A case of isolated Nocardia asteroides brain abscess in a kidney transplant recipient

Management of Brain Abscess

Despite recent advances in neuroimaging techniques, brain abscesses can be difficult to diagnose and may often require surgical intervention. The primary sources of infection are often difficult to locate; hence, even if an abscess is suspected, the organisms may remain unknown. In other patients, the location of the lesion may be in a site of the brain where surgical intervention may not be possible. The types of brain abscesses, their pathophysiology including predisposing conditions, and their characteristic radiologic features are discussed in this review, with particular emphasis on the indications and modes of medical management of brain abscesses. It discusses the use of antimicrobial agents that have the best central nervous system penetration and outlines a strategy for treatment of organisms likely to infect the brain with the different types of predisposing conditions. Also discussed are the indications for empirical therapy, and antimicrobial regimens for this purpose are suggested.

"Primary" nocardial brain abscess in a renal transplant patient

Background

Intracranial abscesses are rare among transplant recipients, and Nocardia is responsible for less than 2 % of them. Nocardiosis, a chronic infection and is difficult to treat. Primary infection involves lungs and eventually disseminates. Primary nocardial abscesses are rare and we report a case from Sri Lanka.

Case presentation

A 38 year old Sri Lankan, who has received his 2nd ABO matched live donor transplantation, which was complicated with perinephric hematoma and massive transfusion syndrome. He presented with fever, worsening headache and papilledema. An urgent magnetic resonance image (MRI) showed an occipital abscess with midline shift. Craniotomy and drainage followed by 3 week course of imipenem and levofloxacin, which rendered him symptom free. After 12 months he has stayed recurrence free. Imaging and bacteriology of the respiratory tract failed to demonstrate Nocardia infection.

Conclusion

Isolated (Primary) nocardial brain abscess are rare, and have an excellent response to medical therapy. We achieved a good response from a relatively short course of antibiotics (not using sulfonamides, due to allergy), where long courses of antibiotic had been the norm.

Nocardiosis of the central nervous system: experience from a general hospital and review of 84 cases from the literature

Central nervous system (CNS) nocardiosis is a rare disease entity caused by the filamentous bacteria Nocardia species. We present a case series of 5 patients from our hospital and a review of the cases of CNS nocardiosis reported in the literature from January 2000 to December 2011. Our results indicate that CNS nocardiosis can occur in both immunocompromised and immunocompetent individuals and can be the result of prior pulmonary infection or can exist on its own. The most common predisposing factors are corticosteroid use (54% of patients) and organ transplantation (25%). Presentation of the disease is widely variable, and available diagnostic tests are far from perfect, often leading to delayed detection and initiation of treatment. The optimal therapeutic approach is still undetermined and depends on speciation, but lower mortality and relapse rates have been reported with a combination of targeted antimicrobial treatment including trimethoprim/sulfomethoxazole (TMP-SMX) for more than 6 months and neurosurgical intervention.

Neurologic complications in renal transplantation

Neurologic complications following kidney transplant are more common than in the general population with the reported incidence around 10-21%. Need for multiple drugs, decreased cellular immunity, accelerated atherosclerotic disease, and frequency of metabolic abnormalities are the most common predisposing factors for neurologic abnormalities. Neurologic side-effects of calcineurin inhibitors range from mild tremors to paraplegia or posterior reversible encephalopathy syndrome (PRES) and are generally reversible by lowering the dose or complete discontinuation of the drug when possible. Clinical presentation of central nervous system infection in transplant recipients can be different from the normal population as the anti-inflammatory effects of immunosuppressive therapy may obscure signs of meningeal inflammation and changes in the level of consciousness may be subtle. Bacterial infections remain the most common infections but unusual pathogens figure prominently in the differential diagnosis. The most frequent malignancies of the brain are lymphomas and metastatic tumors which are for the most part, de novo malignancies from immunosuppression. Decreasing immunosuppression is almost always a part of treating malignancy. The prevalence of stroke is reported to be around 8% with age>40 years, diabetic nephropathy as the underlying cause of end-stage kidney disease, and peripheral vascular disease being the strongest predictors.

Nocardiosis in solid-organ transplant recipients: spectrum of imaging findings

Nocardiosis is an infrequent but severe infection that primarily affects the lung and thence is able to produce disseminated disease. Prompt diagnosis of pulmonary and disseminated nocardiosis is of utmost importance in solid-organ transplant recipients to reduce mortality. Knowledge of the different radiological manifestations in the appropriate clinical setting is key to successful management of these patients. The aim of this review is to describe the radiological features of nocardiosis in immunosuppressed patients, particularly in solid-organ transplant recipients.

Cerebellar nocardiosis and myopathy from long-term corticosteroids for idiopathic thrombocytopenia

Infection of the central nervous system with Nocardia sp. usually manifests as supratentorial abscesses. Supratentorial and cerebellar abscesses from infection with Nocardia sp. following immunosuppression with long-term corticosteroids for idiopathic thrombocytopenia (ITP) have not been reported. An 83 years-old, human immunodeficiency virus (HIV)-negative, polymorbid male with ITP for which he required corticosteroids since age 53 years developed tiredness, dyspnoea, hemoptysis, abdominal pain, and progressive gait disturbance. Imaging studies of the lung revealed an enhancing tumour in the right upper lobe with central and peripheral necrosis, multiple irregularly contoured hyperdensities over both lungs, and right-sided pleural effusions. Sputum culture grew Nocardia sp. Neurological diagnostic work-up revealed dysarthria, dysphagia, ptosis, hypoacusis, tremor, dysdiadochokinesia, proximal weakness of the lower limbs, diffuse wasting, and stocking-type sensory disturbances. The neurological deficits were attributed to an abscess in the upper cerebellar vermis, myopathy from corticosteroids, and polyneuropathy. Meropenem for 37 days and trimethoprime-sulfamethoxazole for 3 months resulted in a reduction of the pulmonary, but not the cerebral lesions. Therefore, sultamicillin was begun, but without success. Long-term therapy with corticosteroids for ITP may induce not only steroid myopathy but also immune-incompetence with the development of pulmonary and cerebral nocardiosis. Cerebral nocardiosis may not sufficiently respond to long-term antibiotic therapy why switching to alternative antibiotics or surgery may be necessary.

Intracranial lesions mimicking neoplasms

CONTEXT

A broad spectrum of nonneoplastic conditions can mimic a brain tumor, both clinically and radiologically. In this review we consider these, taking into consideration the following etiologic categories: infection, demyelination, vascular diseases, noninfectious inflammatory disorders, and iatrogenic conditions. We give an overview of such diseases, which represent a potential pitfall for pathologists and other clinicians involved in patient care, and present selected cases from each category.

OBJECTIVE

To illustrate the radiologic and pathologic features of nontumoral intracranial lesions that can clinically and radiologically mimic neoplasia.

DATA SOURCES

Case-derived material and literature review.

CONCLUSIONS

A variety of nonneoplastic lesions can present clinically and radiologically as primary or metastatic central nervous system tumors and result in surgical biopsy or resection of the lesion. In such situations, the pathologist has an important role to play in correctly determining the nature of these lesions. Awareness of the entities that can present in this way will assist the pathologist in the correct diagnosis of these lesions.

Nocardia exalbida brain abscess in a patient with follicular lymphoma

Nocardial brain abscess is a rare but severe complication in patients with malignancy. Nocardia exalbida was isolated in Japan and characterized within the genus Nocardia. We present the first report of N. exalbida brain abscess in a 63-year-old male patient with follicular lymphoma. He developed abnormal neurological findings during follicular lymphoma treatment, brain CT revealed ring-enhancing, multiloculated lesions, and N. exalbida was detected by aspiration of the lesion. He was successfully treated with trimethoprime-sulfamethoxazole (TMP-SMX) and meropenem without craniotomy or repeat aspirations. It should be noted that such an infection can occur in patients treated with conventional chemotherapy against malignant lymphoma.