Obstructive sleep apnoea warrants early diagnosis, treatment | Multidisciplinary

With the increase in obese and overweight patients, physicians may need to have a high degree of suspicion for obstructive sleep apnoea (OSA), says a prominent respirologist.
OSA is a disorder caused by obstruction of the upper airway, either partially or completely, during sleep. This obstruction occurs intermittently and repeatedly throughout sleep, yet the patient may not be aware of it. While one of the symptoms of OSA is sleepiness in the morning, some patients do not exhibit this morning somnolence, or they are unaware of being sleepy during the daytime. Instead, physicians can ask their spouse if the patient snores or has disturbed sleep.

Speaking at the recent Malaysian Endocrine and Metabolic Society Annual Congress 2022 (MEMS MAC12), Associate Professor Dr Andrea Ban Yu-Lin, a senior consultant physician and pulmonologist in Hospital Tuanku Muhriz Universiti Kebangsaan Malaysia, said: “You can also ask them if they feel a little tired when they wake up, or have they woken up with a headache? If yes, how often does it occur?” The answer to these questions will give the physician a better idea of whether the patient is suffering from OSA or further investigation is warranted. Regardless of how a patient is approached, these are the symptoms to watch out for:

1. Excessive daytime sleepiness.

2. Loud snoring, often punctuated by gasping or choking.

3. Headaches in the morning that may persist for several hours after waking.

4. Dry mouth in the morning after awakening.

5. Restless sleep with periods of wakefulness during the night.

6. Increased need to get up from bed to urinate.

7. Irritability or frustration.

8. Reduced focus.

One useful tool for physicians to help in the diagnosis of OSA is the STOP-BANG online questionnaire, which has a list of eight symptoms. Answering a yes or no to the list of symptoms, plus inputting the patient’s age, BMI, gender, and neck circumference will generate an OSA risk score.

Even though history taking and questionnaires help in determining OSA risk, the gold standard for diagnosis is polysomnography that will measure electroencephalogram, electrooculogram, electromyogram, electrocardiogram and respiratory channels.
The STOP-BANG questionnaire can be accessed here. https://www.mdcalc.com/calc/3992/stop-bang-score-obstructive-sleep-apnea

What are the risk factors that predispose a patient to OSA?
At the top of the list are obesity and high BMI. With these, come a neck circumference greater than 43 cm in men and 38 cm in women. Men are more likely to have OSA. Also, anyone above the age of 50 is at increased risk. Other risk factors include menopause, neuropathy, or myopathy. Of note are those suffering from acromegaly, who may develop OSA due to macroglossia or enlarged tongue.

The current treatment options include weight loss and use of continuous positive airway pressure (CPAP) machine. An OSA diagnosis in a patient who is overweight or obese presents a critical window of opportunity for the physician to implement a weight loss intervention to improve OSA and its cardiovascular risks. Weight loss in itself leads to unpredictable improvements in OSA severity, thus the best treatment for OSA is still CPAP.

However, Ban likened the use of a CPAP machine to driving at 70 km/h with the windows down on a highway with one’s mouth open. “It’s very uncomfortable and drying. You have to motivate the patient [to wear it].” To reap the benefits of CPAP, the patient should wear it for a minimum of 4 hours a night.

What happens during an episode of OSA:

Ø Change in airway muscle tone during sleep leads to collapse of the upper airways

Ø Leads to intermittent episodes of apnoea and/or hypopnoea

Ø Causing the arterial oxygen saturation to drop

Ø Autonomic nervous system dysfunction.

The autonomic nervous system is responsible for the regulation of bodily wellbeing and any dysfunction may lead to hypertension, cerebrovascular accidents, pulmonary hypertension, and heart failure