Optometry case study: Pituitary adenoma

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By Anthony Kim, Specsavers Munno Para, SA

History

Px: 34-year-old Caucasian male
Reason for visit: First time eye test. Noticed blurring of vision in RE. Onset of symptoms: a few months ago.

Clinical Assessment

Unaided VA: 6/7.5 OU
Pupils: Normal PERRL, no RAPD
Motility: Full and smooth
Confrontation field test: Gross loss of nasal field with his RE. LE was unremarkable.

Ocular health:
Anterior – Clear and quiet OU
Posterior – Obliquely inserted but otherwise unremarkable looking optic discs OU (Figures 1 and 2)
No other remarkable findings seen

OCT widefield scans:
RE – Generalised RNFL thinning but more severely affecting the temporal region
LE – Similar pattern of temporal RNFL thinning; quite subtle compared to the RE

Threshold visual fields examination:
RE – Dense temporal field defect, respecting a vertical midline (Figure 3)
LE – Subtle superior temporal quadrantanopia (Figure 4)
Visual field observation – Asymmetric bi-temporal field loss, more severe in the RE (Figures 3 and 4)

Diagnosis & Management

Differential diagnosis:

  • Pituitary adenoma
  • Carotid artery aneurysm
  • Optic atrophy
  • Optic nerve glioma
  • Optic nerve sheath meningioma
  • Retrobulbar optic neuritis

Management: An urgent referral was made to a neurologist for MRI and CT scans. A diagnosis was made based upon the results.

Diagnosis: Pituitary adenoma

Prognosis: Visual recovery is mostly dependent on pre-operative visual acuities, severity of field loss, age of patient, and duration of symptoms. If an operation is required, timeframe of recovery ranges from a few hours to a few years after operation. Most improvement can be seen in the early months after a treatment.

Discussion

Pituitary adenoma is a benign and slow-growing tumour that accounts for 10-15% of intracranial neoplasms. It is mostly known to develop spontaneously, but there are also cases of an inherited tendency to develop pituitary adenoma.

The most common ocular sign and/or symptom is a visual field defect. Other less common signs include ocular motility deficits, diplopia and nystagmus.

A bi-temporal field defect is the most commonly seen visual field defect, as pituitary adenoma usually grows upward from the pituitary stalk, compressing against the chiasm from below and affecting inferior nasal nerve fibres. For patients that present with a bi-temporal visual field defect that respects the vertical midline, pituitary tumours should be at the forefront of the differential diagnoses being considered. However, referral to tertiary care is required to confirm cause and diagnosis.

OCT is a non-invasive way of imaging ocular structures. Overall, information provided by an OCT leads to better confidence in clinical investigation and decision-making. This can, in turn, more effectively lead to diagnosis of ocular-related tumours, amongst many other eye conditions/diseases. This is a helpful tool in optometric practice.

Correction: This case study was originally published with a reference to a nasal field loss. The case study has since been corrected to reflect that a temporal field loss was observed in the visual field results.


REFERENCES
Gittinger JW. Tumors of the Pituitary Gland. In: Miller NR, Newman NJ, eds. Walsh and Hoyt’s Clinical Neuro-Ophthalmology, 6th Ed. Volume Two. Philadelphia, PA: Lippincott Williams & Wilkins; 2005:1531-1546. ISBN 978-1-61525-133-9

Johansson, C. and Lindblom, B. (2009). The role of optical coherence tomography in the detection of pituitary adenoma. Acta Ophthalmologica, 87(7), pp.776-779.

Neuro-Ophthalmology. Basic and Clinical Science Course, Section 5. American Academy of Ophthalmology; 2010:159-165. ISBN 978-1-61525-133-9

Unusual visual manifestations of pituitary tumours. (2018). Kerala Journal of Ophthalology, XIX(2), pp.148-155.

Yanoff M, Duker JS. Ophthalmology, 3rd Ed. Elsevier; 2009:986-994

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