Excessive Daytime Sleepiness Algorithm

Safety

Red Flags — Acute Drowsiness, Driving and Safety-Critical Work

Done

Separate acute drowsiness (a medical emergency until shown otherwise) from chronic sleepiness. Then ask about driving at every presentation.

Acute drowsiness or reduced consciousness New over hours to days, with confusion, headache, fever, neck stiffness, focal signs or vomiting → 999 Intracranial event, encephalitis, raised intracranial pressure, intoxication or overdose

Several people in the household drowsy or with headaches Worse at home, better away, faulty boiler or heater → 999 Possible carbon monoxide poisoning — leave the property

Sleepiness with breathlessness, morning headache, cyanosis or ankle swelling Low resting SpO₂, obesity, neuromuscular or chest-wall disease → Same-day Possible hypercapnic respiratory failure or obesity hypoventilation

Hypoglycaemia Drowsy or confused episodes in someone on insulin or a sulfonylurea → Same-day Check glucose and treat now; review the regimen and driving (DVLA hypoglycaemia rules)

Falling asleep at the wheel or a near miss → Same-day Advise to stop driving now, document the advice, expedite sleep-service referral and explain DVLA notification

Group 2 (HGV, bus) driver or safety-critical worker with sleepiness → Urgent Must not drive or do safety-critical work while sleepy; expedited sleep-service assessment

Sudden sleep attacks on a dopamine agonist Ropinirole, pramipexole, levodopa → Urgent Advise not to drive; review the medicine with the prescriber

Sleepiness with low mood and hopelessness Suicidal thoughts or unable to stay safe → Same-day Crisis assessment

Excessive sleepiness is a public-safety issue: drowsy driving causes serious road collisions. The driving advice cannot wait for the sleep study. Under DVLA rules, excessive sleepiness that is, or is likely to be, affecting driving means the person must not drive until it is satisfactorily controlled; whether formal notification is needed depends on the cause and severity — for example confirmed moderate or severe OSA with excessive sleepiness must be notified.

Diagnose

History — Sleepiness or Fatigue? Then Find the Cause

Done

Sleepiness vs fatigue

Sleepiness = falling asleep or struggling to stay awake (dozing when reading, watching TV, in meetings, driving). Fatigue = exhaustion or lack of energy without dozing — see the fatigue pathway

Sleep quantity and timing

Usual bed and wake times on work days and days off, total sleep, naps, catch-up sleep at weekends; a 2-week sleep diary

OSA features

Loud habitual snoring, witnessed apnoeas (ask the partner), choking or gasping, unrefreshing sleep, morning headache, nocturia, poor concentration, low libido

Narcolepsy features

Irresistible sleep attacks, cataplexy (sudden muscle weakness with laughter or emotion), sleep paralysis, vivid hallucinations on falling asleep or waking, disturbed night sleep; onset often in teens or twenties

Restless legs and limb movements

Evening urge to move the legs, relieved by moving; partner reports kicking

Shift work and circadian timing

Night or rotating shifts, long commutes, late bedtimes with early starts, jet lag

Drugs and alcohol

Sedating medicines (opioids, gabapentinoids, benzodiazepines, Z-drugs, sedating antihistamines, antipsychotics, some antidepressants, antiepileptics, beta-blockers, dopamine agonists), alcohol, cannabis; stimulant withdrawal

Mood and medical

Depression, hypothyroidism symptoms, anaemia, diabetes, kidney or liver disease, heart failure, Parkinson's disease, previous head injury, pregnancy

Driving and work

Licence group, occupational driving, safety-critical work, near misses, sleepiness on monotonous journeys

The commonest cause of daytime sleepiness is simply not getting enough sleep. Asking about sleep on work days and days off quickly reveals chronic sleep restriction and shift-work problems.

Diagnose

Examination, Scores and Targeted Tests

Done

Examination

BMI, neck circumference, BP, upper airway (tonsils, retrognathia, nasal obstruction), thyroid, pallor, SpO₂ at rest, ankle oedema, neurological examination if the history suggests

Epworth Sleepiness Scale

8 situations scored 0–24; above 10 is conventionally excessive. Quantifies sleepiness but does not decide referral alone; driving risk depends on the history, not the score

STOP-BANG

Snoring, tiredness, observed apnoea, pressure (hypertension), BMI over 35, age over 50, neck over 40 cm, male sex — 3 or more suggests increased risk of OSA. Risk stratification, not diagnosis

Bloods by indication

FBC + ferritin TSH HbA1c U&E, LFTs — guided by the history; ferritin also if restless legs

Sleep study

Arranged by the sleep service (home oximetry, respiratory polygraphy or polysomnography) — not by primary care

Not routine

Brain imaging without neurological signs; stimulant trials in primary care

NICE NG202 asks clinicians to assess for OSA when there are at least two features such as snoring, witnessed apnoeas, unrefreshing sleep, sleepiness or nocturia, and not to rely on the Epworth score alone because some people with significant OSA do not report sleepiness.

Diagnose

Differentials

Done

Insufficient sleep

Commonest

Short sleep on work days, catch-up at weekends; resolves with extended sleep

Obstructive sleep apnoea

Snoring + apnoeas

Obesity, large neck, hypertension, morning headache, nocturia (NICE NG202)

Shift work and circadian disorders

Timing problem

Night or rotating shifts; delayed sleep phase in young people

Drugs and alcohol

Sedation

Sedating medicines, alcohol, cannabis; dopamine agonist sleep attacks

Depression

Hypersomnia

Low mood, anhedonia, long sleep without refreshment

Medical

Systemic

Hypothyroidism, anaemia, diabetes (hyper- or hypoglycaemia), CKD, liver disease, heart failure, obesity hypoventilation

Restless legs / limb movements

Fragmented sleep

Evening leg urge; check ferritin; pregnancy, CKD, neuropathy

Narcolepsy and hypersomnias

Sleep attacks

Cataplexy, sleep paralysis, hypnagogic hallucinations; idiopathic hypersomnia; post head injury

Neurological

Other

Parkinson's disease, multiple sclerosis, previous stroke; rarely a hypothalamic lesion

Several causes often coexist — for example OSA, sedating medicines and short sleep. Address each; treating one alone may not resolve the sleepiness.

Diagnose

Driving — the Advice That Cannot Wait (DVLA)

Done

Any cause, sleepy at the wheel

If excessive sleepiness has, or is likely to have, an adverse effect on driving, the person must not drive until it is satisfactorily controlled. Snoring alone is not a reason to stop driving

Suspected or mild OSA with excessive sleepiness

Must not drive until sleepiness is satisfactorily controlled; notify the DVLA if control is not achieved within 3 months

Moderate or severe OSA with excessive sleepiness

Must not drive and must notify the DVLA; relicensing once sleepiness is controlled and treatment adhered to, confirmed by the sleep service

Group 2 drivers

More stringent: medical confirmation of control before relicensing, then at least annual review

Narcolepsy or cataplexy

Must not drive and must notify the DVLA; driving may resume once there is satisfactory symptom control (specialist confirmation)

Document

The advice given, licence group, occupational driving, and the plan; the duty to notify rests with the driver

DVLA "Assessing fitness to drive" (current edition) treats excessive sleepiness from any cause, including OSA of any severity, as relevant to driving. The rules here mirror the Snoring and sleep apnoea and Driving and the DVLA protocols; check the current DVLA guidance for the specific condition.

Refer

Referral — Sleep Service and Others

Done

999 / Same-day

Acute drowsiness with neurological or systemic features; suspected CO poisoning; hypercapnic respiratory failure; hypoglycaemia; suicide risk

Urgent / expedited

Suspected OSA in a Group 2 driver, safety-critical worker, after a near miss, or with unstable cardiovascular disease or resting hypoxaemia — expedited sleep-service assessment (NICE NG202)

Sleep service

Suspected OSA with two or more features; sleepiness unexplained after the primary-care work-up; suspected circadian rhythm disorder

Neurology or sleep medicine

Suspected narcolepsy, idiopathic hypersomnia, REM sleep behaviour disorder; sleepiness after head injury or with neurological signs

Mental health

Depression with hypersomnia per the depression pathway; NHS Talking Therapies

Other

Weight management service; occupational health for shift-work problems; drug and alcohol services

The sleep service diagnoses and grades OSA and other hypersomnias and starts CPAP or wakefulness-promoting drugs. Primary care identifies the problem, gives the safety advice, addresses contributing causes and refers with the right urgency.

Treat

Treatment at This Consultation

Done

All

Driving and safety advice Today

Advise and document; explain DVLA rules for the likely cause; no driving or safety-critical work while sleepy

Insufficient sleep or shift work

Protect sleep

Extend and regularise sleep (7–9 hours for most adults); planned naps before night shifts; avoid driving home drowsy after a night shift

Suspected OSA

Refer + risk factors

Sleep-service referral; weight loss support, reduce evening alcohol, avoid sedatives, sleep on the side if positional; manage hypertension and other comorbidities

Drug or medical cause

Review and treat

Reduce or re-time sedating medicines; treat hypothyroidism, anaemia, diabetes, depression; check ferritin and treat iron deficiency in restless legs

Do notStart stimulants or wakefulness-promoting drugs (modafinil, pitolisant, sodium oxybate) in primary care — specialist-initiated only; modafinil is not licensed for residual sleepiness in OSA (MHRA)

Do notPrescribe hypnotics or sedatives for poor sleep in suspected OSA without individual caution — they can worsen apnoeas

Insomnia too?If poor night sleep is the main problem, use the insomnia and sleep problems pathway; if tiredness without dozing, the fatigue pathway

Next steps: see Snoring and sleep apnoea · Driving and the DVLA · Restless legs syndrome · Obesity · Depression · Hypothyroidism · Iron deficiency

For OSA, NICE NG202 recommends lifestyle advice (weight, alcohol, smoking, sleep position) for everyone and CPAP via the sleep service for moderate or severe disease, or mild disease with symptoms affecting quality of life. Specialist sleep services manage narcolepsy and hypersomnia drugs.

Lifestyle

Self-Care

Done

Sleep opportunity Regular bed and wake times; enough time in bed; limit screens late at night

Weight Even modest weight loss improves OSA; refer to weight management where appropriate

Alcohol and sedatives Avoid alcohol in the evening; no more than 14 units a week; review sedating medicines

Smoking Stopping reduces upper-airway inflammation; offer support

Driving Plan rest breaks; pull over if drowsy — caffeine and a short nap are only a stop-gap

Shift workers Protected daytime sleep in a dark, quiet room; consistent schedule where possible

Lifestyle changes address the main reversible contributors and are recommended for everyone with OSA alongside any device treatment.

Safety

Follow-Up and Safety-Netting

Done

2–4 weeks

Review results, sleep diary and Epworth; effect of extended sleep or medicine changes; confirm referral received

Each contact

Re-check driving status and document until sleepiness is controlled

Safety-net 999

Sudden drowsiness with confusion, severe headache, weakness or fits; several people at home drowsy or with headaches (leave and call 999)

Safety-net same-day

Breathlessness, swollen ankles or blue lips with sleepiness; hypoglycaemic episodes; low mood with thoughts of self-harm

Driving

"Don't drive while you feel sleepy — not until it is controlled. Whether you need to tell the DVLA depends on the cause and the sleep-study result; we will guide you."

Safety-netting covers both the medical emergencies and the road-safety duty, which continues until the sleep service confirms control.

😴 Excessive Daytime Sleepiness

Red Flags — Acute Drowsiness, Driving and Safety-Critical Work

History — Sleepiness or Fatigue? Then Find the Cause

Examination, Scores and Targeted Tests

Differentials

Driving — the Advice That Cannot Wait (DVLA)

Referral — Sleep Service and Others

Treatment at This Consultation

Self-Care

Follow-Up and Safety-Netting