Makindo Medical Notes

Related Subjects: |Metabolic acidosis |Lactic acidosis |Acute Kidney Injury (AKI) / Acute Renal Failure |Renal/Kidney Physiology |Chronic Kidney Disease (CKD) |Anaemia in Chronic Kidney Disease |Analgesic Nephropathy |Medullary Sponge kidney |IgA Nephropathy (Berger's disease) |HIV associated nephropathy (HIVAN) |Balkan endemic nephropathy (BEN) |Autosomal Dominant Polycystic kidney disease

Rapid diagnosis, especially of the rapidly progressive form, can allow early treatment and significantly improve outcomes. Measuring ANCA and anti-GBM antibodies is essential for early diagnosis.

About

• Glomerulonephritis (GN): Inflammation of the glomerulus, often triggered by an immune-mediated response.
• Involves structural changes to the basement membrane, mesangium, or capillary endothelium in the glomeruli.
• Can be caused by antibody-mediated injury, complement activation, or cell-mediated immunity.

Classifications

• Clinical: Nephritic vs. Nephrotic syndrome.
• Treatment Response: Steroid responsive vs. Non-steroid responsive.
• Aetiology: For example, post-streptococcal GN.
• Histology: Focal (some glomeruli), diffuse (all glomeruli), segmental (part of glomerulus), or with basement membrane changes and sclerosis.

Primary GN: Aetiological Classification

• Minimal Change Disease
• Focal Segmental Glomerulosclerosis (FSGS)
• Membranous Nephropathy
• IgA Nephropathy (Berger's disease)
• Rapidly Progressive Glomerulonephritis (Anti-GBM disease and pauci-immune GN)
• Post-Streptococcal Glomerulonephritis
• Membranoproliferative Glomerulonephritis (MPGN)

Secondary GN

• Lupus Nephritis (associated with Systemic Lupus Erythematosus - SLE)

Clinical Features

• Acute onset of haematuria, proteinuria, and red blood cell casts in urine.
• Hypertension, oedema, and impaired renal function.
• Severe hypertension with headache or neurological symptoms is ominous and may indicate progression.

Investigations

• Full Blood Count (FBC): Anaemia.
• Urinalysis: Red cell casts, proteinuria, and haematuria.
• Urea & Electrolytes (U&E): Measure urea, creatinine, potassium (K⁺), and calcium.
• ESR/CRP: May be elevated, indicating systemic inflammation.
• Blood Gas Analysis: Check HCO₃ for metabolic acidosis.
• Immunological Tests:
• Anti-nuclear antibodies (ANA)
• Extractable nuclear antigen (ENA)
• Anti-neutrophil cytoplasmic antibody (ANCA)
• Anti-glomerular basement membrane (Anti-GBM) antibodies
• Cryoglobulins
• Complement levels (C3, C4)
• Anti-streptolysin O titre (ASOT)
• Serum Protein Electrophoresis: To assess for underlying plasma cell disorders.
• 24-hour Urinary Protein Loss: Helps quantify proteinuria.
• Renal Ultrasound & Renal Biopsy: To assess kidney structure and confirm diagnosis via histology.

Complement Levels

• Complement levels can help in diagnosing the cause of acute glomerulonephritis.
• Low Complement Levels: Seen in cryoglobulinaemia, systemic lupus erythematosus (SLE), bacterial endocarditis, shunt nephritis, membranoproliferative GN, and post-streptococcal GN.
• Normal Complement Levels: Seen in polyarteritis nodosa, Goodpasture syndrome, Henoch-Schönlein purpura, idiopathic rapidly progressive GN, and IgA nephropathy.

Management

• Admit patients if they present with anuria, nephrotic syndrome, massive proteinuria, significant hypertension, or pulmonary symptoms.
• Restrict fluids in patients with significant oedema or fluid overload.
• Loop diuretics are indicated for nephrotic syndrome or massive proteinuria to manage fluid overload.
• Severe hypertension with neurological symptoms requires urgent management with calcium channel blockers and nitroprusside.

Indications for Steroids

• Vasculitis: Steroids are the cornerstone of treatment.
• Systemic Lupus Erythematosus (SLE): Steroid therapy is indicated.
• Henoch-Schönlein Purpura: Steroids may help manage kidney involvement.
• Granulomatosis with Polyangiitis: Initially treat with steroids, followed by oral cyclophosphamide.
• Idiopathic Rapidly Progressive Glomerulonephritis: Pulse intravenous methylprednisolone is used to reduce the risk of progression to end-stage renal disease.
• Goodpasture Syndrome: Plasmapheresis is combined with immunosuppression (prednisone and cyclophosphamide). High-dose pulse steroids are effective for pulmonary haemorrhage.