Renal tubular acidosis complicated with hyponatremia due to cortisol insufficiency

Autoimmune polyglandular syndrome with shock and high anion gap metabolic acidosis

Autoimmune polyglandular syndrome (APS) is a rare group of immune-mediated disorders, which are typically, but not exclusively, related to the presence of endocrine abnormalities. APS type 2 is the most common subtype of the syndrome, more often observed in adulthood, with a characteristic clinical triad, which includes adrenal insufficiency, autoimmune thyroiditis and diabetes mellitus type 1. Adrenal insufficiency is an essential and necessary clinical manifestation of the syndrome, as it is observed in 100 % of the cases, while it can be accompanied by hyperchloremic metabolic acidosis. Herein, we present a 23 years-old patient with adrenal insufficiency in the context of autoimmune polyglandular syndrome type 2 with coexisting autoimmune thyroiditis and metabolic acidosis with an increased anion gap attributed to prolonged malnutrition. Additionally, we analyze the main clinical features of adrenal insufficiency, which is a central component of autoimmune polyglandular syndrome; highlight characteristics that differentiate the major APS subtypes.

PES Syndrome Presenting as Severe Hyponatremia in an Asymptomatic Septuagenarian

Background

Hyponatremia is commonly seen in hospitalized patients. In euvolemic individuals, syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a common differential. However, before establishing a diagnosis of SIADH, it is imperative to evaluate for hypocortisolism and hypothyroidism. The finding of endocrine abnormalities determined to be of pituitary origin should prompt evaluation by brain MRI. Furthermore, primary empty sella (PES) is commonly seen as an incidental neuroradiological finding. However, PES in association with endocrine abnormalities is recognized as a separate entity called primary empty sella syndrome (PESS). Case Presentation. We report the case of a 71-year-old male sans neurological symptoms who presented to us with severe hyponatremia in whom we used a stepwise approach which led us to the diagnosis of PESS. This methodical approach was crucial for timely correction of the endocrine abnormalities which in turn rectified hyponatremia. Intriguingly, the presence of an ectopic pituitary which is a very rare entity and the sudden manifestation of his underlying endocrine deficiencies in the 8th decade of life make this clinical scenario highly unusual.

Conclusion

Clinicians should be aware that absence of an orderly approach to workup presumed SIADH or an assumption of PES (instead of PESS) could both lead to serious consequences in the face of missed endocrine deficiencies.