Diabetes (Pathology) Flashcards
What is diabetes?
disorder of metabolism (carbs, proteins, fats)
due to absolute/relative deficiency in insulin
hyperglycemia
clinical features of Diabetes?
Polyuria
polydypsia
polyphagia
diabetes mellitus?
“sweet urine”
MC non-communicable disease
shortens lifespan by 15 years
leading cause of blindness, kidney disease
cells in normal pancreatic islet?
a cells (glucagon) B cells (insulin)
action of insulin?
transmembrane transport of glucose
insulin action on liver, muscle, fat?
– blood glucose
insulin’s action on liver and skeletal muscle?
++ glucose in blood
blood glucose and other hormone actions
insulin - glucocortidoids + glucagon + growth hormone + epinephrine +
insulin required tissue for uptake of glucose?
striated muscle
cardiac muscle
fibroblasts
fat
non-insulin required tissue for glucose uptake?
red cells
nerves
kidney
eye lens
pathology of diabetes?
low glucose inside cell –> low metabolism
high glucose outside cell –> glycosylation damage, osmotic damage
classes of Primary DM?
I - IDDM/juvenile 10%
II - NIDDM - adult 80%
MODY 5% maturity/genetic
gestational DM
Pathogenesis of Type I DM?
genetic (HLA-DR3/4) environmental Ab to B cells (autoimmune insulitis) B cell destruction insulin def
pathogenesis of Type II DM?
genetic/B cell defect
obesity/life style
abnormal insulin secretion/end organ resistance
relative insulin def
Type I DM
general features
Less common Children < 25 Years Insulin- Dependent Duration: Weeks Acute Metabolic complications Autoantibody No FHx Insulin levels: very low Islets: Insulitis 50% in twins
Type II DM
general features
More common Adult >25 Years Insulin Independent * Months to years Chronic Vascular complications. No Ab Yes FHx Normal or high * insulin islets - Normal / Exhaustion 60-80% in twins
Short term Complications: (metabolic)
Hypoglycemia
Diabetic Ketoacidosis
Non Ketotic hyperosmolar diabetic coma
Lactic acidosis
Long term Complications: (Angiopathy)
microangiopathy - Retinopathy, Nephropathy, Neurophathy, dermatopathy
Macroangiopathy – Atherosclerosis
What will you see diabetic microangiopathy?
Glucose Glycosylation BM damage leak AGE = advanced glication end products Narrow lumen Ischemic Organ damage
What will you see in Diabetic neuropathy?
Sensory –> Motor (myelin)
1. Peripheral Neuropathy (Bilateral, symmetric, Progressive, irreversible, Paraesthesia, pain, Muscle atrophy, claw foot, muscle wasting)
- Visceral neuropathy (Cranial nerve – 4 diplopia, 7 Bell palsy, GIT- constipation, diarrhoea, CVS – orthostatic hypotension)
Features of Neuropathic ulcers?
Painless surrounded by callus pressure points may not be associated with gangrene good foot pulses
What do you see in DM retinopathy?
non-proliferative
proliferative
Non-proliferative retinopathy?
Microaneurysms Dot-blot hemorrhages Hard/soft exudates Cotton wool – infarcts Macular edema
Proliferative retinopathy?
Neovascularization
Large hemorrhages
Retinal detachment
