A case of severe Covid-19 infection as the first manifestation of Cushing's disease.

Summary: Cushing's disease (CD) is characterized by distinct syndromic features, often accompanied by obesity and depression. However, considering its gradual onset of symptoms, it is usually associated with diagnostic delays. In rare instances, CD may lead to severe infections due to the observed immunosuppression in affected individuals. We present a rare case of an undiagnosed CD in a 20-year-old male with a medical history of depression and obesity, complicated by severe COVID-19 infection. He presented to the Emergency Room with respiratory distress, hypertensive crisis, and fever, ultimately receiving the diagnosis of SARS-CoV-2 pneumonia. The patient required mechanical ventilation and intensive care unit (ICU) admission due to severe acute respiratory distress syndrome (ARDS). During ICU care, he received remdesivir and dexamethasone, subsequently developing severe hyperglycemia and worsened hypertension, requiring insulin and multiple antihypertensive agents to manage metabolic disruption. Upon physical examination, classic signs of hypercortisolism were noted. Subsequent laboratory tests and pituitary magnetic resonance imaging confirmed the diagnosis of CD. The patient underwent surgical resection with significant improvements in body composition and metabolic parameters postoperatively. After surgery, remission of hypercortisolism was evident, accompanied by notable improvements in mood and overall health. This case underscores the importance of recognizing hypercortisolism in the context of metabolic, physical, and mood changes. Timely diagnosis of CD is crucial to mitigate complications such as severe opportunistic infections and their outcomes. Learning points: Despite some hallmark features such as proximal myopathy, easy bruising, purple striae, and facial plethora, Cushing's disease (CD) is a challenging diagnosis due to its nonspecific signs and symptoms and gradual onset. The case emphasizes the importance of recognizing subtle signs of CD, such as social isolation, depressive symptoms, and changes in body composition, which may be confounded by external factors like the COVID-19 pandemic. Patients with CD are prone to severe infections due to chronic hypercortisolism-induced immunosuppression. CD diagnostic delays are common, leading to worsening of metabolic and immune dysfunction over time. Heightened clinical suspicion and early intervention are essential to prevent diagnostic delays and optimize patient outcomes.