OSCE — Nephrotic Syndrome

Station instructions (to candidate)

A 35-year-old man presents to the outpatient department with progressive swelling of the face and legs over 3 weeks. He has noticed his urine is frothy. He is otherwise well, with no past medical history. Examine and manage.

Vital signs: BP 138/88 mmHg, pulse 84/min, afebrile, weight ↑3 kg in 3 weeks.

Examiner checklist (assess each — done / partial / not done)

History (2 min)

• Confirms onset, distribution and timing of oedema (periorbital, dependent)
• Asks about frothy urine, weight gain, abdominal distension
• Drug history (NSAIDs, lithium) and systemic symptoms (rash, fever — secondary causes)
• Past history: diabetes, hypertension, malignancy, hepatitis/HIV

Examination (2 min)

• Assesses oedema: periorbital, sacral/ankle, ascites, pleural effusion, genital
• Fluid status: JVP, blood pressure, weight
• Looks for a secondary cause: fundoscopy, skin, joints, macroglossia, lymph nodes, abdominal masses
• Screens for complications: DVT (calf), basal crackles, signs of infection

Investigations (2 min)

• Urinalysis (4+ protein) + quantification: 24-h protein or UPCR (over 300 mg/mmol)
• Bloods: albumin (under 30 g/L), renal function, lipid profile, FBC, glucose/HbA1c
• Urine microscopy: oval fat bodies / Maltese cross (lipiduria); absence of RBC casts
• Serology: ANA, anti-dsDNA, complement, HBsAg/HCV/HIV, serum free light chains, anti-PLA2R
• States indication for renal biopsy (all adults)

Diagnosis (1 min)

• States nephrotic syndrome with the tetrad
• Offers a differential of the cause (membranous nephropathy, FSGS, secondary — diabetes/lupus/amyloid/malignancy)

Management (2 min)

• General: salt restriction, loop diuretic (furosemide 40 mg) for oedema
• Antiproteinuric cornerstone: ACE inhibitor/ARB
• Cause-specific: prednisolone for MCD; rituximab/cyclophosphamide for high-risk membranous; treat secondary causes
• Complication prevention: anticoagulation when albumin under 25-30 g/L; vaccination (pneumococcal, influenza, hepatitis B)
• Recognises red flags: renal vein thrombosis (flank pain, haematuria), spontaneous peritonitis

Key questions to ask the candidate

1. What defines nephrotic syndrome? — Tetrad (proteinuria over 3.5 g/day, albumin under 30 g/L, oedema, hyperlipidaemia/lipiduria).
2. Why must you biopsy this patient? — All adults with nephrotic syndrome are biopsied (children are biopsied only if atypical or steroid-resistant).
3. At what albumin would you anticoagulate, and why? — Under 25-30 g/L (loss of antithrombin III, high fibrinogen); highest risk in membranous nephropathy.
4. Which vaccination is essential? — Pneumococcal, influenza, hepatitis B (loss of IgG/complement — encapsulated organisms).

Common errors to flag

• Forgetting the ACE inhibitor/ARB (the antiproteinuric backbone).
• Not anticoagulating a severely hypoalbuminaemic patient.
• Failing to vaccinate.
• Over-diuresis precipitating AKI.
• Missing renal vein thrombosis in a patient with new flank pain and haematuria.