Sx: pain, LMN findings in UEs, and UMN findings in LEs and a cape-likesensory loss (pain and temp-by damage to the spinothalamic fibers crossing in the anterior commisure)
A/w: Chiari I (90%), tumor, infection, trauma, idiopathic, Charcot shoulder
MoA:
Hydrodynamic Theory (Garder)
Occluded Foramen of Magendie / Luschka
CSF flows through obex --> central spinal canal
Cranial-Spinal Dissociation Theory (William)
Cyst formation: Injury --> liquefaction of cord/hematoma --> cyst/cavity --> differential pressure gradient btw intracranial and spinal space
Enlargement / extension of cyst/cavity:
Slosh: increased epidural venous pressure from valsalva felt more by cyst/cavity --> extension of syrinx
Suck: partial subarachnoid block: fluid slower on the way back down --> negative pressure in cyst/cavity
Olfield’s hypothesis: Valsalva moves CSF --> Virchow-Robin spaces --> syrinx. Spinal cord could be immobile b/c of adhesions
Tx:
If a/w Chiari --> decompression
If persistent & sx --> shunt (syringoperitoneal, syringopleural, syringosubarachnoid)
