CRP-26

CRP-26

Clinical History

The patient is a 37 year old black female. SLE, pericardial effusion and acute renal failure. Currently on hemodialysis. Has received pulse steroids for 3 weeks. BUN 46, creatinine 6.

Gross Description

Received in transport media is one tapering core that measures 4 mm in length and 2 mm at the widest end. The core is bisected at the larger end, and two 1-mm pieces are submitted for electron microscopy. The remaining tissue is submitted for light microscopy. Note that no tissue is submitted for immunofluorescence.

Pathology

Case CRP-026 Trichrome

Microscopic Description, Immunofluorescence, and Electron Microscopy

Microscopic Description

Light Microscopy:

The specimen consist of a fragment of renal cortex that contains 44 glomeruli in the three levels. Nine of these are obsolete, and two contain fibrocellular crescents. All of the nine obsolete glomeruli demonstrate severe ischemic atrophy with marked thickening and wrinkling of the glomerular basement membranes. In addition to the ischemic changes in the basement membranes, however numerous spike-like projections and holes are also noted. Overall the glomeruli have a somewhat hypocellular appearance, with striking increase in mesangial matrix but no mesangial cell proliferation. There is diffuse moderate interstitial fibrosis with corresponding tubular atrophy. There are focal mononuclear cell infiltrates, but tubulitis is not noted. The vessels show striking mucoid intimal fibrous thickening, and the larger arteries show prominent “onion-skinning”. All of the lumina have been obliterated. Some of the vessels contain fibrin thrombi, and most also contain trapped red cells and fibrin in the vessel walls. This change involves the arterioles as well as the small interlobular-sized arteries. Several glomeruli contain red cells in Bowman's space, and red cells are noted in occasional tubules.

Immunofluorescence

No tissue submitted.

Electron Microscopy

Two thick sections containing a total of six glomeruli are available, but one of these is obsolete, and another shows prominent periglomerular sclerosis. The other four are similar to those described above and show marked ischemic atrophy and increased mesangial matrix. Ultrastructural examination reveals extremely thickened and wrinkled capillary basement membranes, and numerous subepithelial and intramembranous electron dense deposits are identified. No subendothelial deposits are noted. Mesangial areas contain markedly increased amounts of matrix, and small mesangial deposits are also noted. There is complete effacement of the epithelial cell foot processes.

Diagnosis and Comments

Kidney, needle biopsy - Thrombotic microangiopathy. Membranous lupus nephritis (WHO class V).

These findings are most consistent with a thrombotic microangiopathy superimposed on membranous lupus nephritis vascular lesions are relatively uncommon in lupus nephritis, but thrombotic microangiopathy is one of the patterns that has been described in association with lupus. In this particular case, it is not clear if the vascular lesion is secondary to lupus or represents a primary thrombotic microangiopathy. This type of vascular lesion is not specific, and the differential diagnosis includes malignant hypertension, hemolytic-uremic syndrome and thrombotic thrombocytopenic purpura. The involvement of the arterioles as well as the small arteries makes scleroderma less likely. The severity of the vascular disease is consistent with an extremely poor prognosis for this kidney.

A normal partial thromboplastin time is 28 to 37 seconds.

A pericardial effusion is a collection of fluid within the pericardial space.

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.

Hypertension which has caused end-organ damage is termed malignant. Without proper treatment, these patients will usually die in less than 2 years. Blood pressures in patients with malignant hypertension are frequently 160/110 mm Hg or greater.