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Extraocular Muscle Enlargement in Acromegaly
Rachel L McInnis1, Hani Rjoob, Pavlo Ohorodnyk
1Departments of Ophthalmology (RLM, JAF, LLCDB), Medicine-Endocrinology & Metabolism (HR, SHMVU), Medical Imaging (PO), and Clinical Neurological Sciences (JAF, LLCDB), Western University, London, Canada.
Background:
To determine whether acromegaly is associated with increased extraocular muscle (EOM) size at time of presentation.
Methods:
Patients with a new diagnosis of acromegaly in a single tertiary care clinic with a CT scan that adequately delineated the EOMs were included. Control subjects were age- and sex-matched patients with a new diagnosis of nonfunctioning pituitary adenoma. Retrospective chart review was performed to extract baseline clinical and laboratory parameters including growth hormone, insulin-like growth factor 1, thyroid stimulating hormone, free T3, and free T4. A single neuroradiologist analyzed all CT scans and measured the maximum diameter and cross-sectional area of the superior rectus, inferior rectus, medial rectus, and lateral rectus in both eyes of all patients.
Results:
We evaluated 17 patients with acromegaly and 18 control subjects. Mean maximum diameter of the superior, inferior, medial, and lateral recti were 4.80 mm (SD = 0.81), 4.67 mm (SD = 0.54), 4.86 mm (SD = 0.77), and 4.53 mm (SD = 0.70) respectively, in the acromegaly group. In the control group, they were 3.62 mm (SD = 0.58),3.71 mm (SD = 0.46), 3.66 mm (SD = 0.32), and 3.21 mm (SD = 0.44), respectively. The maximum diameter and cross-sectional area of all 4 EOMs measured in the acromegaly group were significantly larger ( P < 0.001) compared with the control group.
Conclusions:
Patients with acromegaly present with significantly enlarged EOMs compared with control subjects with nonfunctioning pituitary adenomas.
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