Nephrotic Syndrome

This is an abbreviated version of the full GGC Guideline on Nephrotic Syndrome which can be accessed here.

Introduction

Nephrotic syndrome is defined clinically by:

Common causes of nephrotic syndrome

Multisystem disorders – e.g. Diabetes or Systemic Lupus Erythematous
Chronic inflammatory disorders (e.g. Inflammatory bowel disease, Rheumatoid arthritis)
Primary Glomerulonephritis (GN)
Secondary Glomerulonephritis due to obesity, hypertension or certain drugs
Malignancy including multiple myeloma

Review patient observations: blood pressure is often high and oxygen saturations low.
Outside of critical care areas, measurement of fluid intake/urinary output are often inaccurate. Weigh daily during admission whilst adjusting treatment, ideally using the same scales each time.
Examine daily for pulmonary oedema. Be wary of skin integrity and risk of infection.

Urinary protein:creatinine ratio
GN screen - ANCA, ANA, anti-GBM antibody, rheumatoid factor and C3/C4
Myeloma screen (in those aged >60 years) - serum electrophoresis, immunoglobulins and Bence-Jones protein
Virology testing (HCV, HBV, HIV)
Renal tract ultrasound

Nephrotic syndrome complications: protein malnutrition, hypovolaemia (often iatrogenic), acute kidney injury, thromboembolism and infection.

All cases of nephrotic syndrome should be referred to renal to discuss the need for a renal biopsy.

Salt restrict to <2g daily, fluid restrict to <1.5L daily.
Loop diuretics. IV administration is often necessary as absorption can be inhibited by generalised oedema.
Aim to lose ~1-2kg of body weight per day, using patient-predicted 'dry' body weight as a target.
Examples of diuretic regimes can be seen below in table 1.

Drugs	Initial dose suggestion	Cautions
Furosemide	Currently on diuretics Give usual dose as a stat IV dose, then give usual daily dose (e.g. 80mg daily, give 80mg IV daily). Inadequate response options: Increase dose Add further bolus at ~2pm Commence continuous infusion Diuretic naive: eGFR >60ml/minute: 40mg daily eGFR 30-60ml/minute: 80mg daily eGFR <30ml/minute: 120mg daily	Ototoxicity, hypokalaemia, hypovolaemia, acute renal decline.
Thiazide	Only commence on specialist/senior advice. Addition of bendroflumethiazide 2.5mg or metolazone 5mg on alternate or each day.	Profound hypovolaemia, hypokalaemia, hyponatraemia.
Amiloride	Weak diuretic effect, beneficial in preventing hypokalaemia. Amiloride 5mg daily	Hypovolaemia, hyperkalaemia.

Commence anti-hypertensives if necessary to control blood pressure (<140/90mmHg).
New or uncontrolled hypertension requires further investigations, see GGC Nephrotic Syndrome guidance.
Examples of anti-hypertensive regimens are shown in table 2.

Drug	Initial dose suggestion
ACE inhibitors	Avoid whilst using high dose diuretic due to risk of hypovolaemia induced AKI. Ramipril 2.5mg daily
Beta-blockers	Bisoprolol 2.5mg daily
Calcium channel blockers	Amlodipine 5mg daily

Refer patient to dieticians for protein and fat intake advice.
Commencing lipid-lowering therapy for nephrotic syndrome is not generally recommended in the absence of confirmed aetiology.

The greatest risk of venous thrombus occurs when serum albumin is <20g/L. Use mechanical measures to reduce risk of DVT in all patients
Do NOT commence anticoagulation without discussing with renal as this may delay, or substantially increase the risk from, performing a renal biopsy

All unexplained uPCR results >100mg/mmol should be discussed, non-urgently with renal; out-patient follow-up may be required
Transient proteinuria often occurs in association with a systemic inflammatory response. A repeat sample in convalescence can clarify

Guideline reviewed: February 2023

Page last updated: March 2023