IPLab:Lab 5:Nodular Intercapillary Glomerulosclerosis

Clinical Summary

This 57-year-old white male with a 25-year history of Type I diabetes mellitus (insulin-dependent ) developed an acute myocardial infarction followed by cerebral infarction, pulmonary dysfunction, and renal failure. There was a history of hypertension and proteinuria. Laboratory findings included a BUN and creatinine of 69 mg/dL and 3.3 mg/dL which subsequently rose to 113 and 4.8, respectively. He subsequently died of multisystem failure.

Autopsy Findings

The autopsy showed the expected left ventricular hypertrophy, a large acute myocardial infarction, and a large right cerebral infarction. The pancreas showed amyloidosis of the islets. There was extensive atherosclerosis and arteriolosclerosis. The kidneys were large, weighing 220 and 240 grams respectively, and had smooth glistening surfaces, a few cortical scars, and blurring of the corticomedullary junctions.

Images

• 
  This is a gross photograph of the kidneys from this case. Note that there are multiple shrunken regions (old infarcts) (arrows) and the kidneys have a rough granular appearance on the surface, which is caused by multiple small infarcts of small vessels throughout the cortex.
• 
  This is a low-power photomicrograph of the kidney from this patient. The section extends from cortex (1) to the medulla (2).
• 
  This is a higher-power photomicrograph of the cortical region. In this region there is ischemic obsolescence of glomeruli and one glomerulus with nodular glomerulosclerosis (1). Also note the thickened walls of the blood vessels (2).
• 
  This is a high-power photomicrograph of two glomeruli with intercapillary glomerulosclerosis (arrows).
• 
  This is a photomicrograph of a glomerulus with nodular glomerulosclerosis (1). Also note the intertubular fibrosis and the changes in the blood vessels (2).
• 
  This is a higher-power photomicrograph of a glomerulus with nodular glomerulosclerosis (arrows). These are the classic Kimmelstiel-Wilson lesions ("K-W lesions") seen in diabetics with nodular glomerulosclerosis.
• 
  This is a photomicrograph of kidney with a focal exudative lesion in a glomerulus (arrow) and sclerosis, interstitial fibrosis, and congestion.

Study Questions

• What is another term for nodular glomerulosclerosis?

Kimmelstiel-Wilson disease.

• What material is found within these sclerotic nodules and what happens to these lesions over time?

The Kimmelstiel-Wilson (K-W) lesions are ovoid or spherical, often laminated, hyaline masses situated in the periphery of the glomerulus. They are usually within the mesangium of the glomeruli. The nodules are composed of lipids and fibrin. As the disease progresses the K-W nodules enlarge until they compress and obliterate the glomerular tuft. Because of these glomerular and arteriolar lesions, the blood flow to the kidney is compromised and the kidney becomes ischemic. This results in tubular atrophy and interstitial fibrosis and leads to a roughened renal cortical surface.

• What percent of diabetics develop this lesion and what are the functional consequences?

Approximately 15-30% of long term diabetics develop K-W lesions and in most instances it is associated with renal failure.

Myocardial infarction is necrosis of myocardial tissue which occurs as a result of a deprivation of blood supply, and thus oxygen, to the heart tissue. Blockage of blood supply to the myocardium is caused by occlusion of a coronary artery.

Renal failure is the severe reduction of renal function and often leads to reduced urinary output.

Protein in the urine is indicative of glomerular dysfunction.

These tests are measures of kidney function. High levels mean low function.

A normal BUN for this patient would be 10 to 20 mg/dL.

The normal creatinine level is 0.7 to 1.3 mg/dL.

A normal kidney weighs 157 grams (range: 115 to 220 grams).

Nodular hyperplasia of the prostate--characterized by large discrete prostatic nodules--is a common disorder in men over 50 years of age. The nodules cause the prostate to be enlarged and to have an increased weight. The human prostate is surrounded by a restrictive capsule. These nodules cause increased pressure within the capsule which leads to constriction of the urethra as it passes through the prostate. Urethral constriction leads to retention of urine.