A 75-year-old male presented with a history of 1-week loose stools, nausea, vomiting, decreased urine output

A 75-year-old male presented with a history of 1-week loose stools, nausea, vomiting, decreased urine output, and one episode of high-grade fever.

NO history of sore throat, skin infection, joint pain, respiratory tract infection, urinary tract infection, smoking, alcohol drinking, and NSAID abuse

General

Heent

Neck

Cardiovascular

Lungs

Abdomen

Extremities

Skin

Neurological Exam

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PIGN is an immune-mediated glomerulonephritis. Previously, most of the cases occurred in childhood and followed streptococcal upper respiratory tract or skin infections and were termed as poststreptococcal glomerulonephritis. In the past 3 decades, there is a major shift in epidemiology and outcome [10]. Because infection is usually ongoing at the time, glomerulonephritis is diagnosed, and the term infection-related glomerulonephritis has been suggested [11]. An immunocompromised background (diabetes or malignancy) is usually present for the development of PIGN in elderly [10]. Our patient was an elderly diabetic. The spectrum of causative pathogens, sites of infection, and duration of infection are different in the elderly as compared to children [10]. The sites of adult infection are more miscellaneous, including skin, upper respiratory tract, heart, lung, oral mucosa/teeth, and the urinary tract. However, our patient developed PIGN after acute gastroenteritis and stool culture showed Escherichia coli. Nasr et al. [6, 10] showed that E. coli can cause infection-related glomerulonephritis in adults. The time period between infection and onset of renal disease in children with PIGN is usually 1–6 weeks. But, in approximately half of elderly patients, the infection is first discovered at the onset of renal disease, indicating that infection may go unrecognized for some time [10]. Our patient had a history of one episode of high-grade fever with chills 1 week before and loose stools for 3 days 1 week before. The clinical differential diagnosis of PIGN in elderly is broad and includes other glomerular diseases associated with a low complement level, such as cryoglobulinemic glomerulonephritis, antineutrophil cytoplasmic antibody-associated pauci-immune glomerulonephritis, and C3 glomerulopathy [12]. The presence of a low level of C3 with normal C4 favors PIGN or C3 glomerulopathy, and low C4 with normal C3 is more typical of cryoglobulinemic glomerulonephritis [12]. However, up to one third of adults with PIGN have depression of both C3 and C4 [12]. In our patient, serum ASO titer, ANA, cytoplasmic antineutrophil cytoplasmic antibody, and perinuclear antineutrophil cytoplasmic antibody were negative. He had a very low serum C3 level with a normal serum C4 level. After 2 months of disease onset, repeat serum C3 was normal.

On renal light microscopy, in PIGN the most common histological pattern of injury is diffuse endocapillary proliferative and exudative glomerulonephritis with numerous intracapillary neutrophils [12]. In our PIGN patient, renal light microscopy showed diffuse endocapillary proliferative glomerulonephritis with cellular crescents over 2/13 (15.3%) glomeruli (Fig. 1). Renal immunofluorescence in PIGN typically reveals C3-dominant or co-deposition of one or more immune reactants (IgG, IgM, IgA, C1q). IgG is usually the most frequent and intense immunoglobulin [12]. In our PIGN patient, renal immunofluorescence showed mesangial and capillary wall staining for C3 (Fig. 2) and IgG (2+ mesangial and segmental capillary wall; granular) (Fig. 3). In PIGN, renal electron microscopy by Nasr et al. [10] showed subepithelial electron-dense deposits in most cases (92% of patients), mesangial deposits (87% of patients), and small subendothelial deposits (66% of patients). In our PIGN patient, renal electron microscopy showed thickened glomerular basement membranes, electron-dense deposits in mesangial, subepithelial and subendothelial regions of glomerular capillaries, subepithelial hump-like deposits and widespread effacement of visceral epithelial cell foot processes (50–60%) (Fig. 4). Thickening of glomerular basement membrane was due to diabetic nephropathy and effacement of visceral epithelial cell foot processes were due to both diabetic nephropathy and PIGN.

There is no single pathognomonic clinical or pathologic finding for PIGN diagnosis in adults. At least three of the following criteria should be present [12]: (1) clinical or laboratory evidence of infection before or at the onset of glomerulonephritis, (2) decreased serum complement, (3) endocapillary proliferative and exudative glomerulonephritis, (4) C3-dominant or co-dominant glomerular immunofluorescence staining, and (5) hump-shaped subepithelial deposits on electron microscopy.

Our patient satisfied all 5 criteria for the diagnosis of PIGN. PIGN can be difficult to distinguish histologically from the C3 glomerulonephritis (C3GN) which is associated with abnormalities in the alternative pathway of complement. The glomerular positivity for C3 alone (i.e., without staining for IgG, IgM, IgA, or C1q) is an essential condition for C3GN, but can also occur in one fourth of patients who are in the resolving phase of PIGN [12]. The following features would favor C3GN over PIGN in patients with sole glomerular positivity for C3 [12]: lack of clinical evidence of infection, persistently low C3 for more than several months, persistently active glomerulonephritis for more than several months, and large mesangial, intramembranous and subendothelial deposits. The tendency of subepithelial deposits to localize into the mesangial “waist” and evidence of resorption within the subepithelial deposits on electron microscopy favor PIGN [12]. There is no clear-cut guideline to treat such a type of elderly patients with PIGN with crescents and the duration of therapy is not well defined. Crescentic glomerulonephritis having an underlying immune complex proliferative glomerulonephritis is less responsive to aggressive immunosuppressive therapy as compared to anti-glomerular basement membrane or antineutrophil cytoplasmic antibody crescentic glomerulonephritis but for the minority of patients who have idiopathic immune complex crescentic glomerulonephritis, the most common treatment is immunosuppressive therapy with pulse methylprednisolone, followed by prednisone at a dosage of 1 mg/kg daily tapered over the second to third month to an alternate-day regimen until completely discontinued [13]. Baikunje et al. [9] studied PIGN with crescents in adults and observed that those patients who were treated with steroids had excellent response, but the duration of therapy was variable. Our patient initially was on hemodialysis but after 2 weeks of steroid therapy hemodialysis was stopped. Our patient responded very well to steroid therapy. To treat an elderly diabetic patient with immunosuppressive therapy is more challenging as our patient developed herpes zoster after 3 weeks of steroid therapy and left leg cellulitis after 6 weeks of steroid therapy.