A CASE REPORT OF SERONEGATIVE LUPUS NEPHRITIS

Introduction:

The patient presented with generalized body swelling for the past 6 months which has been progressive and associated with facial swelling worse in the morning that got better during the day. She also complained of intermittent shortness of breath which was worse when sitting up and with activity. She denied constitutional symptoms. She had a history of chronic lower back ache since 2014 for disc prolapse.
The patient did not have hypertension, diabetes or any other underlying illness. There was a family history of hypertension, dyslipidaemias and diabetes mellitus.

Physical examination revealed a hemodynamically stable patient with anasarca. The patient had a normal cardiovascular examination; however, breath sounds were absent in the lung bases in addition to a stony dull percussion. The patient had no liver nor spleen enlargement and no skin stigmata suggestive of autoimmunity. Bedside dipstick showed severe proteinuria.

Methods:

Initial Investigations were suggestive of a nephrotic syndrome. Despite initial work up not being diagnostic of autoimmune disease, the patient was treated as Lupus Nephritis based on the histopathological findings.

Results:

Light microscopy:

Up to 53 glomeruli were present for assessment, none globally sclerosed. Less than 50% of the glomeruli show endocapillary hypercellularity with neutrophils and karyorrhectic debris, (see figure 1 and 2). The silver stain shows subendothelial deposits (figure 2). There is no basement membrane thickening, no mesangiolysis and no fibrin thrombi. No cellular, fibrocellular or fibrous crescents. Within the interstitium, there is a mild chronic inflammatory cell infiltrate comprising lymphocytes and very occasional eosinophils. There is acute tubular necrosis(see Figure 3). The tubular epithelial cells demonstrate protein resorption droplets( see Figure 4, black granules in the cytoplasm of the tubular epithelial cells). Masson trichrome stain shows mild interstitial fibrosis. The arterioles show moderate to severe arteriolar hyalinosis(figure 5)demonstrated by the pink amorphous material within the vessel walls.

Direct immunofluorescence microscopy:

Four glomeruli are present for assessment.  IgG, IgM and C3 show weak deposition in all the glomeruli within the mesangium (1-2+) with a granular morphology. Weak granular staining of less than 1+ is seen on the Lambda light chain which is interpreted as negative. Kappa and C1q are negative. There are no glomeruli on IgA to assess for immune deposits.

The final histological diagnosis is that of focal proliferative glomerulonephritis. The differential diagnosis includes post-infectious glomerulonephritis, lupus nephritis, and pauciimmune glomerulonephritis.

The patient was treated as Lupus nephritis on mycofenolate and prednisolone with supportive treatment with good response as shown in figure 6.

Conclusions:

Patients with biopsy features of SLE and seronegative results may also have Lupus nephritis and clinicians may consider immunosuppressive treatment in selected cases.

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.