Differential Diagnosis for Sudden Onset Headache
- Single most likely diagnosis
- Thunderclap headache (e.g., subarachnoid hemorrhage): The sudden onset of a severe headache, often described as "the worst headache of my life," along with neck pain, chills, and nausea, suggests a thunderclap headache, which could be indicative of a subarachnoid hemorrhage. The rapid onset and extreme severity are key characteristics.
- Other Likely diagnoses
- Meningitis: The combination of headache, neck pain, chills, and nausea could also suggest meningitis, an infection of the protective membranes covering the brain and spinal cord. The presence of fever and chills, in particular, points towards an infectious cause.
- Cervicogenic headache: Given the neck pain, a cervicogenic headache, which originates from the cervical spine, is a possibility. However, the severity and sudden onset are less typical for this condition.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Subarachnoid hemorrhage: As mentioned, this is a critical diagnosis to consider due to its high morbidity and mortality if not promptly treated. The sudden, severe headache is a classic presentation.
- Meningitis (again, due to its potential severity and the need for prompt antibiotic treatment): Delayed diagnosis can lead to severe complications, including death.
- Cerebral venous sinus thrombosis: Although less common, this condition can present with sudden headache and should be considered, especially if there are risk factors such as hypercoagulability or dehydration.
- Rare diagnoses
- Temporal arteritis: While this condition typically presents in older adults with more gradual onset of headache, jaw claudication, and visual symptoms, it's a diagnosis not to be missed due to the risk of blindness if not treated promptly.
- Primary thunderclap headache: A benign condition that mimics the severe onset of a subarachnoid hemorrhage but lacks the dangerous underlying cause. It's rare and diagnosed after ruling out more serious conditions.
- Reversible cerebral vasoconstriction syndrome (RCVS): Characterized by sudden, severe headaches, this condition is often associated with vasoconstriction of the cerebral arteries and can be precipitated by various factors, including certain medications or postpartum state.