A 12-year-old boy is investigated for a purpuric rash on the extensor surfaces of his lower legs. He also has a history of abdominal pain and an urticarial rash. The following results are obtained:
What would be the likely finding on renal biopsy?
Correct Answer D: Henoch-Schonlein purpura is associated with IgA nephropathy.
Henoch-Schonlein purpura:
Henoch-Schonlein purpura (HSP) is an IgA mediated small vessel vasculitis. There is a degree of overlap with IgA nephropathy (Berger's disease). HSP is usually seen in children following an infection.
Features:
Treatment:
Prognosis:
You are asked to review a 75-year-old female on the surgical wards due to hyperkalaemia. Results are as follows:
Plasma Urine:
What is the most likely diagnosis?
Correct Answer D: ATN or prerenal uraemia? In prerenal uraemia think of the kidneys holding on to sodium to preserve volume.
The low urine sodium points towards prerenal uraemia, as does the urine:plasma osmolality and urea ratio.
Acute renal failure: acute tubular necrosis vs. Prerenal uraemia:
Prerenal uraemia - kidneys hold on to sodium to preserve volume:
*Fractional sodium excretion = (urine sodium/plasma sodium) / (urine creatinine/plasma creatinine) x 100
**Fractional urea excretion = (urine urea /blood urea ) / (urine creatinine/plasma creatinine) x 100
Which of the following types of renal stones are said to have a semi-opaque appearance on x-ray?
Correct Answer B:
Renal stones on x-ray:
Renal stones: imaging:
The table below summarizes the appearance of different types of renal stone on x-ray:
*Stag-horn calculi involve the renal pelvis and extend into at least 2 calyces. They develop in alkaline urine and are composed of struvite (ammonium magnesium phosphate, triple phosphate). Ureaplasma urealyticum and Proteus infections predispose to their formation
A 65-year-old man who is known to have colorectal cancer is referred to the renal clinic. His GP performed a protein-creatinine ratio as he had been complaining of 'frothy' urine. The results suggest nephrotic range proteinuria which is confirmed on a 24-hour urinary collection.
Assuming the proteinuria is related to his colorectal cancer what is the renal histology most likely to show?
Correct Answer D: Nephrotic syndrome - malignancies cause membranous glomerulonephritis.
Patients with underlying malignancies such as lung, colon and gastric cancer may develop nephrotic syndrome as a paraneoplastic complication. There appears to be an association with HLA-DR3. Lymphomas tend to be associated with minimal change disease.
Nephrotic syndrome: causes:
Primary glomerulonephritis accounts for around 80% of cases:
Systemic disease (about 20%):
Drugs:
Others:
A 65-year-old man is seen in the Emergency Department complaining of muscle weakness and lethargy. Admission bloods show the following:
What is the most appropriate initial treatment to lower the serum potassium level?
Correct Answer C: Calcium gluconate would stabilize the myocardium but would not reduce the serum potassium level.
Hyperkalaemia: management:
Untreated hyperkalaemia may cause life-threatening arrhythmias. Precipitating factors should be addressed (e.g. acute renal failure) and aggravating drugs stopped (e.g. ACE inhibitors).
Management may be categorized by the aims of treatment: Stabilization of the cardiac membrane:
Short-term shift in potassium from extracellular to intracellular fluid compartment:
Removal of potassium from the body:
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