Hyponatremia accompanying volatile hypertension caused by baroreflex failure after neck surgery: case report and literature review

Abstract

The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is the most common cause of euvolemic hyponatremia, and many disorders have been associated with it. Baroreflex failure is a rare disorder characterized by extreme blood pressure (BP) fluctuations, most frequently caused by neck or head trauma and irradiation. We report a case of a 48-year-old patient referred to our department for asymptomatic hyponatremia and volatile hypertension. His past medical history included nasopharyngeal carcinoma treated with surgery and bilateral neck radiation. Following the diagnostic algorithm for hyponatremia, the diagnosis of SIADH was made. Ambulatory BP monitoring revealed highly variable BP; extensive autonomic nervous system function testing suggested baroreflex-cardiovagal failure. We propose the hypothesis that not only labile hypertension because of baroreflex failure but also hyponatremia can develop as a late consequence of neck trauma and irradiation.

Ambulatory central BP and arterial stiffness in patients with and without intradialytic hypertension

“…One could hypothesize that the phenomenon of BP increase during haemodialysis is instituted or exaggerated when a hypertensive stimulus such as sympathetic nervous system or renin‐angiotensin system activation, or intradialytic gain of sodium are introduced during dialysis on a person with rigid arterial wall, thus producing a higher than average BP increase 4 . Another hypothesis could be that increased arterial stiffness is directly impairing the normal function of carotid and aortic baroreceptors by reducing baroreflex sensitivity and thereby disrupting the overall ability to regulate BP 43,44 . It has to be noted however, that since our observations are cross‐sectional, one cannot exclude the possibility that increased arterial stiffness may be also the consequence of chronically elevated BP load in these individuals.…”

SGLT-2 Inhibitors to Treat Hyponatremia Associated with SIADH: A Novel Indication?

“…Enthusiasm is of the greatest value, so long as we are not carried away by it. Johann Wolfgang von Goethe Hyponatremia is the most frequent electrolyte disorder encountered in clinical practice; it can be classified according to extracellular volume status into 3 categories: hypovolemic, euvolemic, and hypervolemic [1][2][3]. Each of these categories has a wide number of etiologies, including but not limited to gastrointestinal losses, diuretic use, low dietary solute intake, endurance exercise, heart failure, and nephrotic syndrome [1][2][3][4].…”

“…Johann Wolfgang von Goethe Hyponatremia is the most frequent electrolyte disorder encountered in clinical practice; it can be classified according to extracellular volume status into 3 categories: hypovolemic, euvolemic, and hypervolemic [1][2][3]. Each of these categories has a wide number of etiologies, including but not limited to gastrointestinal losses, diuretic use, low dietary solute intake, endurance exercise, heart failure, and nephrotic syndrome [1][2][3][4]. Hyponatremia is associated with increased morbidity, ranging again from bone disorders and increased fracture risk [5] to the most serious complication of acute hyponatremic encephalopathy, a life-threatening condition that can require treatment with hypertonic saline in the emergency setting [6,7].…”

“…Sodium is the most abundant extracellular osmole and changes in serum sodium concentration often reflect abnormal water balance. Serum sodium and serum osmolality are regulated by changing water intake or output through the sense of thirst and secretion of antidiuretic hormone (ADH), which is synthesized in the hypothalamus, is secreted by the posterior pituitary gland, and acts in the renal collecting duct to increase free-water reabsorption [1][2][3].…”

“…The syndrome of inappropriate antidiuretic hormone excess (SIADH) is the most common cause of euvolemic hyponatremia [8]; it is caused by central nervous system disorders (stroke, trauma, tumors, and others), drugs (antidepressants, anticonvulsants, antipsychotics, anticancer agents, and others), malignancies, pulmonary diseases, pain, or stress of various etiologies [1][2][3]. Other causes of euvolemic hyponatremia include adrenal insufficiency, hypothyroidism, and high water and low solute intake.…”