The blood results of a 75 year old who presents with lethargy, confusion and weight loss are shown below:
|
Patient value |
Normal range |
|
|
Sodium |
141 mmol/L |
135 – 145 |
|
Potassium |
3.8 mmol/L |
3.5 – 5.0 |
|
Chloride |
100 mmol/L |
97 – 109 |
|
Bicarbonate |
29 mmol/L |
24 – 32 |
|
Urea |
11.5 mmol/L |
3.0 – 8.0 |
|
Creatinine |
150 µmol/L |
70 – 110 |
|
Calcium |
4.69 mmol/L |
2.10 – 2.60 |
|
Phosphate |
0.4 mmol/L |
0.8 – 1.5 |
|
Albumin |
44 G/L |
38 – 48 |
a) What is the likely diagnosis?
b) What other biochemistry would you request and why?
c) Briefly explain the pathogenesis of the biochemical abnormalities.
d) Outline your management of this patient.
a) What is the likely diagnosis?
Underlying malignancy
b) What other biochemistry would you request and why?
PTH to exclude primary hyperPTH – very high calcium indicates malignancy but patients with malignancy have higher incidence of hyperPTH than general population so both conditions can co-exist
c) Briefly explain the pathogenesis of the biochemical abnormalities.
Hypercalcaemia:
Malignancy:
Increased PTH:
Elevated urea and creatinine:
d) Outline your management of this patient.
• Fluid replacement with NS
• Biphosphonates
• Calcitonin
• Steroids act by decreasing calcitriol
• Dialysis
• Treat underlying malignancy
• Parathyroidectomy if raised PTH
• (Diuretics no longer recommended)
As for the diagnosis- the clue is in the age and the weight loss, and the college does sound as if they are asking for the one most likely diagnosis. But if one were to approach this on classical footing, one would be expected to regurgitate a small pool of differentials.
|
Primary endocrine causes
Paraneoplastic causes
|
Granulomatous disease
Drug-induced hypercalcemia
Random miscellaneous causes
|
One may wish to launch the following investigations:
As for management, one would be well served to organise the response by the physiological aims of one's therapy: