[Afferent baroreflex failure with hyponatremia: A case report].

Area of Science:

• Cardiology
• Neurology
• Endocrinology

Background:

• Afferent baroreflex failure (ABF) is a rare syndrome resulting from impaired baroreflex signaling, often linked to neck trauma, surgery, or radiotherapy.
• Common causes include extensive neck surgery or radiotherapy for head and neck cancers, leading to fluctuating hypertension and orthostatic hypotension.

Observation:

• A young male patient presented with significant blood pressure fluctuations and neurogenic orthostatic hypotension (nOH).
• Previous nasopharyngeal carcinoma treatment involving radiotherapy and neck dissection was identified as the likely cause of carotid sinus baroreceptor damage.
• The patient also exhibited chronic hyponatremia, diagnosed as syndrome of inappropriate antidiuretic hormone secretion (SIADH).

Findings:

• The study suggests that damage to carotid sinus baroreceptors from radiotherapy and surgery can cause ABF, leading to abnormal blood pressure regulation and nOH.
• Impaired baroreceptor function may also weaken the inhibition of antidiuretic hormone (ADH) secretion, resulting in elevated ADH levels and mild hyponatremia.
• This case illustrates a potential link between ABF, nOH, and SIADH, mediated by baroreceptor dysfunction.

Implications:

• Protecting carotid sinus baroreceptors during neck radiotherapy and surgery is crucial to prevent ABF and its severe cardiovascular complications.
• Further research is needed to establish effective long-term treatment strategies for ABF, as current options remain controversial.
• Understanding the complex mechanisms underlying ABF and associated conditions like SIADH is vital for improving patient outcomes.