Although relatively uncommon, interhemispheric subdural hematoma (ISDH) occurs more frequently than was suspected before the advent of computerized tomographic (CT) scanning. When its mass is sufficiently large to compress the medial cerebral hemisphere, specific focal neurological abnormalities may occur. These include weakness of the contralateral leg, or contralateral hemiparesis with the leg being weaker than the arm. On the unenhanced CT scan ISDH is seen as a crescent shaped, midline hyperdensity. Treatment is dictated by the clinical course. Evacuation of the hematoma by parasagittal craniotomy is recommended if the symptoms are pronounced.

We report a case of primary CNS lymphoma in which complete, though temporary, spontaneous clinical and radiologic remission occurred. This is the first such case report to our knowledge.

The MPTP-treated mouse has proven to be a valuable model of parkinsonism. For example, C57 black mice treated with MPTP exhibit a large decrement in the neostriatal content of dopamine and its metabolites, a marked reduction in the capacity of neostriatal synaptosomal preparations to accumulate [3H]dopamine, a large decrease in neostriatal tyrosine hydroxylase activity, a marked loss of nerve cells in the zona compacta of the substantia nigra, and pronounced behavioral deficits. These biochemical, pathological and behavioral deficits are similarly observed in MPTP-treated primates and in humans with idiopathic parkinsonism. A great deal of our current knowledge concerning MPTP has come from experimentation carried out in the mouse.

We report a patient with chronic, untreated idiopathic hypoparathyroidism who presented with papilledema and progressive deterioration of visual function. The papilledema resolved with treatment of the hypocalcemia. Visual acuity progressively improved as the serum calcium rose during treatment with vitamin D and calcium supplements. Lumbar puncture may also have contributed to the normalization of cerebrospinal fluid pressure and recovery of vision in this patient. The association of hypoparathyroidism and pseudotumor cerebri is rare, and a retrospective review of 41 patients with hypoparathyroidism admitted to two local general hospitals revealed no other cases.

This uncommon paroxysmal movement disorder featuring attacks of dystonic spasm with athetoid posturing is usually of idiopathic nature, often familial and starting in childhood. There are a few reported examples due to cerebral pathology, and only four previous cases due to brain trauma. We report here a 21 year old man with left-sided motor spasms, choreoathetoid in type, which were clearly caused by a right frontal penetrating injury with contusion and haemorrhage. The attacks were relieved by phenytoin therapy. In this case, it seems that the post-traumatic paroxysmal kinesigenic choreoathetosis may be a form of reflex epilepsy.

Glutaric aciduria type I is an autosomal recessive metabolic disorder of children associated with severe dystonic motor disturbances and degeneration in the cerebral cortex, striatum and cerebellum. Biochemical studies demonstrate a deficiency in the enzyme glutaryl-CoA dehydrogenase. This enzyme metabolizes substrate derived from dietary tryptophan that could otherwise be converted to quinolinic acid within the brain. The law of mass action predicts that the production of quinolinic acid should be increased in glutaric aciduria type I. Quinolinic acid is a potent neurotoxin and convulsant when it is injected into the central nervous system of experimental animals. This paper argues that quinolinic acid may accumulate within the brain and cause the neuropathology of glutaric aciduria type I.

We report two patients with dyskinesia responding to antidepressants. The first is a 70-year-old man with depression, Parkinsonism and neuroleptic-induced tardive dyskinesia who presented with hysterical mutism. After recovery from the mutism, he was started on desipramine for depression. One week later the dyskinesia improved markedly. The second patient is a 61-year-old man with Parkinson's disease, dementia, depression and L-dopa-induced oro-lingual-facial dyskinesias. He was taking levodopa, trihexyphenydil and bromocriptine. The depression was treated first with desipramine and later with trazodone. The dyskinesia improved significantly on both drugs. The response of the dyskinesias to antidepressant medication may be due to the fact that antidepressants decrease beta-adrenoreceptor sensitivity and density which in turn may result in a diminished release of dopamine since beta-adrenoceptors mediate the noradrenaline-stimulated release of dopamine.

The local concentration of 6-[18F]fluoro-L-dopa (18F) reflects the activity of aromatic acid decarboxylase (AADC), the enzyme that generates dopamine from its precursor amino acid, L-dopa. In young healthy adults, the local concentration of 18F, and hence AADC activity, is constant in coronal slices taken in a rostrocaudal direction. With increasing age a gradient representing decreasing activity in the putamen develops. This decrease is less marked than was expected from the literature. In five children with primary dystonia, the striatal distribution of 18F resembled that seen in the normal older adults. In established clinical Parkinson's disease the rostrocaudal gradient becomes steep; the putamen is more damaged.

The development of positron emission tomography (PET) has enabled us to perform in vivo measurements of certain aspects of regional cerebral function. Regional cerebral glucose metabolism may be readily quantified with [18F] fluoro-2-deoxyglucose (FDG) and presynaptic dopaminergic function may be studied with the labelled dopa analog 6-[18F] fluoro-L-dopa. We have applied a model to the analysis of 6-FD/PET data with which in vivo age-related changes in dopaminergic function may be demonstrated in normal subjects. With this technique, we have studied a series of asymptomatic MPTP-exposed subjects and have shown evidence of subclinical nigrostriatal pathway damage. Studies of regional cerebral glucose metabolism with FDG in early Huntington's disease have shown a characteristic impairment in caudate function which precedes the development of caudate atrophy. In addition, some asymptomatic individuals who are at risk for HD have caudate hypometabolism. We feel that, at the present time, PET provides information which is complementary to the clinical examination in establishing a diagnosis of HD. In the future these studies may also help in the investigation of at risk individuals

The anatomical substrate of eosinophilic fasciitis (EF) was studied in 15 muscle biopsy specimens of this disease, six of which included the dermis and subcutaneous tissue. As controls, 94 postmortem muscle specimens from patients dying of non-muscular diseases were used. Of these 94 specimens, 22 (23.4%) showed practically no deep fascia and 72 specimens showed a single dense bundle of collagen with no distinction between deep fascia and epimysium. The 15 specimens of EF showed thickening and inflammatory infiltration of varying degrees in the deep fascia, epimysium, perimysium, endomysium and also in muscle. We conclude that the anatomical substrate of EF is not confined to the deep fascia, but involves other structures including mysia and muscle itself. Most reported cases of EF in the literature do not even describe muscle. A comparative study of 15 biopsy specimens of polymyositis and dermatomyositis with those of EF revealed only quantitative differences in the histopathological changes of muscle and mysia, inflammatory infiltrate and eosinophilia. We suggest that the diseases are more closely related than previously recognized.