Makindo Medical Notes

Related Subjects: | Metabolic Acidosis | Lactic Acidosis | Acute Kidney Injury (AKI) | Renal Physiology | Chronic Kidney Disease (CKD) | Anaemia in CKD | Analgesic Nephropathy | Medullary Sponge Kidney | IgA Nephropathy (Berger's Disease) | HIV-associated Nephropathy (HIVAN) | Balkan Endemic Nephropathy (BEN) | Autosomal Dominant Polycystic Kidney Disease

Exam information: Patients with nephrotic syndrome have an increased risk of venous thrombosis due to the loss of antithrombin III in the urine. Additionally, while these patients may exhibit significant oedema, their relative circulating volume is often reduced.

About Nephrotic Syndrome

• Proteinuria > 3–4.5 g/day
• Hypoalbuminaemia < 30 g/L
• Peripheral oedema or anasarca (generalized swelling)
• Raised cholesterol levels (often > 10 mmol/L)

Additional Findings

• Thrombophilia: Loss of antithrombin III in urine increases the risk of DVT and renal vein thrombosis.
• Increased Risk of Infection: Renal loss of immunoglobulins raises susceptibility to infections, especially sepsis.
• Renal Vein Thrombosis: Presents with acute renal angle tenderness, pain, and haematuria.

Primary Causes of Nephrotic Syndrome

• Minimal Change Disease (most common in children)
• Focal Segmental Glomerulosclerosis (FSGS)
• Membranous Nephropathy

Secondary Causes

• Diabetes Mellitus
• Amyloidosis
• Multiple Myeloma
• Preeclampsia
• Drugs: Gold, Penicillamine, Captopril, NSAIDs
• Infections: Malaria, Leprosy, Hepatitis B Virus (HBV), Systemic Lupus Erythematosus (SLE)
• Malignancies: Lymphoma, Carcinoma, Chronic Lymphocytic Leukemia (CLL)

Clinical Presentation

• Oedema: Most pronounced in the morning, often affecting the face.
• Anasarca: Massive, generalized oedema.
• Frothy Urine: Caused by proteinuria.

Investigations

• Full Blood Count (FBC) and Clotting tests
• Low serum albumin (<30 g/L)
• Urine protein > 3 g/L (spot urine protein/creatinine ratio)
• Inflammatory markers: CRP, ESR
• Immunoelectrophoresis
• C3 and C4 levels (often low in SLE)
• ANCA (to rule out Wegener's Granulomatosis)
• Chest X-ray (to rule out malignancy or infection)
• Renal ultrasound
• Raised cholesterol and triglycerides

Management of Nephrotic Syndrome

• Identify the underlying cause: Renal biopsy may be required for diagnosis.
• Salt restriction: Helps manage oedema.
• Diuretics: Thiazide, loop diuretics, or Metolazone may be used to control fluid retention.
• IV Salt-Poor Albumin: Rarely used today, but can be considered in cases of severe hypovolaemia.
• Low-Molecular-Weight Heparin (LMWH): For the prevention of DVT/PE due to hypercoagulability.
• Frequent Weighing: To assess fluid balance and adjust diuretics accordingly.

Specific Management Based on Cause

• Minimal Change Disease: First-line treatment is corticosteroids; Cyclophosphamide can be considered in refractory cases.
• Membranous Nephropathy: Options include ACE inhibitors, corticosteroids, Cyclophosphamide, Chlorambucil, or Rituximab.
• Lupus Nephritis: Combination therapy with Prednisolone and Cyclophosphamide or Mycophenolate is used.
• Diabetic Nephropathy: Strict control of blood sugar, BP management with ACE inhibitors/ARBs, and lifestyle changes are essential.
• Vasculitis: Treated with Prednisolone and Azathioprine.
• Amyloidosis: Management focuses on treating the underlying cause.
• HIVAN (HIV-associated Nephropathy): Treatment includes HAART (Highly Active Antiretroviral Therapy) and, in some cases, ACE inhibitors/ARBs for proteinuria control.