What are the red flags for headache that require immediate medical attention?

Red Flags for Headache Requiring Immediate Medical Attention

Patients with headache should be urgently evaluated when presenting with any of the following red flags: thunderclap headache (sudden onset), focal neurological symptoms, fever with neck stiffness, headache following head trauma, positional headache, Valsalva-induced headache, papilledema, or altered mental status. 1

Critical Red Flags Requiring Emergency Evaluation

Immediate Life-Threatening Concerns

• Thunderclap headache: Sudden, severe "worst headache of life" - suggests subarachnoid hemorrhage 2, 1
• Focal neurological deficits: Including weakness, sensory changes, vision changes, speech difficulties
• Altered mental status: Drowsiness, confusion, memory impairment, or loss of consciousness 3
• Papilledema: Optic disc edema visible on fundoscopic examination 1, 3
• Fever with neck stiffness: Suggests meningitis or other CNS infection 1
• Recent head trauma: Especially with subsequent headache 1, 4

High-Risk Patient Characteristics

• Age ≥50 years with new-onset headache: Higher risk of secondary causes 1, 4
• Cancer history or immunocompromised state: Risk of CNS metastases or opportunistic infections 5
• Pregnancy: Risk of preeclampsia, cerebral venous thrombosis 4
• Anticoagulant therapy: Increased risk of intracranial hemorrhage 4

Position and Activity-Related Red Flags

• Positional headache: Worsens when lying down or standing up - suggests intracranial pressure abnormalities or CSF leak 1
• Valsalva-induced headache: Pain triggered by coughing, sneezing, or straining - suggests increased intracranial pressure 1
• Exertional headache: Pain triggered by physical activity - requires exclusion of structural causes 1

Other Important Warning Signs

• Abrupt change in established headache pattern: In patients with known primary headache disorders 1
• Progressive worsening over time: Especially if unresponsive to appropriate treatment 6
• Associated systemic symptoms: Weight loss, night sweats, or other constitutional symptoms 1
• New onset of headache with aura: Especially if atypical or prolonged 6
• Suspicion of glaucoma: Eye pain, halos around lights, nausea/vomiting 4

Clinical Significance of Multiple Red Flags

• The presence of 3 or more red flags significantly increases the likelihood of finding abnormalities on neuroimaging 3
• The most statistically significant predictors of abnormal neuroimaging are:
  1. Paralysis
  2. Papilledema
  3. Altered mental status (drowsiness, confusion, memory impairment, loss of consciousness) 3

Diagnostic Approach When Red Flags Present

• Sudden severe headache: Immediate non-contrast CT scan to evaluate for subarachnoid hemorrhage; if negative but clinical suspicion remains high, proceed to lumbar puncture 2, 1
• Focal neurological symptoms or signs: MRI with and without contrast is preferred 1, 5
• Suspected increased intracranial pressure: Neuroimaging followed by lumbar puncture if safe 1
• Suspected meningitis: CT before lumbar puncture if focal signs present; otherwise proceed directly to lumbar puncture 1

Pitfalls to Avoid

• Failing to recognize red flags in patients with known primary headache disorders 1
• Attributing new headache patterns to previous diagnoses without consideration of secondary causes 1
• Overlooking medication overuse as a cause of changing headache patterns 1
• Confusing migraine aura with transient ischemic attack 1
• Neglecting to perform fundoscopic examination to detect papilledema 1, 3

Remember that while most headaches are benign and primary in nature, the presence of these red flags significantly increases the likelihood of a serious secondary cause requiring immediate medical attention.