Ramesh a 40 yr old male patient presenting with polyuria, pain abdomen, nausea, vomiting, and altered sensorium was found to have bronchogenic carcinoma. Which of the following electrolyte abnormality can be seen in him?

There are several paraneoplastic syndromes associated with bronchogenic carcinoma. This patient's symptoms of polyuria, nausea, vomiting, abdominal pain and altered mental status indicates a diagnosis of hypercalcemia occurring secondary to the release of PTHrP by squamous cell carcinoma of the lung. Small cell carcinoma of the lung is associated with hyponatremia due to the syndrome of inappropriate secretion of antidiuretic hormone or possibly ANP. These patients develop hyponatremia. Small cell carcinoma is also associated with the ectopic production of ACTH resulting in hypokalemia. Ref: Horn L, Pao W, Johnson D.H. (2012). Chapter 89. Neoplasms of the Lung. InLongo D.L., Fauci A.S., Kasper D.L., Hauser S.L., Jameson J, Loscalzo J (Eds),Harrison's Principles of Internal Medicine, 18e