eMedicine Specialties > Pediatrics: General Medicine > Pulmonology

Sleep Apnea: Differential Diagnoses & Workup

Author: Mary E Cataletto, MD, Associate Director, Division of Pediatric Pulmonology, Winthrop University Hospital; Professor of Clinical Pediatrics, State University of New York at Stony Brook; Director of Children's Sleep Services, Winthrop University Hospital
Contributor Information and Disclosures

Updated: Feb 27, 2009

Differential Diagnoses

Other Problems to Be Considered

Obstructive sleep apnea (OSA) must be differentiated from simple snoring, which is a vibratory inspiratory noise that is usually not accompanied by oxygen desaturation, hypercarbia, or sleep disruption. Overnight polysomnography can be performed to differentiate pronounced snoring from true obstructive sleep apnea in the pediatric age group.

Daytime somnolence is a common complaint among individuals with obstructive sleep apnea. For teens and adults, this may be the presenting concern that brings them to medical attention. However, keep in mind that not all children with excessive daytime somnolence have obstructive sleep apnea. Sleepiness during the day may be due to numerous factors in addition to sleep apnea. Many children are sleepy during the day simply because their parents do not have a clear idea as to how much sleep a child actually requires.

Chaotic sleep schedules with inconsistent bedtimes and rise times and with limited time allowed for sleep are major causes of daytime sleepiness and lassitude. Any evaluation for suspected sleep apnea must include a careful history with inquiries about sleep times, bedtime routines, and a description of the sleeping environment. Parents should be asked to complete a sleep diary for 1-2 weeks to evaluate whether a child is sleeping enough.

Narcolepsy is a disease characterized by irresistible sleeping attacks that occur intermittently throughout the day. It is included in the differential diagnosis of excessive daytime sleepiness. Patients with narcolepsy are tired throughout the day; thus, the disorder can be confused with obstructive sleep apnea syndrome. A history of episodic sleep-onset paralysis, hypnagogic (sleep-onset) hallucinations, or daytime memory lapses with automatic behaviors may help differentiate between narcolepsy and obstructive sleep apnea. Sleep paralysis is a frightening experience that lasts from a few seconds to several minutes, during which an individual can breathe and move the eyes but otherwise cannot speak or move.

Hypnagogic hallucinations are vivid lifelike dreams that occur just as one begins to fall asleep. These hallucinations often involve an awareness of another person or an animal in the room, bright colors, or unusual shapes. Often, other senses are involved during the experience, including touch, smell, and hearing. Older patients with narcolepsy may experience cataplexy, or the sudden brief loss of muscular tone without loss of consciousness. Multiple sleep latency testing (MSLT) following overnight polysomnography is necessary to confirm a diagnosis of narcolepsy and differentiate this from obstructive sleep apnea.

Nocturnal gastroesophageal reflux may result in nocturnal restlessness, choking episodes during sleep, frequent awakenings, and labored breathing that resemble symptoms of obstructive sleep apnea syndrome.

Periodic limb movement disorder, nocturnal seizures, rhythmic movement disorder, and various parasomnias can be differentiated from obstructive sleep apnea on the basis of polysomnography.

Workup

Laboratory Studies

• Polysomnography remains the criterion standard for establishing the diagnosis of obstructive sleep apnea (OSA) in infants, children, and adults. Ideally, polysomnography should be performed overnight and during the patient's usual bedtime.
  • Multiple physiologic parameters are monitored during polysomnography, although the specific montage may vary slightly between sleep laboratories. Generally, electrooculography, chin and leg surface electromyography (EMG), and at least 2 EEG channels are included to confirm sleep and assess sleep architecture. Breathing is assessed using nasal/oral airflow sensors, pulse oximetry, and end-tidal (ET) CO₂ measurements monitoring and by placing piezo crystal belts across the chest and abdomen to detect respiratory efforts. At least one ECG channel is necessary to determine heart rate and rhythm. Occasionally, other channels are incorporated into the study as needed. These might include additional EEG leads to better detect seizure activity, esophageal pH measurements, or transcutaneous carbon dioxide monitoring.
  • Polysomnographic normal standards differ between children and adults. In the pediatric age range abnormalities include oxygen desaturation under 92%, more than one obstructive apnea per hour, and elevations of ET CO₂ measurements of more than 50 mm Hg for more than 9% of sleep time or a peak level of greater than 53 mm Hg.
• Daytime nap studies are specific, but not sensitive, in detecting sleep apnea. This is because obstructive events are more likely to occur during rapid eye movement (REM) sleep than during other sleep stages, and very little (if any) REM sleep occurs during daytime naps in noninfants. Therefore, children with symptoms of obstructive sleep apnea who have normal nap study findings must undergo nocturnal polysomnography to exclude the diagnosis. Sleep studies should be performed without sedation.
• Unattended home overnight oximetry has been proposed as a screening study. However, it may miss the child with significant obstructive sleep apnea who does not have marked episodes of oxygen desaturation.
• Multichannel studies lack reliable assessment of sleep disruption.

Imaging Studies

• Anteroposterior and lateral neck radiography: Neck radiography for soft tissue detail help define upper airway anatomy and adenoid size and exclude the possibility of rare nasal pharyngeal neoplasms.
• Cephalometric radiography and 3-dimensional CT reconstruction imaging are rarely, if ever, necessary in the pediatric age group.
• Cine MRI during sleep may be helpful in identifying specific sites of airway obstruction in the complicated patient being evaluated for surgical interventions. This technique is currently only available at a handful of specialized tertiary care facilities.

Other Tests

• Highly sensitive thyroid-stimulating hormone and thyroxine: Thyroid function studies are useful to exclude hypothyroidism, which is associated with tongue enlargement, weight gain, and obstructive sleep apnea .
• CBC count: Chronic hypoxia related to recurrent airway obstruction may lead to polycythemia.
• Electrocardiography and echocardiography: These studies are not necessary in all children with suspected sleep apnea. However if very severe long-standing obstruction is suspected, an ECG and echocardiography are helpful in assessing ventricular thickness and function and to check for evidence of pulmonary hypertension.
• Multiple sleep latency test (MSLT): If the clinical history suggests the possibility of narcolepsy, the MSLT should be ordered in conjunction with overnight polysomnography.
• MRI of the brain and brainstem: A history of severe snoring, headaches, neck pain, urinary frequency, or swallowing problems raises the suspicion of Chiari malformation. Chiari malformations may occur in otherwise normal children and in association with congenital myelomeningocele. If brainstem dysfunction is suspected, MRI is necessary. Cranial CT imaging is not adequate to assess for brainstem and upper cervical cord lesions.

Procedures

• Polysomnography is necessary to document obstructive sleep apnea and gauge its severity. A history of snoring alone is not adequate for making a diagnosis of obstructive sleep apnea or for determining its seriousness.
• Some children with obstructive sleep apnea have primarily obstructive hypoventilation in which repetitive partial obstructions occur with some degree of relative oxygen desaturation and hypercarbia. Because of this, pediatric polysomnographic testing should include some means of determining CO₂ levels, such as end-tidal (ET) CO₂ monitoring or transcutaneous CO₂ monitoring.
• Overnight pulse oximetry by itself is not adequate for establishing the diagnosis or excluding obstructive sleep apnea in children because it provides no information concerning sleep staging/sleep fragmentation or carbon dioxide.

Histologic Findings

• Little consistent difference in tonsil and adenoid weights and volumes is seen in individuals with obstructive sleep apnea compared with patients whose tonsils and adenoids were removed for other reasons.
• No distinct histologic findings separate adenoid and/or tonsillar hypertrophy from hypertrophy associated with obstructive sleep apnea.

• Search for CME/CE on This Topic »

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