What are the subtypes of CSAS?
Primary Central Sleep Apnea
Primary central sleep apnea is of unknown etiology, but presumably involves the above described dysfunction of O2 and CO2 sensors and feedback loops. The resulting gas imbalance results in frequent arousals, leading to complaints of EDS or insomnia.
Central Sleep Apnea Due to Cheyne Stokes Breathing Pattern
Cheyne Stokes breathing is characterized by apneas, hypopneas, or both, alternating with periods of excessive breathing (hyperpneas). This crescendo-decrescendo pattern distinguishes Cheyne Stokes from the other forms of CSAS. However, this distinction is not universally accepted and some consider Cheyne-Stokes breathing to be a separate disease entity unrelated to the sleep disorders. The main predisposing factors for Cheyne Stokes Breathing are congestive heart failure and strokes.1
Central Sleep Apnea Due to a Medical Condition Other Than Cheyne Stokes
The majority of these cases involve brain stem lesions of vascular, neoplastic, or other etiology. Others result are from cardiac or renal dysfunction.
Central Sleep Apnea Due to a Drug or Substance
Numerous drugs may affect the control of respiration. For example, research suggests that the long-term (>2 months) use of long-acting (methadone) opioids, or sustained-release opioid preparations (with morphine or hydrocodone) can induce central sleep apneas.2
- Sin D, Fitzgerald F, Parker J, Newton G, Floras J, Bradley T. Risk Factors of central and obstructive sleep apnea in 450 men and women with congestive heart failure. Am J Respir Crit Care Med. 1999;160:1101-1106.
- Farnery R, Walker J, Cloward T, Rhondeau S. Sleep-disordered breathing associated with long-term opioid therapy. Chest. 2003;123:632-639.