Renal medicine for MRCP Part 1

A 24-year-old man notices his urine turned visibly red a day after the onset of a sore throat. This has happened before with colds. Urinalysis shows blood and protein with red-cell casts, and his creatinine is mildly raised. Complement levels are normal. What is the most likely diagnosis?

1. Glomerulonephritis correct Correct. Blood in the urine within a day of a sore throat, with red-cell casts, is IgA nephropathy, a type of glomerulonephritis.
2. Renal or bladder malignancy Painless, visible blood in the urine, caused by a tumour. That does not match blood in the urine at the same time as a sore throat, with red-cell casts and normal complement.
3. Interstitial nephritis A drop in kidney function caused by a drug or an immune reaction. Here, blood in the urine at the same time as a sore throat, with red-cell casts and normal complement points elsewhere.
4. Benign causes of haematuria Harmless causes of blood in the urine, such as hard exercise. It does not fit blood in the urine at the same time as a sore throat, with red-cell casts and normal complement.
5. Urinary tract infection Pain on passing urine and blood in the urine, caused by infection. But blood in the urine at the same time as a sore throat, with red-cell casts and normal complement does not point to it.

The point: Glomerulonephritis is a group of diseases in which the immune system damages the glomerulus, the tiny filter inside the kidney. This causes protein in the urine (proteinuria), blood in the urine (haematuria), and often a drop in how well the kidney works. It helps to split these diseases into two patterns. A nephritic pattern shows blood in the urine, red-cell casts (clumps of red blood cells shaped like the kidney tubules), high blood pressure, and a variable drop in kidney function. A nephrotic pattern shows heavy protein loss in the urine (over 3.5 grams a day), low blood albumin (hypoalbuminaemia), and swelling (oedema). The main nephritic causes are IgA nephropathy, which causes visible blood in the urine a day or two after a cold or sore throat and is the commonest primary glomerulonephritis; post-streptococcal glomerulonephritis, which appears a week or two after a throat or skin infection and comes with low complement (proteins that help fight infection); and the fast-moving, crescent-shaped pattern of anti-GBM disease (also called Goodpasture disease, where antibodies attack the kidney and lung) and ANCA-associated vasculitis (inflammation of small blood vessels caused by ANCA antibodies). The main nephrotic causes are minimal change disease (mostly in children), focal segmental glomerulosclerosis, and membranous nephropathy (linked to anti-PLA2R antibodies and, in older patients, cancer). Tests include urine testing and microscopy for casts, measuring how much protein is being lost, kidney function tests, complement levels, and a screen for autoimmune disease and infection, with a kidney biopsy as the definitive test that decides treatment. Treatment depends on the cause: controlling blood pressure and protein loss with an ACE inhibitor or an angiotensin receptor blocker (a blood-pressure drug) is the base for most patients, immune-suppressing drugs are used for aggressive or nephrotic disease, and rapidly progressive glomerulonephritis is a kidney emergency needing urgent immune-suppressing treatment, sometimes with plasma exchange (a treatment that filters harmful antibodies out of the blood).

Source: UK Kidney Association — clinical practice guidelines UK Kidney Association · tier 2, specialty society or college

A 24-year-old man notices his urine turned visibly red a day after the onset of a sore throat. This has happened before with colds. Urinalysis shows blood and protein with red-cell casts, and his creatinine is mildly raised. Complement levels are normal. What is the most appropriate management?

1. Nephrology referral Referral to a kidney specialist (nephrologist) for diagnosis and treatment. Here, blood in the urine at the same time as a sore throat, with red-cell casts and normal complement points elsewhere.
2. ACE inhibitor or angiotensin receptor blocker for proteinuria and blood pressure correct Correct. An ACE inhibitor or ARB cuts the protein loss and controls blood pressure, forming the base of treatment for IgA nephropathy.
3. Immunosuppression for aggressive or nephrotic disease Drugs that damp down the immune system, for aggressive or nephrotic disease, guided by the biopsy result. That does not match blood in the urine at the same time as a sore throat, with red-cell casts and normal complement.
4. Treat the underlying cause or trigger Treating the cause behind it, such as an infection or a cancer. But blood in the urine at the same time as a sore throat, with red-cell casts and normal complement does not point to it.
5. Urgent immunosuppression for rapidly progressive disease Urgent immune-suppressing treatment for the fast-moving crescentic form, because it is a kidney emergency. It does not fit blood in the urine at the same time as a sore throat, with red-cell casts and normal complement.

The point: Glomerulonephritis is a group of diseases in which the immune system damages the glomerulus, the tiny filter inside the kidney. This causes protein in the urine (proteinuria), blood in the urine (haematuria), and often a drop in how well the kidney works. It helps to split these diseases into two patterns. A nephritic pattern shows blood in the urine, red-cell casts (clumps of red blood cells shaped like the kidney tubules), high blood pressure, and a variable drop in kidney function. A nephrotic pattern shows heavy protein loss in the urine (over 3.5 grams a day), low blood albumin (hypoalbuminaemia), and swelling (oedema). The main nephritic causes are IgA nephropathy, which causes visible blood in the urine a day or two after a cold or sore throat and is the commonest primary glomerulonephritis; post-streptococcal glomerulonephritis, which appears a week or two after a throat or skin infection and comes with low complement (proteins that help fight infection); and the fast-moving, crescent-shaped pattern of anti-GBM disease (also called Goodpasture disease, where antibodies attack the kidney and lung) and ANCA-associated vasculitis (inflammation of small blood vessels caused by ANCA antibodies). The main nephrotic causes are minimal change disease (mostly in children), focal segmental glomerulosclerosis, and membranous nephropathy (linked to anti-PLA2R antibodies and, in older patients, cancer). Tests include urine testing and microscopy for casts, measuring how much protein is being lost, kidney function tests, complement levels, and a screen for autoimmune disease and infection, with a kidney biopsy as the definitive test that decides treatment. Treatment depends on the cause: controlling blood pressure and protein loss with an ACE inhibitor or an angiotensin receptor blocker (a blood-pressure drug) is the base for most patients, immune-suppressing drugs are used for aggressive or nephrotic disease, and rapidly progressive glomerulonephritis is a kidney emergency needing urgent immune-suppressing treatment, sometimes with plasma exchange (a treatment that filters harmful antibodies out of the blood).

Source: UK Kidney Association — clinical practice guidelines UK Kidney Association · tier 2, specialty society or college

A 24-year-old man notices his urine turned visibly red a day after the onset of a sore throat. This has happened before with colds. Urinalysis shows blood and protein with red-cell casts, and his creatinine is mildly raised. Complement levels are normal. What is the most appropriate definitive treatment?

1. Nephrology referral Referral to a kidney specialist (nephrologist) for diagnosis and treatment. Here, blood in the urine at the same time as a sore throat, with red-cell casts and normal complement points elsewhere.
2. Immunosuppression for aggressive or nephrotic disease Drugs that damp down the immune system, for aggressive or nephrotic disease, guided by the biopsy result. That does not match blood in the urine at the same time as a sore throat, with red-cell casts and normal complement.
3. Renal biopsy correct Correct. A kidney biopsy is the definitive test that confirms IgA nephropathy and decides treatment.
4. Treat the underlying cause or trigger Treating the cause behind it, such as an infection or a cancer. It does not fit blood in the urine at the same time as a sore throat, with red-cell casts and normal complement.
5. Manage oedema with salt restriction and diuretics Cutting salt intake and giving water tablets (diuretics) to manage the swelling of the nephrotic pattern. But blood in the urine at the same time as a sore throat, with red-cell casts and normal complement does not point to it.

The point: Glomerulonephritis is a group of diseases in which the immune system damages the glomerulus, the tiny filter inside the kidney. This causes protein in the urine (proteinuria), blood in the urine (haematuria), and often a drop in how well the kidney works. It helps to split these diseases into two patterns. A nephritic pattern shows blood in the urine, red-cell casts (clumps of red blood cells shaped like the kidney tubules), high blood pressure, and a variable drop in kidney function. A nephrotic pattern shows heavy protein loss in the urine (over 3.5 grams a day), low blood albumin (hypoalbuminaemia), and swelling (oedema). The main nephritic causes are IgA nephropathy, which causes visible blood in the urine a day or two after a cold or sore throat and is the commonest primary glomerulonephritis; post-streptococcal glomerulonephritis, which appears a week or two after a throat or skin infection and comes with low complement (proteins that help fight infection); and the fast-moving, crescent-shaped pattern of anti-GBM disease (also called Goodpasture disease, where antibodies attack the kidney and lung) and ANCA-associated vasculitis (inflammation of small blood vessels caused by ANCA antibodies). The main nephrotic causes are minimal change disease (mostly in children), focal segmental glomerulosclerosis, and membranous nephropathy (linked to anti-PLA2R antibodies and, in older patients, cancer). Tests include urine testing and microscopy for casts, measuring how much protein is being lost, kidney function tests, complement levels, and a screen for autoimmune disease and infection, with a kidney biopsy as the definitive test that decides treatment. Treatment depends on the cause: controlling blood pressure and protein loss with an ACE inhibitor or an angiotensin receptor blocker (a blood-pressure drug) is the base for most patients, immune-suppressing drugs are used for aggressive or nephrotic disease, and rapidly progressive glomerulonephritis is a kidney emergency needing urgent immune-suppressing treatment, sometimes with plasma exchange (a treatment that filters harmful antibodies out of the blood).

Source: UK Kidney Association — clinical practice guidelines UK Kidney Association · tier 2, specialty society or college