Isoniazid liver injury during chemoprophylaxis in children

Screening and treatment for tuberculosis in a cohort of unaccompanied minor refugees in Berlin, Germany

Introduction

In 2015, 4062 unaccompanied minor refugees were registered in Berlin, Germany. According to national policies, basic clinical examination and tuberculosis (TB) screening is a prerequisite to admission to permanent accommodation and schooling for every refugee. This article evaluates the use of an interferon-γ-release-assay (IGRA) during the initial examination and TB screening of 970 unaccompanied minor refugees.

Results

IGRA test were obtained during TB screening for 301 (31.0%) of 970 adolescents not previously screened for TB. Positive IGRA results were obtained in 13.9% (42/301). Most of the 42 IGRA-positive refugees originated from Afghanistan or Syria (n?20 and 10 respectively). Two IGRA-positive adolescents were lost to follow-up, 2 were diagnosed with TB and the remaining 38 diagnosed with latent TB infection (LTBI). Demographic features of the 40 patients with positive IGRA result were as follows: 39 male, median age 16.8 years (IQR 16.0–17.2y), none meeting underweight criteria (median BMI 21.3kg/m²). On initial chest X-ray 2/40 participants had signs of active TB, while in 38 active disease was excluded and the diagnosis of latent TB infection (LTBI) made. Active hepatitis B-co-infection was diagnosed in 3/38 patients. All patients with LTBI received Isoniazid and Rifampicin for 3 months without occurrence of severe adverse events. The most frequently observed side effect was transient upper abdominal pain (n = 5). Asymptomatic elevation of liver transaminases was seen in 2 patients. 29 patients completed treatment with no signs of TB disease at the end of chemoprevention and 9 were lost to follow up.

Conclusion

Screening for TB infection in minor refugees was feasible in our setting with a relatively high rate of TB infection detected. Chemopreventive treatment was tolerated well regardless of underlying hepatitis-B-status. Minor refugees migrating to Germany should be screened for TB infection, instead of TB disease only, regardless of the background TB incidence.

Exposure to Tuberculosis among Newborns in a Nursery: Decision Analysis for Initiation of Prophylaxis

Objective.

Newborns in a hospital nursery were exposed to a mother whose sputum was direct-smear negative for acid-fast bacilli but culture positive for Mycobacterium tuberculosis. Given the low risk for exposure, the high susceptibility of infants to M. tuberculosis infection, and the possibility of hepatotoxicity due to isoniazid therapy, a decision analysis model was used to determine whether administration of isoniazid prophylaxis against tuberculosis is preferable to no administration of prophylaxis.

Design.

A decision analysis tree was constructed with software, using probabilities from the literature and costs from local health facilities. The expected values for each strategy were obtained, and sensitivity analyses were performed.

Results.

For the strategy in which prophylaxis was administered under direct observation (DO), the probability for survival was 0.999980. For the strategy in which no prophylaxis was administered, the probability of survival was 0.999950, which corresponds to 3 more deaths per 100,000 patients than with the DO prophylaxis strategy. The incremental cost-effectiveness of the DO prophylaxis strategy was $21,710,000 per death prevented. Sensitivity analysis for survival showed that the DO prophylaxis strategy was preferable to the strategy in which no prophylaxis is given if the probability of infection was >0.0002, the probability of tuberculous disease in an infected infant who did not receive prophylaxis was greater than 0.12, the probability of dying from tuberculosis was greater than 0.025, the probability of hepatotoxicity was less than 0.004, and the probability of dying from hepatotoxicity was less than 0.04. For the strategy in which prophylaxis was administered under non-DO conditions (ie, by parents), the incremental cost-effectiveness was $929,500 per death prevented, which is approximately 5% of the incremental cost-effectiveness of the DO prophylaxis strategy.

Conclusion.

This model provides a structure for determining the preferable prophylaxis strategies for different risks of exposure to tuberculosis in a nursery. Administration of prophylaxis is preferable to no administration of prophylaxis, unless the probability of infection is extremely low.

Elevated transaminases are common in children on prophylactic treatment for tuberculosis

AIM

The aim of this study was to assess the prevalence of elevated transaminase levels in children undergoing prophylactic treatment for tuberculosis (TB) infection.

METHODS

All children living in a geographically defined area, who started TB prophylaxis during 2009-2011, were included. Data on background factors, treatment regimes and transaminase levels at baseline and follow-up were collected retrospectively.

RESULTS

Of the 277 children who were treated, 113 (41%) had elevated transaminase levels. Of these, 97 (35%) had levels that were less than three times the upper limit of the normal range and 16 (6%) had levels that were more than three times the normal range. Four patients had to discontinue isoniazid treatment and were successfully switched to rifampicin. In 17 patients, the highest transaminase peak did not occur until after 6 months of treatment. Elevated transaminases were significantly more common in patients below 9 years of age (62%) than in those aged 10-18 years (28%). Transaminases were elevated in 44% of all boys and 36% of all girls (p = 0.17).

CONCLUSION

Transaminase elevation was common in children receiving prophylactic treatment for TB and started at different points throughout the treatment period. Younger patients faced an increased risk. Regular blood tests are recommended throughout treatment.

Hepatotoxicity in Children Receiving Isoniazid Therapy for Latent Tuberculosis Infection

BACKGROUND

The frequency of isoniazid hepatotoxicity is low in children receiving isoniazid therapy for latent tuberculosis infection. However, isoniazid hepatotoxicity may cause liver failure and death. We evaluated children who developed isoniazid hepatotoxicity to determine demographic and clinical characteristics.

METHODS

A retrospective review was performed of medical records of 1582 patients aged <18 years who were evaluated for isoniazid therapy at a public health department and clinic in California.

RESULTS

There were 13 patients who had latent tuberculosis infection and who developed isoniazid hepatotoxicity (0.8% of all 1582 patients who started isoniazid; 1.1% of 1235 patients who completed the 9-month isoniazid therapy). There were 8 girls (62%) and 9 Hispanic children (69%) who had hepatotoxicity. Sex, age, and race were not independently associated with the development of isoniazid hepatotoxicity. Symptoms and signs of hepatotoxicity were present in 11 of the 13 patients, and 2 other patients had alanine aminotransferase >5 times the upper limit of normal and no signs of hepatotoxicity. The most common symptoms included abdominal pain, anorexia, vomiting, and nausea. Most patients developed hepatotoxicity within 6 months of starting isoniazid, but 3 patients developed hepatotoxicity ≥6 months after starting isoniazid. After stopping isoniazid, the alanine aminotransferase levels decreased to normal in all patients.

CONCLUSIONS

In children who have latent tuberculosis infection, isoniazid hepatotoxicity has low frequency and typically is reversible when isoniazid is stopped. Evidence of late drug-induced liver injury indicates the importance of monitoring symptoms and serum transaminases throughout isoniazid therapy.

Preventive therapy in children exposed to Mycobacterium tuberculosis: problems and solutions

Young children living with a tuberculosis patient are at high risk of Mycobacterium tuberculosis infection and disease. WHO guidelines promote active screening and isoniazid (INH) preventive therapy (PT) for such children under 5 years, yet this well-established intervention is seldom used in endemic countries. We review the literature regarding barriers to implementation of PT and find that they are multifactorial, including difficulties in screening, poor adherence, fear of increasing INH resistance and poor acceptability among primary caregivers and healthcare workers. These barriers are largely resolvable, and proposed solutions such as the adoption of symptom-based screening and shorter drug regimens are discussed. Integrated multicomponent and site-specific solutions need to be developed and evaluated within a public health framework to overcome the policy-practice gap and provide functional PT programmes for children in endemic settings.

Adherence to isoniazid preventive therapy in Indonesian children: A quantitative and qualitative investigation

BACKGROUND

It is recommended that young child contacts of sputum smear positive tuberculosis cases receive isoniazid preventive therapy (IPT) but reported adherence is low and risk factors for poor adherence in children are largely unknown.

METHODS

We prospectively determined rates of IPT adherence in children < 5 yrs in an Indonesian lung clinic. Possible risk factors for poor adherence, defined as ≤3 months prescription collection, were calculated using logistic regression. To further investigate adherence barriers in-depth interviews were conducted with caregivers of children with good and poor adherence.

RESULTS

Eighty-two children eligible for IPT were included, 61 (74.4%) of which had poor adherence. High transport costs (OR 3.3, 95% CI 1.1-10.2) and medication costs (OR 20.0, 95% CI 2.7-414.5) were significantly associated with poor adherence in univariate analysis. Access, medication barriers, disease and health service experience and caregiver TB and IPT knowledge and beliefs were found to be important determinants of adherence in qualitative analysis.

CONCLUSION

Adherence to IPT in this setting in Indonesia is extremely low and may result from a combination of financial, knowledge, health service and medication related barriers. Successful reduction of childhood TB urgently requires evidence-based interventions that address poor adherence to IPT.

Tuberculosis: evidence review for newly arriving immigrants and refugees

BACKGROUND

The foreign-born population bears a disproportionate health burden from tuberculosis, with a rate of active tuberculosis 20 times that of the non-Aboriginal Canadian-born population, and could therefore benefit from tuberculosis screening programs. We reviewed evidence to determine the burden of tuberculosis in immigrant populations, to assess the effectiveness of screening and treatment programs for latent tuberculosis infection, and to identify potential interventions to improve effectiveness.

METHODS

We performed a systematic search for evidence of the burden of tuberculosis in immigrant populations and the benefits and harms, applicability, clinical considerations, and implementation issues of screening and treatment programs for latent tuberculosis infection in the general and immigrant populations. The quality of this evidence was assessed and ranked using the GRADE approach (Grading of Recommendations Assessment, Development and Evaluation).

RESULTS

Chemoprophylaxis with isoniazid is highly efficacious in decreasing the development of active tuberculosis in people with latent tuberculosis infection who adhere to treatment. Monitoring for hepatotoxicity is required at all ages, but close monitoring is required in those 50 years of age and older. Adherence to screening and treatment for latent tuberculosis infection is poor, but it can be increased if care is delivered in a culturally sensitive manner.

INTERPRETATION

Immigrant populations have high rates of active tuberculosis that could be decreased by screening for and treating latent tuberculosis infection. Several patient, provider and infrastructure barriers, poor diagnostic tests, and the long treatment course, however, limit effectiveness of current programs. Novel approaches that educate and engage patients, their communities and primary care practitioners might improve the effectiveness of these programs.

Antituberculosis drug-induced hepatotoxicity in children

Recent increases in the dosages of the essential antituberculosis agents isoniazid (INH), rifampicin (RMP), pyrazinamide (PZA) for use in children recommended by World Health Organization have raised concerns regarding the risk of hepatotoxicity. Published data relating to the incidence and pathogenesis of antituberculosis drug-induced hepatotoxicity (ADIH), particularly in children, is reviewed. Amongst 12,708 children receiving chemoprophylaxis, mainly with INH, but also other combinations of INH, RMP and PZA only 1 case (0.06%) of jaundice was recorded and abnormal liver functions documented in 110 (8%) of the 1225 children studied. Excluding tuberculous meningitis (TBM) 8984 were children treated for tuberculosis disease and jaundice documented in 75 (0.83%) and abnormal liver function tests in 380 (9.9%) of the 3855 children evaluated. Amongst 717 children treated for TBM, however, jaundice occurred in 72 (10.8%) and abnormal LFT were recorded in 174 (52.9%) of those studied. Case reports document the occurrence of ADIH in at least 63 children. Signs and symptoms of ADIH were frequently ignored in the recorded cases. ADIH can occur in children at any age or at any dosage of INH, RMP or PZA, but the incidence of.ADIH is is considerably lower in children than in adults. Children with disseminated forms of disease are at greater risk of ADIH. The use of the higher dosages of INH, RMP and PZA recently recommended by WHO is unlikely to result in a greater risk of ADIH in children.

Low rates of hepatotoxicity in HIV-infected children on anti-retroviral therapy with and without isoniazid prophylaxis

This study investigates the incidence of hepatotoxicity in HIV-infected children during anti-retroviral therapy (ART) and the impact of concomitant use of isoniazid preventive therapy. It is a retrospective cohort analysis of HIV-infected children who commenced ART or were followed up between September 1998 and November 2005. Alanine transferase levels were measured at baseline, at 1, 3 and 6 months and then 6 monthly thereafter. Of the 598 children included in the study, 425 were taking ART alone, 73 ART and isoniazid, 39 isoniazid alone and 61 neither isoniazid nor ART. There was no increased risk of hepatotoxicity with ART with or without isoniazid compared to the control group over a 2-year period. Grade 3 or 4 ALT elevations occurred in 19 (3.4%) children, with no cases of fulminant hepatic failure. Severe hepatic events are uncommon in children on ART or isoniazid. There is no increased risk of hepatotoxicity with ART and concurrent isoniazid preventive therapy.

Isoniazid-Related Hepatic Failure in Children: A Survey of Liver Transplantation Centers

BACKGROUND

Isoniazid (INH) therapy for tuberculosis carries a known risk for hepatoxicity, and leads to hepatic failure in a small subset of patients. This incidence has been described for adults, but is uncertain in children. Our aim was to estimate the incidence of pediatric referrals for INH-related liver failure, and to describe the characteristics and outcomes of these patients.

METHODS

The 84 U.S. centers performing pediatric liver transplants between 1987 and 1997 were surveyed regarding patients with INH-induced liver failure. Additional transplant statistics were obtained from the United Network for Organ Sharing. Estimates of the number of children taking preventive INH were derived from a nationwide public health database.

RESULTS

Twenty cases of INH-related liver failure were found during a 10-year period. Four patients (20%) recovered spontaneously; 10 (50%) underwent orthotopic liver transplantation (OLT), while six (30%) died awaiting OLT. Mean age at presentation was 9.8 years (range 1.3-17). Mean length of INH therapy was 3.3 months (range 0.5-9). Notably, five patients seen for symptoms of hepatitis were initially told not to stop treatment. INH-associated liver failure accounted for 0.2% (8 of 4679) of all pediatric OLTs, and 14% (8/56) of transplants for drug hepatoxicity. The estimated incidence of liver failure was up to 3.2/100,000 for children on prophylactic INH.

CONCLUSIONS

While INH-associated liver failure in children is rare, discontinuation at the onset of symptoms does not assure recovery. This indicates a need for increased awareness of hepatotoxicity risk, expanded biochemical monitoring for children receiving INH, and prompt withdrawal in symptomatic patients.

Adverse reactions to first-line antituberculosis drugs

INTRODUCTION

Tuberculosis continues to be a major cause of morbidity and mortality worldwide. Currently available drugs are effective for treatment of the disease or latent infection, but may cause serious adverse effects.

METHODS

The authors reviewed the literature for side effects of five first-line antituberculous medications (isoniazid, rifampin, pyrazinamide, ethambutol and streptomycin). Incidence of the major side effects were compiled with particular attention to the incidence of isoniazid hepatotoxicity.

RESULTS

Hepatotoxicity to isoniazid is a serious problem. Although overall incidence may be decreasing, incidence averaged 9.2 per 1000 patients who were compliant, in multiple studies, with a case fatality rate of 4.7%. The incidence is higher with increasing age. Other serious adverse effects include dermatological, gastrointestinal, hypersensitivity, neurological, haematological and renal reactions. They can lead to drug discontinuation (in up to 10% of patients) or even more serious morbidity or mortality.

CONCLUSIONS

Side effects to antituberculosis drugs are common, and include hepatitis, cutaneous reactions, gastrointestinal intolerance, haematological reactions and renal failure. These adverse effects must be recognised early, to reduce associated morbidity and mortality.

Treatment of tuberculous infection and disease in children: the North American perspective

The standard preventive therapy for paediatric patients with tuberculous infection centres on isoniazid therapy. The chosen regimen of isoniazid therapy is based on individual patient factors. In the case of known or suspected resistance, combination therapy [e.g. isoniazid and rifampicin (rifampin)] or alternative therapies (e.g. pyrazinamide, a fluoroquinolone and/or ethambutol) should be employed. The goal of treatment of tuberculous disease is to achieve sterilisation in the shortest possible time. More intensive multiple drug combination regimens (e.g. isoniazid, rifampicin and pyrazinamide) have resulted in successful 6- and 9-month treatment regimens in children. If drug resistance is suspected then a fourth drug is added to the initial treatment regimen and the length of therapy may be extended to 18 months. The paediatric information available on the commonly used antituberculous agents (e.g. isoniazid, rifampicin, pyrazinamide and ethambutol) is reviewed in this article. Agents are described with an emphasis on their formulation availability, mechanism of action, pharmacokinetic properties (e.g. absorption, distribution, metabolism and elimination), adverse effects, and interactions (e.g. drug-drug, drug-food and drug-disease).

Isoniazid dose adjustment in a pediatric population

This retrospective analysis was designed to evaluate the inactivation index (I3) method used to adjust the isoniazid dose during long-term administration in a pediatric population. Before starting on antituberculosis therapy, sixty-one children received one 10 mg.kg-1 isoniazid test-dose (D). The isoniazid and acetyl isoniazid concentrations were measured by high-performance liquid chromatography on a plasma sample collected 3 hours (C3h) after administration. The patients were separated into slow and fast acetylator groups according to the metabolic ratio. The dose adjustment method using the I3 is based on the assumption that there is a linear correlation between C3h and D [C3h = (I3 x D) - 0.6] in which the slope is I3 and the Y intercept is equal to -0.6 mg.l-1. I3 was determined from a single plasma concentration determination and used to calculate the dose recommended to obtain a desired C3h equal to 1.5 micrograms.ml-1: recommended dose (mg.kg-1) = (1.5 + 0.6)/I3.I3 was significantly higher in the slow acetylator group (0.55 +/- 0.16) than in the fast one (0.26 +/- 0.13), which leads us to recommend a significantly lower dose in the slow acetylator group (4.2 +/- 1.5 mg.kg-1) than in the fast one (10.3 +/- 4.6 mg.kg-1). The data obtained in a subgroup of 21 patients who had at least three consecutive determinations of C3h after different dosages allowed us to verify that there was a linear correlation between C3h and the dose. The mean slope of the correlation lines in that subgroup was 0.61 +/- 0.25 and the 95% confidence interval of the estimated Y-intercept include the theoretical value of -0.60, which shows that our data are consistent with those previously reported in adults. The percentage of patients with a C3h plasma concentration within the expected range (1.5 +/- 0.5 micrograms.ml-1) was significantly higher (69%) in those whose dose was derived from the calculation than in the others (25%). Within each acetylator group, the range of the recommended dose varied widely, and these results emphasize the usefulness of individual dose adjustment based on the inactivation index method.

Fatal isoniazid-induced hepatitis. Its risk during chemoprophylaxis

Isoniazid chemoprophylaxis has long been known to be a highly effective means of preventing silent tuberculous infections from spreading to active disease. There has been much controversy, however, about the risk it carries for fatal hepatotoxicity. In this article I review the rate of fatal isoniazid-induced hepatitis during chemoprophylaxis that is done according to current monitoring guidelines. Information was obtained from a MEDLINE literature search and a survey of tuberculosis control officers in large metropolitan areas throughout the country. Data were included of patients who were monitored according to the American Thoracic Society's guidelines or who were treated after 1983 when the guidelines were published. The pooled results of the published studies showed no hepatotoxic deaths in 20,212 patients in whom prophylaxis was started. The unpublished data showed 2 deaths in 182,285 patients, for a combined rate of 0.001% (2 of 202,497). The death rate for those older than 35 years was estimated to be 0.002% (1 of 43,334). This rate is significantly lower than was previously estimated and should be used to reevaluate the benefit of preventive therapy for tuberculin-reactive patients older than 35. The risk of fatal isoniazid-induced hepatitis is negligible for all ages when patients are routinely monitored for liver toxicity.

Pure red cell aplasia and hepatitis in a child receiving isoniazid therapy

A 7-year-old boy had pure red cell aplasia and clinically significant hepatitis during isoniazid therapy. The former complication had been reported only in adults, and the latter is rare in children.

Clinical pharmacology of antitubercular drugs

Isoniazid, rifampin, and ethambutol are the three major drugs used in the modern treatment of patients with tuberculosis. Data on these drugs in children have been derived primarily from their clinical use in pediatrics and extrapolation from experiences in adults. A number of questions remain concerning the clinical pharmacology and appropriate use of these drugs in children. Additional pediatric pharmacokinetic studies are necessary to confirm the current dosage recommendation and use of these agents in the pediatric patient.

Clinical pharmacokinetics of isoniazid

The pharmacokinetics of isoniazid in man are described. Pronounced interindividual variation in circulating isoniazid concentration and clearance which occur after dosing with the drug are associated with hereditary differences in the acetylator status. The variations in rate of isoniazid inactivation and elimination in different (rapid and slow) acetylator phenotypes are primarily due to differences in the rate of acetylation of isoniazid by a genetically controlled polymorphic N-acetyltransferase in liver and small intestine. An appreciable 'first-pass' effect is observed following oral isoniazid administration, particularly in the rapid acetylator phenotype. Liver disease can cause a significant prolongation in the clearance of isoniazid; in the acutely ill patient, the prolongation correlates most closely with serum bilirubin elevation, although the degree of prolongation is less important than the intrinsic genetic difference between acetylator phenotypes. The effect of renal impairment on isoniazid excretion is relatively unimportant, even in slow acetylators. Methods for monitoring blood and urine concentrations of isoniazid and for acetylator phenotype determination which are convenient for the patient and clinician are available. Implications of phenotype differences in acetylator status for the optimal management of tuberculosis with isoniazid are considered. Attempts to devise new isoniazid formulations for this purpose are being evaluated.