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Glomerulonephrites
Essentials
- Findings almost always include some degree of haematuria and proteinuria Proteinuria.
- Clinical signs often include hypertension and oedema. In patients with glomerulonephritis, it is important to treat even mild hypertension effectively.
- In rapidly progressive glomerulonephritis (RPGN), renal function deteriorates progressively over a few days or months. Workup and treatment of RPGN should be started urgently, often as an emergency case.
- The clinical pictures of different types of glomerulonephritis vary and cannot be used to define the type of disease. The course of disease also varies in patients with the same type of disease.
- Accurate diagnosis of glomerulonephritis nearly always requires renal biopsy.
Pathogenesis
- A group of inflammatory diseases of the renal glomeruli leading to structural and functional changes, such as changes in glomerular permeability
- The disease is initiated by immunological mechanisms, probably based on an underlying genetically defined reaction pattern (induced by the patient's own or foreign antigens, microbes, medicines).
- The condition occurs either as a primary disease restricted to the kidneys or part of a systemic disease (SLE, systemic vasculitis).
Clinical pictures of different types of glomerulonephritis
- Glomerulonephritis can have various clinical presentations.
- Clinical picture of nephritis
- Rapidly progressive glomerulonephritis
- Nephrotic syndrome
- Asymptomatic haematuria and/or proteinuria
- Renal failure
- Different types of glomerulonephritis may have a similar clinical picture and, on the other hand, the clinical picture of the same type of glomerulonephritis may vary in individual patients.
- The clinical picture often includes hypertension and, in patients with nephrosis, oedema.
- A nephritic clinical picture is an acute condition and may lead to acute renal failure but the symptoms may also be milder and self-limited.
- All these types of glomerulonephritis have several possible aetiologies.
- Plasma creatinine levels may be normal or elevated and the estimated glomerular filtration rate (eGFR) may be normal or decreased.
- Untreated, all forms may lead to chronic renal failure.
- Chronic forms of disease are often asymptomatic.
- Renal biopsy is needed for diagnosis.
- Glomerulonephritis may be associated with many systemic diseases, of which SLE Systemic Lupus Erythematosus (Sle) and different types of vasculitis are the most significant Vasculitides. In the follow-up of systemic diseases, urinary findings should be monitored, even if infrequently, and especially in association with any disease activation. If haematuria and/or proteinuria occur, a nephrologist should be consulted.
Acute nephritis or rapidly progressive glomerulonephritis (RPGN)
- Primary renal disease caused by an infection or a systemic disease
- Often associated with vasculitis (granulomatous polyangitis [GPA], microscopic polyangitis [MPA]), SLE or basement membrane nephritis (Goodpasture's syndrome).
- Acute glomerulonephritis occurring after a streptococcal disease (1-3 weeks after the primary infection) is an example of a classic postinfectious glomerulonephritis.
- Acute glomerulonephritis may also occur in connection with or after other infections (endocarditis, shunt nephritis, sepsis, viral hepatitis).
Symptoms and findings
- Haematuria, often red cell casts in urine (urinalysis, urine cells) ("nephritic sediment"), proteinuria (urine albumin/creatinine ratio, 24-hour urinary protein excretion)
- Often elevated plasma creatinine levels
- Oedema, hypertension
- Depending on the aetiology, often additionally general symptoms (in patients with systemic disease often mild fever, fatigue, rash, respiratory, joint or gastrointestinal tract symptoms)
- In rapidly progressive glomerulonephritis, renal function deteriorates progressively within a few days or weeks.
- Laboratory tests may help to confirm the diagnosis.
- Positive ANCA antibodies in patients with vasculitis
- Hypocomplementaemia and positive DNA antibodies in patients with SLE
- Positive basement membrane antibodies in patients with basement membrane nephritis
- A renal biopsy should be taken urgently to confirm the diagnosis.
Treatment and prognosis
- Treatment according to aetiology, and supportive treatment: treatment of hypertension and renal failure Treatment of Chronic Renal Failure
- For postinfectious glomerulonephritis treatment of the infection and supportive treatment
- For prolonged cases sometimes glucocorticoids
- The prognosis is good in children; in adults, the disease may become chronic.
- For vasculitis, SLE nephritis and basement membrane nephritis, immunosuppressive treatment (glucocorticoid, cyclophosphamide, azathioprine, mycophenolate, rituximab)
- Treatment for rapidly progressive glomerulonephritis should be started urgently.
- Initially often a massive dose of glucocorticoids i.v.
- For basement membrane nephritis and vasculitis plasma exchange
- For rapidly progressive glomerulonephritis sufficiently aggressive immunosuppressive treatment started early enough will improve the prognosis decisively.
Clinical picture of nephrosis
Aetiology
- Focal segmental glomerulosclerosis (FSGS)
- The most common form of glomerulonephritis causing nephrotic syndrome in adults
- May be primary or secondary to, for example, obesity or loss of nephrons.
- Minimal change glomerulonephritis (MCN)
- The most common form of glomerulonephritis causing nephrosis in children but may also occur in adults
- Adults sometimes have this as a paraneoplastic phenomenon.
- Membranous glomerulonephritis (MGN)
- A common cause of nephrosis in adults
- May be either idiopathic or associated with other diseases (SLE) or malignancies, for instance.
- Antibodies to phospholipase-A2-receptor (PLA2R) can often be detected in the idiopathic disease, in a small share of patients antibodies to thrombospondin type-1 domain containing 7A (THSD7A).
- Membranoproliferative glomerulonephritis (MPGN)
- There may be various underlying disorders such as infections (viral hepatitis, endocarditis, shunt nephritis), SLE, acquired or congenital disorders of the complement system or malignancies (solid tumours or haematological malignancies).
- IgA nephropathy Iga Nephropathy may sometimes present with a clinical picture of nephrosis.
- Renal biopsy will confirm the diagnosis.
Symptoms and findings
- Oedema, weight gain
- Proteinuria > 3 g/day, plasma albumin < 30 g/l, often additionally haematuria
- Sometimes elevated plasma creatinine levels and hypertension
- Severe nephrosis may be associated with acute renal failure.
- Hyperlipidaemia, increased risk of venous thrombosis
- Medication for proteinuria and hypertension: ACE inhibitor, ATR blocker Antiproteinuric and Renoprotective Effects of ACE Inhibitors and Angiotensin II Receptor Blockers
- Symptomatic treatment of oedema: salt restriction, diuretics
- Treatment of hyperlipidaemia; thrombosis prophylaxis should be considered
- Immunomodulatory treatment depending on the aetiology
- The long-term prognosis of minimal change glomerulonephritis is good. In other forms of glomerulonephritis, the prognosis depends on how well proteinuria can be controlled.
- If nephrotic symptoms (oedema, fluid overload) are pronounced and plasma creatinine is clearly elevated or increasing, urgent referral - possibly even as an emergency case - is indicated. Otherwise, normal referral is sufficient.
Clinical picture of haematuria-proteinuria
Aetiology
- May be primary or associated with systemic diseases.
- IgA mesangial glomerulonephritis Iga Nephropathy is the most common type of primary glomerulonephritis causing haematuria and proteinuria.
- Membranous glomerulonephritis, membranoproliferative glomerulonephritis and secondary focal segmental glomerulosclerosis may also present with haematuria and proteinuria.
Symptoms and findings
- Often an asymptomatic, incidental finding
- Haematuria (urinalysis, urine cells) and/or proteinuria < 3 g/day
- Patients with IgA mesangial glomerulonephritis often have periods of macrohaematuria in association with infections.
- Plasma creatinine level normal or elevated
- Hypertension
Follow-up
- Usually in specialized care
- Individual monitoring depending on the disease