tuberculosis

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Tuberculosis

Tuberculosis (TB ) is an infectious disease caused by the mycobacterium tuberculosis which is a strictly aerobic non spore-forming slow-growing , non motile bacteria . It 's only natural reservoir is humans . Two forms of tuberculosis cause a particular danger to humans M . tuberculosis hominis (human tuberculosis ) and M . tuberculosis bovis (bovine tuberculosis . If infection results in disease , the course tends to be chronic and indolent . Other mycobacterium , including M avium-intracellular complex , are much

less virulent than M . hominis and M . bovis and rarely cause disease except in severely immunosuppressed persons , such as those with HIV infection . Rapid progression to fulminant disease may result if the host is immunocompromised

[American Thoracic Society and Centers for Disease Control and Prevention , pp 1376-1395]

The lung is the prime entrance gate of the tuberculous bacillus , which leads to a focal infection in the lung tissue where it is put down after inhalation . If the infection cannot be enclosed at the local level bacilli distribution is produced initially by hematogenic route probably inside phagocytic cells , towards different organs and ultimately , to the neighboring pleura . It reaches hilar lymph nodes by the lymphatic route , and from there , a subsequent systemic spreading can take place , through the thoracic

duct and superior vena cava , with the growth of local foci in the lungs Extrapulmonary foci can also be formed by hematogenic and lymphatic dissemination to other extra pulmonary sites like eye , skin , genital digestive tract and central nervous system . Intestinal tuberculosis can be acquired by the oral route and in countries with a high prevalence of bovine tuberculosis . Before the simplification of milk pasteurization this was a somewhat frequent form of zoonotic tuberculosis produced by Mycobacterium bovis particularly in infants . The majority of the extrapulmonary forms of TB affect organs with suboptimal conditions for bacillary growth . For this reason , the extrapulmonary disease generally has an insidious presentation . HYPERLINK "http /www .aafp .org http /www .aafp .org

The exact signs and symptoms depend on the organ or system affected They are characterized by inflammatory or obstructive phenomena . In acute cases the symptoms manifested by tuberculous are characterized by fever , sweats , and a rapid exhaustion of the patient . Emaciation in these cases is not extreme , while hemorrhages are liable to be profuse The subacute , and particularly the chronic cases , show a steady emaciation , with loss of strength cough , bothersome at night and mainly in the morning feverishness , mostly toward evening or night hemoptysis night sweats , and also more profuse sweating during the day The feverishness is typically irregular , and in some cases the patients present with more of chilliness than of heat . Expectoration is so insufficient in some cases that it requires additional day to obtain a fair sample of the sputum , while in other cases it is plentiful Hemoptysis (blood in phlegm ) seems to be the rule , but in these slower cases is rarely profuse . Dyspnea (difficulty in breathing ) is not a frequent...