Granulomatous hypophysitis: presentation and MRI appearance

Granulomatous hypophysitis (GrHy) is a relatively rare inflammatory disease compared with lymphocytic hypophysitis. Only a few cases with magnetic resonance imaging (MRI) findings have been reported to date. We describe the MRI findings for two patients with GrHy with unusual histories and clinical outcomes.

Rhinocerebral zygomycosis in a young girl undergoing allogeneic stem cell transplantation for severe aplastic anaemia

We report on a 10-year-old girl with severe aplastic anaemia who developed rhinocerebral infection caused by Absidia corymbifera and a possible co-infection caused by Alternaria alternata. Despite prolonged neutropenia, therapy with liposomal amphotericin B and posaconazole improved the clinical condition. Subsequently, the girl underwent allogeneic haematopoietic stem cell transplantation (HSCT) for the underlying disease, but the fungal infection remained under control with the antifungal treatment. No severe side effect of the antifungal drugs was noted. Unfortunately, the girl died 5 months after HSCT due to disseminated adenovirus infection.

Encephalomalacia with Enterococcus durans Infection in the Brain Stem and Cerebral Hemisphere in Chicks in Japan

Fourteen chicks, 7-12 days old, that died or had neurological signs (depression, paralysis, torticollis, incoordination, and rolling) were investigated pathologically and microbiologically. Variably sized foci of malacia were present within the parenchyma of the brain stem (cerebral peduncle, optic lobe, and medulla oblongata) and the cerebral hemisphere. Capillary thrombosis with congestion and hemorrhage was frequently observed within the malacia lesions. Gram-positive cocci were recognized in the blood capillary of malacia lesions. Bacteriologically, Enterococcus durans was isolated from the brain, liver, kidney, lung, and spleen. Detection of gram-positive cocci within the blood vessels in the malacia lesions observed in these cases may more strongly suggest the pathogenic role of E. durans on the malacia lesions in the brain stem and cerebral hemisphere.

Lethal brain abscess due to the fungusScedosporium apiospermum(teleomorphPseudallescheria boydii) after a near-drowning incident: case report and review of the literature

A 39-year-old healthy man developed a brain abscess weeks after a near-drowning incident. Scedosporium apiospermum, the anamorph of Pseudallescheria boydii, was isolated from the abscess. The patient died 153 days after the accident despite antifungal therapy. We discuss the role of antifungals and review the literature for comparable cases.

Direct detection of leptospiral material in human postmortem samples

Leptospiral culture, direct immunofluorescence, and the polymerase chain reaction (PCR) were used to detect leptospiral material in postmortem specimens collected from eight patients who died of leptospirosis. Diagnosis of leptospiral infection was based on clinical summary (premortem) and confirmed by serological analysis and/or culture of leptospires. Leptospiral culture was the least sensitive technique, yielding two isolates (3%) from 65 samples. Both isolates were from the aqueous humour and cerebrospinal fluid of the same patient. Direct immunofluorescence was of intermediate sensitivity for detection of leptospires, confirming the presence of leptospires in 11% (2 of 18) of tissue samples from three patients. PCR analysis was the most sensitive technique for detection of leptospiral material in tissue samples, being positive in 20% (11 of 56) of samples from eight patients. Both samples (cerebellum and liver) positive by immunofluorescence were also positive by PCR. The sensitivity of the PCR assay was 1-10 leptospires ml(-1) sample, and the assay was specific for Leptospira pathogenic species. Multi-system involvement was indicated based on successful amplification of leptospiral DNA from more than one tissue sample, which corroborated with the clinical and pathologic findings. The results suggest that in acute and/or fatal leptospirosis, the pathogenesis of the pathologic features are related to the presence of the organisms in the tissues. In conclusion, PCR combined with serology appears to be a useful tool for diagnosis of leptospirosis and may be invaluable in epidemiological studies.

Acute disseminated encephalomyelitis associated with Pasteurella multocida meningitis

OBJECTIVE

To describe a case of Pasteurella multocida meningitis associated with acute disseminated encephalomyelitis (ADEM).

CASE REPORT

A 33-year-old woman employed in a dog pound presented herself to hospital with fever and meningismus and was found to have culture positive Pasteurella multocida meningitis. Despite appropriate antibiotic treatment her clinical course was characterized by a persistent fever and worsening encephalopathy, which prompted further neurological investigation. Spinal fluid exam and serial MRI scans as well as her one-year clinical course were found to be compatible with ADEM.

CONCLUSION

Persistent fever and worsening encephalopathy in meningitis may indicate a para-infectious immune process such as ADEM, and may serve as indications for further neurological investigation.

Nocardiosis with brain abscess due to an unusual species, Nocardia transvalensis

The identification of Nocardia transvalensis, an unusual and probably underrecognized cause of nocardial infection, is clinically significant because of this species' resistance to aminoglycosides, a standard antinocardial therapy. Diagnosis requires analytic methods available predominately in reference laboratories. We report a case of disseminated infection with N transvalensis with primary pulmonary involvement and subsequent development of brain abscesses, and review the literature to date. Familiarity with the epidemiology, pathologic findings, and clinical significance of this and other unusual Nocardia species may increase early identification and antibiotic susceptibility testing in cases of nocardial infection.

Central nervous system cryptococcoma in a cat

This report describes the gross, histopathological, immunohistochemical and electron microscopic findings in a 4-year-old cat with systemic Cryptococcus neoformans infection. A 1-cm diameter pontine mass, pinpoint lesions in the cerebellum and in the right kidney were the main macroscopic findings. A presumptive diagnosis of cerebral neoplasia with metastasis was formulated. Light microscopy revealed a huge number of yeasts surrounded by a pyogranulomatous inflammatory reaction in the cerebral parenchyma and, to a lesser extent, in the kidney, while the meninges were not involved. The positive mucicarmine stain that coloured the capsule of the yeasts was indicative of cryptococcal infection. Immunohistochemistry confirmed the presence of C. neoformans var. grubii (C. neoformans serotype A). Electron microscopy revealed yeasts with a massive fibrillar capsule and lamellar cell wall free in the cerebral tissue and within macrophages.

Experimental induction of chronic borreliosis in adult dogs exposed to Borrelia burgdorferi-infected ticks and treated with dexamethasone

OBJECTIVE

To develop a method to experimentally induce Borrelia burgdorferi infection in young adult dogs.

ANIMALS

22 healthy Beagles.

PROCEDURE

All dogs were verified to be free of borreliosis. Twenty 6-month-old dogs were exposed to Borrelia burgdorferi-infected adult ticks and treated with dexamethasone for 5 consecutive days. Two dogs not exposed to ticks were treated with dexamethasone and served as negative-control dogs. Clinical signs, results of microbial culture and polymerase chain reaction (PCR) testing, immunologic responses, and gross and histologic lesions were evaluated 9 months after tick exposure.

RESULTS

Predominant clinical signs were episodic pyrexia and lameness in 12 of 20 dogs. Infection with B burgdorferi was detected in microbial cultures of skin biopsy specimens and various tissues obtained during necropsy in 19 of 20 dogs and in all 20 dogs by use of a PCR assay. All 20 exposed dogs seroconverted and developed chronic nonsuppurative arthritis. Three dogs also developed mild focal meningitis, 1 dog developed mild focal encephalitis, and 18 dogs developed perineuritis or rare neuritis. Control dogs were seronegative, had negative results for microbial culture and PCR testing, and did not develop lesions.

CONCLUSIONS AND CLINICAL RELEVANCE

Use of this technique successfully induced borreliosis in young dogs. Dogs with experimentally induced borreliosis may be useful in evaluating vaccines, chemotherapeutic agents, and the pathogenesis of borreliosis-induced arthritis.

Multiple nocardial abscesses of cerebrum, cerebellum and spinal cord, causing quadriplegia

In this paper we present a case of a diabetic patient with nocardial abscesses of cerebrum, cerebellum and the spinal cord. The present case is the first case in the literature of solitary intramedullary abscess in cervical spinal cord, causing tetraplegia. Nocardia asteroides grew in a culture of the abscess pus. After either surgical excision or drainage of lesions, a triple combination regimen of chemotherapy (amikacin, ceftriaxone and trimethoprim-sulfamethoxazole) was given, but the patient was lost in the postoperative period. This case gives suggestive evidence of an association between cervical spinal cord involvement and poor prognosis in CNS nocardiosis.

Protein S-100B: a serum marker for ischemic and infectious injury of cerebral tissue

The S-100B protein is released by injured astrocytes. After passage through a disintegrated blood-brain barrier (BBB) the molecule can be detected in the peripheral circulation. We investigated the association between the extent of brain injury and S-100B concentration in serum in cerebral injury caused by cerebral ischemia and cerebral fungal infection. Study I: The S-100B serum concentration was serially determined in 24 patients with ischemic stroke at 4, 8, 10, 24, 72 hours after the onset of symptoms. We observed that patients with brain lesions larger than 5 cm3 exhibited significantly increased serum levels of S-100B at 10, 24 and 72 hours compared to those with lesion volumes below 5 cm3. Furthermore, an association between S-100B serum concentration and neurological outcome was observed. Study II: In a mouse model of systemic fungal infection with Candida albicans we observed that serum levels of S-100B increased at day 1 after intravenous infection. At this time we could histologically demonstrate brain tissue injury by invading hyphae which had crossed the BBB. Furthermore, reactive astrogliosis was demonstrated by immunohistochemistry. On day 7 we found a significant decrease of S-100B serum level compared to day 1 and 4. This was associated with a demarcation of the fungi with leukocytes in brain tissue at this late phase of infection. No further invasion through the BBB was seen on day 7. In conclusion, serum levels of S-100B reflect the time course of tissue injury in cerebral ischemia and cerebral infection to a similar extent. Thus, S-100B may be a useful marker to assess cerebral tissue injury.

Otitis interna is a frequent sequela to Streptococcus suis meningitis in pigs

Twenty-eight histologically confirmed cases of porcine leptomeningitis were examined retrospectively, with focus on the pathology of the inner and middle ear, brain, and vestibulocochlear nerve. Tissues were evaluated by histology and immunohistochemistry for Streptococcus suis serotype 2 antigen, and the bacteriologic results were recorded. Exudative otitis interna was diagnosed in 20/28 pigs (71%). The lesions primarily affected the perilymphatic ducts, with consistent involvement of the scala tympani. Perineuritis of the vestibulocochlear nerve was seen in all but four of the ears affected with otitis interna. Immunohistochemically, S. suis serotype 2 antigen was demonstrated in the leptomeningeal, perineural, and labyrinthine exudates in 11 cases. Otitis media was diagnosed in 10/28 pigs (34%), but evidence of extension to the inner ear was not observed. The findings were highly similar to descriptions of meningogenic labyrinthitis in humans and in laboratory animal models. Otitis interna in pigs can also develop via the meningogenic route and is not always, as generally stated, tympanogenic.

Surgical treatment of coenurosis (gid) in sheep

During the past six years 623 cases of coenurosis (gid) in sheep have been treated surgically. Cysts were removed successfully from 573 of them (92 per cent) and 517 (83 per cent) were able to return to their flocks, although 36 showed no clinical improvement In 37 cases, the cyst could not be localised, and postmortem examinations showed that in nine cases the cyst was in the brainstem, and in 28 cases it was in the cerebellum. Fifty-six cases deteriorated gradually after surgery and in these cases more than one cyst was found postmortem. Thirteen cases died during surgery.

Infection by coronavirus JHM of rat neurons and oligodendrocyte-type-2 astrocyte lineage cells during distinct developmental stages

Primary telencephalic cultures derived from neonatal Wistar Furth rats were able to support the growth of coronavirus JHM if a viable neuronal population was maintained. This occurred under serum-free defined, but not serum-supplemented, growth conditions. The importance of neurons in establishing infections in mixed cultures was confirmed by immunocytochemical and electron microscopic studies. Glia, although more abundant than neurons in these cultures, were less frequently infected during the initial 48 h postinoculation. The two glial lineages present in mixed telencephalic cultures were separated into type-1 astrocytes and oligodendrocyte-type-2 astrocyte (O-2A) lineage cells and individually assessed for their ability to support virus growth. Infection could not be established in type-1 astrocytes regardless of the culture conditions employed, consistent with our previous study (S. Beushausen and S. Dales, Virology 141:89-101, 1985). In contrast, infections could be initiated in selected O-2A lineage cells grown in serum-free medium. Virus multiplication was however significantly reduced by preconditioning the medium with mixed telencephalic or enriched type-1 astrocyte cultures, suggesting that intercellular interactions mediated by soluble factor(s) can influence the infectious process in O-2A lineage cells. This presumption was supported by eliciting similar effects with basic fibroblast growth factor and platelet-derived growth factor, two central nervous system cytokines known to control O-2A differentiation. The presence of these cytokines, which synergistically block O-2A cells from differentiating into oligodendrocytes was correlated with specific and reversible resistance to JHM virus (JHMV) infection. These data, combined with our finding that accelerated terminal differentiation of the oligodendrocyte phenotype confers resistance to JHMV (Beushausen and Dales, Virology, 1985), suggest that the permissiveness of O-2A cells for JHMV is restricted to a discrete developmental stage.