Chapter 29 - CSF Leak, Encephalocele

Question 1

Most common site of CSF leak from FESS

Answer 1

lateral lamella cribiform

Question 2

Causes of CSF leak

Answer 2

Trauma. 1-3% of acute head injuries, 
Surgery (FESS, neuro)
Tumor
Congenital (foramen cecum 50%)
Spontaneous

Question 3

IIH: Presentation, PE

Answer 3

Decreased CSF Reabsorb
obese middle age female, pressure HA, pulsatile tinnitus, balance dysfxn, diplopia
Bilateral optic disk edema (papilledema)
Empty sella (flat pituitary, sella appears CSF filled)

Question 4

Conservative tx for CSF leak: success, meningitis

Answer 4

70% resolve

7-30% risk ascending meningitis

Question 5

IIH: Tx

Answer 5

Acetazolamide, Furosemide
For HA: propranolol, amitryptilene
Surgery for vision issues - optic n decompress, CSF shunt

Question 6

Meningoencephalocystocele

Answer 6

Meninges and brain herniate through defect, communicates with ventricle

Question 7

How many encephaloceles occur in cranium and nasal cavity

Answer 7

20% cranium, of these, 15% nasal cavity

Question 8

Sincipital vs basal encephaloceles

Answer 8

Sinc: Ant/Sup, 60%, soft compressible mass over glabella
Bas: more posterior. 40%. May be hidden longer.

Question 9

PE findings encephalocele

Answer 9

transilluminate
expand with valsalva, with compress IJVs (Furstenberg)
broad dorsum, hypertelorism

Question 10

CSF volumes (per hour, day, total circulating)

Answer 10

20cc/hr
350-500/d
90-150cc circulating (turns over 3-5x/day)

Question 11

Typical ICP

Answer 11

5-15cm H2O (elevated if >15, but kids can have NL up to 26)

Question 12

How to exacerbate drainage from CSF leak

Answer 12

Dandy maneuver - tilt head forward into chin-tuck, and strain

Question 13

Two CSF leak tests

Answer 13

B2 transferrin: need 0.2ml, 97% sense, 93% spec, in CSF, perilymph, aqueous humor
B-trace protein - newer, more sense/spec, faster

Question 14

False + B2 transferrin test

Answer 14

Liver dz (abnormal transferrin metabolism), glycogen metabolic dz, carcinoma
Must verify + test with neg serum B2 transferrin

Question 15

Finding source of CSF leak

Answer 15

Fine cut Maxillofacial CT sense 92%, spec 96%
CT cisternogram active sense 92%, inactive 40%
MRI cisternogram: neoplasm, meningoencephalocele, encephalocele, iodine allergy

Question 16

Conservative vs Surgical CSF repair

Answer 16

Conservative: if single, <1cm, NL ICP

Question 17

If high clinical suspicion and negative 2 transf and CT, what next?

Answer 17

Surgical exploration, may use intrathecal fluorescein

Question 18

Conservative Tx CSF leak

Answer 18

bed rest, HOB elevation, lumbar drain CSF 5-10d

Question 19

When to use Abx during conservative CSF leak Tx

Answer 19

Very large defect, comminuted bone of SB

Question 20

Infection rate overall for simple CSF leak

Do prophy ABx decrease risk?

Answer 20

7% (meningitis, IC abscess, osteomyelitis), doesn’t decrease with prophylactic ABx

Question 21

ABx after endoscopic repair of CSF leak

Answer 21

1-2d

Cefazolin 1gm q8, Vanc 1g q12, or Clinday 600mg q8

Question 22

Adv/Disadv to intrathecal fluorescein

Answer 22

Adv: 0% false + rate
Disadv: moderate false neg, 0.3% seizures, can’t use if renal dz
Must inject slowly. 0.05-0.1 mL/10kg. 10% fluorescein

Question 23

How to reconstruct skull base

Answer 23

-<1cm: fat plug earlobe/abdomen
-overlay from nasal floor mucosa, turbinate, septum
-underlay bone/cartilage, overlay mucosa (free or pedicled)
Pedicled: NSF
Other flaps: temporalis, TFL

Question 24

Endoscopic vs Open repair

Answer 24

Endoscopic: 90+% success rate
Open: 70-80% success, more morbid