Differential Diagnosis for Thunderclap Headache
Single Most Likely Diagnosis
- Subarachnoid Hemorrhage (SAH): This is often considered the most likely diagnosis for a thunderclap headache due to its severity and sudden onset, which can mimic the description of a "thunderclap." SAH is a medical emergency that requires immediate attention.
Other Likely Diagnoses
- Migraine: Although typically not as severe as a thunderclap headache, some migraines can present with sudden, severe pain. However, migraines usually have other associated symptoms such as aura, nausea, or sensitivity to light and sound.
- Tension Headache: While less likely to be described as a thunderclap, severe tension headaches can occur and may be mistaken for other conditions due to their intensity.
- Cluster Headache: Known for their severe, unilateral pain, cluster headaches can sometimes be described in terms similar to a thunderclap headache, especially if the patient is experiencing their first episode.
Do Not Miss Diagnoses
- Subarachnoid Hemorrhage (SAH): Already mentioned, but crucial enough to reiterate due to its high morbidity and mortality if missed.
- Cervical Artery Dissection: This condition can lead to a stroke and often presents with sudden, severe headache, sometimes accompanied by neck pain.
- Venous Sinus Thrombosis: A rare cause of stroke that can present with headache, often severe and sudden, due to increased intracranial pressure.
- Pituitary Apoplexy: A medical emergency where a pituitary tumor suddenly hemorrhages or infarcts, leading to severe headache, visual disturbances, and potentially life-threatening hormonal imbalances.
Rare Diagnoses
- Reversible Cerebral Vasoconstriction Syndrome (RCVS): Characterized by sudden, severe headaches (often thunderclap) and reversible vasoconstriction of cerebral arteries, which can lead to stroke or SAH.
- Primary Thunderclap Headache: A rare condition where the headache is the primary symptom without an identifiable cause, although this diagnosis is essentially one of exclusion.
- Spontaneous Intracranial Hypotension: Caused by a spontaneous cerebrospinal fluid leak, leading to severe headache that is typically worse when standing and improved when lying down.