diabetes and tuberculosis, an unholy alliance
TRANSCRIPT
Diabetes and Tuberculosis: an unholy alliance
Dr. Mohammad Tanvir IslamAssistant Professor, MedicineBangabandhu Sheikh Mujib Medical University
Dr. Shamim AhmedAssistant Professor, RespiratoryMedicineBangabandhu Sheikh Mujib Medical University
Background Epidemiology 347 million people worldwide have
diabetes 80% diabetes deaths in low- and
middle-income countries 7th leading cause of death in 2030 In Bangladesh between 2% and 21%
Diabetes 2013
Projected prevalence of DM in 2030
Tuberculosis around the world
About 9 million people around the world
A total of 1.5 million people died in 2013
The incidence of TB in Bangladesh is 225 per 100,000
Worldwide Tuberculosis
High burden TB countries
ChinaIndiaBrazilBangladeshIndonesiaPakistanRussia
Intersecting Epidemics
Big concern about twin epidemics Low to middle income countries DM increases the risk of TB 3 fold TB causes glucose intolerance
Association between diabetes and active tuberculosis in studies stratifying by glucose control
14.8% of PTB & 20.2% smear positive PTB cases are directly linked to DM
TB causes glucose intolerance 50 % of which normalizes after ATT
DM increases risk of TB 3 times TB increases risk of DM 2 times
Historical aspects
Since ancient times Susruta in 600 AD Avicenna (780-1027 AD) Roots 1950 Nicholas 1957 McCornick 2007
Pathogenesis of tuberculosis
Four possible outcomes: Immediate clearance of the organism Latent infection The onset of active disease (primary
disease) Active disease many years later
(reactivation disease).
Persons with medical conditions that weaken the immune system
HIV infection Diabetes mellitus Medical treatments such as
corticosteroids or organ transplant Substance abuse Organ transplants Malignancy
Pathophysiology Hyperglycemia favours growth , viability and
propagation of tubercle bacilli and hamper resistance to infection & repair capacity
Increased availability of glycerol and nitrogenous substances aid the growth of tubercle bacilli
High level of insulin have been shown to promote a decrease in Th1 immunity through a reduction in the Th1 cell to Th2 cell ration and interferon gamma to IL-4 ratio
Immunologic abnormalities in Diabetes
Abnormal chemotaxis Decreased peripheral monocytes
with impaired phagocytosis Poor blast transformation of
lymphocytes Defective C3 opsonic function Decrease in Th1 immunity
Pulmonary physiologic dysfunction in diabetes
Diminished bronchial reactivity Reduced diffusion capacity Occult mucous plugging of airways Reduced ventilatory response to
hypoxaemia
Pathophysiologic dysfunction of lung in diabetes
Microangiopathic change in pulmonary vasculature
Non-enzymatic glycosylation of tissue protein
Thickening of epithelial and caplillary BM
Interference with clearance mechanism
Increased risk of
tuberculosis
Diabetes
Neutrophil• Abnormal
Chemotaxis• Phagocytosis• Microbicidal acitvity
Reduction in Th1 cells
Interferon gamma
Increased availability of Glycerol and nitrogenous substances
Lung physiological and pathological
dysfunction
Increased risk of Tuberculosis
Impairment ofInnate immunity Acquired immunity
DiabetesLung Physiologic dysfunction
Lung Pathologic dysfunction
Impact of TB on glycaemic status
Relative and absolute overproduction of adrenocorticotropic hormone
Increased supply of corticosteroids Corticosteroids are insulin
antagonists resulting in insulin resistant diabetes.
Clinical menifastations
More aggressive course Less clinical manifestations Typical features like cough, weight
loss are less prominent Prolonged duration of fever
Clinical menifastations
Features of one disease can mimic the other
Might progress rapidly Flare up or spread of tuberculosis More complications Risk for Drug-resistant TB
Comparison of clinical features
Clinical feature
DM & TB TB only
Fever 64% 98%Night sweat 52% 85%Cough>3wks 71% 96%Weight loss 69% 94%
Hossain D, Latif ZA, Mahtab H Clinical and radiological presentation of pulmonary Tuberculosis in diabetic and non-diabetic patients. J Soc Heart Chest Dis 2004;2:69-72
Radiology of PTB in DM
Frequently atypical Lower lobe opacity Multilobar Cavitary lesion Pleural effusion
Comparison of radiological features in TB patients with or without DM
Radiological feature
DM +TB TB alone
Upper lobe opacity 17% 56%Lower lobe opacity 19% 7%Multi lobe opacity 64% 36%Cavity 82% 59%
C.Perez et.al. 2001
Radiology
Summery
DM & TB prevalence is increasing They are epidemic in identical areas DM is a risk factor for TB TB causes glucose intolerance Clinical and radiological features in a
diabetic TB patient may be atypical