What could be causing a sensation of blood rushing up my neck into my head, resulting in pain at the base of the skull on the left side?

Sensation of Blood Rushing Up Neck with Skull Base Pain

This symptom pattern—particularly when described as "the worst headache" or sudden severe onset—requires urgent evaluation to exclude subarachnoid hemorrhage (SAH), arterial dissection, or other life-threatening vascular pathology. 1

Immediate Red Flag Assessment

The sensation of blood rushing up the neck with skull base pain warrants urgent evaluation for several critical conditions:

• Subarachnoid hemorrhage presents as "the worst headache of my life" in 80% of awake patients, often with sudden onset during physical exertion or stress, and may be accompanied by nausea, vomiting, stiff neck, or brief loss of consciousness 1
• Sentinel or warning leak occurs in 15-37% of patients before major SAH rupture, typically presenting as milder headache lasting a few days—recognizing this pattern is potentially lifesaving 1
• Arterial dissection (carotid or vertebral) should be suspected with sudden severe unilateral headache, particularly when associated with neurological signs like Horner syndrome 1
• Cerebral venous thrombosis can present with headache and may be associated with intracranial hypotension, creating a sensation of vascular congestion 1

Diagnostic Approach

Initial Imaging

Non-contrast CT of the head is the cornerstone initial study and must be obtained urgently for any sudden severe headache or suspected SAH, with 98% sensitivity and 99% specificity for acute SAH 1. The probability of detecting hemorrhage is proportional to clinical grade and time from hemorrhage 1.

• Failure to obtain non-contrast CT is the most common diagnostic error leading to SAH misdiagnosis, which carries a nearly 4-fold higher likelihood of death or disability 1
• If CT is negative but clinical suspicion remains high, MRI with FLAIR and susceptibility-weighted imaging (SWI/GRE) sequences improves diagnosis of acute SAH, with sensitivity ranging from 50-94% for acute SAH 1

Vascular Imaging

If SAH is identified or arterial dissection suspected, CTA of the head and neck should be performed immediately 1:

• CTA is faster and safer than digital subtraction angiography for initial vascular evaluation 1
• CTA detects almost all clinically relevant blunt cervical arterial injuries 1
• Complex skull fractures, scalp degloving, or penetrating trajectories near vessels warrant vascular imaging 1

Advanced Imaging Considerations

MRI brain with MRA should be obtained urgently when CT is unrevealing but symptoms persist, particularly for:

• Posterior fossa pathology poorly visualized on CT 2
• Suspected arterial dissection with higher sensitivity than CT 1
• Evaluation of intracranial hypotension with characteristic diffuse dural enhancement 1
• Small ischemic infarcts that may be missed on CT 2

MRI should ideally be performed within 24-48 hours when encephalitis or other inflammatory conditions are suspected 2.

Critical Time-Sensitive Factors

Untreated ruptured aneurysms carry a 3-4% risk of rebleeding in the first 24 hours (possibly significantly higher), with many rebleeds occurring within 2-12 hours of initial ictus 1. This mandates:

• Urgent evaluation and treatment of suspected SAH 1
• Recognition that 12% of SAH patients die before receiving medical attention 1
• Understanding that misdiagnosis of SAH occurred in up to 64% of cases historically, with more recent rates of 12% 1

Associated Symptoms Requiring Attention

Evaluate for accompanying features that strengthen specific diagnoses:

• Meningismus (stiff neck with headache) suggests need for lumbar puncture following neuroimaging to measure intracranial pressure and evaluate for meningitis 1
• Papilledema or bilateral sixth nerve palsy indicates elevated intracranial pressure requiring urgent workup 1
• Scalp tenderness, jaw claudication, or temporal pain in elderly patients mandates immediate ESR and C-reactive protein testing for giant cell arteritis, with temporal artery biopsy if positive 1
• Postural component (worse when upright, better when lying down) suggests intracranial hypotension with potential CSF leak 1

Common Pitfalls to Avoid

• Never dismiss sudden severe headache as benign without imaging, even if symptoms partially resolve—this may represent a sentinel bleed before catastrophic rupture 1
• Do not rely on history alone when SAH is suspected, as individual findings occur inconsistently and symptom presentation is sufficiently variable to cause frequent misdiagnosis 1
• Avoid attributing symptoms to stress or tension without excluding vascular pathology, particularly in patients describing the headache as different from any previous experience 1
• Do not delay imaging for specialty consultation—obtain non-contrast CT immediately when SAH is suspected 1

When Conservative Management May Be Appropriate

If urgent imaging excludes life-threatening pathology and symptoms suggest mechanical neck pain or cervicogenic headache:

• Self-management strategies, exercise, and NSAIDs are first-line treatment 3
• Physical therapy with supervised neck exercises provides significant pain relief 3
• Manual therapy including trigger point therapy can reduce pain substantially 3

However, this conservative approach should only be considered after excluding serious pathology through appropriate imaging 3, 2.