Pediatric Primary Care Case Studies (91 page)

   Hysteria (somatization disorder) or a conversion disorder

•   Medications or illicit drugs including antidepressant drugs

•   Dehydration/volume depletion

•   Toxins, e.g., carbon monoxide poisoning, inhalant/huffing

Etiology of Syncope

There are multiple causes of syncope that the healthcare provider must consider as part of the differential diagnoses of syncope. Some conditions are life-threatening whereas others are benign. Thus, the challenge for the primary care provider is to correctly distinguish a benign cause from a life-threatening problem, and to do so in a cost-effective manner without ordering unnecessary and costly diagnostic tests. When life-threatening etiologies are identified, the responsibility of the primary care provider is to quickly refer the child or adolescent to the appropriate specialist.
Table 23-1
lists causes of syncope in children from which to establish a list of differential diagnoses you will need to consider in Emma’s situation.

Benign Causes of Syncope

The majority of causes of pediatric syncopal episodes are benign changes in vasomotor tone (Massin et al., 2004) such as breath holding and orthostatic hypotension. Other conditions that imitate syncope are overdose, drugs, seizures, migraine syndromes, hysteria, hyperventilation, and pregnancy.

Neurocardiogenic Syncope

Neurocardiogenic syncope (vasovagal) is a neurally mediated disorder and a common cause of syncope. Children with neurocardiogenic (vasovagal) syncope frequently report symptoms before the event that include dizziness, lightheadedness, sweating, nausea, weakness, and visual changes (blurred vision, tunnel vision, slow visual loss). Patients with orthostatic hypotension or vasovagal syncope may report that symptoms recurred when they tried to sit up immediately after the initial syncopal event. The duration of such activity is usually brief and recovery is rapid. In comparison, prolonged motor activity or postictal recovery time are consistent with a seizure (Reuter & Brownstein, 2002).

Children with a neurocardiogenic/vasovagal cause of syncope typically have been upright or changed position just prior to the event. A trigger such as pain or stress may be the precipitant in some cases. Syncope that occurs during physical exertion is very concerning for a cardiac etiology, whereas syncope after exertion may occur with neurocardiogenic/vasovagal syncope or cardiac conditions (Driscoll, Jacobsen, Porter, & Wollan, 1997; Massin et al., 2004). In a 2001 study reviewing recurrent syncope, neurocardiogenic/vasovagal syncope was considered the cause in 35% of such events (Mathias, Deguchi, & Schatz, 2001). However, neurocardiogenic/vasovagal syncope remains a diagnosis of exclusion.

The diagnosis can also be made by exclusion of other causes of syncope and by a characteristic response to upright tilt table testing, during which the patient may pass out from bradycardia and/or hypotension. These patients do not necessarily require treatment.

Seizure

Seizure refers to a transient occurrence of signs and/or symptoms due to excessive neuronal activity of the brain. Abnormal movement such as tonic clonic movement can occur. The duration of such activity is usually brief and recovery is rapid. Prolonged abnormal movements and/or prolonged recovery time are consistent with a seizure, as are loss of bowel or bladder control. In the patient with prolonged loss of consciousness, seizure activity, or a postictal phase, a routine outpatient electroencephalogram (EEG) or 24-hour video EEG should be considered. Neuroimaging may be indicated emergently for children with focal neurologic deficits, persistently altered mental status, or a significant head injury as a result of the syncopal episode. Syncope is distinguished from seizures by accompanying pallor, prodromal lightheadedness and visual changes, lack of postictal state, and no loss of bowel or bladder control.

Cardiac Causes

Cardiac issues that cause syncope can be life-threatening. Shortness of breath, chest pain, or palpitations prior to or during the event are concerning for a cardiac etiology. Sudden death in the young athlete occurs with an estimated prevalence of between 1:100,000 and 1:300,000 (Maron et al., 1996).

Cardiac issues that cause syncope are primary electrical disturbances and structural heart disease including exercise-related syncope. As stated earlier, syncope that occurs during physical exertion is very concerning for a cardiac etiology, whereas syncope after exertion may occur with vasovagal syncope or cardiac conditions (Driscoll et al., 1997; Massin et al., 2004). This is a major point that must always be considered.

One specific primary electrical disturbance that is worrisome is long QT syndrome. Triggers include a sudden startle or even auditory stimuli such as a fire alarm (Moss, 2003). An electrocardiogram (ECG) is considered a standard part of the syncope work-up. A patient with a normal ECG has a low likelihood of arrhythmia as a cause of syncope (Kapoor, 2000). ECG abnormalities may be variable and/or subtle, thus a cardiologist consult should be considered whenever there are incongruent clinical features, regardless of the ECG findings.

ECG findings consistent with life threatening causes of syncope that should be noted include:

•   Bradycardia or atrioventricular block

•   Prolonged QT interval/short QT interval (less than or equal to 0.30 seconds)

•   Brugada pattern/pseudo right bundle branch block with ST elevation in leads V1 to V3

•   Epsilon waves (arrhythmogenic right ventricular dysplasia)

•   Preexcitation syndrome (Wolff-Parkinson-White)

•   Nonsinus rhythm

•   Signs of myocardial injury

•   Ventricular hypertrophy or strain patterns

Recurrent syncope can be attributed to both psychogenic and cardiac etiologies. In a review of 433 patients, the cumulative incidence of recurrence of syncope at 3 years was 31% for patients with a cardiovascular etiology, 36% for those with a noncardiovascular cause, and 43% for those with syncope of unknown etiology (Kapoor et al., 1987).

What information do you need to evaluate Emma’s fainting spell?

Historical Data Necessary for Syncope Analysis in Children

The first area to investigate relates to the specific facts about the situation immediately preceding the event. This includes a detailed description of the child’s position and the activity the child was participating in prior to the syncopal episode. For example, if the child was in a seated position and then stood up and fainted, such syncope may be considered benign vasovagal or postural hypotension. In contrast, if the child was in full stride at a field hockey game and collapsed, this could indicate a life-threatening cardiac event. When asking for a description of the event, obtain the child’s self-report of symptoms prior to the onset of syncope as well as witnesses’ description of the syncopal event.

Here are a few suggested questions to ask:

•   Did the child or adolescent feel dizzy or experience lightheadedness, sweating, nausea, weakness, numbness in hands or feet, and visual changes?

•   Did the witness observe rapid breathing or emotional stress that may be indicative of hyperventilation or induced syncope?

Positive answers to these questions are consistent with a benign cause. Seek information about whether abnormal movements such as tonic clonic movements or focal movement of one extremity were noted, including the length of the time frame surrounding the abnormal activity, approximate length of loss of consciousness, and loss of bowel or bladder control with the syncopal episode. Positive findings would be consistent with a seizure.

For the child with a history of collapsing and being unresponsive, ask whether cardiopulmonary resuscitation was administered and/or whether an automated external defibrillator was used. If this is the case, obtain a detailed history of the sequence of basic life support interventions.

If a healthcare provider witnesses a syncopal event in a child or adolescent, there are a few additional assessment points to remember. During and immediately after the syncopal event, check for brady-or tachy-arrhythmias, check blood pressure for hypotension, and look for signs and symptoms of dehydration; all could be clinical symptoms and indicators of decreased perfusion. Observe for hyperventilation and ask about numbness of extremities or fingers or toes. If hyperventilation and numbness are consistent with the event, consider a diagnosis of hyperventilation-induced syncope or a conversion disorder.

Red flags
that indicate a cardiac evaluation is needed include the following family issues: a family history of early cardiac death (less than 45 years of age), sudden deaths including unexplained accidents involving a single motor vehicle or drowning, known arrhythmia (long QT syndrome), and familial cardiomyopathy. If positive, any of these factors increases the concern for a cardiac etiology (Gillette & Garson, 1992). A family history may be present in up to 90% of children with vasovagal syncope (Reuter & Brownstein, 2002). A review of the past medical history of congenital heart disease or arrhythmia may focus attention on a potential cardiac etiology. Previous syncopal events suggest a vasovagal, psychogenic cause, or a cardiac etiology.