Nephrotic Syndrome

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | Example Management | References

Definition

Nephrotic syndrome is a kidney disorder characterised by a group of symptoms including proteinuria (excess protein in the urine), hypoalbuminaemia (low blood albumin levels), hyperlipidaemia (high levels of lipids in the blood), and oedema (swelling).

Aetiology

Nephrotic syndrome can result from various causes, including:

• Primary causes: Directly affecting the kidneys (e.g., minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy).
• Secondary causes: Resulting from systemic diseases or conditions (e.g., diabetes mellitus, systemic lupus erythematosus, infections, certain medications, and malignancies).

Pathophysiology

Nephrotic syndrome involves damage to the glomeruli, the filtering units of the kidneys, leading to increased permeability to proteins. This results in significant protein loss in the urine, hypoalbuminaemia, and subsequent oedema. The liver compensates by increasing lipid production, leading to hyperlipidaemia.

Risk Factors

• Genetic predisposition.
• Infections: Such as hepatitis B, hepatitis C, and HIV.
• Autoimmune diseases: Such as lupus and IgA nephropathy.
• Medications: Nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics like penicillamine, and certain chemotherapy drugs.
• Systemic diseases: Diabetes mellitus and amyloidosis.

Signs and Symptoms

• Oedema: Swelling, particularly around the eyes, ankles, and feet.
• Proteinuria: Foamy urine due to excess protein.
• Hypoalbuminaemia: Low levels of albumin in the blood.
• Hyperlipidaemia: High levels of lipids in the blood.
• Weight gain: Due to fluid retention.
• Fatigue and general malaise.
• Increased risk of infections and blood clots.

Investigations

• Clinical history and physical examination.
• Urinalysis: To detect proteinuria and other abnormalities.
• Blood tests: Serum albumin, cholesterol levels, renal function tests, and electrolytes.
• Renal biopsy: To determine the underlying cause of nephrotic syndrome and guide treatment.
• Imaging: Ultrasound of the kidneys to assess kidney size and structure.

Management

Primary Care Management

• Monitoring: Regular follow-up to assess kidney function, blood pressure, and symptoms.
• Medications: Diuretics to manage oedema, angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) to reduce proteinuria and control blood pressure.
• Lifestyle modifications: Dietary changes to reduce salt and fat intake, maintain a healthy weight, and manage cholesterol levels.
• Patient education: Inform about the condition, its complications, and the importance of adhering to treatment and monitoring plans.
• Referral to a specialist: If the patient does not respond to initial treatment or if there are complications.

Specialist Management

• Advanced therapies: Immunosuppressive medications (e.g., corticosteroids, cyclophosphamide, or rituximab) for certain types of nephrotic syndrome.
• Treatment of underlying conditions: Management of systemic diseases such as diabetes or lupus.
• Management of complications: Addressing infections, thromboembolic events, and cardiovascular risk.
• Dialysis: For patients with end-stage renal disease.
• Kidney transplant: In cases where other treatments are ineffective and the patient progresses to kidney failure.
• Multidisciplinary care: Involving nephrologists, dietitians, and other healthcare professionals for comprehensive management.

Example Management for Nephrotic Syndrome

A patient presenting with oedema and proteinuria should undergo a thorough evaluation including urinalysis, blood tests, and possibly a renal biopsy to determine the underlying cause. Initial management may include diuretics to control oedema, ACE inhibitors or ARBs to reduce proteinuria and manage blood pressure, and lifestyle modifications such as reducing salt and fat intake. If the patient does not respond to initial treatment, referral to a nephrologist is necessary for further evaluation and management, which may include immunosuppressive therapy. Regular follow-up is essential to monitor kidney function, manage complications, and adjust treatment as needed.

References

1. NICE. (2024). Chronic Kidney Disease: Assessment and Management. Retrieved from NICE
2. NHS. (2023). Nephrotic Syndrome. Retrieved from NHS
3. National Kidney Foundation. (2021). Nephrotic Syndrome. Retrieved from National Kidney Foundation
4. American Journal of Kidney Diseases. (2022). Guidelines for the Management of Nephrotic Syndrome.

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