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: Pneumonia continues to be as one of the top causes of hospitalisations and deaths in Malaysia despite the advancement in prevention and treatment of pneumonia. One of the possible explanations is the frequent misdiagnosis of pneumonia which had been reported elsewhere but such data is not available locally. Objectives: This is an audit project aiming to evaluate the proportion of misdiagnosis among hospitalised communityacquired pneumonia (CAP) patients in the Respiratory wards of Penang General Hospital based on their initial presentation data, and their associated outcomes. Methods: We reviewed the medical notes and initial chest radiographs of 188 CAP patients who were admitted to respiratory wards. Misdiagnosis was defined as cases which lack suggestive clinical features and/or chest radiograph changes. In-hospital mortality and length of stay (LOS) were the outcomes of interest. Results: The study found that 38.8% (n=73) of the hospitalised CAP patients were misdiagnosed. The most common alternative diagnosis was upper respiratory tract infection (32.8%, n=24). There was no statistical difference between misdiagnosis and CAP patients in the demographic and clinical variables collected. In terms of outcomes, misdiagnosed patients were discharged earlier (mean LOS= 3.5±3.28 days vs. 7.7±15.29 days, p=0.03) but the in-hospital mortality difference was not statistically significant (p=0.07). Conclusions: One third of our CAP admissions were misdiagnosed. Although initial misdiagnosis of CAP in our study did not show any increase in mortality or morbidity, a proper diagnosis of CAP will be helpful in preventing inappropriate prescription of antibiotics and unnecessary admission.