Keywords
recurrent gross hematuria - C3 glomerulopathy - dense deposit disease - complement
system - renal biopsy
Introduction
Clinical manifestations of glomerulonephritis (GN) range from the asymptomatic person
who is discovered to have hypertension or microscopic hematuria during a routine medical
examination to patients who may present with proteinuria, gross recurrent hematuria,
or even rapidly progressing GN.[1] Awareness of such spectrum of clinical presentation is mandatory to practicing physicians,
for early detection and management of these nephritides to avoid progression to end-stage
renal disease.
Renal biopsy is considered a valuable diagnostic tool in glomerular diseases, particularly
in the setting of overlapping clinical presentation, and paucity of definitive serological
marker: moreover, it provides direct exploration of the type and extent of renal pathology,
providing a robust guide for the therapy.[2] Nonetheless, many renal biopsy reports are considered inadequate based on number
of glomeruli obtained in the biopsy core; ideally, they should not be less than 10
to 12 glomeruli, for proper processing for light microscopy or immunohistochemistry
staining (immunofluorescence and immunoperoxidase sections). Nevertheless, even with
a single glom, use of detailed electron microscopy (EM) examination can provide valuable
information. Furthermore, abnormalities of complement system (primary or secondary
defects) play central role in pathogenesis of many glomerulopathies, and we should
consider them in differential diagnosis of patients presenting with recurrent hematuria.
We present a case with rare glomerular disease that her renal biopsy report was initially
not adequate and lacking immunohistochemistry workup. However, E/M report eventually
addressed abnormal glomerular deposits, coupled with clinical and biochemical data
that guided our therapy protocol with remarkable patient outcome.
Case Presentation
In October 2021, a single Libyan woman, in her mid-thirties (35 years) with no previous
medical problems, presented to our nephrology clinic, complaining of several episodes
of red discoloration of her urine over the last 3 months, lasting few days, and subside
spontaneously. No history of dietary or drug was found that may cause urine discoloration.
These episodes of gross hematuria were not associated with pain or other significant
associated urinary tract symptoms. There was no history of lower limb swelling or
facial puffiness. She had reported two episodes of hematuria that are linked to concurrent
upper respiratory infection. She denied bleeding from any site, skin rash, or oral
ulceration. She had no significant family history of similar illness. She denied any
history of coronavirus disease 2019 (COVID-19) infection.
Her physical examination revealed average body-built woman, her blood pressure was
110/70 mm Hg, pulse 88 beats per minute, pale conjunctivae, normal throat, and mild
pitting lower limb edema. No skin rash, photosensitivity, or alopecia was found. Precordial,
chest, and breast examination were normal.
Her initial blood testing showed that hemoglobin was 10.9 g/dl (12–15 g/dL), mean
corpuscular volume 76 fL (80–100 fL), white blood cell (WBC) was 6.1 × 10^3/µL (4–11 × 10^3/µL),
platelet count was 254 × 10^3/µL (150–450 × 10^3/µL). Urine sediment examination showed
protein ++ + , WBC was 1–4/HPF (high-power filed [0-5]), red blood cell (RBC) was
25–50/HPF (0-3) with irregular shape, no cast, no crystals. Blood chemistry showed
urea was 41 mg/dL (15–50 mg/dL), creatinine was 0.5 mg/dL (0.5–0.9 mg/dl), K+ was 3.64 mmol/L (3.5–5.5 mmol/L), Na was 137 mmol/L (135–148 mmol/L), serum albumin
was 3.1 g/dL (4–6 g/dL), calcium was 7.6 mg/dL (8.4–10.2 g/dL), was uric acid 4.3 mg/dL
(3.5–5.7 g/dL), low-density lipoprotein was 254 mg/dL (100–129 g/dL), triglycerides
was 134 mg/dL (50–200 g/dL), hemoglobin A1c was 5.4% (5.5–6.4%), transferrin saturation
was 14% (20–50), C3 was 0.2 g/L (0.9–1.8 g/L), and C4 was 0.3 g/L (0.2–0.5 g/L). Chest
imaging showed no signs of pulmonary or pleural disease. Serological workup for autoantibodies
showed antistreptolysin-O titer was normal, positive for antinuclear antibodies with
titer of 1:64, and was negative for anti-ds-DNA level 0.1 and 0.3 (< 25, repeated
twice), while anticytoplasmic antibodies, antiphospholipid, and antiglomerular basement
membrane (GBM) antibodies were all negative. Urine protein: creatinine ratio (UPCR)
was 2.2 mg/g (< 0.2 mg/mg), which after 2 and 4 weeks became 3.1 and 4.4 mg/mg, respectively
(nephrotic range). COVID-19 immunoglobulin M and immunoglobulin G (IgG) antibodies
were negative. Peripheral blood film showed no evidence of schistocytes. On ultrasonography,
both kidneys were normal in size and Echo showed no evidence of any pelvic or abdominal
masses.
Presence of significant proteinuria mandates renoprotective measures, using low dose
enalapril 2.5-5mg per day, statins for hyperlipidemia, atorvastatin 40 mg once daily,
and starting steroid therapy, prednisolone 1mg /kg, for 6-8 weeks, to achieve clinical
and renal remission, and to proceed with gradual tapering of steroid therapy thereafter.
Patient treatment is further supplemented with iron tablet, to treat her iron deficiency
anemia.
A month later, she came with cushingoid facies, blood pressure of 120/70 mm Hg, biochemical
data—fasting blood glucose, 87 mg/dL (70–110 mg/dL); urea, 34 mg/dL; creatinine, 0.7 mg/dL—and
with improvement of her lipid profile. Urine analysis showed ongoing hematuria of
12–20/HPF and significant proteinuria (UPCR 3 mg/g) and for this reason azathioprine
tablet (50 mg twice daily) was added.
Over a period of 2 months, the patient was monitored. We observe improvement in her
clinical picture (no gross hematuria no more pitting edema) but on laboratory level
she had persistent microscopic hematuria and nephrotic range proteinuria (urine RBC
60–70/HPF, 24 urine collection for protein 4.8 g). Low C3 and normal C4 indicate that
complement-mediated glomerulopathy and immunoglobulin A (IgA) nephropathy have been
excluded on this basis. Renal biopsy was advised for the patient (3 months after her
first presentation) and because of technical issue the biopsy report (January 2022)
was deficient as under light microscopic examination of serial sections only one glomerulus
was seen and showed segmentally thickened capillary basement membrane and mesangial
expansion, EM ultrastructural examination ([Fig. 1]) revealed GBM thickening with extensive subendothelial electron dense deposits (ribbon
like), and large globular mesangial densities, going with the picture of membranoproliferative
C3 GP or lupus nephritis.
Fig. 1 Dense deposit disease with ribbon-like dense deposits along the basement membrane
lamina densa (blue arrow), and large globular mesangial densities (red arrow).
At this stage, mycophenolate mofetil (MMF) tablet 1 g twice per day was prescribed
for 2 months, replacing azathioprine, with prednisolone 0.5 mg/kg mg per day, as we
adopted lupus nephritis-equivalent treatment regimen. In close follow-up over next
6 months, in August 2022, patient showed remarkable clinical and biochemical improvement,
with complete remission, as no microscopic hematuria was found; urine RBC was 0–2
HPF, her UPCR was 0.14, and C3 and C4 returned to normal level of 0.64 and 0.28, respectively,
with normal renal function. She is currently on MMF tablet 500 mg twice per day, and
prednisolone tablet 10 mg daily.
Based on renal biopsy report, together with persistently low C3 level, normal C4 level,
and no serological markers of lupus nephritis, we conveniently diagnosed C3 glomerulopathy;
possibly dense deposit disease (DDD) pattern.
Discussion
Recurrent hematuria is significant clinical problem; screening programs show a prevalence
of 0.18 to 16.1% among apparently healthy individuals, and glomerular hematuria contributes
to a significant proportion of these cases in adults.[3] Presence of glomerular hematuria alerts physicians' attention to broad differential
diagnosis ([Table 1].[4]
[5]
[6]
[7]
[8]
[9]).
Table 1
Systematic approach to recurrent gross hematuria
|
Systematic approach to patients with recurrent gross hematuria
|
|
- Review drug history (anticoagulants)
- Rule out renal stones, polycystic kidneys, or urological malignancies; renal cell
carcinoma or bladder carcinoma (ultrasound/ CT abdomen)
|
|
If above ruled out, and urine sediment examination shows acanthocytes, RBC casts,
and proteinuria
Glomerular hematuria
|
|
Disease characters
|
IgA nephropathy
|
Lupus nephritis
|
C3 glomerulopathy
|
Atypical hemolytic uremic syndrome
|
Thin membrane disease
|
Alport syndrome
|
|
Incidence; per 100,000 of population (related reference)
|
3.1–4.5 cases, according to geographic area[4]
|
20–150 cases, may be higher in woman and black race[5]
|
0.1–0.2 cases,[6] a rare glomerulopathy
|
<0.1 cases,[7] a rare glomerulopathy
|
1000,[8] a common benign condition
|
1–29 relatively rare hereditary disease
|
|
Precipitating factor
|
Synpharyngitic hematuria
|
Provoked by systemic flares of lupus
|
No specific precipitating factor
|
- Pregnancy, kidney transplantation or its therapy, nonenteric bacterial infections
|
No specific precipitating factor
|
No specific precipitating factor
|
|
Family history /genetic mutations
|
Majority are sporadic cases. But familial clustering possible
|
Association with HLA-DR2/DR3 alleles
|
- Mostly acquired form
- Familial cases reported, due to genetic mutations of complement alternative pathway
|
- Mostly acquired form
- 20% Familial/genetic mutations cases reported
|
Autosomal dominant from parents to their children
|
Autosomal dominant X-linked, AR, both males and females are affected
|
|
Systemic manifestations
|
- No systemic manifestations
- Clinical associations; celiac disease, and dermatitis herpetiformis
|
- Involving several organs; skin, joints, pulmonary, cardiac, renal, nervous system
|
Few cases demonstrate partial lipodystrophy, and macular degeneration
|
- Symptomatic anemia
- Petechial skin rash
|
- No systemic manifestations
|
- Sensorineural deafness
- Ocular abnormalities
|
|
Specific serological markers
|
- No specific autoantibody
- Measurement of serum galactosylated-IgA level and IgA/C3 ratio
|
- Several
autoantibodies;
- Anti-ds DNA
- Anti-histone
antiphospholipid
|
- Low C3, normal C4 level
- Circulating C3-nef autoantibodies
- Complement factor- H mutations analysis
|
- Thrombocytopenia
- Peripheral blood schistocytes
- Complement factor- H mutations analysis
|
- No specific autoantibody
|
- No specific autoantibody
|
|
Renal biopsy
|
- Characteristic IgA mesangial deposition
- Few C3 or other Ig deposits
- No C1q deposits
|
- Several histological classes, wire-loop lesions
- Full house immune complex, C3, C4, and C1q deposits
|
- Membranoproliferative pattern on light microscopy
- C3 deposits on immunofluorescence
- Characteristic dense deposits according to DDD or C3 GN pattern (see discussion
paragraph)
|
- Thrombotic microangiopathy pattern with glomerular and arteriolar involvement, and
double contouring of GBM
|
- Uniformly thinning of lamina densa of GBM
- Occasional IgM or IgG deposits,
- No complement deposits
|
- Thich GBM
- Loss of normal staining for alpha 3 and alpha 4 proteins
- No complement deposits
|
Abbreviations: AR, autosomal recessive; CT, computed tomography; GBM, glomerular basement
membrane; HLA-DR2/DR3, human leukocyte antigen; IgA, immunoglobulin A; IgG, immunoglobulin
G; IgM, immunoglobulin M.
The case presented with recurrent episodes of painless hematuria, no history of coagulopathy
medications, no evidence of renal stones, and no evidence of urological malignancies;
urine sediment examination repeatedly showed hematuria with nephrotic range proteinuria
(UPCR 4.2) associated with hyperlipidemia, makes hematuria of glomerular origin is
the most likely pathology. These episodes of hematuria are not associated with history
of Pharyngitis. No features of systemic lupus (photosensitivity, malar rash, arthritis,
or oral ulcers), no features of systemic vasculitis, acrocyanosis, or cutaneous lipodystrophy.
Family history was negative for similar episodes or any renal disease. No evidence
of previous streptococcal infection or COVID-19 infection was found. This clinical
presentation was further supplemented by laboratory data, which showed persistently
low level of C3 and normal C4 level (excluding IgA nephropathy) and absence of thrombocytopenia
(excluding hemolytic uremic syndrome). Patient's screening was negative for glomerulopathy-related
autoantibodies. Due to persistence of microscopic hematuria with no serological diagnosis,
request for renal biopsy was made. Renal biopsy report showed, light microscopic examination
of serial sections, only one glomerulus was seen and segmentally thickened capillary
basement membrane and mesangial expansion. E/M ultrastructural examination ([Fig. 1]) revealed GBM thickening with extensive subendothelial electron dense deposits (ribbon-like).
Segmental GBM duplication was detected, mesangial expansion by electron dense deposits
(ribbon-like appearance). There had been a segmental GBM duplication with mesangial
expansion due to electron dense deposits. Therefore, the diagnosis is in favor of
C3 GP of DDD type, rather than IgA nephropathy or lupus nephritis. Many case reports
addressed the nonbenign nature of this emerging glomerulopathy. We do treat our patient
as lupus nephritis-equivalent disease, with combination of regular dose of MMF 2 g
per day, with prednisolone starting dose of 0.5 mg/kg/day for 8 weeks. Patient is
currently on MMF 500 mg twice per day, and low dose prednisolone (10 mg/day), maintaining
clinical and biochemical remission for 6 months; after renal biopsy diagnosis, prednisolone
dose will be reduced to 5 mg/day, with close monitoring of her clinical and biochemical
status for any relapses.
Abnormalities of complement pathway, whether due to genetic or quired defects (primary
or secondary to immune complex deposition), could result in a variety of diseases,
namely thrombotic microangiopathies and glomerulonephritides. Abnormalities of classical
pathway, such as C1q deficiency, are associated with impaired ability of complement
system to clear immune complexes and cellular debris, resulting in lupus-like illness.
While abnormalities of alternative pathway activation are usually associated with
low circulating C3 levels, and result in overt-deposition of C3 component and development
of C3 glomerulopathy.[10]
Advances in classification of GN have been set out, where, a consensus conference
in Cambridge (UK) in 2012, renamed type II Membranoproliferative GN to a new terminology,
as “C3 glomerulopathy” (C3 GP).[11]
[12]
[13] C3 GP is a recently introduced terminology, a rare form of glomerulopathy ([Table 1]) due to abnormalities of alternative complement pathway activation, in most cases
characterized by membranoproliferative appearance on light microscopy with strong
deposition of C3 component on immunofluorescence,[14] without significant staining for immunoglobulins or components of classical pathway
activation (C1q, C4). Based on E/M appearance, C3 GP has been further classified into;
DDD where GBM is replaced by bands of intramembranous osmiophilic lamina densa deposits,
may be associated with large electron densities in the mesengium, and C3 GN characterized
by presence of less dense deposits of C3 in the mesangial, subendothelial, and subepithelial
portions of glomerulus.[15] The incidence of C3 GP is quite low. Up to now, no known geographic variations.
A British case series study identified 80 cases over 17 years duration, with incidence
of 0.1 to 0.2 per 100,000, the ratio of C3 GN/DDD is 3:1, DDD tends to occur in younger
age group, with female performance, female to male ratio 3:1 compared to C3 GN, where
the latter one occurs around 30 years of age.[6]
[15] They share common clinical presentation, with nephrotic syndrome occurring in two-third
of cases of C3 GP, associated with recurrent hematuria and hypertension; about 20%
of patient's have nephritic syndrome presentation.[16] In minority, DDD is associated with macular degeneration and partial lipodystrophy
(symmetric loss of adipose tissue) of face, arms, and upper trunk. C3 GP is not a
benign glomerulopathy, proteinuria tends to persist, 50% of patient's progress to
end-stage renal disease within 10 years of diagnosis, with young females having greatest
risk.[16] A case series of 26 cases in New Zealand with median follow-up to 30 months, combination
therapy (MMF+ prednisolone) used in 12 cases, resulted in complete remission in 17%
of cases, partial remission (stable disease) in 58% of cases, while, ESRD occurred
in 50% of untreated cases, compared to 25% in treated cases.[17] Recurrence after kidney transplantation is high; up to 50% of recipients eventually
lose their graft within 5 years of transplantation, a fact that requires patient and
family counselling, and need for specific complement 5 (C5) blocking therapy as eculizumab
to save kidney graft from progressive damage and loss.[18]
Conclusions
IgA nephropathy and lupus nephritis are both characterized by recurrent gross hematuria
with nephrotic range proteinuria. Others, such as C3-GN or DDD that are considered
seronegative lupus nephritis-equivalents, must be ruled out in the context of complement
abnormalities and negative serology results for glomerulopathy-related autoantibodies.
Validated C3-GN diagnosis with EM report is essential for appropriate treatment protocol,
planning for kidney transplantation, and prognosis.
