Thursday, January 31, 2008

Retinal hemorrhages

Subhyaloid and preretinal hemorrhages
  • located on retinal surface
  • subhyaloid hemorrhage is located b/w the posterior vitreous base and the internal limiting membrane (ILM)
  • preretinal hemorrhage is located posterior to the ILM and anterior to the NFL
  • "boat-shaped" with sharp demarcation line
  • obscure retinal features
  • tend to clear quickly without any sequelae
  • associated with pathology affecting the major retinal vessels or superficial beds
  • most common etiology: retinal neovascularization
  • other etiologies: PVD, retinal breaks, associated with the tearing of a mjor retinal vessel
  • less common etiologies: Terson's syndrome, retinal trauma, valsava retinopathy

Flame-shaped hemorrhages (NFL hemorrhages)

  • located within the NFL
  • flame shape is the result of the structure of the NFL
  • typically located in the posterior pole
  • tend to resolve within a 6 weeks
  • associated with retinal vasculature pathology affecting the superficial and peripapillary capillary beds
  • etiology: hypertensive retinopathy (AV nicking present), retinal vein occlusions, optic neuropathy (papilledema, NTG, anterior ischemic optic neuropathy)
  • Roth spot = flame-shaped hemorrhage that has a white or pale center; represent non-specific signs of blood dyscrasias (anemia/thrombocytopenia, anoxia, AV malformation, bacterial endocarditis, collagen vascular disease, diabetic retinopathy, HIV, HTN retinopathy, leukemia, multiple myeloma, trauma)

Dot-and-blot hemorrhages

  • located in the retina's inner nuclear and outer plexiform layers
  • configuration is due to intraretinal compression
  • take longer to resolve because they're deeper than flame-shaped hemorrhages
  • commonly associated with microvascular signs of edema
  • etiology: pathology affecting the prevenular capillaries -- diabetic retinopathy, idiopathic juxtafoveal retinal telangiectassis, vein occlusion and OIS
  • OIS: vascular insufficiency associated with carotid artery disease leads to ocular hypoperfusion --> not enough pressure to push blood from retinal arterioles to the venules --> increased capillary congestion results in a breakdown of the capilary walls with subsquent hemorrhage and edema --> venules attempt to compensate for the decreased blood flow by distending, giving them a dilated, but non-tortuous appearance

Subretina and subretinal pigment epithelium (RPE) hemorrhages:

  • located beneath the neurosensory retina and the RPE
  • sub-RPE hemorrhages are located b/w the RPE and Bruch's
  • exhibit a dark coloration with the retinal vessels clearly visible above
  • tend to have an amorphous shape, due to the absence of firm attachments b/w the neursensory retina and RPE, allowing the blood to spread
  • sub-RPE hemorrhages have well-defined borders attributed to the tight cell junctions among RPE
  • may be associated with neurosensory or RPE detachments in the posterior pole
  • tend to resolve slowly
  • may be associated with the functional and/or structural changes at the level of the photoreceptors (therefore, unfavorable prognosis)
  • most common etiology: CNV
  • other etiologies: choroidal tumors, trauma, retinal angiomatous proliferation
  • referal to a retinologist

Management

  • referral if needed
  • patients without systemic history need medical work-up (most common etiologies: HTN, DM; other: clotting disorders such as hemophilia or patients on warfarin)
  • fasting plasma glucose test (<100> 126 is indicative for diabetes)
  • HbA1c (normal <5%)
  • CBC with white cell differential (test for anemias, polycythemias, bleeding disorders, leukemias, infections)
  • prothrombin time (PT) and international normalized ratio (INR) -- evaluates clotting factors
  • OIS: work-up of above plus heart echo, carotid USG and/or Doppler color imaging to rule-out carotid or heart disease
  • in older patients (>60) -- ESR & C-reactive protein & temporal artery biopsy to confirm
  • in younger patients (18-40) -- at risk for blood dyscrasias, diabetes, HTN, hyperlipidemia -- obtain a serum lipid profile, consider antiphospholipid and anticardiolipin enzymes to determine whether they have antiphospholipid syndrome; ANA or double-stranded DNA testing to r/o Lupus; ANA & ESR screening test for autoimmune diseases and inflammatory conditions
  • other tests: HLA-B51, HLA-B27, HLA-B5, ELISA, Western-blot specific testing for HIV, Lyme disease, toxoplasmosis, tuberculosis
  • other tests: FTA-Abs and RpR to r/o syphilis
  • other tests: blood cultures to identify widespread infection (speticemia)

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