Grand Rounds Vanderbilt Eye Institute by BH3fJP

VIEWS: 6 PAGES: 39

									   Grand Rounds
Vanderbilt Eye Institute
      12/15/06




    Ryan Tarantola M.D. PGY-2
          Initial Evaluation 10/18/06
CC: Elevated IOP OS

HPI:
• 69 yo Female
• POAG x 10 yrs
• Treated with gtt and ALT OU
• IOP OS has been poorly controlled
• Red eyes OS>OD for many years
• Referred by outside ophthalmologist for
  possible filtering procedure.
POH: POAG
     S/P ALT OU
     No history of trauma or steroid exposure


Allergies: NKDA


FH: No hx of eye disease
SH: Denies tobacco, alcohol, or drug use.


ROS: Negative


Meds: Lumigan OU QHS
      Azopt OU BID
VAcc at Distance: OD: 20/25
                  OS: 20/25

Pupils: 42mm, no RAPD OU

TA: OD: 19
    OS: 26

Visual Fields: FTFC OU

Motility: Full OU
OD
OS
Slit Lamp Exam:


External: WNL OU


Lids/Lashes: Clear OU


Conjunctiva: Engorged episcleral veins OS>OD
Slit Lamp Exam cont.:


Cornea: Clear OU


AC: D/Q OU


Lens: 2+ NSC OU
Slit Lamp Exam cont.:


Gonioscopy: Open to SS/CBB 360 degrees OU
            No PAS/NV
            Blood in Schlemm's canal OS


Pachymetry: OD:599
            OS:600
Dilated Fundus Exam:

Vitreous: Clear OU

Optic Nerves: C/D: OD:0.5 OS:0.6
              Small nerves OU
              Thin inferiorly OS>OD

Macula: WNL OU

Periphery: WNL OU
Questions?
                  Goldmann Equation



IOP=F/C + Pe

• F=Rate of Aqueous Formation (normally 2-3 µl/min)

• C=Facility of Outflow (normally 0.2 to 0.3 µl/min/mmHg)

• Pe=Episcleral venous pressure (normally 8 to 10 mmHg)
      Three Routes of Orbital Venous Drainage

                       1. Superior Ophthalmic Vein

  Schlemm’s Canal           Cavernous Sinus

                         Internal Jugular Vein
Deep and Mid Scleral
Venous plexus             Superior Vena Cava         Anastamose

                       2. Inferior Ophthalmic Vein

                           Pterygoid Plexus


                       3. Facial and Angular Vein

                          External Jugular Vein
                  Orbital Venous Drainage


Supraorbital v.

 Nasofronal v.
                                            Sup. Ophthalmic v.



      Nasal v.

                                            Cavernous sinus
                                            Inf. Ophthalmic v.
    Angular v.


                                            Infaorbital v.
 Ant. Facial v.                             Pterygoid plexus
• 69 yo female with previous diagnosis of POAG

• Elevated IOP OS>OD

• Engorged episcleral veins OS>OD

• Blood in Schlemm’s canal OS

          Differential Diagnosis?
                 Differential Diagnosis
1. Venous Obstruction
   a. Thyroid Ophthalmopathy
   b. Superior Vena Cava Syndrome
   c. Retrobulbar Tumor
   d. Cavernous Sinus or Orbital Vein Thrombosis
   e. Episcleral or Orbital Vein Vasculitis

2. Arteriovenous Anomalies
   a. Carotid-Cavernous Fistula
   b. Carotid-Dural Fistula
   c. Sturge Weber Glaucoma
   d. Orbital Varix

3. Idiopathic
                Additional History



• Despite 360o ALT OU and maximal medical
 therapy IOP has never been significantly lowered


• Patient reports that she has experienced
 episodic tinnitus in the left ear
Additional Testing?
                     Additional Testing

Hertel: Base 96mm
       OD:16mm
       OS:17mm

Auscultation: No orbital bruit appreciated

Cerebral Angiogram:
• Unremarkable anterior and posterior intracranial circulation.
• No evidence of carotid cavernous fistula
• No evidence of flow-limiting stenosis, aneurysm, occlusion, or
  malformation.
 Idiopathic Elevated Episcleral Venous Pressure

Presentation:

• Typically presents in elderly with no FH

• Most cases are unilateral

• Familial cases have been reported but typically sporadic

• Often have previous diagnosis of POAG

• Often complain of red eye
 Idiopathic Elevated Episcleral Venous Pressure

Signs/Symptoms:

• Elevated IOP despite medical therapy

• Tortuous dilated episcleral veins

• Open-angle glaucoma with characteristic nerve and fields

• Blood in Schlemm’s canal on gonioscopy

• No exophthalmos

• Ruled out other etiologies of increased EVP
 Idiopathic Elevated Episcleral Venous Pressure

Diagnostic Testing:
Orbital ultrasound/MRI: Evaluate retrobulbar space

MRA: Detect carotid-cavernous or dural-cavernous fistula

Carotid Angiography: Gold standard to rule out fistula

Endocrine workup: Evaluated for Thyroid eye disease

Hertel: Detect exophthalmos

Auscultation: Detect orbital bruit
    Idiopathic Elevated Episcleral Venous Pressure

Management:
1. Medical:
                   b-blockers
                   a2 agonists
                   Carbonic Anhydrase inhibitors

2. Surgical:
                   Trabeculectomy
                   Tube Shunt
                   Nonpenetrating deep sclerectomy


•    Increased risk of uveal effusion and expulsive hemorrhage

•    Recommended that prophylactic sclerotomies be routinely performed during surgery
                      Our Patient

Follow up visit 10/26/06:

IOP OD:22 OS:30

Follow up 11/15/06:

IOP OD:22 OS:34

Elected to proceed with ExPRESS mini glaucoma
shunt procedure.
             ExPRESS Mini Glaucoma Shunt




• Biocompatible miniature stainless steel implant

• Previously placed directly beneath conjunctiva but caused many
  complications

• In newer technique shunt is placed beneath a scleral flap

• Diverts aqueous humor to a subconjunctival filtration bleb
A 6 × 3 mm fornix-based conjunctival flap is created in the upper quadrant.
A 50% depth, 5 × 5 mm limbal-based scleral flap is created. Mitomycin C
may be applied beneath the flap at the surgeons discretion
With a 26-gauge needle, a pre-perforation is made into the anterior chamber under the
scleral flap, in the center of the blue-gray transition zone between the white sclera and
clear cornea.
The glaucoma drain is inserted into the anterior chamber via the perforation site.
The scleral flap is then securely sutured with 10-0 nylon sutures.
The conjunctiva is sutured back in place with 1 or 2 buried 8/0 absorbable sutures.
                      ExPRESS Mini Glaucoma Shunt


   • Ex-PRESS implant inserted in 24 eyes of 23 patients with severe OAG

   • Sixteen eyes of the 24 (66%) had had previous failed filtering surgery

   • Remaining 8 eyes (33%) were high risk for failures cases

   • IOP was reduced from 27.2 ± 7.1 mm Hg pre-op to:
     14.5 ± 5.0 mm Hg at 12 months (n = 21)
     14.2 ± 4.2 mm Hg at 24 months (n = 8)

   • Two patients needed anti-glaucoma meds to keep IOP below 21 mm Hg




Dahan et. al. Implantation of a Miniature Glaucoma Device Under a Scleral Flap. Journal of Glaucoma. April 2005.
14(2):98-102.
                      ExPRESS Mini Glaucoma Shunt




Dahan et. al. Implantation of a Miniature Glaucoma Device Under a Scleral Flap. Journal of Glaucoma. April 2005.
14(2):98-102.
                      ExPRESS Mini Glaucoma Shunt




Dahan et. al. Implantation of a Miniature Glaucoma Device Under a Scleral Flap. Journal of Glaucoma. April 2005.
14(2):98-102.
                          Take Home Points


•Understand the venous drainage of the orbit and how abnormalities can result
 in elevated EVP and thus elevated IOP.

•Be suspicious of elevated EVP in patients previously diagnosed with POAG.

• Know the possible causes of elevated EVP and how to evaluate for each.

• Be aware that the ExPRESS mini glaucoma shunt is a new procedure that
  appears to be safe and effective at lowering IOP in Glaucoma patients when
  placed beneath a scleral flap.
                                  References
1. Allingham et al. Shields’ Textbook of Glaucoma p.347-352

2. Clayton et al. CT angiography and MR angiography in the Evaluation of Carotid
   Cavernous Sinus Fistula Prior to Embolization: A Comparison of Techniques. Am J
   Neuroradiol. 26:2349-2356. October 2005.

3. Dahan et al. Implantation of a Miniature Glaucoma Device under a Scleral Flap. J
   Glaucoma 2005;14:98-102.

4. Greenfield et al. Glaucoma associated with elevated episcleral venous pressure.
   J Glaucoma 2000 9:190-194.

5. John et al. Dural and Carotid Cavernous Sinus Fistulas. Ophthalmology 94:1585-
   1600.

6. Moses et al. Mechanism of Glaucoma secondary to increased venous pressure.
   Arch Ophthalmol. 1985;103:1701.

7. Talusan et al. Increased Pressure of dilated episcleral veins with open-angle
   glaucoma without exophthalmos. Ophthalmology 1983;90:257.

								
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