A patient develops a sudden, severe headache while heavy lifting, has a facial and neck rash but no neck pain and a normal neurological exam; what emergent evaluation and management steps are indicated?

Emergent Evaluation and Management of Sudden Severe Headache During Exertion with Facial/Neck Rash

Obtain an immediate non-contrast head CT on a high-quality scanner interpreted by a board-certified neuroradiologist to exclude subarachnoid hemorrhage (SAH), as this presentation meets multiple Ottawa SAH Rule criteria (age ≥40 years, onset during exertion, thunderclap pattern) despite the absence of neck pain. 1, 2

Immediate Diagnostic Workup

Non-Contrast Head CT (First-Line)

• Perform emergent non-contrast head CT immediately, as this patient's sudden severe headache during heavy lifting represents a thunderclap pattern with onset during exertion—two high-risk Ottawa SAH Rule criteria that mandate further investigation regardless of the absence of neck pain or focal neurological deficits. 1, 2

• CT performed within 6 hours of symptom onset detects SAH with 98.7% sensitivity when interpreted by a neuroradiologist on modern equipment, potentially excluding SAH without further testing if negative within this window. 1, 2

• Critical timing consideration: If the patient presents >6 hours from headache onset, CT sensitivity drops to 93% at 24 hours and 57-85% at 6 days, making lumbar puncture mandatory if CT is negative. 2

Lumbar Puncture (If CT Negative and >6 Hours from Onset)

• Perform LP with spectrophotometric analysis for xanthochromia if CT is negative and symptom onset occurred >6 hours prior, as this provides 100% sensitivity and 95% specificity for ruptured aneurysms. 2

• LP must be performed at least 6-12 hours after headache onset to allow xanthochromia development; earlier LP risks false-negative results. 2

• Obtain CSF red blood cell count, white blood cell count, and bilirubin detection for accurate interpretation. 2

CT Angiography (CTA)

• Obtain CTA immediately if SAH is confirmed on non-contrast CT to identify the bleeding source, as CTA detects >95% of aneurysms ≥3 mm with 97% sensitivity for cerebrovascular pathology. 2, 3

• CTA serves as a reasonable alternative to LP when clinical suspicion remains high after negative CT, though it detects only 61% of aneurysms <3 mm. 1, 2

• If diffuse basal cistern or sylvian fissure SAH is identified, proceed to digital subtraction angiography (DSA) regardless of CTA results, as small aneurysms may be missed. 1

Addressing the Facial and Neck Rash

Differential Considerations

• The rash is not a typical feature of SAH and should prompt consideration of alternative or concurrent diagnoses, but does not reduce the urgency of excluding SAH given the high-risk headache features. 1, 2

• Consider meningitis if the rash is petechial or purpuric, particularly if fever develops; however, the absence of neck pain makes bacterial meningitis less likely. 2

• Evaluate for drug reaction, viral exanthem, or dermatologic conditions as secondary concerns after life-threatening intracranial pathology is excluded. 2

Acute Management Pending Diagnosis

Blood Pressure Control

• Initiate titratable antihypertensive therapy to maintain systolic BP <160 mmHg if SAH is suspected or confirmed, balancing rebleeding prevention against cerebral perfusion pressure maintenance. 2

• Early aneurysm rebleeding increases mortality 10-fold; blood pressure control is critical until definitive aneurysm obliteration. 2

Neuroprotective Therapy

• Administer oral nimodipine 60 mg every 4 hours immediately if aneurysmal SAH is confirmed, as this improves neurological outcomes. 2

Disposition

• Admit to a neurosciences intensive care unit if SAH is confirmed, with urgent neurosurgical consultation for definitive treatment (endovascular coiling or surgical clipping). 2

• Transfer to a high-volume center (≥35 SAH cases/year) if your facility treats <10 cases annually, as outcomes are superior at experienced centers. 2

Critical Pitfalls to Avoid

• Do not dismiss the diagnosis based on absence of neck pain alone, as atypical presentations—including isolated neck pain, syncope, seizure, or new focal deficits—still warrant complete imaging workup. 1, 2

• Do not rely on CT alone if >6 hours from onset, as sensitivity declines markedly and LP becomes mandatory when clinical suspicion remains high. 2

• Do not perform LP before 6 hours from headache onset, as xanthochromia may not yet be detectable, leading to false-negative results. 2

• Misdiagnosis of SAH is associated with a nearly 4-fold higher risk of death or disability at one year, particularly in patients with minimal initial neurological deficits. 2

Alternative Diagnoses to Consider After SAH Exclusion

• Cervical artery dissection presents with thunderclap headache in 20% of cases and may be associated with neck pain or Horner syndrome; obtain CTA of the neck if SAH is excluded. 4

• Cerebral venous sinus thrombosis can mimic SAH with thunderclap headache; MRI with venography is diagnostic if initial workup is negative. 2, 4

• Reversible cerebral vasoconstriction syndrome (RCVS) presents with recurrent thunderclap headaches triggered by exertion; brain MRI with vascular sequences (CTA or MRA) is required for diagnosis. 2