Synonyms:
a.k.a. sinking brain syndrome a.k.a. Spontaneous CSF leak
Diagnosis:
Clinical:
- Orthostatic headache a.k.a. postural headache (improves on lying down):
- Worsened by standing in <15 minutes
- Associated symptoms: tinnitus, hypacusia, photophobia, nausea, neck stiffness
- May present with thunderclap headache
- Later stages: drowsiness, coma
- No history of dural puncture or LP
MRI:
- Postcontrast: enhancement of thickened dura i.e. Pachymeningeal enhancement.
- Brain sagging (effacement of the suprasellar cistern, bowing of the optic chiasm over the pituitary fossa, flattening of the pons against the clivus and obliteration of the prepontine cistern) & pseudo-Chiari malformation (hindbrain herniation)
- Dilation of veins & venous sinuses. Subdural fluid collections.
- Also enlarged pituitary gland, dilation of the spinal peridural plexus
If with nasal discharge:
- Test for Beta 2 Transferrin by immunofixation, present in CSF
Lumbar Puncture, LP:
- Low opening pressure (<6 cmH2O) or dry tap
- Protein: usually high,
- Pleocytosis: occurs
- Xanthochromia may occur
CT myelography:
- Study of choice for defining the leak
- Myelography with water-soluble contrast followed by CT scan
Radionuclide cisternography:
- 111 Indium-diethylenetriamine pentaacetic acid
- Not as sensitive as CT myelography
Meningeal biopsy:
- A thin layer of fibroblasts in the subdural zone
- Small thin-walled dilated blood vessels
- No evidence of inflammation
- Meningeal fibrosis in longstanding cases
Treatment:
Epidural blood patch 20mL. [312] This may be repeated 20-100mL.