What type of headache worsens when lying down and improves when sitting up, potentially indicating a spinal headache or cerebrospinal fluid leak?

Orthostatic Headache: Spontaneous Intracranial Hypotension

A headache that worsens upon sitting or standing and improves when lying down is characteristic of spontaneous intracranial hypotension (SIH), typically caused by cerebrospinal fluid (CSF) leak from the spine. 1

Defining Characteristics of Orthostatic Headache

The 2023 multidisciplinary consensus guideline provides specific diagnostic criteria for orthostatic headache 1:

• Absent or only mild headache (1-3/10) upon waking or after prolonged lying flat
• Headache onset occurs within 2 hours of becoming upright
• Greater than 50% improvement in severity within 2 hours of lying flat
• Consistent timing pattern of onset and offset 1, 2

This contrasts sharply with postdural puncture headache (PDPH), which follows the opposite pattern—worsening within 15 minutes of sitting/standing and improving within 15 minutes of lying down after a known neuraxial procedure 1.

When to Suspect SIH

SIH should be your primary diagnostic consideration in patients presenting with 1, 2:

• Orthostatic headache (without recent iatrogenic dural puncture or major trauma)
• "End of the day" or "second half of the day" headache with improvement when lying flat
• Thunderclap headache followed by orthostatic headache
• New daily persistent headache with initial orthostatic quality 1

Associated Symptoms That Increase Diagnostic Certainty

Look for these accompanying features to strengthen your suspicion of SIH 1, 2:

• Neck pain or stiffness
• Tinnitus or hearing changes
• Nausea and vomiting
• Photophobia
• Visual disturbances
• Vertigo 1

Critical Differential Diagnoses to Exclude

Before confirming SIH, you must systematically exclude 1:

Postural Orthostatic Tachycardia Syndrome (PoTS):

• Perform formal standing test documenting heart rate increase >30 beats per minute
• Note that a negative standing test does not exclude PoTS if clinical suspicion remains high
• Obtain detailed autonomic history 1, 2

Orthostatic Hypotension:

• Document blood pressure drop >20 mmHg systolic and/or >10 mmHg diastolic on standing 1, 2

Cervicogenic Headache:

• Headache provoked by cervical movement rather than posture
• Reduced cervical range of motion
• Associated myofascial tenderness 1

Migraine:

• Headache provoked by movement rather than posture
• Migrainous biology including aura and vertigo (rather than hearing impairment and tinnitus) 1

Immediate Diagnostic Workup

Order MRI brain with IV contrast AND MRI complete spine immediately to confirm intracranial hypotension and localize the leak source 2, 3. This is the first-line imaging protocol recommended by the American College of Radiology.

Brain MRI findings confirming intracranial hypotension include 2, 3:

• Diffuse pachymeningeal enhancement
• Venous sinus engorgement
• Midbrain descent (brain sagging)
• Pituitary enlargement
• Ventricular collapse

Important Clinical Pitfall

Do not exclude SIH based on normal CSF opening pressure—clinical presentation and imaging findings are more important than measured CSF pressure 3. This is a critical error that can delay diagnosis, as demonstrated in case reports where normal lumbar puncture opening pressure was observed despite clear clinical and imaging evidence of intracranial hypotension 4.

Pathophysiology

The spine is the anatomical source of most symptomatic CSF leaks due to positive hydrostatic pressure relative to atmosphere, while intracranial pressure is slightly negative in the upright position 3. Diffuse pachymeningeal enhancement occurs through compensatory venodilation and blood volume expansion in response to decreased CSF volume 3.

Risk Factors in Young Females

Consider predisposing conditions such as 3:

• Collagen vascular disease (including Marfan syndrome) 4
• Spinal osteophytes
• History of bariatric surgery
• Idiopathic intracranial hypertension

Rare but Serious Complications

Cerebral venous thrombosis (CVT) occurs in approximately 2% of SIH cases and is life-threatening 3, 5. Any change in headache pattern in SIH should alert you to possible complications including subdural hematoma, which may require urgent evacuation 5.

Treatment Approach

Early epidural blood patch (EBP) is the first-line treatment and should be performed as soon as possible after diagnosis 3, 6, 7. Non-targeted EBP is appropriate initially, with myelography reserved for cases that fail to respond or have persistent symptoms 3. For refractory cases with identified leak location, surgical repair via laminectomy may be necessary 8, 6.