100 Cases in Clinical Medicine

(Rick Simeone) #1

ANSWER 9


This patient presents with the typical symptoms of end-stage renal failure, namely anorexia,
nausea, weight loss, fatigue, pruritus and cramps.


The elevated urea and creatinine levels confirm renal failure but do not distinguish between
acute and chronic renal failure. Usually, in the former, there is either evidence of a systemic
illness or some other obvious precipitating cause, e.g. use of nephrotoxic drugs/prolonged
episode of hypotension, whereas in the latter there is a prolonged history of general
malaise. If the patient has had previous blood tests measuring serum creatinine, these will
be informative about the progression of deterioration of renal function. In this patient, the
anaemia and hyperparathyroidism (raised alkaline phosphatase) are features indicating
chronicity of the renal failure. The normochromic, normocytic anaemia is predominantly
due to erythropoietin deficiency (the kidney is the major source of erythropoietin produc-
tion). Hyperparathyroidism is a result of elevated serum phosphate levels due to decreased
renal clearance of phosphate and reduced vitamin D levels (the kidney is the site of hydrox-
ylation of 25-hydroxycholecalciferol to the active form 1,25-dihydroxycholecalciferol).
A hand X-ray showing the typical appearances of hyperparathyroidism (erosion of the ter-
minal phalanges and subperiosteal erosions of the radial aspects of the middle phalanges),
implying long-standing renal failure can be helpful in distinguishing chronic and acute
renal failure.


Renal ultrasound is the essential investigation. Ultrasound will accurately size the kidneys,
and identify obvious causes for renal failure such as polycystic kidney disease or obstruc-
tion causing bilateral hydronephrosis. Asymmetrically sized kidneys suggest reflux
nephropathy or renovascular disease. In this case, ultrasound showed two small (8 cm)
echogenic kidneys consistent with long-standing renal failure. A renal biopsy in this case
is not appropriate as biopsies of small kidneys have a high incidence of bleeding compli-
cations, and the sample obtained would show extensive glomerular and tubulo-interstitial
fibrosis and may not identify the original disease. The patient’s renal failure may have been
due to hypertension, or a primary glomerulonephritis such as IgA nephropathy. African-
Caribbeans are more prone to develop hypertensive renal failure than other racial groups.


Antihypertensive medications are needed to treat her blood pressure adequately, oral phos-
phate binders and vitamin D preparations to control her secondary hyperparathyroidism,
and erythropoietin injections to treat her anaemia. The case raises the dilemma of whether
dialysis is appropriate in this patient. Hospital-based haemodialysis or home-based peri-
toneal dialysis are the options available. Her age and comorbid illnesses preclude renal
transplantation. Conservative management without dialysis may be appropriate in this case.



  • Patients often become symptomatic due to renal failure only when their glomerular
    filtration rate (GFR) is !15 mL/min, and thus may present with end-stage renal failure.

  • Previous measurements of serum creatinine enable the rate of deterioration of renal
    function to be known.

  • Renal ultrasound is the key imaging investigation.


KEY POINTS

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