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Diabetic Retinopathy in Pregnancy

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					       Diabetic Retinopathy
              in Pregnancy


Chukwuma I. Onyeije, M.D.
  Director of Education
   Lenox Hill Hospital
                 Scope of the Problem

• 6% of American public has diabetes
• Only one half have been diagnosed
• 150,000 deaths per year from diabetes
  related complications
• 12,000 people lose their sight each year due
  to diabetes
                 Scope of the Problem

• Diabetic retinopathy is the leading cause of
  blindness in women between the ages of 24
  and 65.
Other Ocular
Manifestations of Diabetes

•   Senile cataracts
•   Transient cataracts
•   Rubeosis iridis
•   Glaucoma
                                    Anatomy of the Eye
• Pupil
  – Regulates the entry of light
  – Constrictor pupilae
  – Dilator pupilae

• Lens
• Vitreous Humor
  – 99% Water
  – Also contains hyaluronic acid
    and collagen

• Retina
Anatomy of the Eye
   • The Retina
     – Innermost layer of the
       eyeball
     – Posterior portion is
       photosensitive
     – Anterior portion is not
       photosensitive
     – Composed of a chain
       of three neurons in
       ten layers
             Classification of Diabetic
                           Retinopathy

• Background Retinopathy
  – Earliest lesion              Nonproliferative Diabetic
                                 Retinopathy (NPDR)


• Preproliferative Retinopathy
  – Ischemic Lesions                 Proliferative Diabetic
                                     Retinopathy (PDR)
• Proliferative Retinopathy
  – Neovascularization
                Background Retinopathy

• First lesion of diabetic retinopathy seen
  with an opthalmoscope
• Retinal microaneurysms
  – Outpouching of retinal capillaries appear as red dots
  – Can be seen as early as two years after the onset of IDDM

• Blot hemorrhages
• Hard exudates
Background Retinopathy
       Preproliferative Retinopathy

• Lesions related to ischemia
• Cotton wool spots
  – Infarcted areas of the nerve fiber layer
• Venous bleeding and duplication
  – Dilated veins with irregular caliber
• Intraretinal microvascular abnormalities
  – Earliest signs of neovascularization
  – Caused with shunt and collateral vessel formation
Preproliferative Retinopathy
Preproliferative Retinopathy
           Proliferative Retinopathy

• Growth of abnormal blood vessels
• Retinal neovascularization is likely
  stimulated by retinal ischemia
• Untreated neovascular proliferation may
  lead to vitreous hemorrhage and retinal
  detachment
         Neovascularization in
      Proliferative Retinopathy

NVD   Neovascularization of the disc
      BAD Prognosis


NVE   Neovascularization elsewhere
      Prognosis is not as bad
                Severity and Duration

• Microaneurysms as early as two years after
  onset of IDDM
• After 15 years- 98% of patients will have at
  least background retinopathy
• After 25 years- virtually 100% of patients
  will have some form or retinopathy
               Severity and Duration


• Negligible risk of retinopathy in women
  with gestational diabetes

• Minimal risk of retinopathy in women with
  IDDM for less than 5 years
Diabetic Retinopathy is no longer
a contraindication to pregnancy
                       Pathophysiology

• Primary etiologic factor: Chronic
  hyperglycemia producing microvascular
  lesions.
• Structural changes are identical in both
  pregnant and non-pregnant patients
                             Pathophysiology

            The Paradox of Diabetes:

Lack of intracellular glucose for glycolysis in
   spite of excessive glucose in the serum

(Insufficient glucose transport in the absence of insulin)
                       The Polyol Pathway
•   Activated by excessive extracellular glucose
•   Minimal activity in euglycemic patients
•   Aldose reductase converts glucose to D-sorbitol
•   Sorbitol is converted into D-fructose
•   D-sorbitol and D-fructose are trapped intracellularly
•   Intracellular polyol sugars increase osmotic gradient
•   Osmotic insult causes thickening of the basement
    membrane and cellular damage
                     The Polyol Pathway
• Prolonged activation of the polyol pathway leads
  to pericyte death from osmotic damage
• Pericyte loss leads to weakening of the capillary
  wall
• Weakened capillary walls cause microaneurysm
  and closure
• New blood vessels bud in areas of pericyte
  deterioration… setting the stage for
  neovascularization
Therapy for Diabetic Retinopathy

• Laser photocoagulation is now the standard
  of care
• Reduces the risk of severe visual loss by
  50% compared to no treatment
• Mechanism of action not clearly understood
  – Photocoagulation may reduce the level of Vascular
    Endothelial Growth Factor (VEGF) elaborated by the
    peripheral, poorly perfused retina

• SAFE IN PREGNANCY
               Management of Diabetic
                         Retinopathy

• Pre-pregnancy counseling
• Planned pregnancy
• Opthalmologic protocol
  – Baseline exam by retinal specialist at the beginning of
    pregnancy
  – Patients with minimal disease: re-examination every
    trimester and 3 to 6 months postpartum
  – Monthly follow-up for severe NPDR or early PDR
  – Closer follow-up of patients with minimal disease and
    proteinuria, hypertension or nephropathy.
             Controversies

• Does retinopathy “worsen” in pregnancy?

• Is rapid glycemic control dangerous?

• Retinopathy and the valsalva maneuver?

• Impact of hypertension on retinopathy.