Endocrine Abstracts

Background: Adrenal suppression from prolonged corticosteroid exposure can mask or delay the diagnosis of adrenal insufficiency (AI). Establishing adrenal reserve is challenging when dynamic testing yields equivocal results, while clinical features remain non-specific. This case highlights the diagnostic and management dilemmas in iatrogenic secondary AI.

Case Summary: A 55-year-old man with asthma and chronic rhinosinusitis, treated for many years with high-dose inhaled and intermittent oral corticosteroids, presented with persistent fatigue, myalgia, and low blood pressure. His past medical history included multiple musculoskeletal injuries, high BMI(34 kg/m²), B12 deficiency and dermatological problems, further complicating symptom interpretation. Both initial and the following two repeat short synacthen tests (SST) between 2022-2023 were flat cortisol responses. Although the repeat SST from 2024 showed an appropriate response, we performed insulin tolerance test as he was still symptomatic and this confirmed secondary AI. Pituitary MRI and extended pituitary profile were unremarkable. Autoimmune and paraneoplastic screens were negative. Hydrocortisone replacement (10/5/5 mg) was commenced, later changed to prednisolone for practicality. Despite adherence, the patient reported ongoing disabling fatigue, post-exertional myalgia, and mood disturbance. Clinicians faced a dilemma: whether symptoms reflected under-replacement or were multifactorial, given co-morbidities and psychosocial burden. Dose escalation was considered but tempered by the risk of over-replacement, particularly in the context of obesity, dyslipidaemia, and a strong family history of malignancy and autoimmune disease. Multispecialty review excluded alternative unifying pathology.

Discussion: This case illustrates the inherent challenges in diagnosing and managing secondary adrenal insufficiency caused by long-term steroid use. Dynamic testing may yield variable or inconclusive results, necessitating repetition to unmask adrenal suppression with confidence. Clinical assessment is complicated by the non-specific nature of adrenal insufficiency symptoms, which frequently overlap with other chronic conditions such as asthma, chronic pain, or mood disorders. Even once the diagnosis is established, treatment decisions are complex: while under-replacement risks persistent morbidity, over-replacement increases cardiometabolic and bone-related complications. A tailored approach that balances these competing risks is essential, supported by patient education, reinforcement of sick-day rules, and structured monitoring of quality of life.

Conclusion: This case underscores the complexity of managing iatrogenic adrenal insufficiency: diagnostic tests may be ambiguous, symptoms are often multifactorial, and treatment requires balancing safety with efficacy. Recognising steroid-induced adrenal suppression early, using repeat dynamic testing where necessary, and adopting an individualised, multidisciplinary approach is critical to improving outcomes in this increasingly common endocrine problem.