PLAB Endocrinology Practice Exam

The likelihood of hypercalcaemia in a patient diagnosed with squamous cell carcinoma of the lung is closely tied to the paraneoplastic syndromes associated with this type of cancer. Squamous cell carcinoma can induce hypercalcaemia through mechanisms such as the production of parathyroid hormone-related peptide (PTHrP), which mimics the action of parathyroid hormone. This peptide can lead to increased bone resorption and renal tubular reabsorption of calcium, thus raising serum calcium levels.

In the context of malignancies, hypercalcaemia can be present in about 10-30% of patients with squamous cell lung cancer, making it a common and clinically significant finding. It is important for healthcare providers to monitor serum calcium levels in these patients, as hypercalcaemia can lead to a range of symptoms, including weakness, confusion, and cardiac complications.

The other biochemical abnormalities presented in the choices do not typically associate with squamous cell lung cancer in the same way. For example, hyperkalaemia, hypernatraemia, and hypocalcaemia are not common findings related to squamous cell carcinomas. While they may occur in various other medical conditions or types of cancers, they do not have the same direct