What is the appropriate diagnosis and treatment for a patient experiencing a unilateral headache for 5 days that worsens when lying down?

Unilateral Headache Worsening When Lying Down: Diagnosis and Management

This clinical presentation demands urgent evaluation for spontaneous intracranial hypotension (SIH) or, less commonly, increased intracranial pressure from mass lesion or cerebral venous thrombosis, with brain MRI with contrast and whole spine MRI being the diagnostic studies of choice.

Critical Diagnostic Considerations

The key feature here is the paradoxical worsening when lying down, which is atypical for most headache disorders and narrows the differential significantly.

Spontaneous Intracranial Hypotension (Most Likely)

SIH classically presents with orthostatic headache (worse upright, better lying down), but rebound headache following treatment or certain presentations can reverse this pattern 1:

• Rebound headaches after epidural blood patch are characterized by reversal of orthostatic symptoms—relief upright, exacerbation when recumbent 1
• Headache location may shift from occipital to frontal, periorbital, or retroorbital 1
• Associated symptoms include nausea, vomiting, and blurry vision 1

However, untreated SIH typically worsens when upright, so if this is the first presentation without prior treatment, SIH is less likely unless the patient has developed complications 1.

Increased Intracranial Pressure (Critical to Exclude)

Headache that worsens when lying down or bending over suggests increased intracranial pressure from 2:

• Mass lesion (tumor, abscess)
• Cerebral venous thrombosis
• Idiopathic intracranial hypertension

Cerebral venous thrombosis can present with prolonged headache (weeks to months) followed by acute focal neurological deficits 3. SIH itself paradoxically increases risk of cerebral venous thrombosis due to venous stasis 1.

Vaccine-Induced Immune Thrombocytopenia and Thrombosis (VITT)

If the patient received COVID-19 vaccination 5-30 days prior, VITT must be considered 1:

• Presents with severe or unusual headache that worsens and doesn't respond to simple analgesics 1
• Unusual headache worse when lying down or bending over, possibly with blurred vision, nausea, vomiting, weakness, drowsiness, or seizures 1
• Cerebral vein thrombosis occurs in 50% of VITT cases 1

Immediate Diagnostic Workup

Neuroimaging (First Priority)

Brain MRI with contrast and whole spine MRI are the preferred initial studies 1, 2:

• Brain MRI detects diffuse smooth dural enhancement (seen in SIH), venous thrombosis, mass lesions, and hemorrhage 1
• Spine MRI identifies spinal longitudinal epidural collections (SLEC), which suggest ventral CSF leak 1
• If MRI unavailable, non-contrast head CT followed by CT venography to assess for thrombosis 2, 3

Laboratory Studies (If VITT Suspected)

Complete blood count to assess platelet count (thrombocytopenia defined as <150×10⁹/L) 1, 2:

• D-dimer level (>4000 μg/mL supports VITT diagnosis) 1
• Anti-PF4 antibody ELISA assay 1
• Coagulation studies (PT/INR, PTT) 2

Management Based on Diagnosis

If Spontaneous Intracranial Hypotension Confirmed

Conservative management initially 1:

• Bed rest, hydration, caffeine
• If conservative measures fail, epidural blood patch (EBP) is first-line treatment 1
• Following EBP, 2-24 hours bed rest with supine or Trendelenburg positioning for non-targeted patches 1
• Patients should lie flat as much as possible for 1-3 days post-procedure 1

If rebound headache develops post-treatment 1:

• Usually self-limited and managed conservatively
• Acetazolamide to lower CSF production
• Avoid repeat blood patch, which could worsen symptoms 1

If Cerebral Venous Thrombosis Confirmed

EBP should be prioritized as initial treatment of SIH with cerebral venous thrombosis, with consideration of anticoagulation 1:

• Balance risks of anticoagulation against thrombosis progression 1
• Symptomatic subdural hematomas with mass effect may require burr hole drainage 1

If VITT Confirmed

Immediate anticoagulation with non-heparin based anticoagulants and intravenous immunoglobulin 1:

• Start anticoagulation as soon as possible 1
• Report all cases urgently to appropriate authorities 1

Critical Red Flags Requiring Urgent Evaluation

Seek immediate neurological consultation if any of the following develop 1, 2:

• New-onset severe back or leg pain, lower limb motor weakness or sensory disturbance
• Urinary or fecal incontinence, urinary retention, perineal sensory disturbance
• Neurological deficits (weakness, sensory changes, visual disturbances)
• Seizures, altered mental status, or progressive worsening

Common Pitfalls

Do not assume primary headache disorder (migraine) without thorough evaluation 4, 3:

• Migraine typically improves when lying down, not worsens 1
• Side-locked unilateral headache with side shift is common in migraine; persistent same-side headache suggests structural cause 5, 6
• Physical activity aggravates migraine during attacks, but lying down typically provides relief 1

Do not delay neuroimaging in any patient with headache that worsens when lying down 2, 4:

• This pattern is atypical for primary headache disorders and suggests secondary cause
• The threshold for neuroimaging should be low, especially in patients over 50 4