A 67-year-old woman presents for review due to ankle swelling. She has a history of rheumatoid arthritis which was diagnosed when she was 24 years old and a 8 year history of type 2 diabetes mellitus. Her current medication includes metformin and methotrexate. On examination she has bilateral pitting lower limb oedema. A 24 hour urine collection is reported as follows: 24 hr urinary protein 4.8g
What is the most likely cause of her leg oedema?
Correct Answer D: This patient has developed nephrotic syndrome secondary to amyloidosis, a recognized complication of inflammatory conditions such as rheumatoid arthritis. Methotrexate is not a common cause of nephrotic syndrome. Diabetic nephropathy often presents as nephrotic syndrome but typically develops at least 15 years after onset.
Nephrotic syndrome causes:
1- Primary glomerulonephritis accounts for around 80% of cases:
2- Systemic disease (about 20%):
3- Drugs:
4- Others:
An sample of tissue from a renal biopsy is viewed using an electron microscope. Podocyte fusion is seen.
Which one of the following types of glomerulonephritis is most associated with this finding?
Correct Answer E: Podocyte fusion is seen in minimal change glomerulonephritis but may occasionally be a feature of focal segmental glomerulosclerosis as well. Minimal change glomerulonephritis however is far more common.
Minimal change glomerulonephritis:
Minimal change glomerulonephritis nearly always presents as nephrotic syndrome, accounting for 75% of cases in children and 25% in adults.
The majority of cases are idiopathic, but in around 10-20% a cause is found:
Features:
Management:
Prognosis is overall good, although relapse is common. Roughly:
*only intermediate-sized proteins such as albumin and transferrin leak through the glomerulus
A 54-year-old man who had a renal transplant two years ago is reviewed in clinic. He is currently taking a combination of cyclosporin and mycophenolate as immunosuppressive therapy. Two weeks ago he was discharged on oral fluconazole after inpatient treatment for a fungal pneumonia. His creatinine level has increased from 114 μmol/l before hospital admission to 187 μmol/l today.
What is the most likely factor contributing to this rise?
Correct Answer B: Fluconazole inhibits the metabolism of cyclosporin which increases the risk of cyclosporin nephrotoxicity.
Cyclosporin: Cyclosporin is an immunosuppressant which decreases clonal proliferation of T cells by reducing IL-2 release. It acts by binding to cyclophilin forming a complex which inhibits calcineurin, a phosphotase that activates various transcription factors in T cells.
Adverse effects of cyclosporin (note how everything is increased - fluid, BP, K+, hair, gums, glucose):
Interestingly for an immunosuppressant, cyclosporin is noted by the BNF to be 'virtually nonmyelotoxic'.
Indications:
Each of the following is a risk factor for renal stone formation, except:
Correct Answer E: Cystinuria, not cystinosis, is a risk factor for renal stone formation.
Renal stones:
Risk factors:
Risk factors for urate stones:
Drug causes:
Each one of the following is a recognized side-effect of erythropoietin, except:
Correct Answer D: Erythropoietin is a hematopoietic growth factor that stimulates the production of erythrocytes. The main uses of erythropoietin are to treat the anemia associated with chronic kidney disease and that associated with cytotoxic therapy.
Side-effects of erythropoietin:
There are a number of reasons why patients may fail to respond to erythropoietin therapy:
*the risk is greatly reduced with darbepoetin
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