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Glomerulonephritis

Glomerulonephritis is a group of disorders that injure the kidney glomeruli—the microscopic filters that clean the blood. It can present with blood and protein in the urine, swelling, high blood pressure and reduced kidney function, and ranges from mild disease to rapidly progressive kidney failure.

At a glance

Quick facts

Condition snapshot
Affected structure
Kidney glomeruli
Urine clues
Blood · protein
Common signs
Edema · high blood pressure
Key tests
Urine · blood · serology
Definitive test
Kidney biopsy in selected cases
Treatment
Depends on cause and severity

Names & terminology

How this entity may be named or searched

Glomerulonephritis
An umbrella term for inflammatory or immune-mediated injury affecting the glomeruli.
Nephritic syndrome
A clinical pattern often featuring hematuria, reduced filtration, hypertension and variable proteinuria.
Nephrotic syndrome
A different glomerular pattern dominated by heavy protein loss, low albumin and edema; some diseases can overlap.
Rapidly progressive GN
A high-acuity pattern with rapid loss of kidney function, often requiring urgent biopsy and immunologic evaluation.

Structured entity profile

Clinical profile

Condition data
TargetGlomeruliDamage alters filtration of blood and retention of cells/protein.
UrinalysisHematuria + proteinuriaRed-cell casts can strongly support glomerular inflammation.
Kidney functionMay be preserved or decline rapidlyCreatinine trajectory helps determine urgency.
Systemic cluesSkin, joints, lungs, infectionsGlomerular disease may be kidney-limited or part of systemic autoimmune/infectious disease.
DiagnosisLaboratory pattern + serology ± biopsyBiopsy often identifies the exact disease pattern and guides treatment.
TreatmentCause-specificBlood-pressure/proteinuria control, immunosuppression or infection treatment may be needed.

Overview

The glomeruli are clusters of tiny blood vessels that filter water and small molecules while normally retaining blood cells and most proteins. When inflammation or immune injury disrupts this barrier, red blood cells and protein can leak into urine and filtration can fall. “Glomerulonephritis” therefore describes a family of diseases rather than one single diagnosis. [1] [2]

Some forms follow infection; others are associated with IgA nephropathy, lupus, ANCA-associated vasculitis, anti-GBM disease or other immune disorders. Glomerular injury may be acute, chronic or rapidly progressive. The same initial symptom—dark urine or swelling—can arise from very different diseases, so classification with laboratory testing and sometimes kidney biopsy is central to management. [1] [3]

Symptoms and warning signs

Possible features include pink, red or cola-colored urine, foamy urine from protein loss, swelling around the eyes or legs, high blood pressure, reduced urine output, fatigue, nausea and breathlessness from fluid overload. Some patients are discovered through abnormal urine or kidney blood tests before they feel unwell. Fever, rash, joint symptoms, sinus disease, coughing blood or recent infection can point toward a systemic cause. [1] [2]

SYMPTOM MATRIX

The urine pattern often provides the first clue

Rapidly rising creatinine, severe hypertension or lung bleeding greatly increases urgency.

Glomerular kidney disease
Typical clues
  • Blood in urine (visible or microscopic)
  • Protein in urine / foamy urine
  • Swelling around eyes, feet or legs
  • High blood pressure
  • Reduced kidney function on blood tests
Cause-specific clues
  • Recent throat or skin infection
  • Rash or joint pain
  • Sinus or lung symptoms
  • Fever or systemic illness
  • Reduced urine output
High-acuity features
  • Rapid fall in kidney function
  • Very low urine output
  • Breathlessness from fluid overload
  • Coughing blood / pulmonary hemorrhage
  • Severe hypertension with neurologic or cardiac symptoms

These patterns can require urgent nephrology assessment and kidney biopsy.

Diagnosis

Urinalysis measures blood and protein; urine microscopy can identify dysmorphic red cells and red-cell casts that suggest a glomerular source. Blood tests evaluate creatinine, estimated GFR, electrolytes, albumin and blood counts. Quantifying urine protein helps distinguish nephritic, nephrotic and mixed patterns. [1] [2]

Serologic testing is chosen according to the presentation and may include complement levels, ANA and lupus studies, ANCA, anti-GBM antibodies, hepatitis testing and tests for recent infection or monoclonal proteins. Kidney ultrasound assesses anatomy and helps establish biopsy safety. Kidney biopsy is often the key test when the cause is unclear, kidney function is declining or immunosuppressive treatment is being considered. [1] [3]

Diagnostic pathway

Define the glomerular pattern, then identify the immune or infectious cause

Treatment is most precise when urine findings, serology and pathology are interpreted together.

Nephrology work-up
1Confirm glomerular injuryUrinalysis, microscopy, protein quantification and kidney function tests establish the pattern.
2Assess severityTrack creatinine, urine output, blood pressure, edema, potassium and respiratory status.
3Use targeted serologyChoose autoimmune, complement, infection and monoclonal testing based on clinical clues.
4Biopsy when it changes managementKidney pathology can identify the disease pattern and urgency of immunosuppression.
Core urine findingsHematuria + proteinuriamicroscopy adds specificity
Tissue diagnosisKidney biopsyselected cases

The term “glomerulonephritis” is not sufficiently specific to choose immunosuppressive therapy without defining the underlying disease.

Major causes and disease families

Primary glomerular diseases include IgA nephropathy and other immune-complex or complement-mediated disorders. Secondary glomerulonephritis can occur with lupus, ANCA-associated vasculitis, anti-GBM disease, infections, some cancers and other systemic conditions. Post-infectious glomerulonephritis is one familiar pattern but is only one part of a much larger differential diagnosis. [1] [3]

Complications

Severe disease can cause acute kidney injury, fluid overload, hyperkalemia, metabolic acidosis and hypertensive emergencies. Persistent proteinuria and inflammation can scar glomeruli and lead to chronic kidney disease. A smaller group of immune diseases can also cause pulmonary capillaritis and life-threatening lung bleeding. [1] [2]

Treatment and management

Supportive treatment may include salt restriction, carefully managed diuretics for edema, blood-pressure control and renin–angiotensin system blockade when appropriate to reduce proteinuria. Drug doses may need adjustment as kidney function changes. Severe acute kidney injury may require dialysis for metabolic or fluid complications. [1] [2]

Disease-specific treatment varies widely. Some immune-mediated diseases require corticosteroids and other immunosuppressive or targeted agents; anti-GBM disease often requires plasma exchange plus immunosuppression; infection-related disease prioritizes treatment of the infection and supportive kidney care. These therapies can be harmful if used for the wrong pathology, which is why nephrology assessment and biopsy are often important. [1] [3]

Treatment & care hub

Treat the exact glomerular disease — not just the label

Supportive kidney protection runs alongside disease-specific therapy.

Cause-directed nephrology
Kidney protectionCommon

Control pressure, proteinuria and fluid

Supportive measures reduce complications and long-term kidney stress.

ImmunosuppressionSelected diseases

Suppress pathologic immunity

Steroids and other agents are chosen according to biopsy, serology and disease severity.

Infection careWhen causal

Treat the infection

Infection-related glomerular disease requires attention to the infectious trigger and kidney complications.

DialysisIf severe

Support kidney function temporarily or long term

Used for refractory fluid, electrolyte, acid-base or uremic complications.

Define pattern→Find cause→Protect kidney→Treat disease

Immunosuppressive therapy should be based on a specific diagnosis and specialist assessment.

Monitoring and prognosis

Follow-up tracks creatinine/eGFR, urine protein, hematuria, blood pressure, electrolytes and symptoms. Prognosis depends on the underlying disease, degree of chronic scarring, speed of diagnosis, response to therapy and recurrence risk. Even after an acute episode improves, persistent proteinuria or reduced eGFR can require long-term kidney follow-up. [1] [2]

When glomerulonephritis needs urgent assessment

Rapid loss of kidney function, very low urine output, severe fluid overload, hyperkalemia, severe hypertension, or coughing blood with kidney abnormalities can indicate rapidly progressive disease. These findings should not wait for routine outpatient follow-up. [1] [3]

Clinical evidence snapshot

Glomerulonephritis is a family of diseases, not one prevalence entity

Burden varies greatly by specific diagnosis, age, geography and access to kidney biopsy.

NIDDK — Glomerular Disease ↗
Core clinical patternblood + protein in urinewith variable kidney dysfunction
Definitive classificationoften kidney biopsy
Treatmentcause-specific
Scope: A single global prevalence number would mix biologically different glomerular diseases and is therefore not presented.

Common questions

Frequently asked questions

Reference content

Sources

  1. NIDDK — Glomerular Disease
  2. National Kidney Foundation — Glomerulonephritis
  3. NIDDK — Anti-GBM (Goodpasture’s) Disease
  4. NIDDK — IgA Nephropathy

This article is based on trusted medical sources and is awaiting clinician review. It is not a substitute for personalized medical advice.