Introduction: Primary aldosteronism (PA), most commonly caused by aldosterone-producing adenomas (APAs), represents the leading form of surgically curable secondary hypertension. While genomic studies have elucidated the mutational landscape of APAs, the spatial organisation and functional role of immune populations across APAs, aldosterone-producing micronodules (APMs), and adjacent adrenal cortex remain poorly defined at single-cell resolution. Methodology: Single-cell RNA sequencing (scRNA-seq) was integrated with spatial transcriptomics in APAs and paired adjacent adrenal cortex, complemented by immunohistochemical (IHC) validation. Immune populations were spatially mapped using canonical markers (CD14, CD68, CD163, HLA-DR, CD8A, and CD4) across defined adrenocortical regions. Results: The adrenal microenvironment in PA demonstrates structured immune organisation rather than passive infiltration. CD14+ monocyte-lineage cells localize intraparenchymally within APAs (n = 10), intercalating between CYP11B2+ aldosterone-producing cells and forming a pattern distinct from perivascular immune niches. scRNA-seq further identified a transcriptionally distinct CD14+ population within the zona reticularis (zR) that co-expresses steroidogenic markers (CYB5A, SULT2A1, TSPAN12) while lacking canonical monocyte transcripts. IHC supported this observation, demonstrating CD14 expression within adrenocortical zR parenchymal cells (n = 5). In parallel, CD4 and HLA-DRA exhibited diffuse cytoplasmic staining within zR parenchymal cells in the absence of classical macrophage marker coexpression (CD68), suggesting non-canonical or context-dependent expression within steroidogenic compartments. CD68+ and CD163+ macrophages were sparsely distributed across APA, APM and adjacent cortex, consistent with lowdensity tissue-resident populations, while CD8A+ cytotoxic lymphocytes were enriched in APAs and APMs with diffuse parenchymal cytoplasmic staining of CD8A additionally observed within the zR. Conclusion These findings reveal a previously unrecognized spatially organised immune-steroidogenic interface within the adrenal cortex. The presence of immune-associated transcriptional and protein signatures within zR cells suggests potential functional plasticity of steroidogenic cells, possibly extending to antigen presentation-related pathways, warranting further mechanistic investigation
Hyperaldosteronism ; Humans

Introduction: Primary aldosteronism (PA) is a common yet underdiagnosed cause of secondary hypertension, associated with increased cardiovascular and renal morbidity. Early detection and subtype-directed management significantly improve outcomes. However, adherence to recommended diagnostic pathways in real-world practice remains variable. Case: We conducted a retrospective audit of patients diagnosed with PA in a Malaysian tertiary centre from January 2018 to December 2025. Data collected included demographics, clinical presentation, biochemical parameters, diagnostic workup (aldosterone-renin ratio [ARR], confirmatory testing, adrenal imaging, and adrenal venous sampling [AVS]), treatment modality, and outcomes. Audit standards were based on established international guidelines. A total of 14 patients were included, with equal gender distribution. The cohort comprised 57% Malay and 43% Chinese. Most patients presented with hypertension (mean ~170/100 mmHg), and hypokalemia was present in approximately 70% of the patients. ARR and adrenal imaging were performed in all patients (100%), while confirmatory testing was conducted in 85% of the patients. However, AVS utilization remained limited (50%). Contributing factors included failed cannulation, technical challenges in overweight patients, preference for medical therapy, refusal of surgery, and limited access to AVS services. The majority had unilateral adrenal adenoma (~75%). Treatment was divided between surgical (55%) and medical (45%) approaches. Post-treatment, hypokalemia resolved in 90% of patients, with a significant reduction in antihypertensive burden and complete hypertension resolution in approximately 35% of the patients. Quality of life improved in most patients. Conclusion This audit demonstrates good adherence to initial screening and imaging in PA but highlights suboptimal utilization of AVS. Barriers to AVS utilization are multifactorial, encompassing technical, patient-related, and system level limitations. Addressing these barriers is essential to optimize subtype-directed management and improve longterm cardiovascular outcomes in patients with PA. Despite this, clinical outcomes were favorable. Strengthening adherence to diagnostic pathways, particularly subtype confirmation, may further improve patient outcomes.
Hyperaldosteronism ; Treatment Outcome ; Retrospective Studies

Introduction: Ectopic adrenocorticotropic hormone (ACTH)-dependent Cushing syndrome is a rare but important cause of hypercortisolism and can be difficult to diagnose, particularly in the presence of incidental pituitary lesions. Case: A 21-year-old patient presented with recurrent severe hypokalemia, normotension, and rapid weight gain. The hypokalemia was persistent, requiring multiple hospital admissions and ongoing potassium supplementation. Biochemical evaluation confirmed ACTH-dependent Cushing syndrome with elevated ACTH (27.4 pmol/L), elevated late-night salivary cortisol, and failure of suppression on low-dose dexamethasone suppression testing (cortisol 875 nmol/L). Pituitary magnetic resonance imaging demonstrated a 0.5 × 0.3 cm microadenoma, raising suspicion for a pituitary source. However, inferior petrosal sinus sampling (IPSS) showed no central-to-peripheral ACTH gradient, excluding Cushing disease. Computed tomography of the thorax revealed a 0.6 cm right middle lobe pulmonary nodule. Gallium-68 DOTATATE PET-CT demonstrated increased somatostatin receptor uptake, confirming the lesion as the likely ectopic ACTH source. The lesion was not amenable to bronchoscopic resection, and the patient was referred for cardiothoracic surgical excision. During the course of illness, the patient developed resistant hypertension and worsening hypokalemia requiring high-dose potassium supplementation and multiple antihypertensive agents. Medical therapy with ketoconazole and metyrapone was initiated for cortisol control while awaiting definitive surgical resection. Conclusion This case highlights an aggressive and atypical presentation of ectopic ACTH syndrome in a young patient, initially presenting with isolated hypokalemia but rapidly progressing to severe hypercortisolism. It underscores the importance of early recognition, appropriate localization with IPSS, and timely initiation of medical therapy to control cortisol excess prior to definitive surgery.
Cushing Syndrome ; Adrenocorticotropic Hormone

Introduction: Severe hypercortisolism is associated with profound impairment of both innate and adaptive immune responses, predisposing affected individuals to opportunistic infections. Excess glucocorticoids alter leukocyte trafficking, suppress pro-inflammatory cytokine production, and impair cellular immunity, increasing susceptibility to bacterial, viral, and fungal pathogens. In some cases, severe infections may precede the diagnosis of Cushing syndrome and represent the initial clinical manifestation. Early recognition is important as untreated hypercortisolism can lead to substantial morbidity and mortality. Case: A young adolescent male presented with progressive facial fullness and facial hyperpigmentation for 4 months, followed by 1 month of intermittent fever, cough, lower limb weakness, and hallucinations. On examination, he was tachypneic with cushingoid features including moon facies, pigmented acne over the face and chest, and nail bed hyperpigmentation. He was hypertensive and had severe hypokalemia with lymphopenia. Radiological imaging demonstrated multiple cavitary lung lesions and intracranial tuberculomas. Bronchoalveolar lavage identified multiple opportunistic pathogens, including Pneumocystis jirovecii, Aspergillus fumigatus, and Haemophilus influenzae, while cerebrospinal fluid testing was positive for cytomegalovirus. Given the unusual combination of infections, an underlying immunocompromised state was suspected. Endocrine evaluation revealed markedly elevated serum cortisol, with loss of diurnal rhythm and elevated adrenocorticotropic hormone (ACTH). Twenty-four-hour urinary cortisol was significantly increased, confirming severe ACTHdependent Cushing syndrome. Magnetic resonance imaging of the pituitary gland and computed tomography imaging of the thorax, abdomen, and pelvis did not identify the source of ACTH secretion. Conclusion This case highlights that overwhelming opportunistic infections may be the first manifestation of severe Cushing syndrome in children. Excess cortisol disrupts host defenses by impairing neutrophil chemotaxis and macrophage phagocytosis, suppressing T-cell-mediated immunity, and reducing cytokine signaling necessary for pathogen clearance. These mechanisms contribute to susceptibility to simultaneous bacterial, fungal, and viral infections. Clinicians should therefore consider underlying hypercortisolism in patients presenting with multiple or unusual opportunistic infections to enable earlier diagnosis and appropriate multidisciplinary management.
Cushing Syndrome ; Opportunistic Infections

Introduction: Endogenous Cushing syndrome is a rare manifestation of chronic cortisol excess. It may present with severe hypercortisolism complicated by life-threatening opportunistic infections. Surgical management of a cortisol-secreting tumor is the mainstay of therapy. However, when the source is not found or when surgery is not feasible, medical therapies may be employed for rapid control of hypercortisolism. CASE: A 13-year-old male presented with breathlessness for one day. He also had a cough associated with weight loss, weakness, and hallucinations for 1 month. On presentation, he was tachypneic and had moon facies, acne, fine moustache, limb wasting, and pigmented nail beds. He was also hypertensive and developed an episode of seizure during admission. Investigation results showed severe hypokalemia and lymphopenia. Radiological examination revealed pneumothorax with multiple lung cavitations and brain tuberculomas. Bronchoalveolar lavage (BAL) was positive for Aspergillus fumigatus. However, both BAL and CSF PCR and culture for TB were negative. Serum ACTH was 379 pg/mL (0–46), and morning serum cortisol was 2,948 nmol/L with loss of diurnal rhythm. His 24-hour urine cortisol was 14,252 nmol/24 hour (31.7–282). This is consistent with ACTH-dependent Cushing syndrome. He was started on anti-TB and anti-fungal treatment. Serum cortisol levels were persistently high while on high-dose intravenous dexamethasone treatment for TB meningitis. An MRI pituitary and a CT scan thorax, abdomen, and pelvis could not reveal an ACTH-secreting tumor source. Metyrapone was started and titrated upwards to control the hypercortisolism. Serum cortisol reduced to 200–300 nmol/L after 1 month, and 24-hour urinary cortisol was down to 22.4 nmol/24 hour after 4 months, requiring weaning of metyrapone doses. Conclusion Metyrapone is effective in the rapid control of severe hypercortisolism with life-threatening complications, as illustrated in this case. However, it warrants careful monitoring and titration.
Child ; Cushing Syndrome

Excess hormone production from adrenal tumors caused by primary hyperaldosteronism or pheochromocytoma are common etiologies for secondary hypertension. Studies have shown that sustained long-term circulating hormones in excess affect the blood vessels and cardiac structures. Inflammation of cardiomyocytes leads to fibrosis and eventual cardiomyopathy and is clinically presented as arrhythmia, nonfatal myocardial infarction, heart failure, or even death. The tissue changes and/or impaired cardiac function are reversible if early diagnosis and removal of the adrenal tumor by unilateral adrenalectomy is done. However, the condition becomes challenging if the adrenal lesions are bilateral. This article introduces the concept of systemic hormonal unloading and will discuss the philosophy of quality of life in managing bilateral adrenal disease.
Hyperaldosteronism ; Pheochromocytoma ; Quality of Life

Adrenocortical carcinoma (ACC) accounts for 0.05-2% of all malignant tumors. Forty-five percent of ACCs with secretory function have excess glucocorticoids alone and only less than 1% secrete aldosterone.

This is a case of a 44-year-old Filipino female with hypertension and a 12-year-history of an incidentaloma of the left adrenal gland, with recent-onset complaints of increasing abdominal girth, purple striae, amenorrhea, moon facies and a dorsocervical fat pad. Laboratory findings revealed low potassium levels, non-suppressed cortisol on dexamethasone test suggesting Cushing’s syndrome and elevated aldosterone-renin ratio and plasma aldosterone concentration pointing to primary hyperaldosteronism. A computed tomography scan revealed a left-sided adrenal mass measuring approximately 23 cm in largest diameter suggestive of carcinoma without metastasis or lymph node involvement. Complete resection via open adrenalectomy was performed and histopathologic assessment revealed Adrenocortical Carcinoma with Weiss score of 4. The Ki-67 proliferative index was found to be >20%. Radiotherapy was done as an adjuvant treatment.

Although rare, co-secretion of cortisol and aldosterone can occur in functional tumors of adrenocortical carcinoma. Malignancy should always be considered in patients who present with a history of a unilateral adrenal mass and/ or in those with signs and symptoms of adrenal hormone excess. Thus, a proper assessment derived from a thorough medical history, physical examination and laboratory work-up is warranted in patients with an adrenal mass to ascertain the diagnosis and provide adequate management.

Objective: To establish and validate a nomogram-based predictive model for idiopathic hyperaldosteronism (IHA). Methods: This cross-sectional study was conducted with the collected clinical and biochemical data of patients with primary aldosteronism (PA) including 249 patients with unilateral primary aldosteronism (UPA) and 107 patients with IHA, who were treated at the Department of Endocrinology of the First Affiliated Hospital of Chongqing Medical University from November 2013 to November 2022. Plasma aldosterone concentration (PAC) and plasma renin concentration (PRC) were measured by chemiluminescence. Stepwise regression analysis was applied to select the key predictors of IHA, and a nomogram-based scoring model was developed. The model was validated in another external independent cohort of patients with PA including 62 patients with UPA and 43 patients with IHA, who were diagnosed at the Department of Endocrinology, First Affiliated Hospital of Zhengzhou University. An independent-sample t test, Mann-Whitney U test, and χ² test were used for statistical analysis. Results: In the training cohort, in comparison with the UPA group, the IHA group showed a higher serum potassium level [M(Q₁, Q₃), 3.4 (3.1, 3.8) mmol/L vs. 2.7 (2.1, 3.1) mmol/L] and higher PRC [4.0 (2.1, 8.2) mU/L vs. 1.5 (0.6, 3.4) mU/L] and a lower PAC post-saline infusion test (SIT) [305 (222, 416) pmol/L vs. 720 (443, 1 136) pmol/L] and a lower rate of unilateral adrenal nodules [33.6% (36/107) vs. 81.1% (202/249)]; the intergroup differences in these measurements were statistically significant (all P<0.001). Serum potassium level, PRC, PAC post-SIT, and the rate of unilateral adrenal nodules showed similar performance in the IHA group in the validation cohort. After stepwise regression analysis for all significant variables in the training cohort, a scoring model based on a nomogram was constructed, and the predictive parameters included the rate of unilateral adrenal nodules, serum potassium concentration, PAC post-SIT, and PRC in the standing position. When the total score was ≥14, the model showed a sensitivity of 0.65 and specificity of 0.90 in the training cohort and a sensitivity of 0.56 and specificity of 1.00 in the validation cohort. Conclusion: The nomogram was used to successfully develop a model for prediction of IHA that could facilitate selection of patients with IHA who required medication directly.
Humans ; Hyperaldosteronism/diagnosis* ; Nomograms ; Hypertension ; Cross-Sectional Studies ; Aldosterone ; Saline Solution ; Renin ; Potassium

Humans ; Aldosterone ; Hyperaldosteronism/diagnosis* ; Adrenal Gland Neoplasms/complications* ; Adenoma/diagnosis*

Virtually all of the dietary potassium intake is absorbed in the intestine, over 90% of which is excreted by the kidneys regarded as the most important organ of potassium excretion in the body. The renal excretion of potassium results primarily from the secretion of potassium by the principal cells in the aldosterone-sensitive distal nephron (ASDN), which is coupled to the reabsorption of Na⁺ by the epithelial Na⁺ channel (ENaC) located at the apical membrane of principal cells. When Na⁺ is transferred from the lumen into the cell by ENaC, the negativity in the lumen is relatively increased. K⁺ efflux, H⁺ efflux, and Cl^- influx are the 3 pathways that respond to Na⁺ influx, that is, all these 3 pathways are coupled to Na⁺ influx. In general, Na⁺ influx is equal to the sum of K⁺ efflux, H⁺ efflux, and Cl^- influx. Therefore, any alteration in Na⁺ influx, H⁺ efflux, or Cl^- influx can affect K⁺ efflux, thereby affecting the renal K⁺ excretion. Firstly, Na⁺ influx is affected by the expression level of ENaC, which is mainly regulated by the aldosterone-mineralocorticoid receptor (MR) pathway. ENaC gain-of-function mutations (Liddle syndrome, also known as pseudohyperaldosteronism), MR gain-of-function mutations (Geller syndrome), increased aldosterone levels (primary/secondary hyperaldosteronism), and increased cortisol (Cushing syndrome) or deoxycorticosterone (hypercortisolism) which also activate MR, can lead to up-regulation of ENaC expression, and increased Na⁺ reabsorption, K⁺ excretion, as well as H⁺ excretion, clinically manifested as hypertension, hypokalemia and alkalosis. Conversely, ENaC inactivating mutations (pseudohypoaldosteronism type 1b), MR inactivating mutations (pseudohypoaldosteronism type 1a), or decreased aldosterone levels (hypoaldosteronism) can cause decreased reabsorption of Na⁺ and decreased excretion of both K⁺ and H⁺, clinically manifested as hypotension, hyperkalemia, and acidosis. The ENaC inhibitors amiloride and Triamterene can cause manifestations resembling pseudohypoaldosteronism type 1b; MR antagonist spironolactone causes manifestations similar to pseudohypoaldosteronism type 1a. Secondly, Na⁺ influx is regulated by the distal delivery of water and sodium. Therefore, when loss-of-function mutations in Na⁺-K⁺-2Cl^- cotransporter (NKCC) expressed in the thick ascending limb of the loop and in Na⁺-Cl^- cotransporter (NCC) expressed in the distal convoluted tubule (Bartter syndrome and Gitelman syndrome, respectively) occur, the distal delivery of water and sodium increases, followed by an increase in the reabsorption of Na⁺ by ENaC at the collecting duct, as well as increased excretion of K⁺ and H⁺, clinically manifested as hypokalemia and alkalosis. Loop diuretics acting as NKCC inhibitors and thiazide diuretics acting as NCC inhibitors can cause manifestations resembling Bartter syndrome and Gitelman syndrome, respectively. Conversely, when the distal delivery of water and sodium is reduced (e.g., Gordon syndrome, also known as pseudohypoaldosteronism type 2), it is manifested as hypertension, hyperkalemia, and acidosis. Finally, when the distal delivery of non-chloride anions increases (e.g., proximal renal tubular acidosis and congenital chloride-losing diarrhea), the influx of Cl^- in the collecting duct decreases; or when the excretion of hydrogen ions by collecting duct intercalated cells is impaired (e.g., distal renal tubular acidosis), the efflux of H⁺ decreases. Both above conditions can lead to increased K⁺ secretion and hypokalemia. In this review, we focus on the regulatory mechanisms of renal potassium excretion and the corresponding diseases arising from dysregulation.
Humans ; Bartter Syndrome/metabolism* ; Pseudohypoaldosteronism/metabolism* ; Potassium/metabolism* ; Aldosterone/metabolism* ; Hypokalemia/metabolism* ; Gitelman Syndrome/metabolism* ; Hyperkalemia/metabolism* ; Clinical Relevance ; Epithelial Sodium Channels/metabolism* ; Kidney Tubules, Distal/metabolism* ; Sodium/metabolism* ; Hypertension ; Alkalosis/metabolism* ; Water/metabolism* ; Kidney/metabolism*