From the Guidelines
The most common cause of headaches is tension-type headaches, but in an A&E setting, it is crucial to rule out life-threatening causes such as subarachnoid hemorrhage, meningitis, encephalitis, stroke, and intracranial mass lesions, with subarachnoid hemorrhage being a particularly critical condition to consider due to its high morbidity and mortality rates 1.
Key Considerations
When evaluating headaches in A&E, it is essential to focus on identifying "red flag" symptoms that suggest serious pathology, including:
- Sudden onset severe headache ("thunderclap")
- Headache with fever and neck stiffness
- Headache with neurological deficits
- Headache following head trauma
- New headache in patients over 50
- Headache with systemic symptoms like weight loss or fever These symptoms can indicate a range of serious conditions, including subarachnoid hemorrhage, which is characterized by a sudden and severe headache, often described as the "worst headache of my life" 1.
Diagnostic Approach
The diagnostic approach typically includes a thorough history and neurological examination, followed by appropriate imaging (CT or MRI) and possibly lumbar puncture if meningitis is suspected. Noncontrast head CT remains the cornerstone of diagnosis of subarachnoid hemorrhage, with a high sensitivity in the first 3 days after the event 1. However, in cases where the CT scan is negative but clinical suspicion remains high, magnetic resonance imaging of the brain, particularly the use of fluid-attenuated inversion recovery, proton density, diffusion-weighted imaging, and gradient echo sequences, can often allow the diagnosis of subarachnoid hemorrhage to be made 1.
Importance of Early Diagnosis
Early diagnosis and treatment of subarachnoid hemorrhage are critical to improving outcomes, as delayed diagnosis can lead to increased morbidity and mortality 1. Additionally, recognizing a warning leak or sentinel hemorrhage before a catastrophic rupture may be lifesaving 1. Therefore, maintaining a high index of suspicion for secondary headaches is essential in emergency settings, particularly when the presentation is atypical or includes concerning features.
From the Research
Causes of Headache
- The most common cause of headache is primary headaches, which include migraine, tension, and cluster headaches, accounting for 90% of all headaches 2, 3.
- Secondary headaches, which are caused by separate underlying processes with vascular, infectious, or traumatic etiologies, account for 10% of all headaches and are potentially life-threatening 2, 3.
Conditions to be Ruled Out in A&E
- Life-threatening secondary causes of headache, which can be broadly categorized into structural, infectious, and vascular causes, must be identified in the emergency department (ED) 4.
- Specific conditions that should be ruled out in the A&E department include:
- Subarachnoid hemorrhage
- Acute meningitis
- Acute angle-closure glaucoma
- Red flags that cannot be missed in the history and physical examination of patients with headache must be carefully evaluated to minimize the risk of overlooking life-threatening causes 2, 5.
- Diagnostic testing, imaging, and treatment should be initiated in the ED when certain critical features are present 6, 5.