A 71-year-old man has back pain. This has been present for over 3 months and is worse in the lower back. He has also developed upper abdominal pain and constipation over the last month. He has had no serious illnesses in the past. His appetite is poor and he has lost 1 stone in weight over the previous month. His medication includes painkillers (paracetamol and ibuprofen).
On examination, he is pale. His blood pressure is slightly elevated (160/100 mmHg). Urine examination shows 2+ proteinuria.
Investigations show:
Hb 86 g/L
WBC 9.5 × 109/L
Platelets 65 × 109/L
ESR 110 mm/h
Blood film report – rouleaux
Leucoerythroblastic changes present.
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(a) What is the differential diagnosis?
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Correct answer: A history of recent onset of back pain, with poor appetite and weight loss, suggests malignant infiltration of the skeleton. Proteinuria on urine testing suggests renal disease. There is no history of prostatic obstruction. The very high ESR suggests myeloma or carcinoma with bony metastases.
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(b) Give a possible explanation for his abdominal pain and constipation.
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Correct answer: Abdominal pain and constipation are suggestive of hypercalcaemia.
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(c) What conditions give rise to a very high ESR?
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Correct answer: A high ESR indicates an increased levels of ‘acute phase’ proteins and occurs in the setting of acute or chronic illness e.g. infection, inflammation or malignancy. An ESR greater than 100 mm/hour is unsusual and suggests myeloma, a condition where there is an increased level of globulins; temporal arteritis, an inflammatory condition; infection, e.g. TB; or malignancy.
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(d) What further tests are indicated?
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Correct answer: Further tests should include urea and electrolytes, creatinine clearance, calcium level and serum alkaline phosphatase. X-rays of his back are required and this should be followed by other imaging as indicated. Serum and urinary protein electrophoresis are needed to exclude myeloma. A serum β2-microglobulin is a good test of long-term prognosis in myeloma. The serum prostate specific antigen should be assessed to exclude prostate cancer.
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(e) Give possible explanations for his proteinuria
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Correct answer: Myeloma can cause proteinuria and renal failure in various ways. The paraprotein can deposit in the tubules and this is especially likely in the case of light chain myeloma. Myeloma patients have an increased risk of infection including urinary infection. The hypercalcaemia can cause renal impairment. His blood pressure is elevated. He is on analgesics including non-steroidal anti-inflammatory drugs which can cause renal impairment.
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(f) What do you expect the serum alkaline phosphatase level to be?
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Correct answer: The alkaline phosphatase was normal; it generally is in myeloma, and it is high in secondary (metastatic) cancer.
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(g) How would you manage him?
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Correct answer: His hypercalcaemia should be treated with rehydration and steroids. There is a role for bisphosphonate therapy for hyperclacaemia, e.g. intravenous zoledronaic acid or intravenous pamidronate. Intravenous fluids can also help his renal impairment. Supportive therapy and chemotherapy for myeloma are discussed in Chapter 30.
