Differential Diagnosis for Sudden Onset Headache
- Single most likely diagnosis
- Subarachnoid Hemorrhage (SAH): The sudden onset of a severe headache, often described as "the worst headache of my life," along with neck pain, chills, and nausea, strongly suggests SAH. The rapid onset and extreme severity of the headache are classic presentations.
- Other Likely diagnoses
- Meningitis: Inflammation of the protective membranes covering the brain and spinal cord, which can cause severe headache, neck pain, chills, and nausea. The presence of fever and chills increases the likelihood of this diagnosis.
- Tension Headache: Although less likely given the severity, a severe tension headache could present with bilateral temple pain and neck pain. However, the intensity and sudden onset are atypical.
- Cluster Headache: These are extremely painful headaches that occur in cycles or clusters, often waking the patient from sleep. They are usually unilateral but can be bilateral and are accompanied by autonomic symptoms like nausea.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Cervical Artery Dissection: A tear in the wall of one of the arteries in the neck, which can lead to stroke. It often presents with sudden severe headache and neck pain.
- Intracranial Hemorrhage (not limited to SAH): Any bleeding within the brain, which could present with sudden headache, nausea, and altered mental status.
- Meningoencephalitis: Inflammation of both the brain and meninges, which can present similarly to meningitis but with additional symptoms like confusion or altered mental status.
- Rare diagnoses
- Temporal Arteritis: An inflammation of the blood vessels in the temple, which can cause severe headache but typically occurs in older adults and is accompanied by other symptoms like jaw claudication.
- Idiopathic Intracranial Hypertension (IIH): A condition characterized by increased pressure within the skull without a detectable cause, often presenting with headache and vision changes, but the onset is usually more gradual.
- Reversible Cerebral Vasoconstriction Syndrome (RCVS): A condition that mimics many of the symptoms of SAH, including thunderclap headache, but is due to temporary narrowing of the blood vessels in the brain.