Massive posterior fossa tuberculous abscess developing in a young child treated for miliary tuberculosis. Possible role of very rapid acetylation of isoniazid

Recurrent tuberculous cerebellar abscess: A case study and review of the literature

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Recurrent tubercular brain abscess is a rare pathology in immunocompetent children.

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Recurrence is possible despite a well-managed treatment such as surgery and anti-tuberculosis therapy.

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Early management and careful monitoring are important.

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The addition of corticosteroid therapy and readjustment of the dose of anti-tuberculosis drugs are necessary to achieve a cure.

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Our treatment was based on several punctures of the abscess associated with a shunt, a readjustment of doses of antituberculosis drugs and additional corticosteroid therapy which led to a clinical improvement.

Introduction and importance

Tuberculous cerebellar abscess is a rare form of extra-pulmonary tuberculosis. The outcome is often favorable with well-managed treatment; however, they can continue to develop. We share in this article our experience on the management of this rare pathologie.

Case presentation

A 10-year-old boy with a medical history of tuberculous meningitis after 3 months of tuberculosis treatment. He presented to the hospital with acute obstructive hydrocephalus due to a large tuberculous cerebellar abscess. A puncture of the abscess was initially performed, followed by placement of a ventriculoperiotoneal shunt, which resulted in some clinical improvement. However, the child subsequently presented with neurological deterioration due to the massive enlargement of the tuberculous abscess despite adequate antituberculosis chemotherapy. The initiation of corticosteroid therapy associated with a readjustment of the dose of anti-tuberculosis drugs and a repeated puncture ultimately led to clinical improvement.

Clinical discussion

Tuberculous brain abscess is an extra-pulmonary location of tuberculosis rarely seen in immunocompetent children. The treatment consists of surgery associated with antituberculosis chemotherapy and rigorous clinico-radiological monitoring. Recurrence is possible despite well-conducted treatment. Additional corticosteroid therapy is necessary with readjustment of the anti-tuberculosis treatment for an effective cure.

Conclusion

Rarely, the tuberculous abscess of the cerebellum continues to evolve despite proper treatment. This pattern does not necessarily mean treatment failure. Close clinical and imaging monitoring is crucial in the management of these cases.

The pathogenesis of tuberculous meningitis

Tuberculosis (TB) remains a leading cause of death globally. Dissemination of TB to the brain results in the most severe form of extrapulmonary TB, tuberculous meningitis (TBM), which represents a medical emergency associated with high rates of mortality and disability. Via various mechanisms the Mycobacterium tuberculosis (M.tb) bacillus disseminates from the primary site of infection and overcomes protective barriers to enter the CNS. There it induces an inflammatory response involving both the peripheral and resident immune cells, which initiates a cascade of pathologic mechanisms that may either contain the disease or result in significant brain injury. Here we review the steps from primary infection to cerebral disease, factors that contribute to the virulence of the organism and the vulnerability of the host and discuss the immune response and the clinical manifestations arising. Priorities for future research directions are suggested.

Primary tuberculous cerebellar abscess: case report

Tuberculous cerebellar abscess is a rare manifestation of central nervous system tuberculosis. An 8-year-old boy is described who presented with acute hydrocephalus and right hemiparesis owing to a cerebellar abscess.

Tuberculous brain abscesses in immunocompetent patients: management and outcome

BACKGROUND

Tuberculosis (TB) remains an important public health problem in developing countries.

OBJECTIVE

To evaluate the clinical presentation, management, and long-term outcome in 6 patients with tuberculous brain abscesses (TBA), an uncommon form of central nervous system (CNS) TB.

METHODS

A search of medical records of a single referral neurological center in Mexico City from 2002 to 2007 retrieved 149 patients with CNS TB; 6 of them (4%) met Whitener's criteria for TBA and were included in this review.

RESULTS

Five of six patients had a previous history of TB. Three patients were referred to our center under antituberculous treatment (ATT) for pulmonary and lymph node TB, and two patients were receiving ATT for TB meningitis at diagnosis of TBA. All presented with symptoms of intracranial hypertension and hemiparesis. On imaging studies, 3 patients had a single, deep multiloculated lesion and another three had separated lesions, all patients underwent surgery and received long courses of ATT. One patient died after surgery and the rest recovered with moderate to severe neurological sequelae. The residual lesions in 5 patients resolved in follow-up CT or MRI studies at a mean time of 10 months.

CONCLUSIONS

Early surgery confirms the diagnosis of TBA. Some patients may require additional surgical procedures if enlargement or recurrence of the lesion occurs. No evidence of drug resistance was found in our cases, and we found only two reports of TBA with primary resistance to ATT in a selective literature review. TBA does not seem to be a consequence of drug resistance. Sequelae are common, and long-term ATT with close clinical and imaging follow-up is mandatory.

Tuberculous brainstem abscess: case report

OBJECTIVE

Tuberculous brainstem abscess is a clinically rare condition with potentially high mortality and morbidity. We present this report to draw attention to the importance of early recognition and adequate treatment of tuberculous brainstem abscess.

CLINICAL PRESENTATION

A 24-year-old man complained of longstanding fever, headache, and weakness followed by development of progressive slurred speech and hemiparesis of the right extremities. Magnetic resonance imaging revealed a large thick-walled cystic lesion lying within the brainstem.

INTERVENTION

The patient demonstrated a remarkable clinical recovery after microsurgery combined with a course of antituberculous therapy. Microbiological and histological findings confirmed the diagnosis of a tuberculous abscess.

CONCLUSION

Despite its rarity, the tuberculous brainstem abscess must be considered in the differential diagnosis of cystic brainstem mass lesions in vulnerable patients. When confronted with progressing neurological deterioration and poor response to antituberculous therapy, stereotactic or microsurgical management should be considered. Microsurgical excision combined with a complete course of antituberculous therapy in our patient led to a good outcome.

Cerebellar abscess and syringomyelia due to isoniazid-resistant Mycobacterium tuberculosis

A 19-year-old immunocompetent man was admitted to hospital with diplopia, nausea, vomiting and change in mental status. The patient had a history of tuberculous meningitis that was diagnosed at another hospital 6 months before the present admission, and at that time anti-tuberculosis treatment was initiated using a first-line drug combination. A computed tomography (CT) scan of the brain revealed non-communicating hydrocephalus. A ventriculo-peritoneal shunt was inserted surgically. Two months later, the patient was hospitalized again for fever, dysphagia and left hemiparesis. At that time, his cranial CT findings were within normal limits; however, magnetic resonance imaging (MRI) revealed an irregular multilocular peripheral contrast-enhancing lesion in the posterior fossa. The abscess was surgically drained. The presence of acid-fast bacilli in the abscess material was demonstrated by Ziehl-Neelsen staining. Mycobacterium tuberculosis grew on Lowenstein-Jensen culture medium, and the strain was found to be resistant to isoniazid. One month after the operation, the patient became quadriparetic. Cervical MRI revealed a cervico-thoracic syringomyelitic cavity, after which a syringoperitoneal shunt was placed. Treatment with four drugs was continued for 10 months, and then treatment with three drugs for a total period of 18 months. The patient recovered, with residual quadriparesis. Even though very rare, isoniazid-resistant M. tuberculosis may be the causative agent of progressive tuberculosis.

Isoniazid pharmacokinetics in children treated for respiratory tuberculosis

AIMS

To define the pharmacokinetics of isoniazid (INH) in children with tuberculosis in relation to the N-acetyltransferase 2 (NAT2) genotype.

METHODS

The first order elimination rate constant (k) and area under the concentration curve (AUC) were calculated in 64 children <13 years of age (median 3.8) with respiratory tuberculosis from INH concentrations determined 2-5 hours after a 10 mg/kg INH dose. The NAT2 genotype was determined; 25 children were classified as homozygous slow (SS), 24 as heterozygous fast (FS), and 15 as homozygous fast (FF) acetylators.

RESULTS

The mean (SD) k values of the genotypes differed significantly from one another: SS 0.254 (0.046), FS 0.513 (0.074), FF 0.653 (0.117). Within each genotype a median regression of k on age showed a significant decrease in k with age. The mean (SD) INH concentrations (mg/l) two hours after INH administration were SS 8.599 (1.974), FS 5.131 (1.864), and FF 3.938 (1.754). A within genotype regression of 2-hour INH concentrations on age showed a significant increase with age. A within genotype regression of 3-hour, 4-hour, and 5-hour concentrations on age also showed a significant increase with age in each instance. In ethnically similar adults, mean (SD) 2-hour INH concentrations (mg/l) for each genotype were significantly higher than the children's: SS 10.942 (1.740), FS 8.702 (1.841), and FF 6.031 (1.431).

CONCLUSIONS

Younger children eliminate INH faster than older children and, as a group, faster than adults, and require a higher mg/kg body weight INH dose to achieve serum concentrations comparable to adults.

Population screening for isoniazid acetylator phenotype

PURPOSE

To establish a useful method for acetylator phenotypification and therapeutic drug monitoring of patients receiving isoniazid.

METHODS

Sixty patients with uncomplicated pulmonary tuberculosis were given a 5-mg/kg oral dose of isoniazid each. Plasma concentrations of isoniazid and its metabolite, acetyl-isoniazid, were determined by HPLC analyses at various post-dose times. From the isoniazid concentration and the concentration ratio of acetyl-isoniazid and isoniazid (metabolic ratio), phenotypification methods were assessed.

RESULTS

The metabolic ratios at 3 h post-dose revealed a trimodal distribution; a fast, intermediate and slow acetylator phenotype group. The 2-h and 6-h data showed different bimodal combinations of these phenotype groups. The metabolic ratio phenotypification method could be simplified by using the HPLC data directly without converting it to absolute concentrations.

CONCLUSIONS

A single-sample test based upon the plasma isoniazid concentration, combined with the metabolic ratio of acetyl-isoniazid and isoniazid, appears to be a reliable parameter for phenotype discrimination and for bioavailability testing.

Childhood tuberculosis

Childhood tuberculosis will reflect the incidence of cavitating pulmonary tuberculosis in adults and will consequently be encountered most frequently in those areas with a high incidence of tuberculosis. Problem areas include our continuing inability to confirm the diagnosis of tuberculosis in many children, the escalating interaction of the human immunodeficiency virus (HIV) pandemic and tuberculosis, which is now evident with greater frequency in childhood, and the scarcity of data relating to antituberculosis therapy in childhood, which necessitates reliance on adult studies in many cases. This review highlights several options for obtaining material for culture of Mycobacterium tuberculosis in children, aspects of tuberculin testing, which remains one of the cornerstones supporting a diagnosis of tuberculosis in childhood, the potential importance of therapeutic drug monitoring in problem cases, new data giving epidemiologic and clinical details of the interaction of HIV infection and tuberculosis in children, and studies describing the epidemiology of tuberculosis in the developed and developing world.