Why daytime sleepiness matters
Excessive daytime sleepiness is easy to dismiss as tiredness, but it has treatable causes and real dangers, especially for someone who drives for a living. The history, ideally with a bed partner's account, usually points the way.
What to ask in the history
- How sleepy, and in which situations (a sleepiness scale helps)
- Hours in bed, sleep timing, shift work
- Snoring, pauses in breathing seen by a partner, waking choking, morning headaches, passing urine at night
- Weight change
- Alcohol, sedatives
- Mood
- Symptoms of an underactive thyroid
- Blood pressure, diabetes, heart disease
- Near-misses or accidents while driving
Red flags
- Falling asleep while driving
- Breathlessness, ankle swelling
- Low mood with thoughts of self-harm
What to examine
- Weight, body mass index, neck circumference
- Blood pressure
- Nose, mouth, tonsils and jaw
- Thyroid
- Heart and lungs; ankle swelling
First investigations
- A sleep study: overnight oximetry or polysomnography
- Thyroid function
- Glucose or HbA1c, cholesterol
- Full blood count
- Blood gas if he may be under-breathing
Differential diagnosis of daytime sleepiness
Grouped, not ranked. Which one fits this patient is for you to work out in the case.
Medical
- Hypothyroidism
- Depression
- Alcohol or sedatives
- Diabetes
Too little or poor sleep
- Shift work
- Insufficient sleep
- Insomnia
Breathing in sleep
- Obstructive sleep apnoea
- Obesity hypoventilation
Primary sleep disorders
- Narcolepsy
Common mistakes
- Not asking about driving, and not advising him about it.
- Taking eight hours in bed as eight hours of good sleep.
- Leaving out the partner's account.