A 42-year-old woman who has recently returned from a holiday to Spain presents to the clinic with thirst, polyuria and a rash affecting both shins. Her only past medical history of note is mild asthma diagnosed by her GP, but she tells you the inhaler he prescribed has made no difference to her symptoms.
On examination, her BP is 135/85, pulse is 75 and regular. There are small palpable lymph nodes on palpation of the neck and axillae. Her chest is clear on auscultation, and her abdomen is soft and non-tender with a BMI of 29. There is a raised red/purple rash on both shins.
Investigations:
Hb 120 g/l (115-160)
WCC 10.0x109/l (6-10 [atypical lymphocytes seen on film])
PLT 225x109/l (150-400)
Na 140 mmol/l (135-145)
K 4.5 mmol/l (3.5-5.5)
Cr 105 µmol/l (50-90)
CRP 55 mg/dl (<10)
ESR 45 mm/hr (<10)
Ca2+ 2.82 mmol/l (2.1-2.65)
Which of the following is the most likely underlying diagnosis?
(Please select 1 option)
Churg-Strauss syndrome
Idiopathic pulmonary fibrosis
Sarcoidosis
Tuberculosis
Wegener’s granulomatosis
Explanation:
The answer is sarcoidosis. The clues here include the non-responsiveness of chest symptoms to the salbutamol inhaler, erythema nodosum, non-specific elevation in inflammatory markers, and hypercalcaemia.
Patients with sarcoid frequently present with symptoms of hypercalcaemia after a holiday because increased sun exposure results in increased production of vitamin D. A chest radiograph, not reported here, may show a variety of abnormalities, including bilateral hilar lymphadenopathy. The mainstay of treatment of sarcoidosis is with oral corticosteroids, but patients with mild symptoms can be managed with surveillance alone.
None of the other options listed commonly causes hypercalcaemia, and the inflammatory markers are only mildly elevated, reducing the probability of her symptoms being due to a chronic infection such as tuberculosis.
Wegener’s granulomatosis is associated with symptoms of sinusitis due to granuloma formation, and Churg-Strauss syndrome would explain the asthma-like symptoms but not the others.