What are the red flags for headache (Cephalalgia)?

From the Guidelines

Red flags in headaches are warning signs that may indicate a serious underlying condition requiring immediate medical attention, and the most critical ones include sudden onset of severe headache (thunderclap headache), headache with fever or neck stiffness, and headache after head trauma. These red flags are crucial in distinguishing potentially life-threatening headaches from more common types like tension or migraine headaches. According to the American Heart Association/American Stroke Association guidelines 1, a thunderclap headache, which is characterized as being extremely sudden and immediately reaching maximal intensity, is a hallmark of aneurysmal subarachnoid hemorrhage (aSAH). The guidelines also emphasize the importance of recognizing a warning leak or sentinel hemorrhage before a catastrophic rupture, which may be lifesaving.

Some key red flags in headaches include:

• Sudden onset of severe headache (thunderclap headache)
• Headache with fever or neck stiffness
• Headache after head trauma
• Headache with neurological symptoms (weakness, numbness, vision changes, speech difficulties, confusion)
• Headache that worsens with coughing or exertion
• New headache in patients over 50 years old
• Headache with systemic symptoms (weight loss, night sweats)
• Headache that progressively worsens
• Headache in patients with cancer, HIV, or immunosuppression

If any of these red flags are present, seeking emergency medical care immediately is crucial, as they may indicate conditions like subarachnoid hemorrhage, meningitis, brain tumor, stroke, or increased intracranial pressure 1. Early diagnosis and treatment of these serious conditions can significantly improve outcomes and prevent permanent neurological damage or death. The U.S. Headache Consortium guidelines also suggest that neuroimaging should be considered only in patients with migraine who have atypical headache patterns or neurologic signs 1.

In clinical practice, a high index of suspicion is warranted when evaluating patients with headaches, as diagnosis of the warning leak or sentinel hemorrhage before a catastrophic rupture may be lifesaving 1. Noncontrast head CT remains the cornerstone of diagnosis of aSAH, and advances in magnetic resonance imaging of the brain can often allow the diagnosis of aSAH to be made when a head CT scan is negative and there is clinical suspicion of aSAH 1.

From the Research

Headache Red Flags

• Red flag signs and symptoms that can indicate serious underlying pathology include:
  • Focal neurologic signs
  • Papilledema
  • Neck stiffness
  • Immunocompromised state
  • Sudden onset of the worst headache in the patient's life
  • Personality changes
  • Headache after trauma
  • Headache that is worse with exercise 2
• Other red flags for secondary disorders include:
  • Sudden onset of headache
  • Onset of headache after 50 years of age
  • Increased frequency or severity of headache
  • New onset of headache with an underlying medical condition
  • Headache with concomitant systemic illness
  • Focal neurologic signs or symptoms
  • Papilledema and headache subsequent to head trauma 3
• Red flags that may benefit from CT, MRI, or noninvasive vascular imaging include:
  • Head trauma
  • Cancer
  • Immunocompromised state
  • Pregnancy
  • Patients 50 years or older
  • Related to activity or position
  • With a corresponding neurological deficit 4

Diagnostic Evaluation

• A thorough history and physical examination, and an understanding of the typical features of primary headaches, can reduce the need for neuroimaging, lumbar puncture, or other studies 2
• If an intracranial hemorrhage is suspected, head computed tomography without contrast media is recommended 2
• For most other dangerous causes of headache, magnetic resonance imaging or computed tomography is acceptable 2
• Lumbar puncture can help to confirm or rule out hemorrhage, infection, tumor and disorders related to CSF hypertension or hypotension 3
• The utility of lumbar punctures in computed tomography negative suspected subarachnoid hemorrhage has been demonstrated in a systematic review and meta-analysis 5
• The current clinical workflow of an LP after a negative CT head for a patient presenting with a sudden-onset severe headache is observed to have a high enough proportion to warrant its continued use despite the sensitivity of modern CT scanners of ≥97% 5