0071643192.pdf

■ Infection/abscess
■ Headache/backache
■ Late onset of epidermoid tumors of the thecal sac

INTERPRETATION OFRESULTS

■ Normal opening pressure (accurate in lateral decubitus position)
■ 60 – 200 mm H 2 O (6–20 cm H 2 0) in adults
■ 10–100 mm H 2 O in children <8 years old
■ 30–60 mm H 2 O in neonates
■ Low OP = CSF leak, dehydration.
■ High OP = overproduction, infection, bleeding, tumor, falsely ele-
vated with sitting position/valsalva/crying.
■ Normal color = clear.
■ Xanthochromia/yellow = seen in SAH, hyperbilirubinemia.
■ Cells
■ Normal WBC = <5 cells/mm^3 in adults with <3 PMN/mm^3 , <20 cells/
mm^3 in neonates with < 1 PMN/mm^3.
■ Elevated WBC = bacterial/fungal infection, leukemia, vasculitis.
■ PMN predominance = bacterial infection.
■ Normal RBC = < 10 cells/mm^3.
■ Elevated RBC = SAH, traumatic tap.
■ Normal glucose = 45–80 mg/dL.
■ Decreased in bacterial/TB meningitis or CNS tumors
■ Normal protein = <45 mg/dL in adults, <20 mg/dL in children.
■ Increased in bacterial/TB meningitis, blood (SAH or traumatic taps),
multiple sclerosis, and Guillain-Barré syndrome
■ Miscellaneous
■ India ink = cryptococcus.
■ VDRL/RPR = neurosyphilis.
■ PCR for HSV or CMV infections

A patient with a history of hydrocephalus presents with headache. What

imaging tests do you order? How do you evaluate shunt function?

Radiologic shunt series and head CT. Compress shunt to confirm nor-

mal flow. Perform LP or tap shunt if any sign of infection.

Ventriculoperitoneal (VP) Shunt Evaluation

ETIOLOGY

■ Obstruction is the most common cause of shunt malfunction. Presenting
symptoms may be nonspecific (nausea, change in behavior). Proximal
obstructions, often from choroid plexus within the catheter, are more com-
mon than distal obstructions. Distal obstruction of VP shunts may be due
to thrombus.
■ About 8% of VP shunts become infected. The infection most often
results from ulceration of the skin overlying the valve. Skin organisms
(Staphylococcus epidermidisandS. aureus) are the most common bacte-
ria isolated.

INDICATIONS

■ To evaluate cause of shunt malfunction
■ To evaluate cause of increased ICP in a VP shunt patient

PROCEDURES AND SKILLS

Both multiple sclerosis and

Guillain-Barré syndrome can

raise CSF protein levels.