Syndrome of inappropriate anti-diuretic hormone in non-small cell lung carcinoma: a case report

A CASE OF HYPONATREMIA DUE TO PITUITARY METASTASIS OF LUNG CANCER

Context

Hyponatremia is a common electrolyte abnormality.

Objective

We report a patient who presented with hyponatremia and diagnosed as small cell lung cancer metastatic to hypothalamus and pituitary.

Case report

A 68 year old male patient was admitted with fever and cough and pneumonia was considered. Serum sodium level was 113 mmol/L. Syndrome of inappropriate ADH (SIADH) is considered. Thyroid function tests and cortisol levels pointed out a central deficiency in both axes. Pituitary MRI was performed and a hypothalamic and pituitary mass were observed. Prednisolone therapy was started followed by L thyroxine replacement. A chest computer tomography (CT) was taken 2 weeks later revealed a mass lesion. Bronchoscopic biopsy was performed and histopathological diagnosis of the tumor was reported as small cell lung cancer.

Result

Many mechanisms were considered as the cause of hyponatremia in our patient. SIADH, secondary adrenal insufficiency and secondary hypothyroidism due to pituitary metastasis are possible causes.

Conclusion

The reason of hyponatremia is sometimes complex. When the underlying causes of hyponatremia are not evaluated in detail, many diagnoses can be missed.

Syndrome of inappropriate secretion of antidiuretic hormone following high dose rate brachytherapy for prostate cancer: a case report

Background

The syndrome of inappropriate secretion of antidiuretic hormone is a disorder characterized by the excess release of antidiuretic hormone and can result in hyponatremia. If managed inappropriately, severe hyponatremia can cause seizures, cerebral edema, and even death. There are various known causes of this inappropriate release of antidiuretic hormone, including malignancy, CNS disorders, and disturbances in the hypothalamic-pituitary-renal axis. However, reports of syndrome of inappropriate secretion of antidiuretic hormone after brachytherapy for prostate cancer are exceedingly rare.

Case presentation

We report a case of symptomatic hyponatremia secondary to the inappropriate secretion of antidiuretic hormone after prostate high-dose rate brachytherapy under general anesthesia in a patient with adenocarcinoma of the prostate.

Conclusions

In rare instances, inappropriate secretion of antidiuretic hormone can occur after high-dose rate brachytherapy for prostate cancer. The cause is likely multifactorial, involving pain or discomfort ensuing from the surgical procedure, the general anesthesia or intraoperative drugs administered. However, due to the potential severity of the side effects, timely diagnosis is crucial to ensure prompt, and effective management.

A Rare Case of Syndrome of Inappropriate Anti-diuretic Hormone in Non-small Cell Lung Cancer Presenting as Superior Vena Cava Syndrome

Syndrome of inappropriate anti-diuretic hormone (SIADH) secretion is uncommon in small cell lung cancer (SCLC), but even more rare in cases of non-small cell lung cancer (NSCLC). We report a case of a 59-year-old male who presented with superior vena cava (SVC) syndrome. After further investigation, he was diagnosed with adenocarcinoma of the lung. He delayed his medical care and his condition worsened. He was diagnosed with SIADH as an incidental finding on routine lab draw. Radiotherapy was subsequently initiated, and after one week of treatment, the patient showed marked clinical improvement. In this article, we also review the current indications for radiotherapy in various lung cancers and the management of SIADH.

Paraneoplastic syndromes associated with lung cancer

Paraneoplastic syndromes are signs or symptoms that occur as a result of organ or tissue damage at locations remote from the site of the primary tumor or metastases. Paraneoplastic syndromes associated with lung cancer can impair various organ functions and include neurologic, endocrine, dermatologic, rheumatologic, hematologic, and ophthalmological syndromes, as well as glomerulopathy and coagulopathy (Trousseau’s syndrome). The histological type of lung cancer is generally dependent on the associated syndrome, the two most common of which are humoral hypercalcemia of malignancy in squamous cell carcinoma and the syndrome of inappropriate antidiuretic hormone secretion in small cell lung cancer. The symptoms often precede the diagnosis of the associated lung cancer, especially when the symptoms are neurologic or dermatologic. The proposed mechanisms of paraneoplastic processes include the aberrant release of humoral mediators, such as hormones and hormone-like peptides, cytokines, and antibodies. Treating the underlying cancer is generally the most effective therapy for paraneoplastic syndromes, and treatment soon after symptom onset appears to offer the best potential for symptom improvement. In this article, we review the diagnosis, potential mechanisms, and treatments of a wide variety of paraneoplastic syndromes associated with lung cancer.