B75 Diabetic Nephropathy

Question 1

What are the 3 major types of kidney lesions seen in diabetics?

Answer 1

Glomerular lesions

Renal vascular lesions (arteriolosclerosis)

Pyelonephritis

Question 2

Describe the glomerular lesions seen in Diabetic nephropathy

Answer 2

Diffuse thickening of the glomerular basement membrane, associated with the development of nephrosis syndrome

Diffuse mesangial sclerosis, with increased mesangial matrix and mesangial cell proliferation.

Nodular glomerulosclerosis, Kimmelstiel-Wilson nodules of PAS-positive material and hyperplastic mesangial cells.

Question 3

Describe the vascular lesions associated with diabetic nephropathy

Answer 3

Prehepatic renal atherosclerosis and macrovascular disease, can lead to ischemic lesions of the kidney.

Hyaline arteriolosclerosis, occurs in both the afferent and efferent arterioloes. Efferent arteriolosclerosis does not occur in any other condition.

Afferent arteriolosclerosis, elevated glomerular pressure, chronic endothelial damage, diffuse thickening of GBM.

Question 4

Describe diabetic pyelonephritis

Answer 4

A bacterial (usually E coli) suppurative inflammation of the kidney and renal pelvis.

Usually the result of an ascending UTI infection.

These are especially common in diabetic patients because of glucose in the urine.

Acute Presentation:

• Fever
• Flank pain
• White blood cell casts are extremely characteristic due to them invading the infected tubules.
• UTI symptoms
• leukocytosis

Chronic pyelonephritis

• Interstitial fibrosis and atrophy of the tubules
• Cortical scarring with blunted calyces is seen in pyelonephritis caused by vesiculoureteral reflux, and scarring on the poles of the kidney.
  
  • VUR occurs commonly in diabetes due to neurogenic
    bladder dysfunction.
• Atrophic tubules with proteinacious contents look like thryroid glands. Thyroidization of the kidney

Severe pyelonephritis can progress to papillary necrosis: usually in diabetes, patients with outflow obstruction, and chronic analgesic abuse. Causes coagulative necrosis of the papillae. Causes acute renal failure.

In the acute phase, raised yellow/purulent abscesses are seen on the kidney surface, which form deep scars on the surface afterwards.

In severe cases, blunted calyces with overlying retracted scars, especially on the upper and lower poles.

Question 5

What are the causes of pyelonephritis (other than diabetes)

Answer 5

Urinary obstruction

Catheterization of the urinary tract

Vesicoureteral reflux

Pregnancy

Female gender

Immunocompromised state

Question 7

Other characteristics of chronic pyelonephritis

Answer 7

Uneven interstitial fibrosis and an inflammatory infiltrate
of lymphocytes, plasma cells, and occasionally neutrophils

Dilation or contraction of tubules, with atrophy of the
lining epithelium. Many of the dilated tubules contain pink
to blue, glassy-appearing PAS-positive casts, known as
colloid casts, that suggest the appearance of thyroid
tissue—hence the descriptive term thyroidization. Often,
neutrophils are seen within tubules.

Chronic inflammatory cell infiltration and fibrosis involving
the calyceal mucosa and wall
• Arteriolosclerosis caused by the frequently associated
hypertension
• Glomerulosclerosis that usually develops as a secondary
process caused by nephron loss

secondary
glomerulosclerosis, associated with proteinuria;
eventually, these injuries all contribute to progressive
chronic kidney disease.