Tuberculous Meningitis

Manual of Diagnosis and Therapy

Jerome Chin

• Publisher: Academic Press
• Year: 2020
• ISBN:
  9780128188262
• Topic: Medicine
• Subtopic: Physiology

Tuberculous Meningitis: Manual of Diagnosis and Therapy focuses on the most common and most lethal manifestation of tuberculosis of the central nervous system. It includes up-to-date reviews of the diagnosis, treatment, and management of tuberculous meningitis in adults and children. Extensive guidance is provided for the treatment of drug-sensitive and drug-resistant tuberculosis and tuberculous meningitis. Clinicians and researchers will find the beginning chapters on immunopathology and epidemiology of great use in their efforts to develop new strategies for the diagnosis and treatment of tuberculous meningitis.

• Written by international contributors from countries most affected by tuberculosis
• Describes clinical and neuroimaging features of tuberculous meningitis
• Examines laboratory methods for detecting Mycobacterium tuberculosis
• Reviews international and national guidelines for the treatment of tuberculosis and tuberculous meningitis

Chapter 1

Global and regional burden of tuberculosis and tuberculous meningitis

Alexandra Boubour¹, Mandar Paradkar² and Kiran T. Thakur¹, ¹Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States, ²BJ Government Medical College, Johns Hopkins University Clinical Research Site, Pune, India

Abstract

According to the most recent World Health Organization estimates, approximately 10 million tuberculosis (TB) cases and 1.6 million TB deaths occurred in 2017, declining 1.8% and 3.9% respectively from 2016, with the greatest caseload in the Southeast Asia and African regions. TB remains the leading cause of death in the HIV-positive population. An increasing public health threat is the rise in drug-resistant (DR) TB, a significant risk factor for disseminated TB, including central nervous system (CNS) involvement. CNS TB is the most severe manifestation of TB and reportedly accounts for 5%–10% of extrapulmonary TB cases and 1% of all TB cases; however, this is likely a significant underestimate given the lack of microbiological confirmation in many cases and a paucity of robust epidemiological studies. Major public health efforts are required to define the current incidence, prevalence, morbidity, and mortality of CNS TB, especially in light of the growing number of multi-DR TB cases worldwide.

Keywords

Tuberculosis; meningitis; global burden of disease; epidemiology; global health

Key points

• • Tuberculosis (TB) is a global disease and the leading infectious disease killer in the world.
• • The highest incidence estimates for TB are in the World Health Organization African and Southeast Asia Regions.
• • In low-burden countries the majority of TB cases are foreign-born persons from high-burden countries.
• • TB is the leading cause of death for HIV-infected persons.
• • Tuberculous meningitis is estimated to account for 1%–2% of all new cases of TB although reliable population-based data are limited.

Global tuberculosis epidemiology

Prevalence and incidence

Tuberculosis (TB) is the leading infectious cause of death on a global level, caused by Mycobacterium tuberculosis (MTB) [1,2]. According to World Health Organization (WHO) estimates, approximately 10 million (range, 9.0–11.1 million) incident cases of TB and 1.6 million TB deaths occurred in 2017, a small percentage decline from prior years (Fig. 1.1) [1]. Since 2000, global TB incidence has declined by 1.5% per year on average [1]. As of 2017, the incidence and number of TB cases remained greatest in the WHO Southeast Asia and African regions despite regional efforts for case reduction [1,3]. Nine percent of incident cases (920,000) occurred among HIV-positive people, 72% living in the African region [1]. Given these estimates, global TB incidence is not currently on track to meet the 2020 WHO End TB Strategy and United Nations (UN) Sustainable Development Goals (SDGs), which propose a 20% decrease in incidence from 2015 [1,3,4]. This is complicated by the fact that just under two-thirds of new TB cases were reported in 2017, likely due to weak surveillance and registration systems in low-resource regions [1,5]. In 2017 the WHO estimated that 90% of cases were adults (≥15 years old), yet in endemic regions, children remain at highest risk [1].

Figure 1.1 Global trends in the estimated number of incident TB cases and the number of TB deaths (in millions), 2000–2017.

Mortality

Globally, TB is the 10th leading cause of death overall and the leading cause of death in HIV-positive individuals, accounting for 40% of all deaths in this population (300,000 deaths; range, 266,000–335,000) [1]. TB case fatality rate (CFR) in 2017 was 15.7%; a drop from 23% in 2000. To align with the targets of the WHO End TB Strategy, the CFR must drop to 10% by 2020. Country CFRs range from <5% to >20%; most high-CFR countries are located in the WHO African Region, suggesting that many countries globally will not meet the WHO End TB Strategy goals [1,3]. In order to achieve TB eradication goals, TB prevention and treatment strategies must target the HIV-positive population to diminish the high incidence rates and mortality among this population. In the HIV-positive population, TB deaths decreased 44% from 2000 to 2017 (534,000–300,000) with an additional decline of 20% since 2015 [1]. Among HIV-negative persons, TB deaths have also declined from 1.8 million deaths in 2000 to 1.3 million deaths in 2017 (29% decline). TB deaths among HIV-negative people have decreased by an estimated 5% since 2015 (year 1 for the WHO End TB Strategy targets) [1]. The global TB mortality rate is decreasing 3% per year with an estimated 42% reduction from 2000 to 2017. The most rapid regional declines in mortality rates have occurred in the WHO European (11% yearly decline) and Southeast Asia regions (4% yearly decline) from 2013 to 2017 [1].

Regional tuberculosis epidemiology

A 2015 Global Burden of Disease (GBD) Tuberculosis Collaborators report stated that among HIV-negative individuals, mortality rates exceeded 50 per 100,000 population in Indonesia, Kiribati, Myanmar, Nepal, and 25 countries in sub-Saharan Africa [6]. Worldwide and in most regions, age-standardized TB prevalence, incidence, and mortality rates steadily drop with ascending sociodemographic index, a summary measure of a country or region’s sociodemographic development [6]. However, the high incidence of TB in some Eastern European countries is the result of increasing HIV prevalence and insufficient systems for care and treatment [5]. Although TB and HIV are strongly related, TB incidence and mortality remain relatively high among HIV-negative people, particularly in Southeast Asia [6]. Conclusions of the 2015 GBD Study emphasize that countries with a high TB burden despite high sociodemographic development should look into reasons for high burden and formulate a rapid action plan [6]. Among countries with lower socioeconomic development, TB burden can be reduced through health systems strengthening to improve disease detection and provision of quality care, including access to essential TB medications [6].

High-burden tuberculosis settings

Globally, the WHO Southeast Asia and African regions make up an estimated 70% of all TB cases. Eight countries accounted for two-thirds of all TB cases in 2017, including India, Pakistan, Bangladesh, Indonesia, China, the Philippines, Nigeria, and South Africa (Fig. 1.2) [1]. Though the Southeast Asia region has higher total case numbers than the African region, likely due to relative population sizes, both regions had similar incidence rates in 2017 (Southeast Asia, 226 per 100,000; African, 237 per 100,000) [1]. Despite this, the percentage of TB cases with HIV coinfection in the African region (27%) was much greater than in the Southeast Asia region (3.5%) [1]. Following the WHO European Region, the WHO African Region had the steepest regional decline in incidence rates from 2013 to 2017 (5% in the European region and 4% in the African region per year on average) [1]. From 2013 to 2017, incidence rate reductions of 4%–8% per year occurred following an HIV epidemic peak and expanded TB–HIV prevention and care in southern Africa and following strengthened attempts to reduce TB burden in Russia (reductions of 5% per year) [1].

Figure 1.2 Estimated TB incidence rates, 2017.

The outlook of national epidemics differs greatly. Per 100,000 population in 2017, there were <10 new cases in most high-income countries, 150–400 new cases in the 30 high-burden countries, and >500 new cases in Mozambique, the Philippines, and South Africa [1]. It is important to note that in countries where TB is endemic, the disease is fortified by weak surveillance and health systems, underreporting, and underdiagnosis [6]. Furthermore, in several TB-endemic countries, TB incidence has either plateaued or is declining more slowly than mortality, which is likely due to delays in treatment and diagnosis [6]. Despite global declines in incidence, in some countries, particularly in the WHO Southeast Asia and African Regions, population growth has resulted in an increasing absolute number of TB cases [5].

Low-burden tuberculosis settings

Although there is an unequal global distribution of TB, the disease remains a global ep...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of contributors
• Preface
• Chapter 1. Global and regional burden of tuberculosis and tuberculous meningitis
• Chapter 2. Immunopathology of Mycobacterium tuberculosis complex
• Chapter 3. Clinical presentations and features of tuberculous meningitis
• Chapter 4. Laboratory methods for detecting tuberculosis and tuberculous meningitis
• Chapter 5. Identification of Mycobacterium tuberculosis drug resistance
• Chapter 6. Treatment guidelines for tuberculosis and tuberculous meningitis
• Chapter 7. Neurosurgical management of tuberculous meningitis
• Chapter 8. Evidence gaps and future directions
• Index