True about obstructive sleep apnea are all except
**Core Concept**
Obstructive sleep apnea (OSA) is a sleep disorder characterized by repeated episodes of partial or complete upper airway obstruction during sleep, leading to intermittent hypoxia, sleep fragmentation, and daytime sleepiness. The pathophysiology of OSA involves the collapse of the pharyngeal airway, which is often due to a combination of anatomical and physiological factors, including obesity, a narrow airway, and a large tongue or tonsils.
**Why the Correct Answer is Right**
The correct answer is related to the risk factors and clinical presentation of OSA. Patients with OSA often experience snoring, gasping, or choking during sleep, and may also report morning headaches, dry mouth, and decreased libido. The diagnosis of OSA typically involves a combination of clinical history, physical examination, and overnight polysomnography (PSG) or home sleep apnea testing (HSAT). The Epworth Sleepiness Scale (ESS) is a commonly used tool to assess daytime sleepiness in patients with OSA.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because OSA is not typically associated with an increase in lung volumes. In fact, patients with OSA often have a decrease in lung volumes due to chronic hypoxia and decreased lung function.
**Option B:** This option is incorrect because OSA is not typically associated with an increase in the number of red blood cells. In fact, patients with OSA often have a decrease in red blood cell count due to chronic anemia.
**Option C:** This option is incorrect because OSA is not typically associated with an increase in the level of consciousness. In fact, patients with OSA often experience decreased levels of consciousness during episodes of apnea, which can lead to decreased cognitive function and increased risk of accidents.
**Clinical Pearl / High-Yield Fact**
The Mallampati score is a useful tool for predicting the risk of OSA in patients undergoing surgery. Patients with a high Mallampati score (class III or IV) are at increased risk of OSA and may require additional perioperative monitoring and management.
**Correct Answer: D.**