Spondylodiscitis due to Aerococcus viridans.

Aerococcus viridans is a microaerophilic, Gram-positive, catalase-negative coccus, found singly or in tetrads. To date, no case of spondylodiscitis due to this organism has been reported. We report what we believe to be the first case of spondylodiscitis caused by A. viridans, in a patient with decompensated liver failure, and discuss the possible pathogenesis of this rather uncommon pathogen in this case.

Plasmacytoma: an unusual cause of a pituitary mass lesion. A case report and a review of the literature.

A sixty six year old female presented with headache and decreased hearing. Clinical examination confirmed the presence of impaired hearing on the left side. Visual fields were full to confrontation and corrected visual acuity was normal. CT scan of brain revealed a pituitary mass. Preoperative anterior pituitary function was normal. Transsphenoidal decompression was performed, and histology was that of a plasmacytoma. Post operative pituitary function was normal. The patient had no symptoms or signs of multiple myeloma and subsequent investigations revealed no evidence of the disease. One year after diagnosis a course of radiotherapy was administered for local tumour recurrence. During seven years of follow-up, no evidence of multiple myeloma has emerged. Only thirteen similar cases have been described. Four of these had evidence of multiple myeloma at presentation and six progressed to it during follow-up. In twelve patients cranial nerve deficits were recorded. In any cases where it was documented, preoperative anterior pituitary function was normal. In a number of cases histology was reported initially as being that of a non-functioning adenoma, the true diagnosis being discovered, either by electron microscopy findings or after the development of multiple myeloma. Plasma cell tumours of the pituitary area are rare and can present with symptoms and signs indistinguishable from non-functioning adenoma. Atypical symptoms such as cranial nerve involvement or unexpected preservation of anterior pituitary function should arouse suspicion.

Terson's syndrome as the sole presentation of aneurysmal rupture.

The authors report a rare case of aneurysmal haemorrhage that presented with Terson's syndrome without any classical features of subarachnoid haemorrhage. The mechanism of this phenomenon is discussed and the importance of its identification is highlighted.

Vagal nerve stimulation in patients with refractory epilepsy. Effect on seizure frequency, severity and quality of life.

Vagal nerve stimulation using an NCP (Cyberonics) device has been suggested as a potential treatment for patients with epilepsy that has previously proven refractory. Ten patients in Northern Ireland have had this device implanted and been fully audited pre- and post-operatively. Twelve months post-implantation, five patients have demonstrated a greater than 50% reduction in seizure frequency. A statistical reduction in seizure severity of the ictal phase of the major seizures has also been shown. Improvement in the patients' overall quality of life has, however, not been demonstrated in parallel to seizure reduction.

The Chiari/hydrosyringomyelia complex presenting in adults with myelomeningocoele: an indication for early intervention.

OBJECTIVE: To determine how adults with myelomeningocoele who develop the Chiari/hydrosyringomyelia complex present, and to determine if surgical intervention influences outcome in these patients. METHODS: A chart review of the 220 patients who attend a clinic for adults with spina bifida and hydrocephalus (CASBAH), and follow-up of the five cases with myelomeningocoele who had surgical intervention for associated symptomatic Chiari/hydrosyringomyelia complex. RESULTS: Bilateral upper limb weakness and wasting were the commonest presenting symptoms (four patients). Sensory disturbance (three patients) was also common, dysphagia (one) and ataxia (one) occurring less often. The median time to surgical intervention was 36 months. Two patients had a shunting procedure performed in isolation, two foramen magnum decompression in addition to a shunting procedure and one a foramen magnum decompression. Surgical intervention did not completely reverse problems attributed to the Chiari/hydrosyringomyelia complex in any of the cases. One patient died post-operatively. Of the four who survived one had some improvement in function post-operatively, two remained static and one had further mild deterioration. CONCLUSION: All adults with myelomeningocoele should be questioned about changes in upper limb function for early detection of Chiari/hydrosyringomyelia complex. Our results suggest that early intervention is needed if further deterioration is to be avoided, and to improve the chances of neurological and functional recovery.

An intramolecular DNA triplex is disrupted by point mutations associated with hereditary persistence of fetal hemoglobin.

Several investigators have suggested that secondary structures in DNA may be involved with physiologic gene regulatory processes in higher organisms. This hypothesis has been difficult to prove, however, since naturally occurring mutations that alter secondary DNA structures have not yet been identified. In this report, we describe a secondary DNA structure upstream from the human gamma-globin genes; this structure is formed in a homopyrimidine-homopurine tract and is stabilized by acidic pH and negative supercoiling of plasmid DNA. Since this structure is asymmetrically cleaved by S1 nuclease, it probably contains a single-stranded region and an intramolecular triplex. The single-stranded region is actually accessible for Watson-Crick base pairing with exogenous oligomers, a characteristic that permitted us to directly map the secondary DNA structure without additional chemical modifications of the supercoiled DNA. Five different point mutations just downstream from the single-stranded region are associated with hereditary persistence of fetal hemoglobin; four of these mutations dramatically reduce the stability of the secondary DNA structure, suggesting that these mutations alter formation of the intramolecular triplex by destabilizing critical Hoogsteen (triple-stranded) base pairs. These mutations may therefore represent a novel class of genetic defects that alter gene expression by changing the interaction of a critical regulatory molecule with a secondary DNA structure.

Dislocation after total hip arthroplasty. Causes and prevention.

In this prospective study, a technique of positioning the acetabulum by bony landmarks of the pelvis in the standing position was developed using a standing lateral preoperative roentgenogram with the X-ray tube centered over the trochanter. Since 1984, 441 total hip arthroplasties (THAs) were done through the posterior approach with a 1.14% dislocation rate through 1988 and no dislocations in 1989. To prevent impingement and dislocation, it was determined that the safest range for cup position was 30 degrees-50 degrees abduction and 20 degrees-40 degrees flexion from the horizontal. To measure postoperative cup position, a standing true lateral roentgenogram of the operated hip allowed direct measurement of cup flexion and was reproducible within 10 degrees. No special instruments are necessary for this technique, which can be used with any THA system.

Fibrinolytic agents in the treatment of thrombotic disorders.

The oncology patient is often at increased risk of bleeding when thrombolytics are administered. Fortunately, the factors placing the patient at risk are easily identified and include intracranial disease, vascular defects produced by surgery, instrumentation or tumor invasion, underlying coagulopathy, and severe thrombocytopenia. Unfortunately, new clot-specific agents have not eliminated the problem of undesirable bleeding; in fact, they may cause more bleeding by more efficiently dissolving both pathological thrombi and hemostatic plugs. The development of a means of delivering thrombolytics solely to the target clot is desirable and should be performed when possible. Despite the need for caution, thrombolytics are remarkably effective in treating both venous and arterial thrombi, and it is a disservice to the patient not to carefully consider their use.

Team physician #8. Osteochondritis dissecans of the patella in a competitive fencer. A case report and review of the literature.

Osteochondritis dissecans of the patella, a rare condition producing knee pain in the athlete, is considered to be the result of repeated shear forces producing microtrauma. We present the case of a fencer who developed this injury. The confirmation of the diagnosis by magnetic resonance imaging scan is demonstrated, and the literature is reviewed with an emphasis on treatment. The physician treating athletes with anterior knee pain must consider this entity in making the differential diagnosis.

Subdural haematoma associated with long term oral anticoagulation.

Twenty-two patients with subdural haematomas associated with long term oral anticoagulation have been reviewed. Clinical presentation was similar to other subdural haematomas, but patients were generally older and the clinical course was more rapid. The incidence of over-anticoagulation was 23% and there was no correlation between anticoagulant status and the extent of bleeding or prognosis. Mortality was 27%, a residual neurological deficit was present in 14% and 59% made a complete recovery. The results suggest that morbidity and mortality could be reduced by early diagnosis and treatment and any patient on oral anticoagulant therapy who develops a headache or confusion should have urgent neurological investigation, including a CT scan. The indications for long term anticoagulation, particularly in the elderly, should be critically reassessed.

Pressure-volume index as a function of cerebral perfusion pressure. Part 1: The effects of cerebral perfusion pressure changes and anesthesia.

The pressure-volume index (PVI) was measured as a function of cerebral perfusion pressure (CPP) in 12 adult cats. Anesthesia was induced with methohexital in six animals and with pentobarbital in six animals; all were maintained on an N2O:O2 (70%:30%) mixture. The CPP was either increased in 10-torr increments using norepinephrine or decreased by a combination of adenosine triphosphate and hemorrhage in subgroups. Three estimations of PVI were made at each level of CPP. The PaCO2, body temperature, and hematocrit were controlled at normal levels throughout. In both groups there was a linear relationship between PVI and CPP with increasing CPP being reflected by a rise in PVI. This relationship was more marked in the methohexital group: PVI = 0.37 ml + 0.0005 mm Hg CPP in the pentobarbital group, and PVI = 0.14 ml + 0.0019 mm Hg CPP in the methohexital group. These results indicate that the PVI is not independent of CPP but is a function of CPP and is profoundly influenced by anesthesia.

Pressure-volume index as a function of cerebral perfusion pressure. Part 2: The effects of low cerebral perfusion pressure and autoregulation.

The pressure-volume index (PVI) was measured in six adult cats while cerebral perfusion pressure (CPP) was reduced from normal levels to below the autoregulatory range by a continuous infusion of adenosine triphosphate. Anesthesia was induced with methohexital and maintained with an N2O:O2 (70%:30%) mixture. Body temperature, hematocrit, and PaCO2 were held constant throughout each experiment. Cerebral blood flow (CBF) was measured by the hydrogen clearance method. At CPP levels over 50 mm Hg, CBF remained relatively constant despite changes in CPP. Within this range, the PVI varied directly with CPP (PVI = 0.24 ml + 0.0013 mm Hg CPP). Below the autoregulatory range, CBF fell progressively with further decreases in CPP; in this range, PVI was found to increase as CPP fell (PVI = 0.84 ml - 0.0071 mm Hg CPP). These results indicate that the PVI is a complex function of CPP, varying directly with CPP within the autoregulatory range and indirectly with CPP below the autoregulatory range.

Effects of atracurium on intracranial pressure in man.

Intravenous administration of 0.6 mg/kg of atracurium to nine patients did not produce any significant change in intracranial, mean arterial or cerebral perfusion pressures. In another three patients, anaesthesia was induced with thiopentone 5 mg/kg after muscle relaxation with atracurium 1 mg/kg. Intracranial pressure was below pre-induction levels in two patients whose tracheas were intubated 90 seconds after atracurium. The vocal cords were not fully relaxed at 90 seconds in the third patient. Intubation at 150 seconds in this patient was associated with a rise in intracranial pressure above pre-induction values.