Canavan disease: CT and MR imaging of the brain.

Canavan disease (spongy degeneration of the brain) is a rare lethal neurodegenerative disorder of infancy; fewer than 100 cases have been reported. We describe a series of nine patients with enzymatic defects and clinical features consistent with Canavan disease; in two patients the disease was proved by biopsy. All patients were examined with CT and seven with MR. In every instance, both CT and MR showed white-matter disease, sometimes sparing the external and internal capsules, the corpus callosum, and the deep cerebellar white matter. Atrophic changes were found in six patients; the changes were marked in one and slight in five. There was no obvious correlation between the severity of the white-matter disease and the clinical presentation--one patient with severe white-matter disease was clinically normal. The CT and MR findings in Canavan disease are nonspecific and somewhat nonuniform: its preautopsy diagnosis relies primarily on biochemical findings.

Increased density of the thalamus on CT scans in patients with GM2 gangliosidoses.

In 13 patients, the GM2 gangliosidoses, Sandhoff disease and Tay-Sachs disease, were found to be constantly associated with homogeneously and symmetrically increased CT attenuation within the thalami. In the only patient examined with MR imaging, a T2-weighted sequence showed hypointense thalami. It is suggested that this finding is caused by an accumulation of calcium, associated with the intracellular storage of GM2 ganglioside. The finding of dense thalami may be useful as a specific diagnostic criterion for GM2 gangliosidoses. In a few patients with blocks in adjacent steps in the sphingolipid metabolism, this finding was not present.

Maple syrup urine disease: findings on CT and MR scans of the brain in 10 infants.

Ten infants with classical maple syrup urine disease (MSUD) and two with variant MSUD had a total of 26 CT scans and 13 MR examinations of the brain during different stages of their disease. We found that inter- and intrapatient analyses of CT and MR findings at times ranging from 3 days to 7 months were typical enough to suggest the MSUD diagnosis. Imaging studies showed the natural course of the disease and, in a few cases, illustrated the effects of therapy. CT scans typically are negative during the first few days of life, then a marked, generalized, diffuse edema appears. In addition, a localized, more severe edema (the MSUD edema) is seen, which involves the deep cerebellar white matter, the dorsal part of the brainstem, the cerebral peduncles, and the dorsal limb of the internal capsule. Both the generalized and the MSUD edema subside during the second month of life, then may disappear totally or leave a well-defined, low-density zone around the lateral ventricles and small, low-attenuation lesions within the brainstem, respectively. With the disappearance of the edema, some loss of brain substance becomes obvious.

Saudi variant of multiple sulfatase deficiency.

We describe eight patients with multiple sulfatase deficiency (MSD, or Austin's disease) who differ phenotypically from classic neonatal-, childhood-, or juvenile-onset MSD. The age of onset was in childhood. The patients presented with somatic and facial features of mucopolysaccharidosis reminiscent of Maroteaux-Lamy and Morquio syndromes. They differed from classic MSD by the presence of corneal cloudiness, macrocephaly, severe dysostosis multiplex, and gibbus and the absence of ichthyosis, retinal degeneration, severe deafness, severe mental retardation, and dementia. The main neurologic presentation was cervical cord compression due to axis abnormalities. Despite neuroradiologic evidence of white-matter changes, neurologic presentation was not like metachromatic leukodystrophy. The sulfatase deficiencies were more marked than in the classic juvenile form of MSD, but less marked than in the classic childhood-onset form of MSD. Steroid sulfatase activity was spared except in one patient. This Saudi variant of MSD accounts for 5% of all lysosomal storage diseases in the Cell Repository Registry of our Inborn Errors of Metabolism Laboratory.

Spontaneous carotid-cavernous fistulas. Clinical symptomatology.

The symptomatology in six cases with spontaneous carotid-cavernous fistulas is discussed. All six patients presented with exophthalmos, dilated veins, pain and restriction of ocular movements. In four patients a bruit was found objectively as well as subjectively, four patients exhibited an increase of the intraocular pressure and in three cases vision was impaired. Of special interest is the finding that discrete symptoms such as venous congestion and slight pain appeared early in the course of the disease in all patients, and that in some of the patients an increase in intraocular pressure as well as disturbances in ocular motility were diagnosed long before the appearance of the exophthalmos.

Orbital phlebography. Technique and clinical applications.

The technique for orbital phlebography is described and the phlebographic anatomy of the orbit and the skull base presented. The possibilities and limitations of phlebography in the diagnosis of different intraorbital and ophthalmoneurological disorders is discussed and illustrated out of personal experiences from 200 cases.

Spontaneous carotid-cavernous fistulas: phlebographic appearance and relation to thrombosis.

Six consecutive cases with spontaneous carotid-cavernous fistulas were examined with orbital phlebography and bilateral carotid angiography. One of the fistulas was fed only by one internal carotid artery, 1 only by the accessory meningeal branch of the maxillary artery, while 4 were supplied by external as well as internal carotid arteries. The findings at phlebography seem to be characteristic. Thrombosis was demonstrated in all 6 cases. Different mechanisms for the genesis of thrombosis in association with carotid-cavernous fistulas are proposed. Alternative therapy methods are discussed.

Bilateral exudative retinal detachment in pregnancy.

A case of bilateral exudative retinal detachment associated with otherwise normal pregnancy is presented. Similar cases, but associated with toxemia of pregnancy from the literature are discussed. As far as we know, this is first reported case where bilateral exudative retinal detachment presented in a normal pregnancy and the re-attachment started promptly after a normal, spontaneous delivery. The re-attachment was complete, and the visual acuity after one year was 20/20 o.u. This case supports earlier theories that hypertension is not the only cause of exudative retinal detachment during pregnancy.

Aseptic thrombosis of orbital veins and cavernous sinus. Clinical symptomatology.

Occlusion or thrombosis of the superior ophthalmic vein or of the cavernous sinus is an unspecific finding that may be secondary to different disorders such as tumours of the skull base or nasopharynx. Sometimes, however, no underlying disorder is found in spite of an extensive clinical and radiological evaluation. Eight such cases are here presented. Similar cases have previously been described, both as examples of the Tolosa-Hunt syndrome and as aseptic cavernous sinus thrombosis. The literature on these two disorders is reviewed and different diagnostic criteria discussed.

Thrombosis of the intraorbital veins and cavernous sinus.

Eight cases with phlebographic appearances consistent with aseptic thrombosis of the cavernous sinus or of the posterior part of the superior ophthalmic vein are presented. The clinical course is briefly described and the phlebographic findings and possible differential diagnoses discussed. Even if recent methods may obviate the need for phlebography in the demonstration of orbital tumors in certain cases, the possibility of intraorbital or cavernous sinus thrombosis constitutes an important indication for phlebography.

Orbital phlebography in evaluation of the cavernous sinus and adjacent basal veins of the skull.

Frontal vein phlebography has proven to be of great diagnostic value in the evaluation of pituitary tumours and of lesions in the vicinity of the sella turcica. It permits the diagnosis of venous thrombosis; similar phlebographic changes may be the only positive radiologic finding in cases with malignant tumour of the skull base. Phlebography is thus to be recommended as an early method to be used in possibly malignant lesions at the skull base.

Complications of orbital and skull base phlebography.

Two complications, one in association with frontal vein phlebography and one in association with inferior petrosal sinus phlebography, are presented. Possible mechanisms for complications are discussed. It is concluded that a significant risk exists in association with inferior petrosal sinus phlebography, particularly in association with vascular disorders of the skull base, while the risk in association with orbital phlebography after frontal vein puncture is minimal if compression of the jugular veins is omitted.

Unilateral endocrine exophthalmos. Diagnostic problems in association with computed tomography.

Swollen orbital extraocular muscles may mimic an orbital apex tumor on computed tomography. In five of our patients, in spite of highly suggestive findings on CT scanning, indicating the presence of an orbital apex lesion, the correct diagnosis proved to be endocrine exophthalmos. The value of complementary CT projections and of orbital ultrasonography to assist in the differential diagnosis is discussed, and the additional contribution of orbital phlebography for the confirmation of lesions in the orbital apex is emphasized.