the phenomenon of 
 immigration has an immense impact on the health care of population in the united states . cases of tuberculosis ( tb ) among foreign - born nationals , currently living in 
 the united states , account for more than half of the total . also the absence of systemic symptoms does not rule out tb . 
 radiological imaging , sputum smear , and ppd only aid in the diagnosis but a 
 high degree of suspicion is required to ascertain an accurate diagnosis . 
 establishing an early diagnosis of tb infection and disease in a pregnant woman a 21-year - old hispanic female with a 32-week twin pregnancy presented in 
 preterm labor . she had immigrated to the united states 
  two years prior , and 
 her pregnancy course was uncomplicated except for complaints of an occasional 
 nonproductive cough . she was a nonsmoker , denied any history of tb exposure , 
 and was hbsag and hiv negative . on general exam , she was tachypneic and anxious 
 but in no apparent respiratory distress . she was found to have a low oxygen 
 saturation of 89% on room air with a respiratory rate of 30/min and her blood 
 pressure was 127/76  mmhg . her uterine 
 fundal height corresponded to 32-week twin pregnancy and she had bilateral 
 pedal edema . she was initially admitted to the labor and delivery unit in our hospital and 
 subsequently transferred to the medical icu . abg showed ph of 7.41 , paco2 of 
 29 , pao2 of 64 , bicarbonate of 18 , and the base excess of 6 , saturating at 93% 
 on 21% fio2 . cbc showed wbc 9.9  th / mm , hb , and hct 10.8  g / dl and 32.8% , 
 respectively , platelets 432  th / mm . the chest x - ray demonstrated a right 
 paratracheal soft tissue opacity measuring approximately 
 4  4  cm with a slight 
 elevation of the right hemidiaphragm with a linear density in the right lower 
 lung consistent with atelectasis ( see figure 1 ) . patient was put in respiratory isolation early on and the pulmonary team was 
 consulted . ct showed a large extensive mediastinal soft tissue mass in the 
 right paratracheal region extending into the hilar and subcarinal region . an 
 associated atelectasis on the right upper and lower lobe with questionable 
 alveolar infiltrate in the right lower lobe was also found . an abdominal 
 ultrasound showed twin - twin transfusion with reversed end - diastolic flow on 
 umbilical artery doppler in twin b and the patient had an emergent low 
 transverse cesarean section the next day with delivery of two male infants . infant a had apgars of 7 and 9 , and infant b had apgars of 0 , 4 , and 5 , 
 respectively . both infants went to the nicu , and the patient returned to the 
 micu . successful 
 samples of sputum could not be obtained but a bronchoscopy with endobronchial 
 biopsy and bronchoalveolar lavage ( bal ) was done . bronchoscopy showed a trachea 
 with diffuse mucosal 
 swelling and the mucosal abnormalities persisted throughout the right bronchial 
 tree . she also had irregular tumor growth from the anterior wall of the 
 proximal bronchus intermedius and the base of the proximal right upper lobe 
 bronchus . there was an abundant growth of staphylococcus aureus but no acid - fast bacilli ( afb ) , fungus , 
 or hyphae from the bal . the patient was started on vancomycin and clindamycin 
 to cover methicillin - resistant staphylococcus aureus ( mrsa ) which was later changed to moxifloxacin based on 
 sensitivities . transbronchial biopsy of the right bronchus intermedius showed 
 inflammatory and squamous debris with ulceration , reactive squamous epithelium , 
 and colonizing coccal bacteria . the treatment of this young hispanic immigrant 
 female with an occasional cough , positive ppd , questionable alveolar 
 infiltrate , caseating granulomatous inflammation and no significant evidence of 
 tb infection posed a definite challenge . given her high risk for tb , she was 
 empirically started on inh , rifampin , ethambutol , and pyrazinamide . it was only 
 on day 26 that mycobacterium tuberculosis was isolated by dna probe from her right lung tissue which was subsequently 
 confirmed on culture . the infants were started on inh prophylaxis after 
 placental pathology did not demonstrate evidence of tb . patient was discharged 
 to home in a stable condition to be followed up at the local tb center for 
 direct observation therapy . among the communicable diseases , tb is the second leading cause of death 
 worldwide , killing nearly 2 million people each year . the world health 
 organization estimates that 2 billion people have latent tb , in addition to the 
 3 million people worldwide who die each year due to tb . after a resurgence of 
 tb in the united states 
  between 19851992 , the decline 
 noticed during 19932005 has slowed 
 down causing concerns that the progress achieved in eliminating tb is slowing 
 down . immigration demographics demonstrate that asians , blacks , and 
 hispanics essentially bear the burden of tb in immigrants . the number of tb 
 cases due to foreign - born individuals has increased each year since 1993 . in 
 1996 , 10% of the 20,973 us tb cases were among foreign - born hispanic persons , 
 with the four states bordering mexico 
  accounting for 83% of foreign - born hispanic cases . mexicans accounted for 22.9% 
 of foreign - born patients or 8.4% of all us cases and persons born in central america comprised an additional 4.7% of foreign - born 
 patients or 1.7% of all us cases . guatemala and el salvador contributed to nearly 75% of these 
 cases and the remaining were from the rest of central 
  america . in 2005 , when 
 compared between foreign - born persons in the united states 
  and us - born persons , 
 the tb rates were 8.7 times higher in 
 immigrants ; with hispanics , blacks , and asians having tb rates 7.3 , 8.3 , and 
 19.6 times higher , respectively , than those of whites . m. tuberculosis is transmitted by airborne droplet nuclei , which may 
 contain fewer than 10 bacilli and humans are the only known reservoir for m. 
 tuberculosis . individuals at high risk for m. tuberculosis infection in industrialized countries include ( i ) individuals likely to be 
 exposed to or become infected with m. tuberculosis : close contacts of a 
 patient with infectious tb , foreign - born individuals from high - incidence areas , 
 the elderly , residents of long - term care facilities ( e.g. , correctional 
 facilities and nursing homes ) , iv drugs abusers , other groups identified 
 locally as having increased prevalence of tb ( e.g. , migrant farm workers or 
 homeless persons ) , and individuals who may have occupational exposure to tb ; and 
 ( ii ) individuals at high risk of developing tb disease once infected : individuals 
 recently infected with m. tuberculosis ( within the past 2 years ) , 
 hiv - infected individuals , individuals with immunosuppressing conditions or 
 medication use , individuals with a history of inadequately treated tb , and 
 infants . chances that an individual acquires infection depend on the 
 infectiousness of the index case , duration of the exposure , environment 
 ( crowding , poor ventilation ) , and virulence of the organism . atypical presentations and slow confirmation by culture often delay the 
 diagnosis and treatment of patients with tb . other reasons include an under use 
 of tuberculin skin tests , misinterpretation of unusual chest x - rays , and 
 waiting for culture results in patients with afb - negative smears . generally , 
 in tb , a segmental pneumonic process is seen but may be too small to visualize 
 radiographically or complicated by atelectasis from the raised diaphragm 
 compressing the lower lung fields in pregnancy [ 7 , 8 ] . upper zone shadowing , 
 often bilateral and likely associated with cavitation or miliary shadowing are 
 the classic findings . new findings like soft 
 shadowing amongst old , fibrotic changes generally indicate a relapse . paratracheal , mediastinal , and hilar lymphadenopathy , though not unusual in 
 african and indian patients with tb or in children , are generally unusual in 
 immunocompetent adults like ours . in patients infected with hiv , the 
 radiological appearances could often be nonspecific . in our patient the infiltrate could have been misdiagnosed as atelectasis in a woman with a 32-week 
 twin pregnancy . five 
 millimeters is considered to be positive in individuals with hiv , on steroid 
 therapy , or in individuals in close contact with a person with active tb . larger reactions of greater than or equal 
 to 10  mm are considered positive in recent ( within the last five years ) 
 immigrants from high - prevalence countries , in individuals with diabetes , renal 
 failure , and health - care workers , among others . our patient falls into this 
 category . in individuals with no known risks for tb many patients with suspected pulmonary tb do not produce sputum spontaneously 
 or are smear - negative for afb . we could not obtain sputum sample in our patient 
 due to absence of a productive cough and sputum induction was also 
 unsuccessful . though the bal sample did not show any afb , the biopsy showed 
 caseating granuloma which could be found both in tubercular and nontubercular 
 mycobacterial infections or fungal infections due to coccidioides immitis and histoplasma capsulatum . it was ultimately a dna probe from her lung 
 tissue that grew m. tuberculosis after 26 days . with the use of pcr , nucleic acid sequences unique to m. tuberculosis can be detected directly in clinical specimens with better accuracy and urgency 
 than afb smear and culture , respectively . probes are used for rapid 
 identification and maximizing cost effectiveness . used alone or in combination 
 with other identification methods , they serve as a substitute for biochemical 
 testing and are also more accurate . can enhance the diagnostic ability particularly in 
 pauci - bacillary infections and in patients with atypical presentations like 
 ours . the risk of tb to health - care workers is real . in the early 1990s , many urban us 
  hospitals reported purified protein derivative ( ppd ) conversion rates in health - care 
 workers of 35% . a survey of us 
  hospitals conducted by the centers for disease control and prevention ( cdc ) 
 found a mean conversion rate of 1.6% [ 16 , 17 ] . efficient control of nosocomial tb is 
 compromised by the same difficulties complicating community control hence a high degree of suspicion is required to recognise and isolate patients with 
 tb . an improved clinical acumen , development of rapid diagnostic tests , and the 
 institution of early empiric therapy are desirable to control this disease . we 
 combined the use of bronchoscopy and m. tuberculosis complex - pcr which 
 provided a good diagnostic yield in our patient . an early diagnosis of tb infection in a pregnant woman is important as better 
 results are seen in women who are detected with tb and have been treated before 
 the onset of pregnancy or earlier in its course , when compared with untreated 
 patients with tb . infant and 
 maternal mortality are between 30% and 40% in untreated active tb cases . treatment should also be initiated when the probability is moderate - to - high . although the drugs in the initial treatment regime cross the placenta , these 
 concentrations do not appear to have harmful effect on the fetus . pregnant 
 women with tb should also be tested for hiv as there is a higher incidence of 
 extrapulmonary tb and multidrug - resistant tb ( mdr tb ) in this set of patients . breast feeding should not be discouraged in women being treated with first - line 
 antituberculosis drugs because the concentrations in the breast milk are 
 subtherapeutic and too low to produce toxicity in the nursing new born . the effect would likely be much 
 lower if the mother breast feeds before taking the medication . similarly , 
 breast milk is also inadequate as a treatment option for tb or latent tb 
 infection in newborns . close follow up of patients is essential since 
 current therapy for tb infection is long and suboptimal adherence may result in 
 failure of therapy . congenital tb is rare with symptoms typically developing during the second or 
 third week of life which include poor feeding , poor weight gain , cough , 
 lethargy , and irritability . two possible routes of m. tuberculosis infection in utero 
 are ( a ) hematogenous infection through the umbilical vein , with primary lesions 
 in the liver and occasional porta hepatis lymphadenopathy ; and ( b ) prenatal 
 aspiration of infected fluid , with predominant pulmonary and gastrointestinal 
 disease [ 21 , 22 ] . the criteria for congenital tb requires the infant to have a 
 tuberculous lesion ( e.g. , infiltrates on the chest radiograph or granulomas ) 
 and at least one of the following : ( a ) onset during the first week of life , ( b ) 
 presence of a primary hepatic tb complex or caseating hepatic granulomas , ( c ) 
 infection of the placenta or maternal genital tract , or ( d ) exclusion of 
 postnatal transmission . the role of bacillus of calmette - gurin ( bcg ) vaccine in preventing tb in 
 adults is debatable due to its variable efficacy ( 080% ) . its efficacy in 
 prevention of tuberculous meningitis and miliary tb in young children has been 
 easier to document than in adults or in the prevention of pulmonary tb in both 
 children and adults . the centers for disease control has made the 
 following recommendations concerning bcg vaccination in the us 
  . ( i ) 
 bcg vaccination should be considered in infants and children 5 years if 
 the child is exposed continually to an untreated or ineffectively treated 
 patient with infectious pulmonary tb , if the child can not be separated from the presence 
 of the infectious patient or be given long - term primary preventive therapy , or if the child is exposed 
 continually to a patient with infectious pulmonary tb caused by m. 
 tuberculosis strains resistant to isoniazid and rifampin and the child 
 can not be separated from the presence of the infectious patient . ( ii ) health - care 
 workers in high - risk settings should be considered on an individual basis 
 in settings in which a high percentage of tb patients are infected with m. 
 tuberculosis strains resistant to both isoniazid and rifampin , transmission 
 and subsequent infection are likely and where comprehensive tb 
 infection - control precautions have been implemented and have not been 
 successful . our case emphasizes the significance of identifying infectious diseases like tb 
 in developing countries due to a change in demographics . it also underscores 
 the importance of an early diagnosis and treatment even in the backdrop of 
 confounding evidence in pregnant women due to better maternal and perinatal 
 outcomes . a heightened index of suspicion and awareness of the rapid advances 
 and innovations made in the diagnosis of tb is also essential for better 
 control of this disease .