A Case Report of Growth Hormone–Secreting Pituitary Adenoma Complicated by Apoplexy With Atypical Clinical Presentation

Pituitary macroadenomas are prevalent benign tumors that can present with insidious symptoms, leading to delayed diagnoses. We report the case of a 29-year-old South Asian male who presented with acute neurological symptoms including severe headache, confusion, and vomiting, initially diagnosed as meningitis with syndrome of inappropriate antidiuretic hormone secretion (SIADH). Despite initial improvement, the patient developed central diabetes insipidus (CDI) and was found to have physical features consistent with acromegaly. Magnetic resonance imaging (MRI) revealed a large sellar/suprasellar lesion, and hormonal profile confirmed elevated insulin-like growth factor 1 (IGF-1) with low levels of prolactin, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone, consistent with pituitary apoplexy. The patient underwent successful transnasal transsphenoidal resection of a hemorrhagic macroadenoma. This case highlights the importance of considering pituitary apoplexy in the differential diagnosis of acute neurological symptoms and its potential for atypical complications such as SIADH followed by CDI. Timely diagnosis and appropriate management are crucial to mitigate risks and improve outcomes.