Makindo Medical Notes

💥 Introduction

Exploding Head Syndrome (EHS) is a benign parasomnia in which individuals perceive a sudden loud bang or explosive sensation in the head during sleep-wake transitions. Despite its alarming presentation, EHS is harmless — there is no pain, no neurological damage, and no risk of stroke or seizure. The main clinical importance lies in patient reassurance and avoiding misdiagnosis as a neurological emergency.

📊 Epidemiology

• Often underreported due to embarrassment or misdiagnosis.
• Prevalence: Up to 10–15% of people may experience it at least once.
• Any age, but more common over 50 years; children/adolescents also reported.
• Affects men and women equally.

⚙️ Pathophysiology (hypotheses)

• Brainstem dysfunction: abnormal activity in reticular formation controlling sleep-wake transitions.
• Temporal lobe activity: inappropriate auditory cortex activation.
• Delayed inhibition: failure of normal neural “switching off” at sleep onset.
• Peripheral auditory system involvement is unlikely but has been suggested.

🩺 Clinical Features

• Key symptom: sudden loud noise inside the head (bang, crash, explosion, gunshot, ringing).
• Often occurs at sleep onset (hypnagogic) or awakening (hypnopompic).
• May be associated with flash of light or muscle jerk.
• No pain, no focal deficits.
• Episodes can cause distress, anxiety, or insomnia due to fear of recurrence.

🧾 Differential Diagnosis

Condition	Key Features
Exploding Head Syndrome	Loud bang, no pain, no deficits, occurs in sleep transitions
Thunderclap Headache	Sudden, severe pain (possible SAH); needs urgent CT/LP
Temporal Lobe Epilepsy	Auditory hallucinations + seizure features; abnormal EEG
Hypnic Headache	Dull headaches waking patient from sleep, older adults
Hypnagogic Hallucinations	Complex multisensory imagery, not just noise

🔬 Investigations

• Classical history + normal neuro exam → no tests required.
• Polysomnography if atypical or to rule out other sleep disorders.
• EEG if epilepsy suspected.
• Neuroimaging (MRI/CT) if focal signs, persistent headaches, or suspicion of structural pathology.

🛠️ Management

• Reassurance: key intervention – emphasise benign, self-limiting nature.
• Stress & Anxiety Management: relaxation techniques, CBT if needed.
• Sleep Hygiene: regular sleep pattern, avoid stimulants late in day, calming bedtime routine.
• Pharmacotherapy: rarely needed; low-dose tricyclics (e.g. amitriptyline), nimodipine, or SSRIs tried in severe/refractory cases.
• Avoid sleep deprivation: as episodes often cluster when overtired.

🌟 Prognosis

• Excellent: no progression to epilepsy, stroke, or dementia.
• Episodes may spontaneously reduce or resolve over time.
• Good sleep hygiene + reassurance often sufficient for control.

⚠️ When to Seek Further Advice

• Symptoms persist or worsen despite lifestyle measures.
• New neurological symptoms (weakness, seizures, focal deficits).
• Sudden severe headaches (exclude subarachnoid haemorrhage).

📚 References

• Sharpless BA. Exploding Head Syndrome. Sleep Med Rev. 2014;18(6):489-493.
• Arnold J. Curr Pain Headache Rep. 2008;12(5):394-398.
• AASM. International Classification of Sleep Disorders, 3rd ed. 2014.