Ординатура / Офтальмология / Английские материалы / Field of Vision A Manual and Atlas of Perimetry_Barton, Benatar_2003

DISCUSSION

Field description: Subtle superior bitemporal hemifield depression in paracentral region.

Localization: Optic chiasm.

Pathology: Pituitary adenoma with apoplexy.

Confrontation testing was normal.

The patient’s bitemporal defects are subtle and only apparent near the center of vision. Nevertheless, the perimetrist has been careful to document clear vertical steps in the smallest (03e) isopter.

Coronal T1-weighted MRI (below) revealed a pituitary tumor with hemorrhage (pituitary apoplexy). The optic chiasm is bowed upward above the bright enhancing rim of the tumor. Fibers from the inferior nasal retina (superior temporal visual fields) cross in the inferior aspect of the optic chiasm. Compression of the chiasm from below, as by pituitary masses, will tend to produce superior bitemporal defects first.

Pituitary apoplexy is the sudden expansion of the pituitary gland from hemorrhage, infarction, or edema. Typically, these are complications of an underlying pituitary tumor. Infarction or hemorrhage in a normal gland can occur in the postpartum state (Sheehan syndrome) but less frequently affects vision than apoplexy related to a tumor (107). Pituitary apoplexy presents with sudden severe headache, nausea and vomiting, and a variable degree of hypopituitarism, a major threat being acute adrenal insufficiency. Other symptoms depend on the direction of expansion (107,108). Extension into the cavernous sinus causes acute ophthalmoplegia of one or both eyes, as in this patient. Downward extension causes epistaxis with the risk of exsanguination. Upward extension impairs vision. Rupture into the subarachnoid space causes meningismus and stupor.

HISTORY AND EXAM

This 27-yr-old man had not been able to wear his hats or gloves for a year or two, and his shoe size had increased from 13 to 14-wide over this time. He had occasional headaches but no visual symptoms. Visual acuity was 20/20 OU and color vision was

normal. There was no RAPD. Optic disks were normal. He was clearly acromegalic, with large spade-shaped hands and a prominent brow and jaw.

DISCUSSION

Field description: Subtle bitemporal defects; also probably a supraorbital artifact from his enlarged brow.

Localization: Optic chiasm.

Pathology: Pituitary adenoma, growth hormone (GH) secreting.

Other features: Acromegaly. Confrontation testing was normal.

The patient’s fields show some mild superior depression that does not respect the vertical meridian. This is likely lid or brow artifact. However, there are clearly defects that line up at the meridian OS. It is less clear whether there is a chiasmal defect OD, although there may be more superior field depression temporally than nasally. Coronal

T1-weighted MRI showed a moderately large pituitary lesion with a cystic component, bowing the optic chiasm upward (arrow).

Acromegaly results from excess secretion of GH during adulthood (109,110). This causes bone and soft-tissue enlargement (especially of the face, hands, and feet), visceromegaly, and glucose intolerance. Not surprisingly, these clinical symptoms mean that pituitary adenomas associated with acromegaly present at a smaller size than do nonsecreting adenomas. Therefore, visual field defects arise less frequently with GH-secreting tumors than with other pituitary adenomas. This patient’s field defects are clearly more subtle than many of the others in this atlas. Automated perimetry was chosen because no defect was evident on confrontation testing, despite knowing that such a tumor was likely. Transsphenoidal resection is the treatment of choice.

HISTORY AND EXAM

This 67-yr-old man, on anticoagulants for earlier deep venous thrombosis, went to an emergency room for a sudden severe headache. He was confused and drowsy with meningismus and a mild left inferior rectus paresis. INR was 2.2. CT of his brain showed an enlarged sella with hemorrhage in the interhemispheric fissure. He developed acute adrenal insufficiency and hydrocephalus, requiring an intraventricular drain. He was dis-

charged without surgery and returned 2 months later for assessment. Acuity was 20/15 OD and 20/40 OS, and Ishihara color scores were 12/14 OD and 11/14 OS. There was no RAPD. Optic disks were normal but there was (known) macular degeneration OS. Ductions were full.

DISCUSSION

Field description: Relative bitemporal depression, greater OS, with relative central scotoma OS.

Localization: Optic chiasm and retina.

Pathology: Pituitary adenoma with apoplexy, macular degeneration.

Confrontation testing was normal OU.

The patient’s bitemporal defects again affect mainly the central fields. On the left, there is also a shallow central scotoma for the smallest isopter. While this might raise the question of added compression of the left intracranial optic nerve, this is probably explained by his known macular degeneration, which is worse OS.

The sudden headache suggests subarachnoid hemorrhage or pituitary apoplexy. The subarachnoid blood explains the meningismus and stupor, but the enlarged pituitary

suggests that the subarachnoid hemorrhage is secondary to apoplexy, as confirmed on these coronal T1-weighted and axial susceptibility MRI images (note the dark spot on the latter indicating blood; see arrow). Misdiagnosis as meningitis or subarachnoid hemorrhage frequently delays the diagnosis of pituitary apoplexy. The importance of the early diagnosis of apoplexy lies in the need to recognize the potential for life-threatening hypoadrenalism requiring immediate iv steroid replacement. Risk factors for apoplexy include diabetes; atherosclerosis; earlier pituitary irradiation; use of bromocriptine; and use of anticoagulants, as in this man (107,111). Surgical treatment is not always necessary and is mainly indicated for altered consciousness, visual loss, and progressive enlargement of the pituitary (107).

DISCUSSION

Field description: Mild relative bitemporal hemifield defects.

Localization: Optic chiasm.

Pathology: Descent of the optic chiasm, post-radiation/surgery.

Confrontation testing showed red desaturation in the temporal paracentral fields OU, with sudden steps at the vertical meridians.

On perimetry, the patient’s bitemporal defect is a relative depression evident only in the central field, with testing using the smallest (I2e) isopter. On confrontation, a subtle bitemporal reduction in color was the only clue to this mild field defect.

Old charts eventually revealed that her earlier brain tumor had been a craniopharyngioma. In the absence of knowledge of her visual fields in the past, tumor recurrence must be considered, although it is rare when this type of tumor is treated with both resection and radiation (112). Instead of recurrence, her coronal T1-weighted MRI shows “descent of the optic chiasm” (113). The middle of the chiasm is drawn down toward the sella, causing a V-shaped configuration on coronal images. This has been reported to worsen preexisting bitemporal defects, presumably via a traction mechanism. In this woman, is the visual defect a remnant from her prior tumor and surgery, or is it due to her current chiasmal descent? Without earlier visual fields, one cannot know for sure.

HISTORY AND EXAM

This 49-yr-old woman with symptoms of polyuria and polydipsia was diagnosed with diabetes insipidus. MRI demonstrated a pituitary mass, which partial resection showed to consist of lymphocytic infiltration, without tumor. Visual field screening showed a defect,

and she was referred for evaluation. Visual acuity was 20/20 OD and 20/30 OS, and Ishihara color plates were 13/14 OD and 14/14 OS. There was no RAPD. Optic disks appeared normal. The remainder of the neurologic examination was normal.

DISCUSSION

Field description: Superior arcuate defect OD. Localization: Intracranial optic nerve. Pathology: Lymphocytic hypophysitis.

Confrontation testing showed superotemporal paracentral scotoma for red targets OD.

30° shows essentially the same defect (shown this page). T1-weighted coronal MRI revealed a heterogeneously enhancing mass in the pituitary (arrow) near where the optic nerves join the chiasm. The combination of the biopsy result with pituitary and focal optic nerve enlargement suggests a limited differential that includes lymphocytic hypophysitis and sarcoidosis. The absence of granulomas on biopsy is somewhat against the latter, and a CT scan of her chest and Gallium scan were normal.

Lymphocytic hypophysitis (adenohypophysitis) is a rare, probably autoimmune disease (114). It occurs most often in women during pregnancy and the postpartum period (see also Case 64). Patients present with symptoms of an expanding sellar mass (headache, decreased visual acuity, visual field defect, and diplopia) or with pituitary dysfunction. It more commonly affects the anterior pituitary, causing hypoadrenalism, hypothyroidism, amenorrhea, or disturbances of lactation, than the posterior pituitary, as in this patient.

HISTORY AND EXAM

This 50-yr-old woman had a known right anterior communicating artery aneurysm, discovered and treated 14 years earlier because of visual loss in the right eye. A few weeks prior to evaluation, she had noted new worsening of vision in the right eye as well as in the left upper field of the left eye, accompanied by episodic hallucinations of colors in this

left upper quadrant. Visual acuity was counting fingers at 6′ OD and 20/20 OS. She read 13/14 Ishihara color plates OS. There was a prominent RAPD OD and optic disk pallor, more severe OD than OS.