In our #AMreport this week at@WCHospital, we reviewed a case of a patient presenting with diastolic hypertension and hypokalemia and later found to have pulmonary nodules consistent with a diagnosis of small cell lung cancer. About 25% of all cases of ectopic ACTH production is due to small cell lung cancer [1].
#AMreport 5 take home points:
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Lung cancer is divided into two main histological categories, non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) accounting for 85% and 15% of cases respectively.
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SCLC can result in many paraneoplastic syndromes including:
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SIADH → hyponatremia
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Ectopic ACTH → Cushing’s
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Neurologic syndromes → cerebellar degeneration, optic neuritis, Lambert-Eaton syndrome.
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Usually, ectopic ACTH production has high ACTH levels (>20 ng/L) and cortisol levels are not be suppressed with high doses of dexamethasone ~ 8mg.
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Management of patients with ectopic ACTH centres around controlling hypercortisolism as soon as the diagnosis has been established with ketoconazole and metyrapone being the agents of choice.
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Amongst all tumour related causes for ectopic ACTH, patients with SCLC carry a poor prognosis, with median survival of 6-8 months.
References:
- http://www.hindawi.com/journals/crie/2012/215038/
- http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(05)67569-1/abstract?cc=y=