Nephritic syndrome is a clinical picture of glomerular inflammation that leads to:
Haematuria (often dark, cola-coloured urine)
Proteinuria (usually mild–moderate, not nephrotic range)
Hypertension
Oedema (commonly periorbital or in the legs)
Reduced kidney function (low GFR)
🚨 It can progress rapidly, especially in severe cases such as rapidly progressive glomerulonephritis (RPGN).
Glomerular inflammation damages capillary walls.
This allows red blood cells and proteins to leak into urine.
Inflammatory injury also reduces filtration, causing sodium retention, hypertension, and oedema.
💡 A key urine clue is the presence of red cell casts, which strongly suggests glomerular bleeding.
| Cause | Typical Context |
|---|---|
| Post-streptococcal GN | Children, after throat/skin infection |
| IgA nephropathy | Young adults, haematuria after URTI |
| Lupus nephritis | Patients with systemic lupus erythematosus |
| Membranoproliferative GN | Often infection-related or with immune complexes |
| Rapidly progressive GN (RPGN) | ANCA vasculitis, anti-GBM disease, severe lupus |
| Alport syndrome | Inherited, with hearing loss and eye involvement |
🚨 RPGN is a medical emergency and can cause renal failure within days to weeks.
Haematuria (microscopic or visible)
Oedema (especially around eyes, legs)
Hypertension
Oliguria (low urine output)
Proteinuria (but not usually nephrotic range)
Symptoms linked to cause (rash in lupus, sore throat post-strep, arthralgia in autoimmune disease)
Urine dipstick/microscopy: blood, protein, red cell casts
Blood tests: U&E, creatinine, eGFR
Serology: may help point to cause (e.g. ANA for lupus, ANCA for vasculitis)
Imaging: renal ultrasound mainly to exclude obstruction
Renal biopsy: often needed in adults for diagnosis and treatment planning
💡 A renal biopsy is especially important in suspected RPGN to guide urgent therapy.
Supportive care: fluid and salt control, diuretics for oedema, blood pressure management, dialysis if severe
Treat underlying cause: e.g. immunosuppression in autoimmune disease, supportive care post-streptococcal infection
Urgent therapy may be life-saving in RPGN (specialist input needed)
🚨 Always involve nephrology early if RPGN is suspected.
Acute kidney injury (AKI)
Chronic kidney disease (CKD)
Pulmonary oedema
End-stage renal disease if uncontrolled
| Feature | Nephritic | Nephrotic |
|---|---|---|
| Proteinuria | Mild–moderate | Heavy (>3.5 g/day) |
| Haematuria | Common | Rare |
| Oedema | Periorbital/leg, moderate | Generalised, severe |
| BP | Often raised | May be normal or raised |
| Serum albumin | Normal/slightly ↓ | Markedly ↓ |
| Lipids | Normal/mild ↑ | High (hyperlipidaemia) |
| Key risk | AKI, CKD | Thrombosis, infection |
💡 Nephritic = inflammation, Nephrotic = permeability defect.
Fries Tips
Think of nephritic syndrome when you see haematuria, proteinuria, and hypertension together.
Red cell casts on microscopy are a hallmark sign.
Always consider autoimmune causes in adults.
Rapidly progressive cases need urgent specialist treatment.
Distinguishing nephritic from nephrotic syndrome is crucial for management decisions.
