What is the likely diagnosis for a patient presenting with neurological sensation events, head and intracranial pressure syndrome, neck-origin symptoms, and systemic complaints such as orthostatic intolerance, fatigue, and gastrointestinal disturbances?

Likely Diagnosis: Spontaneous Intracranial Hypotension (SIH) with Possible Comorbid POTS and/or hEDS/Hypermobility Spectrum Disorder

This constellation of symptoms—particularly the positional headaches worse when upright, intracranial pressure sensations, neck-origin symptoms, orthostatic intolerance, and multisystem involvement—is most consistent with spontaneous intracranial hypotension (SIH), potentially overlapping with postural orthostatic tachycardia syndrome (POTS) and hypermobile Ehlers-Danlos syndrome (hEDS) or hypermobility spectrum disorders (HSDs). 1, 2, 3

Primary Diagnostic Consideration: Spontaneous Intracranial Hypotension

Cardinal Features Present

• Positional headache pattern: The head/intracranial pressure symptoms that worsen with upright positioning and neck movements are pathognomonic for intracranial hypotension 1, 2
• Associated neurological symptoms: The waves of dizziness, lightheadedness, visual disturbances, and "brain swollen" feeling align with compensatory venodilation and downward traction on meninges and brain parenchyma that occurs with decreased CSF volume 1
• Neck-origin symptoms: Deep neck ache, positional symptom flares, and occipital/skull base headaches are characteristic of SIH due to meningeal traction 1, 2

Critical Diagnostic Workup Required

You must obtain MRI brain WITH IV contrast and MRI complete spine immediately to confirm intracranial hypotension features and localize the spinal CSF leak source 1, 2. Look specifically for:

• Diffuse pachymeningeal (dural) enhancement
• Cerebellar tonsillar descent
• Pituitary gland enlargement
• Obliteration of prepontine cisterns
• Spinal epidural fluid collections 2

Important Clinical Pitfall

Do not exclude SIH based on normal CSF opening pressure if obtained—clinical presentation and imaging findings are more important than measured CSF pressure, as 20-30% of SIH cases have normal pressure 1, 2

Secondary Diagnostic Consideration: POTS

Overlapping Features

• Orthostatic intolerance: The severe fatigue, lightheadedness, shakiness, and autonomic dysregulation strongly suggest POTS 4, 3
• Autonomic symptoms: Night sweats, chills, hot/cold swings, heartbeat felt in neck/head, and post-meal reactions are consistent with autonomic dysfunction 4, 3

Diagnostic Testing Required

Perform an active standing test: Measure heart rate and blood pressure supine, then at 1,3,5, and 10 minutes of standing 3. POTS diagnosis requires:

• Heart rate increase ≥40 bpm within 10 minutes (for adolescents/young adults) or ≥30 bpm (adults) 4, 3
• No significant blood pressure drop (to exclude orthostatic hypotension) 4, 3
• Reproduction of symptoms during standing 3

If active standing test is inconclusive but symptoms strongly suggest orthostatic intolerance, consider tilt-table testing 3

Tertiary Consideration: hEDS/Hypermobility Spectrum Disorder

Supporting Clinical Features

The multisystem involvement—particularly the combination of:

• Gastrointestinal symptoms (nausea, post-meal flares, possible food sensitivities) 4
• Peripheral neuropathy patterns (burning/tingling extremities) 4
• Neck hypermobility symptoms (cracking, locking, positional flares) 4
• Autonomic dysfunction 4

This triad of GI symptoms, POTS, and widespread pain/neuropathic symptoms is highly characteristic of hEDS/HSDs 4

Additional Evaluation

• Assess for joint hypermobility using Beighton score
• Consider mast cell activation syndrome (MCAS) given the episodic nature of symptoms, post-meal flares, flushing/temperature dysregulation, and multisystem involvement 4
• If MCAS suspected, obtain serum tryptase at baseline and 1-4 hours following symptom flares 4

Diagnostic Algorithm

Step 1: Immediate Imaging

Order MRI brain with IV contrast AND MRI complete spine with fluid-optimized sequences 1, 2

Step 2: Orthostatic Vital Signs

Perform active standing test with heart rate and blood pressure measurements at specified intervals 3

Step 3: Laboratory Evaluation

• Complete blood count (evaluate for anemia) 3
• Comprehensive metabolic panel (electrolytes, renal function) 3
• Thyroid function tests 3
• Iron studies including ferritin (iron deficiency common in POTS) 3
• ESR/CRP (if inflammatory process suspected) 3

Step 4: Cardiovascular Assessment

• 12-lead ECG to evaluate for conduction abnormalities 3
• Consider 24-hour Holter monitoring if arrhythmia suspected 3

Step 5: Specialized Testing if Initial Workup Supports Diagnosis

• If SIH confirmed: Early epidural blood patch is first-line treatment 1
• If POTS confirmed without SIH: Initiate volume expansion, salt supplementation, compression garments, and exercise reconditioning 3
• If hEDS/HSDs suspected: Refer to genetics and consider gastroenterology evaluation for GI symptoms 4

Critical Differential Diagnoses to Exclude

Cerebral venous thrombosis (CVT): This is a rare but life-threatening complication of SIH occurring in approximately 2% of cases 1. If SIH is confirmed and symptoms worsen or new focal neurological signs develop, obtain CT or MR venography urgently 1

Common Pitfalls to Avoid

1. Don't dismiss orthostatic symptoms as "just dehydration" or anxiety—these represent real autonomic dysfunction requiring specific evaluation 3
2. Don't order MRI brain without contrast—this is inadequate and will miss the dural enhancement pathognomonic for SIH 2
3. Don't measure standing vitals for only 1-2 minutes—delayed orthostatic changes require full 10-minute assessment 3
4. Don't assume a single diagnosis explains everything—these conditions frequently overlap, and 78% of patients with medically unexplained symptoms have multiple comorbid conditions 5

Management Implications

If SIH is confirmed, early epidural blood patch should be performed as soon as possible, with non-targeted EBP appropriate initially 1. For POTS, treatment focuses on volume expansion, increased salt intake (8-10g daily), compression garments, and graduated exercise reconditioning 3. For GI symptoms in the context of hEDS/POTS, management follows general DGBI principles with neuromodulators, prokinetics, and antiemetics as appropriate 4.

The "whole-body illness episodes" and catastrophic symptom flares suggest these conditions are significantly impacting quality of life and require urgent, comprehensive evaluation rather than piecemeal symptom management 4, 6.