Test 1: Diabetes Flashcards
etiology of diabetes
incidence is higher in Hispanics and African americans
type 1 diabetes
5-10%
characterized by destruction or loss of function of the insulin producing pancreatic beta cells resulting in absolute dependence on exogenous insulin to prevent hyperglycemia and ketoacidosis
inherited/genetic component
formerly called insulin dependent or juvenile diabetes
two forms of type 1
immune mediated disease
idiopathic-more common in African and Asian populations
most patients with type 1 DM demonstrates classic signs of
polyuria
polydipsia
polyphagia
unexplained weight loss
patients commonly present with diabetic ketoacidosis
patients with T1 DM should have dilated eye exam within 3-5 years of dx
type 2 DM
90-95%
caused by relative insulin deficiency, either the body doesn’t produce enough insulin or the body can’t use the insulin it makes effectively (insulin resistance)
formerly termed non-insulin dependent or adult onset diabetes
people diagnosed with T2 DM should have dilated retinal examination
pts typically undiagnosed for 5-8 years
pre-diabetes
when blood glucose levels don’t meet the criteria for diabetes but are higher than normal levels
persons with pre-diabetes have: impaired glucose tolerance (IGT), impaired fasting glucose (IFG) levels, an A1C test level between 5.7% and 6.4%
currently pre-diabetes, IGT and IFG aren’t billable reasons or dilated retinal exam
gestational diabetes
5-10% of pregnancies
gestational diabetes any degree of glucose intolerance with onset or first diagnosis during pregnancy
GDM is caused by the hormones secreted during pregnancy or by a shortage of insulin
more common in black, hispanic, and american indian women, as well as women who are obese or have a family history of type 2
onset of GDM is usually during 2nd or 3rd trimester, glucose tolerance typically returns to normal within 6 weeks postpartum
due to short duration of GDM, DR doesn’t usually occur hx of GDM increased the risk of developing type 2 in the next 10-20 years by 35-60%
other types of diabetes
1-5%
diabetes can also occur secondary to genetic defects n beta cell function or insulin action, pancreatic diseases or other endocrinopathies, medications (steroids), toxic chemicals, infections, or uncommon forms of immune mediated diabetes
DM diagnosis based on
plasma glucose criteria or A1C criteria FPG >/= 126 2-h PG >/= 200 random plasma glucose >/= 200 A1C >/= 6.5%
therapeutic principles of T2 DM meds
individualized treatment ask the patient what their target A1C is
14 step algorithm - use meds that minimize the risk of hypoglycemia, minimize weight gain, considers the starting A1C levels and lifestyle factors (including cost)
clinical diabetic exam
careful VA and refraction if needed
carful pupils and EOMs
slit lamp exam with gonio when appropriate
dilated fundus exam
check blood pressure
if BVA reduced - consider OCT to evaluate for the presence and extent of DME, consider IVFA to detect areas of non-perfusion including foveal ischemia and/or subclinical neo
ocular complications of DM
transient refractive shifts - data is mixed but both hyperopic shifts seem to be more common in hyperglycemia
cornea - decreased sensitivity and increased risk of abrasions, caused by reduced adhesion of corneal epithelium to stroma
lens - cataracts occur more often and younger, caused by osmotic stress from intracellular accumulation of sorbitol in the lens secondary to elevated intraocular glucose
other complications of DM
EOM palsy: neuropathy of CN 3, 4, 6, likely caused by localized demyelination of the nerve due to ischemia, can be first manifestation of DM, usual recovery 1-3 months
optic neuropathy: increased risk of subclinical neuropathy, anterior ischemic optic neuropathy and diabetic papillopathy
diabetic papillopathy: disc edema without pallor, bilateral 50% doesn’t always have APD, can occur with macular edema, VA usually recovers to 20/50
glaucoma: uncertain association with POAG, increased risk of NVG with PDR
diabetic retinopathy
the most common microvascular complication of diabetes
the leading cause of new cases of blindness and low vision among americans 20-74
diabetic retinopathy accounts for ~12% of all new cases of blindness each year
the strongest predictor for the development of DR is duration of disease
grading systems of DR
- ETDRS - one of the major outcomes was a standardized grading system of the different levels of DR, some argue the ETDRS scale is overly complicated and not practical for clinical practice
- international grading is a simplified system that is commonly used
NPDR characterized by the presence of
hemorrhages and/or micro aneurysms hard exudates soft exudates CWS IRMA venous beading
characteristics of PDR
new vessels on or within 1 DD of disc (NVD)
new vessels elsewhere on the retina but not on or within one DD of the optic disc NVE
fibrous proliferation on or within 1 DD of the optic disc FPD or elsewhere on the retina FPE
pre retinal hemorrhage
vitreous hemorrhage
CSME
retinal thickening = 500 um from the center of the macula
HE = um of the center of the macula with thickening of the adjacent retina
an area of retinal thickening >/= DA of which any portion is within = DA from the center of the macula
diabetes and pregnancy
the main risk factor of DR worsening during pregnancy is the baseline severity of DR
women with pre existing diabetes who are planning or become pregnant should have a dilated retinal exam to a planned pregnancy or during the first trimester, with f/u during each trimester of pregnancy
pts with GDM don’t develop retinopathy therefore retinal evaluation for DR in these patients is not indicated
recommend exams in DR pregnancy
gestational - none no to minimal NPDR - 1st & 3rd tris mild to mod NPDR - every try high risk NPDR - monthly PDR - monthly - treat
treatment of DR and DME
laser photocoagulation: focal laser, grid laser, pan retinal photocoagulation used for severe NPDR and PDR
intravitreal injections - used for neo and DME, steroid triamcinolone, anti-vegfs
intravitreal implants
vitrectomy - used for non clearing VH, traction RD, combo retinal detachment, macular pucker
peripheral retinal cryotherapy: can be used for high risk complications in eyes with hazy media that prevents PRP, rarely used because of accelerated traction detachment
laser photocoagulation focal treatment
ETDRS established as standard treatment for CSME
a focal laser pattern is used to photocoagulative discrete leaking micro aneurysms identified with a prior FA