What could be causing my severe, sharp, stabbing headaches that started 2-3 days ago, are moderate to severe in intensity, last a few seconds, occur every 15-20 minutes, and are unresponsive to Tylenol (acetaminophen) Extra Strength, despite being able to sleep with the pain and having no eye pain, vomiting, or weakness?

Urgent Neuroimaging Required for Possible Primary Stabbing Headache vs. Secondary Cause

You need urgent neuroimaging (CT or MRI) immediately because this headache pattern has multiple red flags that could indicate a life-threatening secondary cause, despite some features suggesting primary stabbing headache. 1

Critical Red Flags Present in This Case

Your patient has several concerning features that mandate immediate evaluation:

• "Worst headache ever experienced" - This is a classic red flag for subarachnoid hemorrhage (SAH), even though the headache is intermittent rather than continuous 1, 2, 3
• New-onset severe headache within 2-3 days - Recent onset of severe headache always raises concern for secondary causes including SAH, arterial dissection, or mass lesion 1, 4
• Sharp/stabbing quality with severe intensity - While this could represent primary stabbing headache ("ice pick headache"), the severity and pattern require exclusion of secondary causes first 2, 3
• Unresponsive to acetaminophen - Failure of typical analgesics increases suspicion for secondary pathology 1

Why This Could Still Be Dangerous Despite Reassuring Features

The ability to sleep through pain and absence of vomiting do not rule out serious pathology 1, 5:

• Approximately 12% of patients with SAH die before receiving medical attention, and sentinel bleeds (warning leaks) often present with milder, intermittent headaches that can last days before catastrophic rupture 1
• Sentinel hemorrhages occur in 19.4% of patients before major SAH rupture, typically 2-8 weeks prior, and are characterized by sudden severe headache that may be intermittent and last several days 1
• The intermittent nature (every 15-20 minutes) does not exclude vascular pathology or other dangerous causes 4, 5

Immediate Diagnostic Algorithm

Step 1: Obtain non-contrast head CT immediately 1, 2, 3

• CT sensitivity for SAH in first 3 days approaches 100%, making it the cornerstone test 1
• If CT is negative but clinical suspicion remains high, proceed to Step 2 1

Step 2: Lumbar puncture if CT is negative 1, 3

• Xanthochromia detection by spectrophotometry remains 100% sensitive at 12 hours through 2 weeks after SAH 6
• This is mandatory when "worst headache ever" is reported, even with negative CT 1, 3

Step 3: Consider MRI/MRA if both CT and LP are negative 1, 4

• MRI with gradient echo sequences can detect subtle hemorrhage missed on CT 1
• MRA can identify unruptured aneurysms that may cause sentinel symptoms 6

Common Pitfall to Avoid

Do not dismiss this as benign primary stabbing headache or migraine without neuroimaging first 1. The most common diagnostic error in SAH is failure to obtain neuroimaging, which is associated with nearly 4-fold higher likelihood of death or disability 1. Misdiagnosis of SAH occurred in 12-64% of cases historically, often because physicians were reassured by atypical features 1.

If Imaging Is Completely Normal

Only after dangerous secondary causes are excluded can you consider primary stabbing headache (idiopathic stabbing headache) 2, 3. This condition presents with:

• Brief (seconds) sharp/stabbing pains
• Irregular frequency throughout the day
• Often in the distribution of the first division of the trigeminal nerve
• Typically responds to indomethacin 25-50 mg three times daily 1

However, treatment should not begin until life-threatening causes are definitively ruled out through appropriate imaging and, if indicated, lumbar puncture 1, 2, 3.