Post-infectious encephalitis in adults: diagnosis and management

The serine protease subtilisin suppresses epileptiform activity in rat hippocampal slices and neocortex in vivo

Serine proteases of the S8A family and those belonging to the subtilase group generate a long-lasting inhibition of hippocampal evoked potentials, which shows little recovery and resembles long-term depression. The present work investigates the effects of subtilisin A on epileptiform activity induced in hippocampal slices. Interictal bursts were generated by perfusion with 4-aminopyridine in magnesium-free medium, whereas ictal bursts were produced by the addition of baclofen. Subtilisin A superfused for 10 min at concentrations of 50 nM and above reduced the duration of ictal bursts, whereas higher concentrations reduced the frequency of interictal activity with little or no recovery, indicating similarity with the long-term depression reported previously. The anti-epileptiform activity was not prevented by inhibitors of phosphatases or several kinases, but the inhibition of ictal activity was selectively reduced by the tyrosine kinase inhibitor genistein. The rho-activated coiled-coil kinase (ROCK) inhibitor Y-27632 had no effect on the suppression of ictal or interictal bursts. Subtilisin applied at nanomolar concentrations to the surface of the cerebral cortex in vivo also suppressed epileptiform spikes induced by bicuculline. It is concluded that serine proteases of the subtilase group are highly potent inhibitors of epileptiform activity, especially ictal bursts, and that tyrosine kinases may be involved in that inhibition. The mechanism of inhibition is different from the long-lasting depression of evoked potentials, which is partly mediated via ROCK.

Comparative brain stem lesions on MRI of acute disseminated encephalomyelitis, neuromyelitis optica, and multiple sclerosis

Background

Brain stem lesions are common in patients with acute disseminated encephalomyelitis (ADEM), neuromyelitis optica (NMO), and multiple sclerosis (MS).

Objectives

To investigate comparative brain stem lesions on magnetic resonance imaging (MRI) among adult patients with ADEM, NMO, and MS.

Methods

Sixty-five adult patients with ADEM (n = 17), NMO (n = 23), and MS (n = 25) who had brain stem lesions on MRI were enrolled. Morphological features of brain stem lesions among these diseases were assessed.

Results

Patients with ADEM had a higher frequency of midbrain lesions than did patients with NMO (94.1% vs. 17.4%, P<0.001) and MS (94.1% vs. 40.0%, P<0.001); patients with NMO had a lower frequency of pons lesions than did patients with MS (34.8% vs. 84.0%, P<0.001) and ADEM (34.8% vs. 70.6%, P = 0.025); and patients with NMO had a higher frequency of medulla oblongata lesions than did patients with ADEM (91.3% vs. 35.3%, P<0.001) and MS (91.3% vs. 36.0%, P<0.001). On the axial section of the brain stem, the majority (82.4%) of patients with ADEM showed lesions on the ventral part; the brain stem lesions in patients with NMO were typically located in the dorsal part (91.3%); and lesions in patients with MS were found in both the ventral (44.0%) and dorsal (56.0%) parts. The lesions in patients with ADEM (100%) and NMO (91.3%) had poorly defined margins, while lesions of patients with MS (76.0%) had well defined margins. Brain stem lesions in patients with ADEM were usually bilateral and symmetrical (82.4%), while lesions in patients with NMO (87.0%) and MS (92.0%) were asymmetrical or unilateral.

Conclusions

Brain stem lesions showed various morphological features among adult patients with ADEM, NMO, and MS. The different lesion locations may be helpful in distinguishing these diseases.

Decompressive craniectomy for acute disseminated encephalomyelitis

BACKGROUND

Acute disseminated encephalomyelitis (ADEM) is a rare, acute demyelinating condition. Although it usually presents in an acute or subacute manner over days, its clinical course may be rapid with symptoms and signs of severe intracerebral mass effect secondary to cerebral oedema.

METHODS

Case report and literature review.

RESULTS

We report a case of a patient presenting with a hyperacute course manifested by rapid loss of consciousness and focal neurological signs. Management with emergency hemicraniectomy and steroids resulted in rapid neurological improvement and minimal long-term deficit.

CONCLUSIONS

We believe that only surgical decompression is likely to be life saving in similar cases of hyperacute cerebral oedema due to ADEM. The wide decompression performed was concordant with that indicated for traumatic brain swelling. Such aggressive management is vindicated by the rapid recovery shown by our patient within days of surgery and the finding of minimal neurological sequelae at 3 months.

[Neurological catastrophes in demyelinating diseases]

Demyelinating diseases may cause neurological catastrophes in several ways. Rapidly progressing disease or severe acute bouts may seriously threaten the patient's life. Diagnostic procedures, errors in identifying the clinical picture and even treatments themselves may result in a catastrophe. This article reviews the most frequent catastrophic scenarios.

Causes of encephalitis and differences in their clinical presentations in England: a multicentre, population-based prospective study

BACKGROUND

Encephalitis has many causes, but for most patients the cause is unknown. We aimed to establish the cause and identify the clinical differences between causes in patients with encephalitis in England.

METHODS

Patients of all ages and with symptoms suggestive of encephalitis were actively recruited for 2 years (staged start between October, 2005, and November, 2006) from 24 hospitals by clinical staff. Systematic laboratory testing included PCR and antibody assays for all commonly recognised causes of infectious encephalitis, investigation for less commonly recognised causes in immunocompromised patients, and testing for travel-related causes if indicated. We also tested for non-infectious causes for acute encephalitis including autoimmunity. A multidisciplinary expert team reviewed clinical presentation and hospital tests and directed further investigations. Patients were followed up for 6 months after discharge from hospital.

FINDINGS

We identified 203 patients with encephalitis. Median age was 30 years (range 0-87). 86 patients (42%, 95% CI 35-49) had infectious causes, including 38 (19%, 14-25) herpes simplex virus, ten (5%, 2-9) varicella zoster virus, and ten (5%, 2-9) Mycobacterium tuberculosis; 75 (37%, 30-44) had unknown causes. 42 patients (21%, 15-27) had acute immune-mediated encephalitis. 24 patients (12%, 8-17) died, with higher case fatality for infections from M tuberculosis (three patients; 30%, 7-65) and varicella zoster virus (two patients; 20%, 2-56). The 16 patients with antibody-associated encephalitis had the worst outcome of all groups-nine (56%, 30-80) either died or had severe disabilities. Patients who died were more likely to be immunocompromised than were those who survived (OR = 3·44).

INTERPRETATION

Early diagnosis of encephalitis is crucial to ensure that the right treatment is given on time. Extensive testing substantially reduced the proportion with unknown cause, but the proportion of cases with unknown cause was higher than that for any specific identified cause.

FUNDING

The Policy Research Programme, Department of Health, UK.

A case of fever of unknown origin: co-existence of Kikuchi-Fujimoto disease and acute disseminated encephalomyelitis (ADEM)

It is believed that viral infections and the hyperimmune reaction due to these infections are involved in the etiology of Kikuchi-Fujimoto Disease (KFD), a rare cause of fever of unknown origin. Axillary lymphadenopathy and neurologic involvement are rare in KFD. We present a patient diagnosed with KFD histopathologically during an investigation of the origin of fever and axillary lymphadenopathy. Subsequently, incidental sinus aspergilloma was diagnosed radiologically in the patient and acute disseminated encephalitis developed during follow-up. This report aims to draw attention to the co-existence of KFD and Acute Disseminated Encephalomyelitis, two diseases of which the origins are not clear.

Extensive demyelinating change in cerebrum after a total knee replacement -A case report-

Demyelination is characterized by the loss of myelin with the preservation of axons. Demyelinating diseases can be classified into several categories: demyelination due to inflammation, viral infection, osmotic derangements and hypoxic ischemia. In particular, osmotic myelinolysis is representative, and is associated with hyperosmolality, hypokalemia or rapid correction of hyponatremia. Osmotic myelinolysis was reported to be associated with underlying conditions, such as alcoholism, diuretics and malnutrition. A 67-year-old woman with hypertension was scheduled to undergo both total knee replacements (TKR). She was observed to be lethargic with dysphagia and quadriplegia after the second TKR. She had been taking diuretics for a long time, and did not have an adequate amount of food intake due to patient controlled analgesia and a gastric ulcer after the first TKR. A laboratory examination revealed hypokalemia but normonatremia. T2 weighted-MRI revealed abnormal high signal intensity in the basal ganglia and periventricular area. This case was diagnosed with osmotic myelinolysis associated with hypokalemia without an apparent sodium imbalance.