Published ahead of print on February 29, 2008
doi: 10.3174/ajnr.A1020
American Journal of Neuroradiology 29:1003-1005, May 2008
© 2008 American Society of Neuroradiology
Case Report
PEDIATRICS
Imaging Findings of Congenital Glaucoma in Opitz Syndrome
A.K. Choudharya and
B. Jhab
a Department of Radiology, Hershey Medical Center, Hershey, Pa
b Department of Neurology, Hershey Medical Center, Hershey, Pa
Please address correspondence to Arabinda K. Choudhary, MD, Department of Radiology, H066, Hershey Medical Center, 500 University Dr, Hershey, PA 17036; e-mail: achoudhary{at}hmc.psu.edu
SUMMARY: Opitz syndrome is a rare autosomal recessive disorder
of cholesterol metabolism associated with mental retardation
and multiple congenital malformations. It is also uncommonly
associated with congenital glaucoma. We describe the orbital
findings on CT in this rare case of a patient with Opitz syndrome
who presented with congenital glaucoma, with a review of the
literature. The CT findings of congenital glaucoma, which have
not been described before in the literature, are also discussed.
It is important for the radiologist to be aware of this rare
association. It is also important to be aware of the findings
of congenital glaucoma on CT because patients with Opitz syndrome
and other syndromes associated with learning difficulties may
not present with typical clinical features of glaucoma. A high
index of suspicion will lead to a correct diagnosis and earlier
intervention.
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Introduction
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Opitz syndrome is a rare autosomal recessive disorder caused
by a defect of cholesterol metabolism. It is associated with
mental retardation and multiple congenital malformations. Multiple
midline neurologic abnormalities have been described in the
literature. There have been rare reports of congenital glaucoma
in association with Opitz syndrome. To the best of our knowledge,
radiologic findings on CT of congenital glaucoma have not been
described before in the literature. We describe the association
as well as radiologic findings on CT of congenital glaucoma.
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Case Report
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A 12-year-old female patient with Opitz syndrome came to the
emergency department with a history of increasing prominence
of right eye. She had profound mental retardation; cleft palate;
nasal, forehead, finger, and foot deformities; and micrognathia.
On previous barium swallow study, her epiglottis was described
as short and stubby. A CT study was obtained to exclude a retro-orbital
mass and showed a markedly enlarged anterior chamber of the
right eye, which measured 6.7 mm in the anteroposterior dimension
compared with 4.0 mm on the left side, which is also enlarged
(
Figs 1 and
2). Trigonocephaly was noted (
Fig 3). Bilateral
optic nerve atrophy (
Fig 4) was also noted. On ophthalmologic
examination, she was found to have large cornea with a pressure
of more than 40 bilaterally, worse on the right side. She subsequently
was given a topical beta-blocker, systemic carbonic anhydrase
inhibitor, and brimonidine. One week later, she had trabeculotomy
and trabeculectomy of her right eye and, a few weeks later,
trabeculotomy and trabeculectomy of her left eye.
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Fig 1. Axial CT image through the orbits after administration of intravenous (IV) contrast medium, which demonstrates a markedly enlarged anterior chamber of the right globe (arrow) and mildly enlarged anterior chamber of the left globe (arrowhead).
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Fig 2. Sagittal reconstructed CT images through the orbit after IV contrast medium, which demonstrates a markedly enlarged anterior chamber of the right globe (arrow) and a mildly enlarged anterior chamber of the left globe (arrowhead).
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Fig 4. Axial CT images through the optic nerve after IV contrast medium showing bilateral optic nerve atrophy (arrows).
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Discussion
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Opitz syndrome is a rare autosomal disorder caused by a defect
in cholesterol metabolism. It is a heterogeneous disorder ranging
from lethality to minor abnormalities. The abnormalities involve
multiple systems including mental retardation; structural brain
abnormalities; craniofacial abnormalities; and abnormalities
of the heart, bowel, liver, lung, extremities, and genitalia.
The ophthalmologic findings described have included blepharoptosis,
congenital cataracts, optic atrophy, nystagmus, blepharoptosis,
epicanthal folds, convergent strabismus, downslanting small
palpebral fissures, mild exophthalmos, retinal pigment epithelial
defects, pale disks, nystagmus, microcornea, aniridia, congenital
cataracts, postlenticular membrane, Duane retraction syndrome,
absence of lacrimal punctaopsoclonus-like eye movements, lack
of visual-following responses and opticokinetic reflexes, corneal
enlargement, abnormal iris insertion, bilateral optic pits,
sclerocornea, and optic nerve demyelination.
1 Congenital glaucoma
is uncommonly seen with Opitz syndrome.
2,3 Glaucoma can also
be associated with other congenital disorders including Sturge-Weber
syndrome, neurofibromatosis, Lowe syndrome, Pierre Robin syndrome/sequence,
Marfan syndrome, homocystinuria, aniridia, Axenfeld anomaly,
and Reiger syndrome.
4 Secondary causes of infantile glaucoma
causing similar appearance include maternal rubella, syphilis,
retinopathy of prematurity, infantile xanthogranuloma, trauma,
and retinoblastoma.
5
The dimensions of the globe are relatively constant, varying within a millimeter or so with the average sagittal diameter measuring approximately 24.15 mm (outer) and 22.12 mm (inner). In boys, the diameter is approximately 0.5 mm more than that in girls. At birth, the sagittal diameter of the eyes varies from 16 to 17 mm and then increases to an average value of 22.5 to 23 mm at the age of 3 years. It further increases by approximately 1 mm between the ages of 3 and 13 years and then stays stable. The overall incidence of congenital glaucoma is 1:5000 to 1:10,000 live births. It is more common in boys (60%–70%) and is bilateral in 64% of 88% of patients.4 In congenital glaucoma, developmental abnormalities cause obstruction to the flow of the aqueous humor from the anterior chamber, resulting in increased intraocular pressure. The different theories to explain obstruction include the Barkan membrane covering the trabecular meshwork, congenital absence of the Schlemm canal, and an embryonic anterior chamber angle.4 In young children, this results in enlargement, stretching, and thinning of the coats of the eye, as the eyes are of sufficient plasticity. This is especially marked in the anterior chamber, resulting in a deep anterior chamber. The appearance is said to resemble the eyes of an ox (buphthalmos). In the adult, a similar degree of raised pressure will only cause stretching in the region of the lamina cribrosa.5 The normal mean anterior chamber depth is approximately 3 mm, which varies with the measuring method and the age and sex of the patient.6,7 In congenital glaucoma, the mean anterior chamber depth is 6.3 mm.5 In our patient, the sagittal diameter of the globe on the right side measured 27 mm, with the anterior chamber measuring 6.7 mm. Therefore, it has been predominantly an enlargement of the anterior chamber. These eyes may develop subluxated lens. Complications include atrophy of the optic nerve, which was noted on our study. The optic nerve should measure approximately 3 to 4 mm in the orbit.6 On our patient, it measured approximately 2 mm. It is also important to note that the primary closed-angle glaucoma is associated with a narrow anterior chamber.8 The condition tends to stabilize in early youth, possibly because of a stretching process opening up the trabeculae of the angle of the anterior chamber. In the absence of effective treatment, the end result is almost invariably blindness.5
On the axial sections, it is important to measure the depth of the anterior chamber at the equator because a globe rotated superiorly or inferiorly may give an erroneous measurement. The best way to assess the anterior chamber is on sagittal images, which on CT examination can be easily reconstructed from the raw data of most of the modern multidetector CT studies. A significant difference in the size of the 2 globes or an absolute measurement of more than 5 mm may also be considered abnormal.9 An enlarged anterior chamber can also be seen in other causes of glaucoma, including posttrauma. Hampton10 has compiled a comprehensive classification of pseudodevelopmental glaucoma with its differentiating features. It has also been reported in cases of posterior scleral rupture.9 However, the diagnosis may be suspected by the clinical history of trauma as well as other signs of globe trauma including loss of volume, significant change in globe contour, or vitreous hemorrhage.11 Subluxation of the lens may also cause an enlarged anterior chamber, but the lens is usually rotated and the diagnosis is obvious clinically. Other differential diagnoses would include megalocornea, high congenital myopia, congenital staphyloma, and also congenital hereditary dystrophies of the cornea. Megalocornea may appear similar with enlarged anterior chamber but is because of a primary overgrowth rather than secondary to distension and, as such, does not have raised intraocular pressure or optic nerve atrophy.5 The other differential diagnoses listed above are usually clinically obvious.
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Conclusion
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It is important for the radiologist to be aware of the association
of Opitz syndrome with congenital glaucoma. It is also important
to be aware of the findings of congenital glaucoma on CT because
patients with Opitz and other syndromes associated with learning
difficulties may not present with typical clinical complaints
of glaucoma. An enlarged anterior chamber sign in the absence
of trauma may be a sign of congenital glaucoma, particularly
in the presence of optic nerve atrophy, and additional clinical
assessment to evaluate for raised intraocular pressure would
be required. A high index of suspicion will lead to a correct
diagnosis and earlier intervention.
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References
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- Atchaneeyasakul LO, Linck LM, Connor WE, et al. Eye findings in 8 children and a spontaneously aborted fetus with RSH/Smith-Lemli-Opitz syndrome. Am J Med Genet 1998;80:501–05[CrossRef][Medline]
- Kelley RI, Hennekam RC. The Smith-Lemli-Opitz syndrome. J Med Genet 2000;37:321–35[Abstract/Free Full Text]
- Curry CJ, Carey JC, Holland JS, et al. Smith-Lemli-Opitz syndrome-type II: multiple congenital anomalies with male pseudohermaphroditism and frequent early lethality. Am J Med Genet 1987;26:45–57[CrossRef][Medline]
- Yanoff M, Fine BS. Ocular Pathology, 4th ed. St Louis: Mosby-Year Book; 1996:580–83
- Duke-Elder S. System of Ophthalmology. Vol III: Congenital Deformities. St Louis: Mosby; 1961:489–565
- Duke-Elder S. System of Ophthalmology. Vol II: The Anatomy of the Visual System. St Louis: Mosby; 1961:187–277
- Lavanya R, Teo L, Friedman DS, et al. Comparison of anterior chamber depth measurements using the IOLMaster, scanning peripheral anterior chamber depth analyser, and anterior segment optical coherence tomography. Br J Ophthalmol 2007;91:1023–26[Abstract/Free Full Text]
- Duke-Elder S. System of Ophthalmology. Vol XI: Diseases of the Lens and Vitreous, Glaucoma and Hypotony. St Louis: Mosby; 1961:571
- Weissman JL, Beatty RL, Hirsch WL, et al. Enlarged anterior chamber: CT finding of a ruptured globe. AJNR Am J Neuroradiol 1995;16(4 Suppl):936–38[Abstract]
- Hampton RF. Pseudodevelopmental glaucoma. Appearance of developmental glaucoma. Ann Ophthalmol 2005;37:245–51[CrossRef]
- Arey ML, Mootha VV, Whittemore AR, et al. Computed tomography in the diagnosis of occult open-globe injuries. Ophthalmology 2007;14:1448–52
Received November 14, 2007;
accepted after revision December 16, 2007.
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Introduction