What is the likely cause of a 47-year-old male's new onset headaches, worsened by bending over, with associated personality changes, unsteadiness, and near-falls, considering his history of hypertension, type 2 diabetes, asthma, and 10 pack-year smoking history?

Differential Diagnoses for New-Onset Headaches with Red Flag Features

Most Likely Diagnosis: Space-Occupying Lesion (Brain Tumor or Mass)

This patient requires emergency neuroimaging with MRI brain with and without contrast within 24-48 hours due to multiple red flags indicating increased intracranial pressure from a probable space-occupying lesion. 1

Critical Red Flags Present (7 Major Red Flags)

• New-onset headache at age >40 years (47 years old) 1
• Progressive worsening pattern (once weekly to daily over 4 weeks) 1
• Headache worse in mornings (8/10 AM, 4/10 PM) - classic for increased intracranial pressure 1
• Aggravation by Valsalva maneuver (bending over) - strongly suggests elevated intracranial pressure 1
• Personality changes (increased irritability, anger outbursts) - indicates frontal lobe involvement 1
• Memory impairment (forgot 20-year anniversary) - suggests cognitive dysfunction from mass effect 1
• Focal neurological signs (unsteadiness, near-falls, ataxia) - indicates cerebellar or brainstem involvement 1

Pathophysiology Supporting This Diagnosis

The constellation of morning-predominant headache that improves throughout the day occurs because intracranial pressure increases during recumbent sleep due to decreased venous drainage and increased cerebral blood volume. 1 The throbbing quality with mild acetaminophen response, nausea without vomiting (yet), and progressive frequency all support a mass lesion causing gradual elevation of intracranial pressure. 1

Immediate Diagnostic Approach

• MRI brain with and without contrast is the preferred initial study for this subacute progressive presentation with suspected tumor or space-occupying lesion 1
• MRI provides superior resolution for detecting tumors, inflammatory processes, and posterior fossa lesions without radiation exposure 1
• If MRI unavailable within 24 hours, perform urgent CT head without contrast, followed by MRI when available 2

---

Second Most Likely: Idiopathic Intracranial Hypertension (IIH)

Supporting Features

• Headache progressively more severe and frequent 2, 3
• Morning predominance (though less specific than with mass lesions) 4
• Cognitive disturbances (memory problems, personality changes) 2
• Unsteadiness/dizziness 2
• Male patient with possible obesity risk factors (outdoor occupation, alcohol consumption) 2

Features Against IIH

• Age 47 is atypical - IIH typically affects women of childbearing age with BMI >30 kg/m² 2
• Male gender is atypical - IIH has strong female predominance 2
• No mention of pulsatile tinnitus or transient visual obscurations - common IIH symptoms 2, 4
• Focal neurological signs (ataxia, near-falls) are NOT typical of IIH - only sixth nerve palsy is expected 2

Diagnostic Workup if Mass Excluded

• MRI brain must show no hydrocephalus, mass, structural or vascular lesion, and no abnormal meningeal enhancement 2
• CT or MR venography mandatory within 24 hours to exclude cerebral venous sinus thrombosis 2
• Lumbar puncture with opening pressure measurement in lateral decubitus position with legs extended - must be ≥25 cm H₂O (≥250 mm H₂O) for diagnosis 2
• Fundoscopic examination for papilledema - hallmark finding, though absent in >5% of IIH cases 2, 3

---

Third Consideration: Cerebral Venous Sinus Thrombosis (CVT)

Supporting Features

• Progressive headache over weeks 5
• Personality changes and cognitive dysfunction 5
• Nausea 5
• Risk factors: hypertension, diabetes (prothrombotic states) 5

Features Against CVT

• Absence of seizures (present in 22% of CVT cases) 5
• No mention of focal motor deficits (present in some CVT cases) 5
• Gradual onset over 4 weeks rather than acute/subacute presentation 5

Diagnostic Approach

• CT or MR venography is mandatory if CVT suspected 2
• CVT can present with signs mimicking increased intracranial pressure and may coexist with spontaneous intracranial hypotension 5

---

Fourth Consideration: Hypertensive Emergency with Posterior Reversible Encephalopathy Syndrome (PRES)

Supporting Features

• Known hypertension on treatment (Lisinopril 20mg BID) 1
• Personality changes and altered mental status 5
• Headache with neurological symptoms 5

Features Against Hypertensive Emergency

• Subacute progression over 4 weeks - hypertensive emergency presents acutely 5
• No mention of severely elevated blood pressure at presentation 1
• Well-controlled hypertension on medication makes acute crisis less likely 1

Diagnostic Approach

• Blood pressure measurement in both arms at presentation is critical 1
• MRI brain without contrast is usually sufficient for PRES diagnosis if suspected 5

---

Fifth Consideration: Subdural Hematoma

Supporting Features

• Progressive headache 5
• Personality changes 5
• Unsteadiness and near-falls (though no documented trauma) 5
• Risk factors: age >40, hypertension, possible alcohol use (1-2 glasses wine nightly) 5

Features Against Subdural Hematoma

• No history of head trauma or major accidents 5
• No anticoagulant use (Lisinopril is not anticoagulant) 5
• Subacute progression more consistent with mass lesion 5

---

Diagnoses to Exclude

Spontaneous Intracranial Hypotension (SIH)

This diagnosis is definitively excluded because the headache worsens in the morning rather than improving, which is opposite to the orthostatic pattern required for SIH diagnosis. 1 Orthostatic headache must improve >50% within 2 hours of lying flat. 1 This patient's morning-predominant headache indicates increased intracranial pressure, not decreased pressure. 5

Migraine with Aura

This diagnosis is unlikely because:

• New-onset at age 47 without prior headache history 6
• No visual aura, bright shimmering jagged lines, or typical migraine features 6
• Progressive daily pattern rather than episodic 6
• Focal neurological signs (ataxia) are not typical of migraine 6
• Personality changes and memory impairment are not migraine features 6

Tension-Type Headache

This diagnosis is excluded because tension-type headache does not cause visual symptoms, personality changes, memory impairment, or focal neurological signs. 6

---

Immediate Management Plan

Urgent Actions Required

1. Emergency admission or urgent neurology referral within 48 hours due to multiple red flags mandating immediate evaluation 1
2. MRI brain with and without contrast as first-line imaging 1
3. Blood pressure measurement to exclude hypertensive emergency 1
4. Fundoscopic examination to assess for papilledema 2
5. Complete neurological examination including gait assessment, cranial nerves, cerebellar testing 2

Common Pitfalls to Avoid

• Do not dismiss this as "stress headache" or "tension headache" - the progressive pattern with red flags demands urgent evaluation 1
• Do not delay imaging for "trial of migraine medication" - this patient has never had headaches before and has multiple concerning features 1
• Do not perform lumbar puncture before neuroimaging - risk of herniation if mass lesion present 2
• Do not assume well-controlled hypertension excludes serious pathology - the headache pattern and associated symptoms are the key 1