Distinguishing features of alternative diagnoses that occasionally mimic spontaneous intracranial hypotension
| Distinguishing Features | SIH | |
|---|---|---|
| Radiologic mimickers | ||
| Chiari type I malformation | Cerebellar tonsils inferiorly pointed Midbrain descent absent | Normal cerebellar tonsil shape Midbrain descent present |
| Subdural fluid collections | Usually unilateral | Usually bilateral Brain sag and focal dural enhancement |
| Conditions with dural thickening (IgG4-related disease, neurosarcoidosis, tuberculosis, autoimmune diseases, infectious diseases) | Focal or diffuse May have leptomeningeal involvement, skull base prominence, hypertrophic pachymeningitis Usually systemic symptoms and involvement of other organs | Diffuse, non-nodular dural thickening and enhancement |
| Clinical mimickers | ||
| POTS | Increased heart rate with minimal change in blood pressure on standing from a seated or supine position | Stable heart rate with postural changes |
| Orthostatic hypotension | Autonomic failure, medication effect, hypovolemia Fall in systolic (20 mm Hg) and/or diastolic (10 mm Hg) blood pressure on standing from a seated or supine position | Stable blood pressure with postural changes |
| Cervicogenic headache | Headache with neck pain that worsens with cervical motion, relieved with medication | Pain is typically centered in the head and not worsened by cervical motion or improved with medications |
| Vestibular migraine | Vertigo, unilateral headache, nystagmus, presence of aura, history of migraine | Hearing changes and tinnitus more than vertigo or nystagmus |