Differential Diagnosis of Sleep Apnea Syndrome

1. Muhammad Abdullah Munir

    Khan Mantasha

2. Dr Samatbek Turdaliv

(1. Students, Osh state university, Osh, Kyrgyzstan.

2. Teacher, Osh State University, Osh, Kyrgyzstan)

Abstract

Sleep‑disordered breathing includes obstructive sleep apnea (OSA) and central sleep apnea (CSA), as well as related conditions such as primary snoring and upper airway resistance syndrome (UARS). These disorders often present with overlapping symptoms including snoring, fragmented sleep, daytime fatigue, and impaired concentration. Because similar manifestations may occur in several respiratory, cardiovascular, neurological, endocrine, and psychiatric disorders, accurate differential diagnosis is essential. This review analyzes major conditions that may mimic OSA and CSA and highlights the key clinical and diagnostic features that help distinguish them. (1,2)

Introduction

Sleep apnea is characterized by recurrent episodes of airflow reduction or cessation during sleep. The two main forms are obstructive sleep apnea (OSA), which results from repeated collapse of the upper airway, and central sleep apnea (CSA), which occurs due to impaired central regulation of respiration (1). These disturbances lead to intermittent hypoxia, sleep fragmentation, and daytime symptoms such as excessive sleepiness, fatigue, reduced attention, and morning headaches. Because these clinical manifestations are nonspecific, several other medical conditions may present with similar symptoms. Therefore, establishing an accurate differential diagnosis is essential for appropriate management and prevention of complications (2,10).

Methods

This narrative review was prepared using established medical textbooks and clinical guidelines related to sleep‑disordered breathing. Relevant literature describing the pathophysiology, clinical features, and diagnostic criteria of obstructive and central sleep apnea was analyzed. Conditions that may mimic the clinical presentation of sleep apnea were identified, and their distinguishing features were summarized. Particular attention was given to disorders that produce symptoms such as snoring, excessive daytime sleepiness, or nocturnal respiratory disturbances (2,6).

Results

Primary Sleep Disorders

Primary snoring represents the mildest form of sleep‑related breathing disturbance. Individuals with primary snoring produce loud snoring sounds during sleep due to vibration of upper airway structures (2). However, unlike obstructive sleep apnea, primary snoring does not involve repeated episodes of airflow cessation or significant oxygen desaturation during sleep studies (9).

Upper airway resistance syndrome (UARS) is another condition that may mimic sleep apnea. In UARS, increased resistance within the upper airway leads to repeated arousals from sleep and fragmented sleep architecture. Patients frequently report daytime fatigue and non‑restorative sleep, but classical apnea or hypopnea events are usually absent.

Insomnia is characterized by persistent difficulty in initiating or maintaining sleep. Although individuals with insomnia often experience daytime tiredness and impaired concentration, objective sleep studies typically show normal breathing patterns without apneic episodes.

Narcolepsy is a neurological disorder associated with excessive daytime sleepiness and sudden sleep attacks. Some patients may also experience cataplexy, sleep paralysis, and hypnagogic hallucinations. These features help differentiate narcolepsy from sleep apnea, which primarily causes sleep fragmentation due to breathing disturbances.

Respiratory Disorders

Respiratory diseases such as chronic obstructive pulmonary disease (COPD) may also present with nocturnal dyspnea and fatigue. However, pulmonary function tests in COPD demonstrate persistent airflow limitation, which distinguishes it from obstructive sleep apnea (6,9).

Cardiovascular Disorders

Cardiovascular disorders, particularly congestive heart failure, may produce symptoms such as fatigue and nocturnal breathing abnormalities. In many cases, heart failure is associated with central sleep apnea characterized by periodic breathing patterns such as Cheyne‑Stokes respiration (3,6).

Neurological Disorders

Brainstem lesions affect respiratory centers and present with neurological deficits. Neuromuscular disorders cause hypoventilation due to muscle weakness (3).

Endocrine Disorders

Endocrine disorders such as hypothyroidism may mimic sleep apnea because patients often experience fatigue, weight gain, and decreased metabolic activity. Laboratory testing demonstrating elevated thyroid‑stimulating hormone levels helps establish the diagnosis (3,10).

Psychiatric Disorders

Psychiatric conditions, particularly depressive disorders, can also produce sleep disturbances and daytime fatigue. However, these conditions are usually accompanied by persistent low mood, loss of interest, and other psychological symptoms rather than breathing abnormalities during sleep (10).

Substance-Induced Conditions

Alcohol and sedatives can depress respiration and mimic sleep apnea (8).

Discussion

The differentiation of obstructive and central sleep apnea from other conditions requires a comprehensive clinical approach. Detailed medical history, physical examination, and appropriate diagnostic investigations are essential. Polysomnography remains the gold standard method for confirming sleep apnea because it measures respiratory events, oxygen saturation, and sleep architecture throughout the night. Additional investigations such as pulmonary function tests, cardiac evaluation, endocrine assessment, and neurological examination may be necessary to identify alternative diagnoses or coexisting conditions. (1,6,7)

Conclusion

Obstructive and central sleep apnea are common forms of sleep‑disordered breathing but share clinical features with several other disorders. Primary snoring, upper airway resistance syndrome, insomnia, narcolepsy, cardiopulmonary diseases, endocrine disorders, and psychiatric conditions should all be considered during the diagnostic evaluation. Careful clinical assessment combined with polysomnography allows accurate differentiation and ensures appropriate management (1,6).

References

1.       American Academy of Sleep Medicine. International Classification of Sleep Disorders – Third Edition (ICSD-3). 2014

2.       Kryger MH, Roth T, Dement WC. Principles and Practice of Sleep Medicine. 6th ed. Elsevier; 2017

3.       Harrison’s Principles of Internal Medicine. 21st ed. McGraw-Hill; 2022.

4.       Harrison’s Principles of Internal Medicine. 20th ed. McGraw-Hill; 2018.

5.       World Health Organization. International Classification of Diseases (ICD-11). 2018

6.       American Thoracic Society. Clinical practice guideline for sleep apnea. Am J Respir Crit Care Med. 2012.

7.       Epstein LJ et al. Clinical guideline for OSA. J Clin Sleep Med. 2009.

8.       National Heart, Lung, and Blood Institute. Sleep Apnea. 2020.

9.       Oxford Handbook of Respiratory Medicine. 3rd ed. Oxford University Press; 2021.

10.    Davidson’s Principles and Practice of Medicine. 24th ed. Elsevier; 2022.

11.    Kryger MH, Roth T, Dement WC. Principles and Practice of Sleep Medicine. 6th ed. Philadelphia: Elsevier; 2017.

12.    American Academy of Sleep Medicine. International Classification of Sleep Disorders. 3rd ed. Darien, IL: AASM; 2014.

13.    Jameson JL, Fauci AS, Kasper DL, Hauser SL, Longo DL, Loscalzo J. Harrison’s Principles of Internal Medicine. 21st ed. New York: McGraw‑Hill; 2022.

14.    Epstein LJ, Kristo D, Strollo PJ, et al. Clinical guideline for the evaluation and management of obstructive sleep apnea in adults. J Clin Sleep Med. 2009;5(3):263–276.

15.    World Health Organization. International Classification of Diseases 11th Revision (ICD‑11). Geneva: WHO; 2019.