Hyponatremic hypertensive syndrome secondary to renal ischemia – Case report

Joana Cunha Oliveira, Mariana Matos Martins, Esmeralda Martins, Gustavo Rocha, Cláudia Moura, Helena Pinto, Ana Teixeira

Abstract


Hyponatremic hypertensive syndrome (HHS) is characterized by hypertensive crisis, and hyponatremia secondary to unilateral renal damage with glomerular and tubular dysfunction. Elevated plasma levels of renin in most cases suggest that the stimulation of renin release from the ischemic kidney plays an important pathophysiologic role. Activation of the renin-angiotensin system results in hypertension and causes secondary hyperfiltration, pressure diuresis and sodium loss from contralateral non-damaged kidney. An elevated renin level is a pathognomonic finding in HHS. Potassium deficiency from hyperaldosteronism may further stimulate renin secretion and intensify this vicious circle.
We report a female term newborn, who presented with hypertensive crisis on the seventh day after traumatic birth. The first three days of life were uneventful. Initial treatment with captopril resulted in severe hypotension and hemodynamic instability. Lab work revealed hyponatremia, hypokalemia, and elevated peripheral renin activity and aldosterone levels. Complementary sonography and magnetic resonance confirmed right adrenal gland hematoma and several ischemic areas in the upper pole of the right kidney. The diagnosis of HHS secondary to renal ischemia was evoked.
HHS is a rare condition in the neonatal period, though still under-recognized. In the neonatal and early infancy period, renovascular disease is the most common cause of secondary hypertension. In this case, there was no sign of vascular disease, the renin-angiotensin system was activated secondary to direct renal ischemia and infarction. The intense renin stimulation and pressure through the contralateral normal kidney results in high pressure natriuresis facilitating a severe volume-depleted state. Although the use of renin-angiotensin system inhibitors is the treatment of choice, it is imperative to re-establish hydration and renal perfusion before starting this antihypertensive medication. We aimed to improve awareness of HHS diagnosis and prompt treatment, to prevent continuous renal damage and other life-threatening complications.

Keywords


hypertension; hyponatremia; hyponatremic hyper­tensive syndrome; newborn; renin-angiotensin system; tubular dysfunction

Full Text: PDF Number of abstract views: 783 Number of PDF views/downloads: 871

 

N.B. All JPNIM articles are accessible in Open Access. You can access the page containing the full PDF article just by clicking on the “Full Text: PDF” link at the bottom of the abstract page. On the full article page, if the article doesn’t load properly in the PDF view window, please wait a few seconds or click on the “Download this PDF file” link.

Technical advice. If you are using Firefox and you are experiencing problems, please set the browser preferences as follows: Firefox > Preferences > Advanced > General > Accessibility > deselect "Warn me when web sites try to redirect or reload the page".

Privacy Policy. English text: Privacy Policy; Italian text: Privacy Policy.

Cookie Policy. English text: Cookie Policy; Italian text: Cookie Policy.