SIADH versus adrenal insufficiency: a life-threatening misdiagnosis

Abstract

BackgroundPrimary adrenal insufficiency (PAI) in children is an uncommon but severe condition which can be either inherited or acquired. It consists in clinical manifestation of defective production or ineffective action of endogenous glucocorticoids; deficiency in mineralocorticoids and adrenal androgens may coexist. Diagnosis of PAI in children and young people can be challenging; while adrenal crisis (acute decompensation) is a life-threatening condition, with patient presenting with characteristic features of hypoglycemia, hypotension, collapse and coma, chronic adrenal insufficiency may present with vague and non-specific symptoms, making the diagnosis more difficult.1 Gastroenteritis and Syndrome of Inappropriate Secretion of Antidiuretic hormone (SIADH) are the most frequent reported misdiagnosis in patients with adrenal insufficiency (AI). While intravenous fluid replacement in the suspect of a gastroenteritis would be beneficial, a SIADH misdiagnosis can be harmful since the treatment of this condition is based primarily on fluid restriction.Case presentationWe report the case of a child admitted to the emergency department whose condition was ultimately diagnosed as autoimmune adrenal insufficiency after few hours of inappropriate fluid restriction following a SIADH misdiagnosis.ConclusionsAI is a rare condition in children and the diagnosis can be challenging. A missed diagnosis of AI or an inadequate treatment may cause severe complications, especially if a SIADH is erroneously diagnosed. Emergency physicians and pediatricians should be familiar with this diagnosis to enhance early recognition of this potentially life-threatening condition.

Chronic hyponatremia based on maxillary sinus mass

“…The most common laboratory finding associated with primary adrenal insufficiency is hyponatremia (90% of cases) along with hyperkalemia (50% of cases) and hypoglycemia (30% of cases). Given the fact that the diagnosis of adrenal insufficiency cannot be ruled out by the absence of hyperkalemia and hypoglycemia, initial presentation with hyponatremia accompanied by high natriuresis may imitate SIADH ( 8 ). Restriction of fluid intake as the first line of therapy for SIADH may, in patients with adrenal insufficiency, precipitate a life-threatening condition, which emphasizes the importance of correct diagnosis of these clinical entities ( 8 ).…”

“…Given the fact that the diagnosis of adrenal insufficiency cannot be ruled out by the absence of hyperkalemia and hypoglycemia, initial presentation with hyponatremia accompanied by high natriuresis may imitate SIADH ( 8 ). Restriction of fluid intake as the first line of therapy for SIADH may, in patients with adrenal insufficiency, precipitate a life-threatening condition, which emphasizes the importance of correct diagnosis of these clinical entities ( 8 ). A further challenge in establishing the diagnosis is to distinguish SIADH from cerebral/renal salt loss syndrome (C/RSW) due to a different therapeutic approach.…”

Advances in paediatrics in 2019: current practices and challenges in allergy, endocrinology, gastroenterology, public health, neonatology, nutrition, nephrology, neurology, respiratory diseases and rheumatic diseases

“…SIADH [17] can be idiopathic or due to multiple causes (neurological, pulmonary, malignant diseases, medications, acute conditions as stress, pain, general anesthesia) because various non-osmotic stimuli may cause AVP release. The classic criteria for diagnosis are those found in the clinical case described by Pintaldi et al [18] (hyponatremia, high urinary osmolarity, high urinary sodium concentration, absence of edema or clinical signs of volume depletion). However, it is important to remember that the diagnosis of SIADH requires a normal renal, cardiac, hepatic, adrenal and thyroid function [19].…”

“…AI may be due to ACTH/CRH insufficiency (secondary and tertiary form particularly important in patients who present with neurosurgical conditions, such as traumatic brain injury, subarachnoid hemorrhage and intracranial tumors) or due to a primitive alteration of the adrenal gland which could be congenital or acquired [21,22]. In fact, in the above mentioned clinical case [18] the analysis of the functional parameters of the ACTH / Cortisol axis led to change the initial diagnosis to the final one of an autoimmune adrenalitis (Addison's disease) which is considered,after the congenital adrenal hyperplasia (CAH), the second more frequent cause of primary AI. Finally, it is interesting to underline the similarities of the case described by Pintaldi [18] with others reported in Literature [23].…”

“…In fact, in the above mentioned clinical case [18] the analysis of the functional parameters of the ACTH / Cortisol axis led to change the initial diagnosis to the final one of an autoimmune adrenalitis (Addison's disease) which is considered,after the congenital adrenal hyperplasia (CAH), the second more frequent cause of primary AI. Finally, it is interesting to underline the similarities of the case described by Pintaldi [18] with others reported in Literature [23]. In particular, the initial normality of the values of potassium which would be assumed to be high in case of adrenal insufficiency but which were normal, probably due to the vomiting presented by the patients and in addition, the presence of some slight hyperpigmentation of the skin creases and gingival pigmentations which may be useful for diagnostic orientation during clinical evaluation.…”