Sleep apnoea: a primer

• A. Persistent difficulty falling asleep despite adequate time in bed
• B. Repeated episodes of partial or complete collapse of the upper airway during sleep ✓
• C. Excessive movement of the limbs during sleep that disrupts rest
• D. Waking up early in the morning and being unable to return to sleep

Why: Sleep apnoea is characterised by repeated pauses in breathing (apnoeas) or reductions in airflow (hypopnoeas) during sleep, caused mainly by the upper airway narrowing or collapsing.

• A. Central sleep apnoea
• B. Complex sleep apnoea
• C. Obstructive sleep apnoea ✓
• D. Mixed sleep apnoea

Why: Obstructive sleep apnoea (OSA) is the most common type, occurring when the airway physically collapses during sleep even though the brain continues to send signals to breathe.

• A. A blocked nasal passage due to allergies
• B. Excess tissue in the throat pressing on the airway
• C. The brain failing to send consistent signals to the muscles that drive breathing ✓
• D. Shallow breathing caused by a stuffy chest from infection

Why: Central sleep apnoea occurs when the brainstem fails to transmit the normal respiratory drive, so the body temporarily stops attempting to breathe, rather than a physical blockage.

• A. Increased appetite in the early morning
• B. Excessive daytime sleepiness ✓
• C. Improved concentration and memory
• D. Heightened alertness after waking

Why: Repeated disruptions to sleep prevent restorative rest, leading to excessive daytime sleepiness, fatigue, and sometimes difficulty concentrating.

• A. Symptoms only occur when the person is awake and active
• B. The episodes usually wake the person fully, so they remember them clearly
• C. Breathing pauses typically happen during sleep, so the individual is usually unaware of them ✓
• D. It only affects people who sleep alone and have no bed partner

Why: Because the breathing interruptions occur while asleep, the person is typically unaware of them, and a bed partner is often the first to notice snoring, gasping, or pauses in breathing.

• A. Obstructive sleep apnoea
• B. Central sleep apnoea ✓
• C. Mixed sleep apnoea
• D. Positional sleep apnoea

Why: Central sleep apnoea happens because the brain's respiratory control centre fails to send the appropriate signals to the breathing muscles, so the person briefly stops making respiratory effort. It differs from obstructive apnoea, where the airway is physically blocked despite continued effort to breathe.

• A. Central sleep apnoea
• B. Obstructive sleep apnoea ✓
• C. Complex sleep apnoea
• D. Congenital sleep apnoea

Why: Obstructive sleep apnoea (OSA) is by far the most common form. It occurs when the soft tissues of the throat relax and collapse during sleep, blocking the upper airway and interrupting breathing.

• A. Absence of any breathing effort during pauses
• B. Continued breathing effort despite a blocked upper airway ✓
• C. Breathing that is always rapid and shallow
• D. Loss of consciousness during the night

Why: In obstructive sleep apnoea, the chest and diaphragm keep trying to breathe during the pauses, but airflow is blocked at the throat. This is why people with OSA often snore heavily, gasp, or show struggling movements during an episode.

• A. Obstructive apnoea that develops only in childhood
• B. Central apnoea that appears when obstructive apnoea is treated with positive airway pressure ✓
• C. A combination of snoring and daytime sleepiness with no airway blockage
• D. Apnoea caused exclusively by sleeping on the back

Why: Complex sleep apnoea refers to the persistence or emergence of central apnoeas during treatment of obstructive sleep apnoea, typically with continuous positive airway pressure (CPAP). It shows that both obstructive and central components are present and that treatment must be reassessed.

• A. Being underweight
• B. Having a larger neck circumference ✓
• C. Sleeping in a cool room
• D. Regular daytime exercise

Why: A larger neck circumference is associated with increased fat deposits and narrower airways, which raises the risk of upper airway collapse during sleep. Obesity, male sex, older age, and alcohol use are other well-recognised risk factors.

• A. Central sleep apnoea
• B. Obstructive sleep apnoea ✓
• C. Complex sleep apnoea
• D. Mixed sleep apnoea

Why: Obstructive sleep apnoea (OSA) is the most common form. It occurs when the muscles supporting the soft tissues of the throat relax and the airway becomes blocked during sleep, unlike central apnoea, which results from the brain failing to send proper breathing signals.

• A. Being under the age of 18
• B. Having a higher body mass index (obesity) ✓
• C. Regularly exercising in the morning
• D. Sleeping on your side

Why: Excess body weight, particularly fat deposits around the neck and upper airway, increases the likelihood of airway collapse during sleep. Obesity is one of the strongest and most widely recognised risk factors for OSA.

• A. Males have a lower risk than females
• B. Males and females have exactly the same risk
• C. Males have a higher risk than females ✓
• D. Risk only applies to females after menopause

Why: Men are generally at higher risk of obstructive sleep apnoea than women. Differences in fat distribution and hormonal influences, such as the protective effects of progesterone in premenopausal women, contribute to this difference.

• A. A long, narrow nasal bridge
• B. A small or recessed lower jaw ✓
• C. Large, well-defined cheekbones
• D. A high, arched palate

Why: A small or recessed lower jaw (micrognathia or retrognathia) reduces the space behind the tongue, making it easier for the airway to collapse during sleep. Other features such as enlarged tonsils and a thick neck can also contribute.

• A. Drinking alcohol, especially close to bedtime ✓
• B. Drinking water before bed
• C. Reading before sleep
• D. Keeping a regular sleep schedule

Why: Alcohol relaxes the muscles of the upper airway, including the throat, which can worsen airway collapse and make apnoeic episodes more frequent and severe. Smoking and sedative use have similar effects.

• A. Waking up feeling refreshed
• B. Loud snoring with breathing pauses ✓
• C. Increased appetite during the night
• D. Difficulty falling asleep at the start of the night

Why: Loud, habitual snoring often punctuated by observed breathing pauses is the hallmark symptom of obstructive sleep apnoea, caused by repeated collapse of the upper airway during sleep.

• A. Excessive energy and alertness
• B. Excessive daytime sleepiness ✓
• C. Improved concentration and memory
• D. Heightened sense of smell

Why: Fragmented sleep caused by repeated breathing interruptions leads to poor-quality rest, resulting in excessive daytime sleepiness, fatigue, and difficulty concentrating.

• A. Waking with a dry mouth or sore throat ✓
• B. Waking with a strong appetite for sweet foods
• C. Waking with improved joint flexibility
• D. Waking with clear and quiet sinuses

Why: Mouth breathing during apnoeic episodes can cause dryness of the mouth and throat, and many people wake with a sore throat or dry mouth as a result.

• A. Enhanced long-term planning ability
• B. Morning headaches and difficulty concentrating ✓
• C. Faster reaction times throughout the day
• D. Increased verbal fluency

Why: Repeated drops in oxygen and disrupted sleep architecture can cause morning headaches, memory problems, and difficulty concentrating during the day.

• A. The affected person themselves, through self-monitoring
• B. A bed partner or family member ✓
• C. A dentist during a routine check-up
• D. A blood test taken in the morning

Why: Because the person is asleep, they usually cannot observe their own breathing pauses or gasping. A bed partner or family member is often the first to notice these signs.

• A. Actigraphy
• B. Attended in-laboratory polysomnography ✓
• C. Home pulse oximetry alone
• D. Multiple sleep latency test

Why: Attended in-laboratory polysomnography records multiple channels simultaneously, including airflow, respiratory effort, oxygen saturation, EEG and EMG, allowing accurate measurement of apnoeas and hypopnoeas and sleep stages. It is the gold standard, though home sleep apnoea testing is increasingly used for uncomplicated cases.

• A. The average duration of each breathing pause in seconds
• B. The number of apnoeas and hypopnoeas per hour of sleep ✓
• C. The lowest oxygen saturation reached during the night
• D. The percentage of time spent in REM sleep

Why: The AHI is the total number of apnoeas and hypopnoeas per hour of sleep. It is used to grade severity: mild (5 to 15), moderate (15 to 30), and severe (30 or more events per hour).

• A. Home tests always record EEG to determine sleep stages
• B. Home tests typically do not measure sleep stages, so sleep time is estimated from other signals ✓
• C. Home tests can only be used in patients with severe disease
• D. In-laboratory studies cannot detect oxygen desaturation

Why: Home sleep apnoea tests usually record airflow, respiratory effort, and oxygen saturation but omit EEG, so they cannot directly measure sleep stages. Total sleep time must be estimated, which can affect the calculated AHI. They are less suitable for patients with significant comorbidities.

• A. Increased metabolic rate during dreaming
• B. Reduced ventilation during airway collapse, leading to hypoxaemia ✓
• C. Excessive production of carbon dioxide by the brain
• D. Decreased haemoglobin levels overnight

Why: During obstructive events the upper airway collapses, ventilation falls or stops, and oxygen uptake drops. This causes intermittent hypoxaemia, seen as repeated desaturations on oximetry, which is one reason untreated apnoea is linked to cardiovascular risk.

• A. Waking early with sudden clear-headedness
• B. Loud snoring with witnessed breathing pauses and daytime sleepiness ✓
• C. Frequent nighttime urination without snoring
• D. Vivid dreams with normal daytime alertness

Why: Loud snoring, witnessed apnoeas (pauses in breathing), and excessive daytime sleepiness are the classic clinical features of obstructive sleep apnoea. Combined with risk factors such as obesity or neck circumference, they justify diagnostic sleep testing.

• A. Oral appliance therapy
• B. Continuous positive airway pressure (CPAP) ✓
• C. Surgical removal of the tonsils
• D. Sleeping pills (hypnotics)

Why: CPAP delivers a constant stream of pressurised air through a mask that keeps the upper airway open during sleep. It is the gold-standard, first-line treatment for moderate to severe obstructive sleep apnoea, though it works only while it is being used.

• A. To increase the amount of oxygen in the blood
• B. To suppress the drive to breathe during sleep
• C. To move the lower jaw forward and keep the airway open ✓
• D. To reduce nasal congestion

Why: A mandibular advancement device is a custom-fitted oral appliance worn during sleep. It positions the lower jaw slightly forward, which stops the soft tissues of the throat from collapsing into the airway. It is often used for mild to moderate sleep apnoea or for people who cannot tolerate CPAP.

• A. Drinking more alcohol before bed to relax the throat
• B. Sleeping on the back in all cases
• C. Weight loss, where appropriate ✓
• D. Increasing caffeine intake in the evening

Why: Excess weight, particularly around the neck and upper body, narrows the airway and worsens obstructive sleep apnoea. Losing weight can reduce the severity of the condition and in some people significantly improve it. Alcohol and sedatives relax the throat muscles and should be avoided near bedtime.

• A. It is always the first treatment offered to every patient
• B. It is usually reserved for selected patients, such as those with enlarged tonsils or specific anatomical blockages ✓
• C. It cures sleep apnoea permanently in all cases
• D. It replaces the need for any follow-up care

Why: Surgical options such as tonsillectomy, uvulopalatopharyngoplasty or nasal surgery are generally considered for patients with a clear structural cause of obstruction. They are not routinely the first choice and do not work for everyone, so careful assessment is needed beforehand.

• A. To confirm the treatment is working and that side effects are managed ✓
• B. Because treatment is no longer needed after the first night
• C. Because monitoring replaces the need for any therapy
• D. To ensure the patient stops using all medications

Why: Follow-up allows clinicians to check whether symptoms such as daytime sleepiness and snoring have improved, whether the device or mask fits well, and whether side effects such as dry mouth, jaw discomfort or mask leaks need addressing. Adherence and effectiveness are reviewed over time.

• A. Central sleep apnoea
• B. Obstructive sleep apnoea ✓
• C. Complex sleep apnoea
• D. Mixed sleep apnoea

Why: Obstructive sleep apnoea (OSA) is the most common form. It occurs when the muscles of the throat relax during sleep and the airway becomes partially or fully blocked, interrupting breathing.

• A. Increased appetite at night
• B. Excessive daytime sleepiness ✓
• C. Improved concentration
• D. Heightened physical energy

Why: Repeated interruptions in breathing fragment sleep, so people with untreated sleep apnoea often feel excessively tired or sleepy during the day, even after a full night in bed.

• A. Drinking alcohol before bedtime
• B. Sleeping on your back
• C. Maintaining a healthy weight ✓
• D. Avoiding regular exercise

Why: Excess weight, especially around the neck and upper airway, can narrow the airway. Losing weight can reduce the severity of obstructive sleep apnoea for many people.

• A. Surgery to remove tissue from the throat
• B. A device that delivers a steady stream of pressurised air through a mask during sleep ✓
• C. Medication that stimulates breathing during the day
• D. A dental appliance that moves the jaw forward only

Why: Continuous positive airway pressure (CPAP) uses a machine to deliver pressurised air through a mask worn during sleep, keeping the airway open. It is the most widely used treatment for obstructive sleep apnoea.

• A. They increase the amount of deep sleep
• B. They relax the throat muscles further, making airway blockage more likely ✓
• C. They speed up breathing rate during sleep
• D. They prevent snoring completely

Why: Alcohol and sedatives relax the muscles of the upper airway more than normal sleep does. This makes airway collapse and breathing pauses more frequent and severe.