Case of 33 yrs old female with RPGN (Rapidly progressive glomerulonephritis) | DNS

Summary

The video is a teaching conference built around a 33-year-old woman with rapidly worsening kidney function, edema, blood and protein in the urine, and abnormal blood counts. The discussion uses the case to teach systematic assessment of rapidly progressive glomerulonephritis (RPGN), interpretation of urine and biopsy findings, and clear clinical case presentation.

Case presentation

The patient had been generally healthy before developing:

• Gradually worsening facial and leg swelling over about two months.
• Foamy urine.
• Pain in multiple joints for about one month, without joint swelling, redness, or morning stiffness.

At an outside hospital, she was found to have hypertension, proteinuria, hematuria, anemia, and a low platelet count. Her serum creatinine rose from about 1.1 to 2.5 and then 3.5 over roughly ten days.

She had one episode of painless visible hematuria. A kidney biopsy was performed, followed by intravenous methylprednisolone.

Her history included a prior pregnancy-related blood transfusion. She reportedly had no known chronic illnesses, though the history was obtained from her husband because she was distressed and unable to provide it reliably at the time.

Examination later showed pitting edema up to the knees. The presentation did not describe several symptoms often relevant to autoimmune or systemic disease, including rash, oral ulcers, photosensitivity, fever, and respiratory symptoms.

Diagnostic reasoning and evolving differential

• RPGN was proposed as the clinical syndrome because kidney function deteriorated rapidly alongside hematuria and proteinuria, suggesting glomerular disease.
• The speakers emphasized distinguishing a clinical syndrome from a pathological diagnosis. RPGN describes the clinical course; biopsy findings and other tests are needed to establish the underlying cause.
• Early possibilities included lupus nephritis, IgA nephropathy, and membranoproliferative glomerulonephritis (MPGN). The group noted that MPGN is a biopsy pattern with several possible causes, rather than a single etiology.
• Other possibilities raised included ANCA-associated vasculitis, anti-GBM disease, immune-complex glomerulonephritis, infection-related disease, TTP/TMA, and other causes of acute kidney injury.
• The discussion also distinguished AKI from acute kidney disease (AKD). AKD was described as a useful term for kidney problems that last beyond the short AKI period but have not yet met the duration criteria for chronic kidney disease.

Urine testing and protein measurement

Proteinuria in a patient with hematuria supports renal parenchymal, and potentially glomerular, disease. The speakers stressed that urine microscopy can help locate the source of bleeding:

• Dysmorphic red blood cells, including acanthocytes, can support a glomerular source.
• Red-cell casts point toward glomerular bleeding.
• Muddy brown casts or prominent granular casts can support acute tubular necrosis.

The teaching point was to examine urine sediment directly when possible, rather than relying only on automated reports or dipstick results. The presenter encouraged trainees to learn microscopy hands-on, with help from clinical pathology staff.

Proteinuria can be quantified with a spot urine albumin-to-creatinine ratio (ACR), a protein-to-creatinine ratio (PCR/UPCR), or a 24-hour urine collection. The discussion emphasized choosing a test that fits the suspected level and type of proteinuria:

• ACR is useful for detecting and quantifying lower levels of albuminuria, such as diabetic microalbuminuria.
• UPCR may be more useful when substantial, gram-range proteinuria is expected, especially if the albumin assay has a limited measurement range.
• A 24-hour collection can quantify protein excretion but is cumbersome and can be incomplete or over-collected.

Creatinine excretion can help assess the completeness of a 24-hour collection, but expected values depend on body size, muscle mass, and kidney function. The speakers cautioned that assumptions about daily creatinine excretion can be unreliable, particularly in AKI, and that spot ratios may be misleading when creatinine excretion is abnormal.

The group also advised checking laboratory units, measurement limits, and whether a sample was diluted before calculating or interpreting a ratio.

Classification of crescentic glomerulonephritis and complement testing

The speakers recommended organizing crescentic GN by immunofluorescence (IF) pattern:

• Pauci-immune: Little or no immune staining; commonly associated with ANCA-related disease.
• Linear: Raises concern for anti-GBM disease.
• Granular: Suggests immune-complex disease; further classification may include patterns such as full-house staining or IgA-dominant deposits.

For low complement levels, the discussion highlighted lupus nephritis, infection-related glomerulonephritis, MPGN/C3 glomerulopathy, and cryoglobulinemia among the possibilities.

Suggested investigations included CBC and peripheral smear, kidney function and electrolytes, urinalysis and protein quantification, complement levels, ANA and related antibodies, ANCA, hemolysis testing such as LDH, and tests for relevant infections such as hepatitis B, hepatitis C, and HIV. Additional testing would depend on the clinical picture.

Biopsy findings and later results

The biopsy description included glomerular capillary thrombi, areas of double contouring and endothelial proliferation, and deposits considered suspicious for cryoglobulin. These features were discussed as an MPGN-like pattern, but not as proof of a specific cause.

IF showed IgM, IgG, and C1q staining, with IgA and C3 reported as negative. The speakers noted that this was not the classic “full-house” pattern often associated with lupus nephritis, making lupus less typical based on the biopsy pattern alone, though not necessarily impossible.

ANA and anti-Ro were reported positive; anti-dsDNA and anti-Smith were negative, complements were low, ANCA was negative, and the cryoglobulin test was positive. Hepatitis C antibody and RNA were reported negative.

The interpretation remained open: cryoglobulinemia and another immune-complex process were considered, while the team also discussed complement-mediated disease and other possibilities.

The patient later developed worsening thrombocytopenia and fragmented red cells on smear, raising concern for a thrombotic microangiopathy (TMA). ADAMTS13 was reported as normal and antiphospholipid testing as negative. Plasmapheresis was described as part of her management.

The discussion explored possible explanations for the TMA and anemia, including autoimmune disease, complement-related TMA, and hemophagocytic lymphohistiocytosis (HLH). These were presented as considerations requiring further evaluation, not as settled diagnoses.

Because the biopsy deposits were not definitively identifiable as cryoglobulin by light microscopy alone, the speakers emphasized electron microscopy and careful cryoglobulin sample handling. The sample should be kept warm—around body temperature—during collection and transport, using appropriate pre-warmed equipment, because mishandling can affect the test result. The group also mentioned rheumatoid factor as a possible supporting test when cryoglobulinemia remains suspected despite an unreliable or negative cryoglobulin test.

Lessons on case presentation and clinical learning

• Make clear who provided the history. If a family member supplied it, present the history as coming from that source rather than implying the patient gave it directly.
• Avoid vague phrases such as “treated conservatively” unless specific treatment options were offered and declined, or a definitive intervention was deliberately not pursued. Name the actual treatment given.
• Avoid saying urine output was “normal” without useful context. More informative wording may be that the patient had no reported oliguria or anuria.
• Organize hospitalizations and symptom progression chronologically, including dates or approximate durations. Keep pregnancy and other past events in a clear timeline.
• In the physical examination, prioritize relevant positive and negative findings and explain why they matter.
• The senior clinician’s broader diagnostic method was to:
  1. Begin with the clinical syndrome and avoid prematurely committing to one disease.
  2. Build a structured differential diagnosis and keep alternatives open.
  3. Use history, examination, urine microscopy, laboratory tests, and biopsy findings together.
  4. Ask what additional findings would support or weaken each possibility.
  5. Seek specialist input and review pathology details, including IF and electron microscopy, when needed.
• For clinical learning, trainees were encouraged to write and present a differential diagnosis for at least one patient each day, ask an attending to review their reasoning, and learn directly from patients and test results. The speakers emphasized that a sound, systematic approach matters more than guessing the final diagnosis immediately.

Speakers and sources featured

• Case presenter/trainee: Presented the patient’s history, examination, investigations, and treatment course.
• Senior professor/attending: Led the questioning and teaching discussion, including feedback on clinical reasoning and case presentation.
• Other trainees/audience members: Answered questions and contributed diagnostic possibilities.
• Patient and husband as history sources: The case history was reported as having been obtained reliably from the husband because the patient was distressed and unable to provide it clearly at the time.
• Clinical records and test results: The discussion referred to laboratory studies, kidney-biopsy findings, and subsequent clinical developments; these are presented through the case discussion rather than as separate speakers.