20 Sept 2026 · Case #015
Anti-GBM disease (Goodpasture syndrome)
This page works the case through in full, answer included. If you would rather reason it out yourself: Play this case
Diagnosis
Anti-GBM disease (Goodpasture syndrome)
First-line treatment
Plasma exchange with cyclophosphamide and corticosteroids
How the diagnosis is reached
A creatinine that was normal six weeks ago and reads 4.2 mg/dL today is what makes this glomerulonephritis rapidly progressive, and set beside haemoptysis it defines a pulmonary–renal syndrome. The differential there is narrow: anti-GBM disease, ANCA-associated vasculitis (granulomatosis with polyangiitis or microscopic polyangiitis), and lupus nephritis. The serology separates them decisively here: a high anti-GBM titre with negative ANCA, negative ANA and normal complement. The absence of ENT involvement, rash, arthralgia and neuropathy argues further against systemic vasculitis, and normal complement with a negative ASO titre excludes post-streptococcal disease. Dysmorphic red cells and red cell casts confirm a glomerular rather than urological source of bleeding. The biopsy is definitive: linear IgG along the basement membrane reflects antibody directed at the α3 chain of type IV collagen, in contrast to the granular deposits of immune-complex disease or the pauci-immune pattern of ANCA vasculitis. Crescents all of the same age indicate a single injurious event rather than the relapsing course typical of vasculitis. Smoking is a recognised trigger for alveolar involvement, since it damages the capillary endothelium and grants the antibody access to pulmonary basement membrane. Treatment is urgent: plasma exchange to strip circulating antibody, cyclophosphamide to halt its production, and corticosteroids to control the inflammation already under way, with exchange continued until antibody is undetectable, typically two to three weeks. Timing decides the kidney here. A creatinine of 4.2 mg/dL with no dialysis requirement yet puts him on the treatable side of the line, since patients presenting above roughly 5.7 mg/dL or already dialysis-dependent seldom recover renal function whatever is given.
Key clinical clues
- Pulmonary–renal syndrome: haemoptysis with rapidly progressive glomerulonephritis
- Dysmorphic red cells and red cell casts confirming a glomerular bleeding source
- High anti-GBM titre with negative ANCA, negative ANA and normal complement
- No ENT, skin, joint or nerve involvement, argues against ANCA vasculitis
- Linear IgG along the glomerular basement membrane on immunofluorescence
The case in full
Presenting complaint
Patient history
A 27-year-old smoker has three weeks of fatigue and breathlessness on stairs. For four days he has coughed up small amounts of blood, and yesterday his urine turned cola-coloured. There is no rash, joint pain, sinus congestion, nosebleed, sore throat or skin infection.
Examination and observations
Physical examination
He is pale with fine bibasal inspiratory crackles and mild pitting edema to the ankles. There is no purpuric rash, no nasal crusting or septal collapse, and no evidence of scleritis or peripheral neuropathy.
| Parameter | Value | Reference |
|---|---|---|
| Blood pressure | 162/98 mmHg | – |
| Heart rate | 98 bpmRef 60–100 | 60–100 |
| SpO₂ (room air) | 91 %Ref 95–100 | 95–100 |
| Temperature | 37.1 °CRef 36.1–37.5 | 36.1–37.5 |
Blood count and renal function
Laboratory results
Bloods are sent. A creatinine checked by his family doctor six weeks ago was normal.
| Parameter | Value | Reference |
|---|---|---|
| Creatinine | 4.2 mg/dLRef 0.7–1.3 | 0.7–1.3 |
| Urea | 78 mg/dLRef 8–24 | 8–24 |
| Potassium | 5.6 mmol/LRef 3.5–5.1 | 3.5–5.1 |
| Hemoglobin | 8.4 g/dLRef 13.5–17.5 | 13.5–17.5 |
| Platelets | 312 ×10⁹/LRef 150–400 | 150–400 |
Urinalysis and microscopy
Laboratory results
A fresh urine sample is examined under the microscope by the renal registrar.
| Parameter | Value | Reference |
|---|---|---|
| Blood (dipstick) | 3+Ref Negative | Negative |
| Protein (dipstick) | 2+Ref Negative | Negative |
| Urine protein:creatinine | 1.8 g/gRef <0.2 | <0.2 |
| Red cell morphology | DysmorphicRef Isomorphic | Isomorphic |
| Red cell casts | PresentRef Absent | Absent |
Immunology panel
Laboratory results
A full vasculitis and autoimmune screen is sent urgently.
| Parameter | Value | Reference |
|---|---|---|
| Anti-GBM antibody | 184 U/mLRef <7 | <7 |
| c-ANCA (anti-PR3) | NegativeRef Negative | Negative |
| p-ANCA (anti-MPO) | NegativeRef Negative | Negative |
| ANA | NegativeRef Negative | Negative |
| C3 / C4 | NormalRef Normal | Normal |
| ASO titre | Not raisedRef Not raised | Not raised |
Renal biopsy
Pathology
An urgent renal biopsy shows crescents in 68% of glomeruli, all at a similar stage of evolution. Immunofluorescence demonstrates smooth, continuous linear deposition of IgG along the glomerular basement membrane, with no granular deposits and no pauci-immune pattern.