FENTANYL THERAPY CONTROLS AUTONOMIC HYPERACTIVITY IN TETANUS

SUMMARY This report describes the use of fentanyl in severe tetanus after failure of established therapeutic modalities (heavy sedation, neuromuscular blockade and ventilation). Cardiovascular instability accompanying severe tetanus secondary to sympathetic overactivity and raised catecholamine levels is associated with a mortality of over 50%.¹ In this clinical situation, a variety of drugs with a primary or secondary action on the cardiovascular system has been used with varying success. The following case of severe generalised tetanus in the adult associated with autonomic hyperactivity, was successfully managed with large doses of intravenous fentanyl.     

A case of a femoral neck tumor: painless osteroid osteoma?

We report herein a unique, previously unreported, successful outcome for a patient untreated for a tumor affecting a femoral neck considered as painless osteoid osteoma. The lesion was detected by chance at examination for groin injury. Diagnosis was based on the plain radiography, bone scan, and computed tomography. The results of the full blood examination were normal. Neither pharmacomedical nor surgical treatments were given. Two years later, radiological resolution of the lesion was revealed. The patient was observed between 1995 and 2002. We conclude that painless osteoid osteoma should be included in the differential diagnosis of asymptomatic femoral neck lesions. Our case suggests that osteoid osteoma has a tendency to regress over time and that conservative management appears to be a reliable option.     

Clinical experience with a new detection algorithm for differentiation of supraventricular from ventricular tachycardia in a dual-chamber defibrillator

INTRODUCTION: Inadequate therapy for supraventricular tachyarrhythmias (SVT) is a frequent problem of implantable cardioverter defibrillators (ICD). Dual-chamber ICDs have been developed to improve discrimination of SVT from ventricular tachycardia (VT). We investigated the positive predictivity, sensitivity, and specificity of a new algorithm, the SMART detection trade mark algorithm, incorporated in the Phylax AV (Biotronik) dual-chamber ICD. METHODS AND RESULTS: Two hundred nine patients (185 men, age 64 +/- 11 years) received a Phylax AV ICD with SMART detection trade mark activated. In 138 of these patients, 1,245 sustained tachycardia episodes with a detailed electrogram were stored in the device during a follow-up period of 10 +/- 6 months. Episodes were correctly classified as ventricular fibrillation (VF, n = 178) in 52 patients, VT (n = 641) in 98 patients, and SVT (n = 385) in 48 patients by the algorithm. Forty-one true SVT episodes (3.3%) were misclassified as VT: atrial fibrillation (n = 7) and flutter (n = 1), sinus tachycardia (n = 12), and other SVT (n = 21). The positive predictivity for VF/VT was 94.5% (95% CI 92.7-95.8) uncorrected and 94.5% (95% CI 92.9-95.8%) corrected with the generalized equation estimation (GEE) method. The positive predictivity for SVT was 100%. The specificity was 88.9% (95% CI 85.6-91.6%) uncorrected and 89.0% (95% CI 85.6-91.6%) corrected with the GEE method with a sensitivity of 100%. CONCLUSION: The SMART detection trade mark algorithm was safe and reliable for the detection of all ventricular tachycardias. Although its specificity was high, it should be improved with regard to SVT to avoid inappropriate ICD therapies.     

Acute demyelination: diagnostic difficulties and the need for brain biopsy

Summary ¶Background. Despite the rapid development in neuro-imaging over the past two decades, ring like contrast-enhancing lesions on CCT or MRI still may pose a diagnostic challenge. The main differential diagnoses of these lesions include metastatic carcinoma, high-grade glioma and brain abscess. Acute demyelination seldom turns out to be the underlying pathology. Method. Retrospective analysis was done on six patients with acute demyelination treated at our neurosurgical department between 1990 and 2001. Clinical, radiological, PET, intra-operative and histological findings were evaluated. Findings. In five patients, the diagnosis of acute demyelination was established by histopathological evaluation of stereotactic biopsy specimen, in the sixth patient following microsurgical extirpation of the lesion. Neuropathology revealed demyelination with the presence of myelin-phagocytosing macrophages. In addition, lymphocytic infiltrates were present. Symptoms and signs improved significantly after high-dose steroid therapy. Conclusions. Despite CNS tissue destruction, necrosis and cyst formation are not usually found in demyelinating disease, being rather more common in young patients with ring-like contrast-enhancing lesions on CCT and MRI. Though an incorrect diagnosis can lead to a potentially fatal therapeutic intervention, histological diagnosis should be made in all cases. Due to minimum morbidity, stereotactic biopsy is the method of choice to obtain representative specimens for histological diagnosis. Open microsurgery of these lesions is not indicated since conservative medical treatment with steroids results in a favourable outcome in most cases.Published online October 13, 2003     

Differential effects of inorganic lead on hippocampal long-term potentiation in young rats in vivo

Tetanic stimulation at 50 Hz elicited long-term potentiation (LTP) in the hippocampal CA1 region of 28-day-old control animals. In contrast, no significant potentiation was seen following the same tetanus in animals chronically exposed to 1000 ppm of lead acetate during development. Gender differences were observed in animals exposed to 500 ppm of lead. In females, LTP was significantly attenuated, while in males the LTP was identical to that of controls.     

Electrophysiological properties of frog spinal dorsal horn neurons and their responses to serotonin: an intracellular study in the isolated hemisected spinal cord

Frog dorsal horn neurons and their responses to serotonin (5-HT) were studied in intracellular recordings from isolated hemisected spinal cords. Electrophysiological properties were comparable to those of mammals. Bath application of 5-HT (10-50 microM) increased the excitability and caused membrane depolarizations in 7/14 cells, reduced or abolished activity and caused hyperpolarizations in 4 neurons, exerted a biphasic effect in two cells, and produced no detectable change in one neuron. The multiple effects of 5-HT may be mediated through different 5-HT receptor subtypes.     

Retrograde tracing of projections between the nucleus submedius, the ventrolateral orbital cortex, and the midbrain in the rat.

The fluorescent tracers fluoro-gold and 1,1'-dioctadecyl-3,3,3,3-tetramethyl indocarbocyanine perchlorate were used as retrograde markers to examine reciprocal connections between the rat nucleus submedius and the ventrolateral orbital cortex. In addition, midbrain projections to each of these regions were examined. In the prefrontal cortex, we found that input from the nucleus submedius terminates rostrally within the lateral and ventral areas of the ventrolateral orbital cortex. Conversely, the cortical input to the nucleus submedius originates from the medial and dorsal parts of the ventrolateral orbital cortex. Our data also demonstrated that neurons from the ventrolateral periaqueductal gray and the raphe nuclei project to the midline nuclei of the thalamus, including a small projection to the nucleus submedius. We further determined that regions within the ventrolateral periaqueductal gray and raphe nuclei project to the ventrolateral orbital cortex, and that these regions overlap with those that project to the nucleus submedius. These findings suggest that the nucleus submedius might be part of a neural circuit involved in the activation of endogenous analgesia.     

Immunocytochemical identification of serotonin axonal contacts on characterized neurons in laminae I and II of the cat dorsal horn

Serotonergic pathways from brainstem to spinal cord play an important role in the modulation of pain perception. To establish where that modulation occurs, we examined serotonin-immunoreactive axonal contacts on individually characterized laminae I and II dorsal horn neurons intracellularly filled with horseradish peroxidase. We found serotonin axonal contacts on marginal, stalked, and islet cells. Contacts preferentially occurred on dendritic shafts rather than on spines. Marginal and stalked cells received the heaviest innervation.