From the Guidelines
For a new posterior headache evaluation, I recommend applying the Ottawa SAH Rule to determine the need for additional investigation, considering factors such as age, neck pain or stiffness, witnessed loss of consciousness, onset during exertion, thunderclap headache, and limited neck flexion on examination. This approach is based on the most recent and highest quality study, which emphasizes the importance of a thorough evaluation to rule out serious conditions like subarachnoid hemorrhage (SAH) 1.
Key Considerations
- The Ottawa SAH Rule serves as a method to screen out individuals with a low likelihood of aSAH, with a high sensitivity of 100% but low specificity of 15.3% in the initial study and 7.6% in external validation 1.
- Noncontrast head CT remains the cornerstone of SAH diagnosis, especially when performed within 6 hours of symptom onset, with a sensitivity of 98.7% and specificity of 99.9% 1.
- For patients presenting > 6 hours from ictus with high suspicion for SAH, lumbar puncture for xanthochromia evaluation should be performed 1.
- Red flags requiring immediate medical attention include sudden onset ("thunderclap" headache), neurological deficits, fever, neck stiffness, or headache worsening with position changes.
Diagnostic Approach
- A comprehensive approach starting with a detailed history and physical examination, focusing on neurological assessment, is crucial.
- Key diagnostic tests include neuroimaging (preferably noncontrast head CT initially), and possibly lumbar puncture if SAH is suspected.
- The role of MRI and other imaging modalities may be considered based on the clinical presentation and initial findings.
Treatment and Management
- Treatment depends on the underlying cause but may include analgesics such as NSAIDs for pain management while diagnosis is pending.
- The management of SAH and other serious conditions requires prompt and specialized care, emphasizing the importance of early recognition and referral.
From the Research
Evaluation for New Posterior Headache
The evaluation of a new posterior headache involves a thorough history and physical examination to identify secondary headache and determine the need for immediate referral to the emergency department or a non-emergent referral to a neurologist 2.
- A focused history is essential to identify secondary headache and find out whether an immediate referral to the emergency department or a non-emergent referral to the neurologist is warranted 2
- A complete neurological examination, consideration of neuroimaging, and serum/spinal fluid analysis if indicated, are part of the evaluation and workup 3, 4
- Careful attention to the patient's history and physical examination will guide the diagnostic work-up and management 3, 4
Red Flags and Secondary Etiologies
It is essential to screen for headache "red flags" as they can suggest life-threatening secondary etiologies 3.
- The Ottawa headache rule is a clinical decision tool that can help identify patients presenting to the ED with acute non-traumatic headache who require investigation to rule out subarachnoid hemorrhage 5
- Characteristics in the clinical history that can distinguish the headache of subarachnoid hemorrhage from other causes include occipital location, stabbing quality, presence of meningism, and onset of headache during exertion 5
Diagnostic Approach
A practical and systematic approach to evaluating and treating headache is key to making the correct diagnosis, or possibly overlapping diagnoses 4.
- Taking a thorough and methodical headache history is the mainstay for diagnosis of both primary and secondary headache disorders 4
- Evaluation and workup should include a complete neurological examination, consideration of neuroimaging in specific limited situations, and serum or spinal fluid analysis if indicated 4