal dyskinesia, episodic ataxia, tics, panic disorder, and psychogenic non-epileptic seizures in children.
Short pauses in breathing are normal in infants. Apnea in a premature infant is longer than 20 seconds, and in a mature infant is more than 15 seconds. The more premature the infant, the greater the risk of apnea. There is often associated temporary paleness or bluish skin, and decreased muscle tone. In a premature infant, apnea can be associated with bradycardia. There is an increased risk of infant apnea if the infant is male, is of premature birth, has a teenage mother, or is one of multiples (twins or multiple-birth siblings).
In the neonate, apnea if often due to respiratory center immaturity. In an infant up to 1 year of age, apnea can be caused by a number of medical conditions. These include stroke, meningitis, hypoglycemia, infection, airway obstruction, gastroesophageal reflux, and medication effect. If apnea is associated with eye deviation or rhythmic jerky eye or body movements, one should consider the possibility of a seizure.
Treatment is dependent on the underlying mechanism, if one can be found. Tactile stimulation of the infant during an event can often abort the apnea. An apnea monitor, continuous positive airway pressure (CPAP) machine or an oxygen hood may be used to treat the infant.
Hypnogogic myoclonic jerks are common in all ages and are commonly called “sleep starts.” In infants before 3 months of age, benign myoclonic jerks are seen in non–rapid eye movement (NREM) sleep and are usually symmetric and bilateral. Usually, they involve both arms and legs but can rarely be isolated to a single extremity.
Electroencephalography during the episode is normal. Movements can happen repetitively every 2 to 3 seconds sounding similar to a seizure.1 However, they only happen in sleep, and the child’s examination and development is usually normal. If the child is awoken during these movements, they stop immediately. If the movements continue after the child is awoken, seizure should be considered. Benign sleep myoclonus is different than the many other causes of non-epileptic myoclonus.
Pathologic focal, multifocal, or generalized myoclonus can be seen during wakefulness or sleep. It is sometimes stimulus induced. Hypoxic-ischemic encephalopathy, metabolic encephalopathy, head trauma, stroke, and medications can all cause myoclonus.
As children, people with hyperekplexia have an exaggerated startle response to tactile or auditory stimulation. Upon awakening infants become markedly stiff with forced closure of the eyelids and extension of the extremities and often have a brief apneic episode. This can often be reproduced by gently tapping the infant on the nose. Nocturnal myoclonus may be seen in some infants with hyperekplexia. Abdominal and inguinal hernias and hip dislocations have been noted as a result of the sudden increase in tone.
Usually autosomal dominant, this disease has been associated with an abnormality on chromosome 5q2 and is thought to be from a defect in a glycine receptor. Autosomal recessive families have been noted.
Caregivers can be taught a technique that often helps to overcome a spell by gently flexing the child’s legs at the hip. In older children clonazepam, diazepam, phenobarbital, or valproic acid are sometimes useful.
Common in the neonatal care unit, jitteriness in a neonate or infant is often precipitated by auditory or tactile stimulation. The movement is a tremor and is often associated with irritability. The infant is usually alert and responsive. There may be an exaggerated Moro response or an increased startle response. It can be caused by medications given to the mother before birth or to the infant after birth. It can be observed as an infant is withdrawing off medications the mother took during the pregnancy. Hypoglycemia, hypocalcemia, and hypoxia can cause jitteriness. The tremor stops when the limb is repositioned. Often, holding the baby and rocking suppresses the tremor. This helps differentiate jitteriness from seizures.
Shuddering is a paroxysmal shiver-like movement of the head, shoulder, and trunk that usually lasts 5 to 15 seconds. The elbows are often held close to the trunk. The episodes only happen during wakefulness and are not associated with any alteration of consciousness. Spells can be occasional or occur multiple times a day. Feeding may evoke spells of shuddering. An EEG during the spells is normal. The vast majority of children with even frequent shuddering need no medication. If felt clinically necessary, propranolol may help. There is no increased risk of epilepsy in children who have shuddering spells. Of note, children with frequent shuddering are more commonly seen in families with people manifesting essential tremor.3
Stereotypies are repetitive suppressible stereotypic actions such as finger tapping, blinking, hair pulling, body rocking, and head banging. It is believed that the self-stimulatory action helps relieve some inner anxiety or stress. Body rocking or repetitive limb movements can be seen as the child falls asleep, and requires no specific treatment. This is often called rhythmic movement disorder.
Although common in children with autism or mental retardation, children of normal intelligence can have these movements.4 The underlying cause is unknown. In extreme cases, benzodiazepines, tricyclic antidepressants, and antipsychotic medications may be useful.
Behavioral management is sometimes useful if the behavior persists into childhood. An alternative activity that is less harmful can be promoted. For instance, instead of pulling the hair, the child could twist beads on a bracelet. A positive reward system is sometimes helpful.
An infant who has recently been fed can suddenly and temporarily stiffen, stare, and become apneic from gastroesophageal reflux disease. In rare cases, the back can actually arch and the child can have opisthotonic posturing for 1 to 3 minutes (Sandifer syndrome). The child is often referred for possible seizures.5 The key in diagnosis is that these episodes usually occur within an hour of feeding. EEG during the episode is normal. If the reflux persists, treatment with metaclopramide may be useful.
Infants with spasmus nutans have repeated episodes of nystagmus, head bobbing, and head tilting, or torticollis. The nystagmus may be horizontal, vertical, or pedular. Consideration should be given to possibly obtaining an MRI of the head to rule out a tumor of the third ventricle or an optic glioma. If the MRI is normal, no specific therapy is needed. EEG is normal during the spells. The symptoms become less as the child grows older and usually disappear before school age.
Syncope can be defined as cerebral hypoperfusion sufficient to cause transient loss of consciousness. There are many potential causes, and most are benign. However, there are some life-threatening causes of syncope, and anyone who falls from syncope of any reason could injure themselves. Between 20% and 50% of people say they have had syncope at some point. It appears most commonly in females.
Abnormal circulatory control or cardiovascular volume can lead to situational syncope, vasovagal syncope, orthostatic hypotension, or reflex asystolic (pallid) syncope.
There are tachyarrhythmias, bradyarrhythmias, and structural heart defects that can lead to syncope. Toxic or metabolic abnormalities such as hypoglycemia, hypocalcemia, hypomagnesemia, hypoxia, and alcohol/medication overdose are associated with syncope. Addison disease can cause syncope through volume depletion.
A good history and physical examination are absolutely necessary if the cause of syncope is to be determined. Blood pressures should be checked lying, sitting, and standing. A drop in the systolic blood pressure of more then 20 mm Hg or a significant increase in pulse indicates probable volume loss or abnormal neurocardiac control. Check the pulse in all extremities. Check for a detectable mass in the abdomen. Listen for a heart murmur.
Check the mental status of the patient after the spell is over. An EKG to look for long QT syndrome, heart block, and ventricular hypertrophy should be performed. Cardiac monitoring for an arrhythmia may be indicated depending on the situation. A complete blood count to look for evidence of anemia and infection, electrolytes, glucose, calcium, magnesium, blood urea nitrogen, and creatinine should be checked. If appropriate, a pregnancy test, toxicology screen, or medication blood level should be done. If a seizure is suspected, an EEG should be ordered. An echocardiogram should be performed if there is a cardiac murmur, if the syncope occurred during exercise, or if there is a family history of cardiomyopathy or sudden death. Magnetic resonance imaging of the brain and cerebrovasculature is advised if any focal neurological signs were present at any time during the syncope. Tilt table testing is reasonable if there is suspicion of an inducible arrhythmia or hypotension. The most common finding on tilt table testing is hypotension and bradycardia or hypotension alone. Implanted loop recorders should be considered if syncope is recurrent and the workup is unrevealing. Repeated episodes of syncope that only occur when a certain parent or caregiver is present should raise the possibility of a factitious disorder.
This is the most common cause of syncope in childhood. It is often triggered by pain, fear, or the sight of something unpleasant. Diaphoresis, light-headedness, and nausea are common before loss of consciousness but are often of short duration in children. It does not occur while supine, but may. The child will appear still while briefly unresponsive for usually under 1 minute. Occasionally, there may be brief jerks of the extremities for a second or two. The child may even have incontinence. These phenomena often raise the question of the possibility of a seizure. However, the patient with vasovagal syncope usually has no or only very limited jerking, little or no cyanosis, rarely bites the tongue, and usually awakens without much of a postictal state. Afterwards, there may be headache or fatigue.
Vasovagal syncope is caused by involuntary reflex activation of the vasovagal nervous system leading to bradycardia and vasodilation, resulting in a drop in blood pressure and cardiac output. Avoidance of the activity that triggers the response is sometimes helpful. Lying the person down flat is recommended. If a person is prone to vasovagal syncope they should pay particular attention to avoid becoming dehydrated. Fludrocortisone, midodrine, beta-blockers, serotonin reuptake inhibitors, and even pacemakers have been useful.6
A variety of activities can lead to an abnormal vasovagal response in some individuals, resulting in syncope. Coughing, micturation, defecation, and swallowing cold fluids or food have all lead to syncope in susceptible children. This is really just a form of vasovagal syncope caused by certain actions.
A healthy child who has breath-holding spells may become still and stop breathing after an episode of normal crying. It is often accompanied by cyanosis. The apnea usually occurs on expiration. If the apneic episode is long enough, hypoxia will occur. The child may lose consciousness and become limp. Further, the child may have short, limited muscle clonic jerks for a second or two after loss of consciousness. The episode usually lasts less than a minute and often ends with a deep inspiration. It usually starts between 6 and 24 months and disappears by 6 years. The breath holding is involuntary and scolding the child does not help. It is felt to be due to an immature autonomic nervous system. Parents or caregivers should be informed that the child has no control over these spells. Iron deficiency has been reported in some children with breath-holding spells. Treating these children with iron often helps reduce the number of spells.7 It seems reasonable to check the iron and ferritin level of any child with breath-holding spells. Iron deficiency states should be treated with iron supplementation. In a study by Daoud and colleagues,8 some children without iron deficiency responded to therapy and some with iron deficiency did not.
While reported between ages 3 months and 14 years, reflex asystolic syncope is usually seen in toddlers.9 These events were once called “pallid” breath-holding spells, but many of these children will not hold their breath during the episodes. The child will suddenly become pale or dizzy following a sudden painful or frightening event. As they lose consciousness and become limp, the child may or may not cry out. If the child is hypoxic long enough, there may be stiffening, twitching, and incontinence. The EEG shows no epileptiform activity during the spell and is usually attenuated. The EKG shows bradycardia or even asystole for several seconds immediately after the stimulus. It is felt to represent an abnormal vagal response to the painful or frightening event. To help the child regain consciousness, the child should be laid down flat and not carried around. Most children do not require any specific medical therapy. Atropine has been used successfully in some cases.
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