What could be causing progressive intracranial fullness, heaviness, and pain, particularly when laying down, with greater severity on the left side, and waking from sleep due to repositioning of the head, in a patient with no known allergies or sinus issues?

Progressive Positional Headache with Intracranial Pressure Features

This patient requires urgent neuroimaging with MRI brain and complete spine with contrast to evaluate for spontaneous intracranial hypotension (SIH), followed by immediate ophthalmologic examination to assess for papilledema and exclude increased intracranial pressure. 1, 2

Critical Diagnostic Pathway

Primary Concern: Spontaneous Intracranial Hypotension

The constellation of progressive headache that worsens with upright positioning, heaviness that improves when lying down, and symptoms that wake the patient from sleep when repositioning the head strongly suggests spontaneous intracranial hypotension from CSF leak. 2, 3

Key diagnostic features present:

• Positional worsening (worse when upright/laying down attempts, better when flat) 2
• Progressive nature of symptoms 2
• Awakening from sleep with head repositioning 2
• Sensation of brain "heaviness" and pressure 3, 4

However, a critical caveat: Up to 66% of patients with SIH have normal or even elevated opening pressures on lumbar puncture, and over 25% have normal imaging initially. 3 The absence of classic orthostatic features does not exclude this diagnosis.

Immediate Imaging Protocol

Order MRI brain with IV gadolinium contrast AND MRI complete spine immediately. 2

Brain MRI findings to identify: 2, 4

• Diffuse pachymeningeal (dural) enhancement
• Venous sinus engorgement
• Midbrain descent or sagging
• Pituitary enlargement
• Ventricular collapse
• Subdural fluid collections

Spine MRI findings to identify: 2, 4

• Ventral epidural fluid collections (CSF leak site)
• Diskogenic microspurs 3
• Meningeal diverticula

Critical Differential: Increased Intracranial Pressure

The lateralized nature (greater on left side) and positional worsening could paradoxically indicate increased intracranial pressure rather than decreased pressure. 1, 5

Urgent ophthalmologic examination is mandatory to assess for: 1

• Papilledema on fundoscopy
• Optic disc swelling
• Venous engorgement
• Visual field defects by confrontation

If papilledema is present, this represents idiopathic intracranial hypertension (IIH) and requires immediate ophthalmology referral to prevent permanent vision loss. 1, 5

Life-Threatening Consideration: Cerebral Venous Thrombosis

The progressive nature with lateralization raises concern for cerebral venous sinus thrombosis, which can complicate SIH or occur independently. 6, 1

MRI brain with venography (MRV) must be included to exclude: 6, 1

• Superior sagittal sinus thrombosis
• Transverse or sigmoid sinus thrombosis
• Cortical vein thrombosis

This is particularly critical because CVT can present with positional headaches mimicking SIH, and delayed diagnosis can lead to hemorrhagic venous infarction. 6

Physical Examination Priorities

Perform immediately: 1

• Fundoscopic examination for papilledema, disc swelling, venous engorgement
• Pupil examination for size, shape, reactivity, and relative afferent pupillary defect
• Visual acuity testing and visual field assessment by confrontation
• Cranial nerve examination particularly CN VI (abducens) for palsy suggesting increased ICP 6

Assess for associated symptoms that increase diagnostic certainty: 2

• Neck pain or stiffness
• Nausea and vomiting
• Tinnitus or hearing changes
• Photophobia

Laboratory Testing

Order immediately: 1

• Complete blood count
• Basic metabolic panel (glucose, sodium, renal function)
• ESR and CRP (if age >50 years to exclude giant cell arteritis)
• Coagulation studies if CVT suspected 6

Management Based on Findings

If SIH Confirmed:

Initial conservative management: 4

• Strict bed rest with head flat
• Aggressive hydration (oral and IV)
• Caffeine supplementation
• Abdominal binder to increase CSF pressure

If conservative measures fail after 1-2 weeks: 4

• Targeted epidural blood patch at identified leak site
• Consider fibrin glue injection if blood patch fails
• Surgical repair if leak site identified and less invasive measures fail

If Increased ICP/IIH Confirmed:

Immediate treatment to prevent vision loss: 5

• Acetazolamide initiation
• Weight loss counseling (if applicable)
• Serial ophthalmologic monitoring
• Consider urgent surgical intervention (optic nerve sheath fenestration or CSF shunting) if rapid visual decline 5

If CVT Confirmed:

Immediate anticoagulation unless contraindicated by hemorrhage. 6

Common Pitfalls to Avoid

Do not assume normal CSF opening pressure excludes SIH - only 34% have pressure ≤60 mmCSF, and 5% have pressures ≥200 mmCSF. 3

Do not dismiss the diagnosis based on atypical positional features - the headache phenotype in both SIH and IIH can resemble migraine or tension-type headache without classic orthostatic features. 3

Do not delay imaging waiting for "typical" symptoms to develop - both conditions can cause permanent neurological damage if untreated. 1, 5

Recognize that SIH can paradoxically lead to increased ICP (rebound intracranial hypertension) after treatment, or can be complicated by CVT. 6, 4