A 36-year-old woman presented to the emergency department with loss of vision in the right eye that had initially involved the peripheral field and progressed over 2 months to the central and nasal fields. During this period, she also had headaches, vomiting, and generalized weakness. She had had amenorrhea for 1 year. She took acetaminophen and NSAIDs as needed for the headaches. She had not seen a physician in more than 5 years.
The patient was alert and well-oriented. Blood pressure was 120/70 mm Hg; heart rate, 86 beats per minute; temperature, 36.1°C (97°F); and respiration rate, 16 breaths per minute. She had impressive facial features (Figure 1) and large hands and feet. She was unable to detect peripheral-to-nose moving objects with the right eye until the midline plane was crossed. Visual field examination of the left eye was normal. Neurological, cardiopulmonary, and abdominal findings were normal.
Figure 1 – These photos show the coarse facial features characteristic of acromegaly, including macrognathia, prominence of the cheekbones and supraorbital ridges, protruding jaw, and malocclusion of teeth.
MRI scans of the brain revealed a 6 × 6 × 4-cm sellar mass with suprasellar and parasellar extension encasing the right cavernous sinus and carotid artery (Figure 2), which explained the vision loss.
Initial laboratory results included a sodium level of 144 mEq/L; potassium, 3.7 mEq/L; chloride, 111 mEq/L; bicarbonate, 29 mEq/L; blood urea(Drug information on urea) nitrogen, 7 mg/dL; creatinine, 0.8 mg/dL; and glucose, 85 mg/dL. A complete blood cell count was normal.
A pituitary biochemical workup for suspected acromegaly revealed the following levels: insulinlike growth factor 1 (IGF-1), 768 ng/mL (normal, 109 to 284 ng/mL); prolactin, 20 ng/mL (normal, 2.5 to 17 ng/mL); luteinizing hormone, 0.2 mIU/mL (normal, 1.1 to 11.6 mIU/mL); follicle-stimulating hormone, 2.1 mIU/mL (normal, 2.8 to 11.3 mIU/mL); thyroid-stimulating hormone, 0.89 mIU/L (normal, 0.46 to 4.7 mIU/L); free thyroxine, 0.86 ng/dL (normal, 0.89 to 1.76 ng/dL); free triiodothyronine, 2.57 pg/mL (normal, 2.7 to 4.2 pg/mL); adrenocorticotropic hormone, 6 pg/mL (normal, 7 to 50 pg/mL); and cortisol, 4 μg/dL (normal, 5 to 22 μg/dL).
The patient underwent resection of a macroadenoma; however, only part of the tumor could be removed (Figure 3). Because preoperative laboratory results suggested central adrenal insufficiency, she received a stress dose of corticosteroids intraoperatively, which was reduced to a maintenance dosage after surgery. The postoperative course was complicated by rhinorrhea and partial central diabetes insipidus. Oral desmopressin(Drug information on desmopressin) (0.1 mg bid) was initially required to maintain her euvolemic status; this was slowly decreased over 2 months. Longacting formulations of octreotide(Drug information on octreotide) and cabergoline(Drug information on cabergoline) were also started and then titrated to maximally recommended doses.
Unfortunately, the patient's IGF-1 levels remained elevated 6 months after surgery. Her future treatment plan included radiation therapy and octreotide and pegvisomant. The maintenance corticosteroids were eventually discontinued after repeated evaluation of her hypothalamic-pituitary-adrenal axis showed recovery.
