Handwritten Video Lecture on the Pathophysiology, Symptoms and Management of Diabetic Nephropathy for the USMLE Step 1 and USMLE Step 2
PATHOPHYSIOLOGY OF DIABETIC NEPHROPATHY
Damage begins with dilation of the afferent dilation in the glomerulus. This is due to Advanced Glycosylated Enzymes (AGE). These AGE forms crosslinks in the collagen which increaes permeability of the glomerulus. This is one of the main factors leading to diabetic nephropathy.
Protien Kinase C is increased due to increase in Diacyl Glycerol which increase vascular permeability.
Efferent Constriction also occurs in Diabetic Nephropathy due to direct activation of Renin by glucose by an unknown mechanism. This eventually leads to intraglomerular hyperfiltration and eventual hyperfiltration or high GFR. This will eventually leads to glomerulosclerosis (Hyaline). Hyaline deposits in afferent and efferent which leads to diabetic nephropathy.
Mesangium is also affected in diabetic nephropathy. Cytokines are released due to elevated glucose leading to formation of nodule in mesangium known as kimmelstiehl wilson nodule.
SYMPTOM OF DIABETIC NEPHROPATHY
Diabetes mellitus type 1 is more severe than Diabetes Mellitus Type 2. Moderate albuminuria is defined as albuminura between 30 to 300mg of albumin in urine. This is a mild form of diabetic nephropathy. Moderate albuminuria is when there is more than 300mg of albumin in urine. These patient will lead to End Stage Renal Disease in Diabetic Nephropathy.
RISK FACTORS OF DIABETIC NEPHROPATHY
Family history of diabetic nephropathy. Poor glycemic control, hypertension, smoking, certain races, Diabetic Retinopathy usually occurs before diabetic nephropathy.
TREATMENT OF DIABETIC NEPHROPATHY
First line treatment is good glycemic control.
ACE inhibitors should be given at first sign of albuminuria or if there is concurrent hypertension.
Protein restriction also can help manage Diabetic Nephropathy.
Finally BP Control, and weight loss is also helpful in controlling progression of Diabetic Nephropathy