Tuberculosis droplet nuclei between 1 to 5um
Tuberculosis is aserious chronic pulmonary and systemic disease caused by infection with one ofthe three members of the Myobacteriumtuberculosis, a tuberclebacillus.
Complex: Myobacteriumtuberculosis, Mycobacterium africanum or Mycobacterium bovis. Myobacteriumtuberculosis was identified and described on 1882 by a German physicianRobert Koch, which is slightly curved to straight bacillus. Myobacterium tuberculosis is obligateaerobic, acid fast, non-motile and non-forming bacilli and contain mycolic acidin their cell wall.
Tubercle bacilli IMMUNOPATHODENESIS AND PATHOLOGY Transmissionof Myobacterium Tuberculosis by airborne and they also may be produced throughmanipulation of lesion or processing of tissue or secretions. The size of dropletnuclei between 1 to 5um which they can live in indoor space for a period oftime. They are dispersed throughout the room once released from the host,.
Microorganism do notinvade tissue but accumulated on the intact mucosa or skin,so larger particlesgenerate by the patients with tuberculosis do not serve as effective vehiclesfor transmission. When large particles with numerous bacilli are inhaled, they donot reach alveoli but impact on the wallof the upper airway or trachea, where they are trapped in the mucous blanket,carried to the oropharynx and swallowed or expectorated.Preventingthe airborne transmission of tuberculosis is one of the way that reduce thenumber of droplet nuclei indoor. Ventilation with fresh air by keeping room-airchanges an hour being fascinating. The number of viable airborne tuberclebacilli can be reduced by ultraviolet irradiation if air in the upper part ofthe room.
Effective antituberculosis chemotherapy reduces the number of bacillireleased into the air by reducing the number of organisms in the sputum and thefrequency of coughing. Covering the mouth and the nose with tissues whilecoughing or sneezing, or more effectively with a mask, reduce the number oforganisms by reducing the number of droplet nuclei put into air. If masks areto be used, they should be fabricated to filter out droplet nuclei and moldedto fit tightly around the nose and mouth. Methods once thought to be importantin preventingthe transmission of tuberculosis—disposing of such personal itemsas clothes and bedding, sterilizing fomites, using caps and gowns and gauze orpaper masks, boiling dishes, and washing walls—are unnecessary because theyhave no bearing on airborne transmission.M. bovismay penetrate the gastrointestinal mucosa or invade the lymphatic tissue of theoropharynx when ingested in milk containing large numbers of organisms.
Humaninfection with M.bovis hasessentially been eliminated in developed countries as a result of thepasteurization of milk and effective tuberculosis control programs for cattle.Airborne transmission of M.bovis canalso occur. Humans with active TBwho release mycobacteria present in the sputum (open case) act as reservoir ofinfection. The primary sites of infection are stated below: Lung: Pulmonary tuberculosis Intestinal tract: Gastrointestinal tuberculosis Orophynx: Oropharyngeal tuberculosis Skin: Tuberculosis of the skinOropharyngealand Intestinal tuberculosis contracted by drinking milk contaminated with M.bovis.
Except myocardium, skeletalmuscle, pancreas and thyroid, tuberculosis can affect any organ or tissue inthe body. The factor controlling pathogenesis are the virulence of theorganism: mycosides; cord factor and hypersensitivity against the organism. Theinfection by M. tuberculosis commonlycausing the development of delayed hypersensitivity to M. tuberculosis antigens, which can be detected by the tuberculinskin test (Mantoux test). EPIDEMIOLOGY OF TUBERCULOSIS Transmissionoccurs when droplet nuclei(airborne particle about 1-5 microns) are inhaled andreach the alveoli of the lungs, via nasal passages, respiratory tract andbronchi 2 billion people infected worldwide (1/3of the world’s population).Thenumber of new TB cases in the country increased from 15,000 in 2005 to 19,251 in2011 as shown in figure.
CLINICAL FEATURES OF TUBERCULOSIS Typical TB clinical presentation Insidious onset and chronic course Chest symptoms Cough (usually productive) Hemoptysis Chest pain (usually pleuritic) Nonspecific constitutional symptoms (more common in children and HIV) Extrapulmonary symptoms (if involved)Themain site of Extrapulmonary disease are Miliaryor Disseminated tuberculosis and Tuberculousmeningitis. Miliary or Disseminatedtuberculosis cause by haematogenous spread of bacteria and can be due toeither primary infection or reactivation. Nonspecific signs such as fever,night sweats, anorexia, weakness and weight loss are the presenting symptoms.Plain chest X-ray is used to diagnose military TB although liver biopsy issometimes done.Tuberculous meningitisare seen most often in the children or immunocompromised adults and result fromhaematogenous spread of pulmonary disease. Some symptoms may present withheadache and slight mental changes, weeks of low-grade fever, anorexia, malaiseand irritability. TB meningitis often diagnosed by microscopic, biochemical andbacteriological examination which requires cerebrospinal fluid. Lymphadenitispresent in cervical, mediastinal, axillary and inguinal is most commonextrapulmonary site.
CONTENT: MANAGEMENT OF TUBERCULOSIS DIAGNOSIS OF TUBERCULOSIS DIAGNOSIS OF TUBERCULOSIS DIAGNOSIS OF TUBERCULOSIS · Clinical · Radiological · Laboratory Themost common form of tuberculosis in adults is post-primary pulmonary tuberculosis.It is the only form of tuberculosis which is infectious and insidious onset ofa productive cough, night sweat, anorexia and weight loss. It is not possibleto distinguish between progressive primary and “post-primary” or reactivationTB. Signs can be subtle as in minimal cases or obvious such as consolidation,fibrosis or stony dullness due to pleural effusion. Chestradiographs often reveal more disease than suggested by physical examination. A 1.
1-1.5cm grey white inflammatoryconsolidation emerges-lesions (Ghon lesion) in the apical and posteriorsegments of the upper lobes developed as sentilization. In most cases thecenter of this focus undergoes caseating necrosis. Tubercle bacilli travel toipsilateral regional lymph nodes either as free bacilli or withinmacrophages.This combination of parenchymal lesion and nodal involvement isreferred as Ghon complex. In 95% cases development of cell mediated immunitycontrols the infection.
Hence, the Ghon complex undergoe progressive fibrosis,often followed by radiologically detectable calcification. Thelaboratory investigations include sputum direct smears for acid fast bacilliwhich are usually positive in cavitary disease. Three specimens are collectedfor diagnosis. Cultures using Lowenstein-Jensen medium take up to 8 weeks for afinal result.
There are radiometric methods such as the BACTEC test which giveresults within a week; subsequently sensitivity tests can be done within thefollowing week. The tuberculin or Mantoux test has some role in the diagnosisof tuberculosis especially in paediatric cases and cases of extra-pulmonarytuberculosis. The Mantoux test is used in Malaysia using the strength of 10 IUPPD. The result is read after 72 hours. TREATMENT OF TUBERCULOSIS TREATMENT OF TUBERCULOSIS IN ADULTS For treatment ofadults, ant tubercular therapy (ATT) can be divided into 2 groups:1. Primary drugs (1st-linedrugs)· Rifampin· Isoniazid· Pyrazinamide· Ethambutol· Streptomycin2.
Secondary drugs (2nd –linedrugs)· Cycloserine,Ethionamide, Para-aminosalicylic acid (PAS)· Amikacin,Kanamycin, Capreomycin· Ciprofloxacin,Levofloxacin, Moxifloxacin· Rifabutin· RifapentineRifampin is sensitiveto both gram positive and negative bacteria, sensitive mycobacterias are: M tuberculosis, M kansasi, M intracellulare,M avium and M leper. Rifampin binds to the B subunit of bacterialDNA-dependent RNA polymerase and thereby inhibit RNA synthesis.Isoniazid is sensitiveto M. tuberculosis and also to M. kansasi (in high doses) atypicalmyobacteia.
Bacteriostatic for resting cells and bactericidal for rapidlydividing cell, and the active form of isoniazid inhibits the synthesis ofmyocolic acids which are essential components of mycobacterial cell walls.Isoniazid is a prodrug and is activated by KatG, the mycobacterialcatalase-peroxidase enzyme. Active form of isoniazid inhibits key enzymesinvolved in mycolic acids synthesis.Pyrazinamide is abactericidal with excellent cerebrospinal fluid penetration. Ethambutol isbacteriostatic which inhibits enzymes arabinasyl transferases require for cellwall synthesis.
Short coursechemotherapy (SCC) is the combination of isoniazid, rifampin, pyrazinamide andethambutol or with streptomycin is given together to all patients withpulmonary tuberculosis for the first 2 month. The second line drugs are used inMDR-TB. TUBERCULOSIS IN CHILDREN If the culture from thesource case is fully susceptible anti-tuberculosis drugs isoniazid is used inthe treatment for 6 month along with pyrazinamide for the first 2 months forthe therapy.
Treatment duration will increase to 9 or 12 months due to thepossible damaged immune system in children younger than 12 months. Bacillus Calmette-Guérin(BCG) vaccine is used for infant around the world.By the reason difficultiesmonitoring visual acuity and colour perception, ethambutol should be avoided intreatment of children.
However, studies show that ethambutol (15 mg/kg) is welltolerated and can prevent further resistance if the child is infected with aresistant strain. TUBERCULOSIS DURING PREGNANCY, LACTATION & USE OF ORAL CONTRACEPTIVE PILLS The treatment for pregnantwomen with active TB is similar to the normal patient should be treated, evenin the first stage of pregnancy. Isoniazid, rifampin, and ethambutol are usedin the standard treatment.
In the Malaysia, pyrazinamide is for the standardtreatment but in US pyrazinamide is reserved for women withsuspected multidrug-resistant TB (MDR-TB). Streptomycin should not be used,because risk of ototoxicity to the foetus.Rifampicin isrecommended to use in pregnant patients. Tuberculosis treatment in lactatingmothers is safe as the amount of drug ingested by the nursing infant isminimal. Breast-feeding is best avoided during this two weeks and expressedmilk should be given to the child.
There is lower risk for the congenitaltuberculosis, if infant born to tuberculous mother fails to thrive. LIVER & RENAL IMPAIRMENT Anti-tuberculosis drugssuch as (isoniazid, rifampicin and pyrazinamide) which consider hepatotoxichence patients with liver impairment, non-hepatotoxic drugs are commonly use inthe therapy. Treatment should be stopped if the liver enzymes rise more thanthree times normal or if the patient becomes jaundiced clinically duringtreatment drugs.For renal impairment,the nephrotoxicity drug (Streptomycin) should be avoided and Ethambutol shouldbe dosage reduced or averted in renal failure as normal dosages lead to opticnerve damage. HIV INFECTION The clinical situationof the patient with HIV infection can be classified into 2 groups:· Intensive phase· Maintenance phaseDuring intensive phaseif there is no suspicion of drug resistance, anti-tuberculosis drugs(isoniazid, rifampicin and pyrazinamide) are for daily treatment. If the drugresistance the therapy should be modified by additional of ethambutol will usein the treatment.
During the maintenancephase, isoniazid, rifampicin, pyrazinamide (HRZ) daily for 2 months followed byRH for 7 months biweekly or 6 months after cultures are negative for thedrug-susceptible organism. For isoniazid resistance, ethambutol,rifampicin and pyrazinamide (ERZ) daily for 2 months followed by RE daily for12-16 months. For rifampicin intolerance, isoniazid, Pyrazinamide, Ethambutol(EHZ)daily for 18 -24 months.
MULTIDRUG-RESISTANT TUBERCULOSIS (MDR-TB) Second line drugs suchas enviomycin, kanamycin, capreomycin, clarithromycin, ciprofloxacin,ofloxacin, clofazamine, cycloserine and rifabutin are the drugs available inMalaysia for treatment of tuberculosis resistant to first line drugs.Due to ineffectiveness usingisoniazid and rifampin lead to the complexity of MDR-tuberculosis treatment.Isoniazid has the strongest antibactericidal action and significantlycontributes to making patients rapidly noninfectious; rifampin has uniqueantibacterial properties against dormant bacilli that are no longer in theactive phase of replication. CONCLUSION: STRATEGIES FOR MANAGEMENT OF TUBERCULOSIS In my opinion,prevention is better than cure which plays an important role to stop thetransmission of tuberculosis from one adult to another. The presence oftuberculosis vaccine called Bacillus Calmette-Guerin (BCG) where it is one ofthe most widely used of all current vaccines. Besides that,tuberculosis education is important for public, the public needs to know the basicinformation about the tuberculosis for a number of reasons including reducingthe stigma still associated with tuberculosis.