CRP-38

CRP-38

Clinical History

The patient is a 34 year old female with positive family history of chronic renal failure. Urinary protein 500 mg per 24 hours, BUN 10, creatinine 0.9. Rule out familial nephropathy.

Pathology

Case CRP-038 PASH

Microscopic Description, Immunofluorescence, and Electron Microscopy

Microscopic Description

Light Microscopy

The specimen consists of two fragments of cortex, one of which contains the corticomedullary junction and a small portion of medulla. There are at least twelve glomeruli in the biopsy. One is obsolete. The remaining glomeruli are all similar and show mild local increase in mesangial matrix without mesangial cell proliferation. Capillary basement membranes are remarkable with the special stains and the peripheral capillary loops are patent. There are no areas of segmental sclerosis. There is minimal interstitial fibrosis, and the tubules are generally well preserved. No interstitial foam cells are identified. The vessels are essentially unremarkable. No inflammatory infiltrates are present.

Immunofluorescence

There are two glomeruli in the sections. There is focal and segmental 1+ staining for C3 in the mesangium. Stains for IgG, IgM, IgA, C1q, fibrinogen and light chains are negative in the glomeruli. Occasional tubules contain albumin droplets in the epithelium. There is no staining of the vessels.

Electron Microscopy

One thick section containing four glomeruli is present. All of these are similar and show the same characteristics noted in light microscopy. Ultrastructural examination shows variable thickening, thinning and lamellation of the glomerular basement membrane. The thick segments measure up to 800 nm, while the thin segments measure as little as 130 nm. The lamina densa has focal areas of clear electron-lucent areas, which sometimes contain round electron-dense granules. The altered capillary walls show epithelial foot process obliteration. No electron dense deposits are identified in capillary basement membranes or mesangial regions.

Diagnosis and Comments

Kidney, needle biopsy – Alport Syndrome (Hereditary nephritis)

These findings are most consistent with hereditary nephritis. The most characteristic ultrastructural feature in this disease is the variable thickening, thinning, and lamellation of the glomerular basement membranes. However, in females there may simply be diffusely attenuated segments of glomerular basement membranes. This finding may also be present in thin basement membrane nephropathy. However, the additional presence of focal lamellation of basement membranes in this case, as well as the history of relatives with chronic renal insufficiency, is more consistent with hereditary nephritis.

Females tend to have a milder clinical course, and the good preservation of the tubules and the interstitium in this case suggests that this patient has a relatively good prognosis.

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

Blood urea nitrogen (BUN) is used as a measure of the glomerular filtration rate and is increased in renal failure.

An infiltrate is an accumulation of cells in the lung parenchyma--this is a sign of pneumonia.

Aortic insufficiency refers to the inability of the aortic valve to close properly, thus allowing regurgitation of blood into the left ventricle during diastole -- i.e., volume overload. Disease of the aortic valve leaflets is a common cause of insufficiency.