Syndrome of Inappropriate Antidiuretic Hormone Secretion in a Patient with Mucosa-associated Lymphoid Tissue Lymphoma

The prevalence and prognosis of hyponatraemia in non-Hodgkin lymphoma-associated hemophagocytic lymphohistiocytosis

Non-Hodgkin lymphoma associated hemophagocytic lymphohistiocytosis (NHL-HLH) in adult secondary HLH is a common and universally highly lethal critical disorder. Hyponatraemia is the most common electrolyte disorder in the critical illness setting and acts as a negative prognostic factor. The aim of our study was to evaluate the prognostic role of hyponatraemia among patients with NHL-HLH. The results showed that 81 (52.9%) patients had hyponatraemia. After a median follow up 47 (range 14-180) days, there were 72 (88.9%) cumulative deaths in hyponatraemia group while 50 (69.4%) in normonatremia group. After adjustment for confounders, multivariate analysis revealed that hyponatraemia was an independent prognostic factor for OS (HR:1.51, 95% CI: 1.03-2.20; p = 0.033). Restricted cubic spline confirmed a linear and positive association between serum sodium and the risk of mortality. Hyponatraemia is relatively frequent in NHL-HLH. As a readily available biomarker in clinical routine, it was a promising prognostic predictor for NHL-HLH.

Hyponatremia in Patients with Hematologic Diseases

Hyponatremia is the most common electrolyte disorder in clinical practice and is associated with increased morbidity and mortality. It is frequently encountered in hematologic patients with either benign or malignant diseases. Several underlying mechanisms, such as hypovolemia, infections, toxins, renal, endocrine, cardiac, and liver disorders, as well as the use of certain drugs appear to be involved in the development or the persistence of hyponatremia. This review describes the pathophysiology of hyponatremia and discusses thoroughly the contributing factors and mechanisms that may be encountered specifically in patients with hematologic disorders. The involvement of the syndrome of inappropriate antidiuretic hormone (SIADH) secretion and renal salt wasting syndrome (RSWS) in the development of hyponatremia in such patients, as well as their differential diagnosis and management, are also presented. Furthermore, the distinction between true hyponatremia and pseudohyponatremia is explained. Finally, a practical algorithm for the evaluation of hyponatremia in hematologic patients, as well as the principles of hyponatremia management, are included in this review.

Natural killer/T-cell lymphoma with concomitant syndrome of inappropriate antidiuretic hormone secretion: A case report and review of literature

We report a case of natural killer (NK)/T-cell lymphoma with concomitant syndrome of inappropriate antidiuretic hormone secretion (SIADH). The patient was a 64-year-old woman with a history of nasopharyngeal carcinoma of over 30 years. She was admitted with a chief complaint of intermittent fever for 2 mo. Palpation after admission indicated a swollen lymph node below the left jaw. Multiple imaging examinations on admission indicated multiple enlarged lymph nodes throughout the body. We performed a left submandibular lymph node biopsy, and the results revealed NK/T-cell lymphoma. A biochemical examination indicated Epstein-Barr virus positivity. At the same time, the patient developed hyponatremia. Based on her laboratory examination and clinical manifestation, decreased plasma osmolality, urine osmolality greater than plasma osmolality, lack of skin swelling, normal blood pressure, normal renal function, no adrenal function detected on serology, and no abnormalities in imaging examination of the adrenal glands, the likelihood of SIADH in the patient was high. After fluid restriction and administration of sodium chloride, the patient’s blood sodium level gradually increased. Subsequently, the immune function of the patient declined, there were severe symptoms of infection, and she died of respiratory failure. NK/T-cell lymphoma associated with SIADH has not, to our knowledge, been previously reported in PubMed. This case emphasizes the importance of monitoring serum ion levels, especially serum sodium, in patients with NK/T-cell lymphoma.