A 34-year-old man who has injected heroin for the past 10 years is admitted to the Emergency Department. You notice on the computer that his serum creatinine has been slowly rising over recent years. His latest results show the following:
What is the most likely cause of his deteriorating renal function?
Correct Answer A: Heroin is a known cause of focal segmental glomerulosclerosis.
Focal segmental glomerulosclerosis:
Focal segmental glomerulosclerosis is cause of nephrotic syndrome and chronic kidney disease. It generally presents in young adults.
Causes:
Focal segmental glomerulosclerosis is noted for having a high recurrence rate in renal transplants.
A 43-year-old is referred to the renal clinic after presenting with peripheral oedema. He has no past medical history of note. Routine bloods ordered by his GP showed the following:
On examination in the clinic he has pitting oedema of the ankles and his blood pressure is 160/92 mmHg. A renal biopsy is ordered and reported as follows:
Light microscopy:
Given the likely diagnosis, which one of the following drugs is most likely to be beneficial?
Correct Answer A: This patient has membranous glomerulonephritis. The history is typical with a middle-aged man presenting with nephrotic syndrome and characteristic biopsy findings.
Corticosteroids by themselves have not been shown to be effective in membranous glomerulonephritis. ACE inhibitors have however been shown to reduce proteinuria.
Membranous glomerulonephritis:
Membranous glomerulonephritis is the commonest type of glomerulonephritis in adults and is the third most common cause of end-stage renal failure (ESRF). It usually presents with nephrotic syndrome or proteinuria.
Renal biopsy demonstrates:
Prognosis - rule of thirds:
Management:
A 29-year-old man has his renal function checked. The eGFR is calculated to be 54 ml/min.
Which one of the following factors is most likely to explain this unexpectedly low result?
Correct Answer E: The eGFR is often inaccurate in people with extremes of muscle mass. Body builders often have an inappropriately low eGFR.
Chronic kidney disease: eGFR and classification:
Serum creatinine may not provide an accurate estimate of renal function due to differences in muscle. For this reason formulas were develop to help estimate the glomerular filtration rate (estimated GFR or eGFR). The most commonly used formula is the Modification of Diet in Renal Disease (MDRD) equation, which uses the following variables:
Factors which may affect the result:
CKD may be classified according to GFR:
*i.e. normal U&Es and no proteinuria
Which one of the following is associated with a better prognosis in patients with IgA nephropathy?
Correct Answer D:
IgA nephropathy:
Basics:
Differentiating between IgA nephropathy and post-streptococcal glomerulonephritis:
Presentations:
Associated conditions:
Prognosis:
Autosomal dominant polycystic kidney disease type 2 is associated with a gene defect in:
Correct Answer A: ADPKD type 2 = chromosome 4 = 15% of cases.
ADPKD:
Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited cause of kidney disease, affecting 1 in 1,000 Caucasians. Two disease loci have been identified, PKD1 and PKD2, which code for polycystin-1 and polycystin-2 respectively.
The screening investigation for relatives is abdominal ultrasound:
Ultrasound diagnostic criteria (in patients with positive family history):
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