TB1

TB is the most infectious disease in the world with an estimation of 1/3 of population infected & 2.5 million deaths annually. If untreated, fatal in over 50% of cases. It was isolated by Robert Koch in 1882 Risk factors for increasing TB among developing countries:*ineffective control programs.*lack of access to health care.*poverty, civil unrest.*HIV.*population increase.*drug resistance. 
While risk factors for increasing TB in developed countries: *immigration from high-prevalence areas.*HIV.*social deprivation(homeless, poverty).*increasing proportion of elderly.*drug resistence.()Organism:A- mycobacterium tuberculosis complex(M. bovis, M. africanum).B- opportunistic mycobacterium (M. kansasii, M. xenopi etc…)() Pathology & pathogenesis:*smallest particles (1-5 Mm) enter the periphery of the lung & are engulfed by MQ*in response to antigen, CD4 T lymphocyte produce interferon gamman that lead to recruitment of monocytes & formation of granuloma (tuberculous caseous granuloma).*this mass of granuloma called “Ghon focus”.
*Ghon focus + regional LN termed as Ghon complex.*occasionally , the tonsil, intestine or skin may be the site of primary disease.*in 85-90% healing occur in 1-2 months, TST become +.*in 10-15% lymphatic spread to pleura, pericardium, & pulmonary blood vessels (miliary, meningeal, bone, GIT).*In immunodeficiency like HIV patients: more likely to ()extrapulmonary & dissemeneted.()reduced smear-positive rates.()less cavitation.()atypical CXR.()adverse drug reaction.
()predisposing factors to TB:@ pateint related:*age .*first-generation immigrants from high-prevalence TB.*close contact to smear +ve pulm TB.*drug abuse *overcrowding.*CXR evidence with self-healed TB.*had primary infection < 1 year.@ associated disease:*immunosuppression: HIV, infximab, CS,.*Mlignancy.*type I dm.*CRF.*silicosis.*gastrectomy, malabsorption.*deficiency of Vit D OR A
() Timetable of TB:1- first 3-8 weeks: +ve TT, erythema nodusum, fevers, phlyctenular conjuctivitis.2- after 3-8 weeks: CXR show primary Ghon complex.3- after 3-6 months: meningeal, miliary, pleural, pericardial.4- up to 3 years: GIT, bone, joint,.5- after 5 years: skin involvment.6- around 8 years: renal tract diseases.7- from 3 years on wards: post-primary disease() clinical features: divided into:pulmonary & nonpulmonaryregarding pulmonary divided into:primary pulmonary post primary miliary 
() primary pulmonary TB:*refere to infection in previosly uninfected individual.*usually occur in childhood.*generally asymptomatic.*a history of contact with active pulmonary TB*clinical features include: @infection(4-8 weeks)influenza-like illness.+ve TTCXR primary complex. @disease: LAP, collapse, consolidation(RT middle lobe)cavitation, pleural effusion, miliary, pericarditis, erythema nodosum, phlyctenular conjuctivitis.
() post primary TB:*Is the most form of TB in adults.*typically insidoius. With fever, night sweating, maliase, anorxia, wt loss.*the disease often involves 2 or more areas of lung: opacity in upper lobe, consolidation, collapse, cavitation, miliary, pleural effusion,.*you should suspect post primary TB in:()chronic cough often with hemoptysis.()PUO()unresolved pn.()exudative pleural effusion.()wt loss.()spontenous pneumothorax.
Miliary TB:* Arise from blood dissemination.*presentes with 2-3 weeks (puo) of fever, night sweat, anorxia, wt loss, dry cough. Hepato splenomeagally,* ascultation of chest usually normal.*fundoscopy reveal choroidal tubercles.*anemia, & leucopenia.The term cryptic miliary TB presented as:*age > 60 years.*intermittent low-grade fever, PUO.*unexplained wt loss.*normal CXR*leukmiod reaction, pancytopnea.*confirmed by biopsy.
Extra-pulmonary TB:() Lymphadenitis:*most common site cervical , mobile , painless matted togther to form caseation “collar-stud” abscess & sinus formation.*TT strongly +ve, M. avium complex.
() GIT:1- rarly involve tounge.2- iliocecal 50% present as fever, wt loss, RIF mass.3- up to 30% as acute abdomen.4- mesentric adenitis & intestinal obstruction.5- tuberculous peritonitis. 6- anorectal ulceration.7- hepatic dysfunction.8- DX --- U/S or CT may reveal thickend bowel wall abd LAP. BIOPSY is defenitive test.
() pericardial disease:pericardial effusion, constrictive pericarditis.Pericardial calcification.()CNS:1- lymphocytic meningitis, hydrocephalus & tuberculoma.2- CN palsy.
() bone & joint diseases:1- pott’s disease: the spine most common typically involve lower thoracic & lumbar spine.The infection starts as diskettes then spread to spinal ligament to involve ant vertebral bodies causing angulations with subsequent kyphosis.2- par vertebral &psoas abscess.3- TB can affect any joint (hip & knee)
()GUT:1- Asymptomatic remains years.2- sterile pyurea. 3- endometritis, epididymitis, prostatis.()dermatology:lupus vulgaris & erythema nodosum.