In a 28‑year‑old man with a one‑week history of intermittent frontal and occipital squeezing headache lasting 10–15 minutes, brief orthostatic dizziness with transient visual darkening on standing, undocumented fever, symptom relief with paracetamol (acetaminophen) and sleep, and normal vital signs and physical examination, what is the most likely diagnosis and appropriate next steps in management?

Diagnosis and Management

The most likely diagnosis is tension-type headache or viral syndrome with orthostatic intolerance, but you must actively exclude spontaneous intracranial hypotension (SIH) given the orthostatic dizziness component before reassuring this patient.

Primary Diagnostic Consideration: Rule Out Spontaneous Intracranial Hypotension

While this patient's presentation is atypical for classic SIH, the orthostatic dizziness (visual darkening upon standing) requires careful evaluation:

Why SIH is Less Likely Here:

• Headache pattern does NOT meet SIH criteria: The headache is intermittent (10-15 minutes), not continuous; it responds to paracetamol and sleep rather than lying flat specifically; and there's no clear documentation that symptoms worsen with upright posture and improve dramatically (>50%) within 2 hours of lying flat 1
• The orthostatic symptoms are brief (2 seconds) and described as visual darkening only, not the sustained positional headache characteristic of SIH 1, 2
• Normal vital signs argue against orthostatic hypotension as a cause 1

Critical Red Flags to Assess:

• Ask specifically: Does the headache worsen significantly when standing and improve dramatically when lying flat? Is it absent or mild upon waking? 1, 2
• Perform active standing test: Measure heart rate and blood pressure supine, then at 1,3,5, and 10 minutes of standing to exclude postural orthostatic tachycardia syndrome (POTS, defined as heart rate increase ≥30 bpm in adults) or orthostatic hypotension (systolic BP drop >20 mmHg or diastolic >10 mmHg) 1, 3

Most Probable Diagnosis: Viral Syndrome (Influenza-like Illness)

This presentation is most consistent with a self-limited viral upper respiratory infection with tension-type headache features:

Supporting Features:

• Bilateral frontal and occipital squeezing headache with moderate intensity fits tension-type headache phenotype 1, 4
• One-week duration with undocumented fever is typical for influenza or viral syndrome, where headache is an early symptom lasting median 4 days (range 2-6 days) 4
• Response to paracetamol and rest is expected for viral-associated headache 4
• Brief orthostatic visual symptoms likely represent mild dehydration or autonomic dysregulation from the viral illness, not true orthostatic intolerance 1

Important Caveat:

• Influenza-associated headache typically presents with rhinorrhea (79%), nasal congestion (76%), and photophobia (59%) 4
• If these features are absent and symptoms persist beyond 7-10 days or worsen, reconsider the diagnosis 5, 4

Immediate Next Steps

1. Detailed Orthostatic History (Critical):

• Clarify headache timing: "Is your headache absent when you wake up, then develops within 2 hours of getting out of bed?" 1, 2
• Assess positional relief: "Does lying completely flat for 1-2 hours reduce your headache by more than half?" 1, 2
• Evaluate consistency: "Does this pattern happen every single day in the same way?" 1

2. Perform Active Standing Test:

• Measure supine heart rate and blood pressure after 5 minutes rest 3
• Have patient stand and measure at 1,3,5, and 10 minutes 3
• Document reproduction of symptoms during standing 3

3. Assess for Connective Tissue Disorder Risk:

• Joint hypermobility (Beighton score), skin hyperextensibility, or family history of Ehlers-Danlos syndrome increase SIH risk 1, 3

4. Neurological Examination Refinement:

• Look for subtle findings: Sixth nerve palsy, neck stiffness, or any focal deficits that might suggest intracranial pathology 1, 2

Management Algorithm

If Orthostatic Pattern is CONFIRMED (headache clearly worse upright, better flat):

• Order MRI brain with IV contrast to look for diffuse pachymeningeal enhancement, venous sinus engorgement, midbrain descent, or pituitary enlargement 1, 2, 3
• Order MRI complete spine with fluid-sensitive sequences to identify CSF leak source 1, 2, 3
• Refer to neurology within 2-4 weeks if patient can care for himself (which he can, given he's ambulatory and consulting outpatient) 1

If Orthostatic Pattern is NOT CONFIRMED (most likely scenario):

• Reassure and provide symptomatic treatment: Continue paracetamol 500-1000 mg every 6 hours as needed (maximum 3000-4000 mg/day) 6
• Hydration and rest for viral syndrome 4
• Safety-net advice: Return immediately if headache becomes constant, positional, thunderclap in onset, or if new neurological symptoms develop (confusion, seizures, focal weakness) 5, 7
• Follow-up in 1 week: If symptoms persist beyond 10-14 days or worsen, reconsider diagnosis and obtain brain imaging 8, 5, 4

Critical Pitfalls to Avoid

• Do not dismiss orthostatic symptoms in a young patient: SIH can occur without trauma or procedures, and 20-30% have normal CSF opening pressure if lumbar puncture is performed 2, 3
• Do not anchor on "flu" diagnosis: Prolonged or atypical symptoms (>7-10 days, focal findings, severe illness appearance) require expanded differential including sinusitis with complications, meningitis, or encephalitis 5, 7
• Do not confuse movement-provoked headache with positional headache: Migraine worsens with physical movement; SIH worsens specifically with upright posture regardless of movement 1
• Cervicogenic headache would show reduced cervical range of motion and myofascial tenderness, provoked by neck movement rather than posture 1