Document 6430671

August 15, 2011
Innersense Voice 122
Laboratory Diagnosis of Genital Tuberculosis
Despite decades of research and availability of a number of diagnostic tests and therapieutic
regimens (TB) is an increasing public health concern worldwide. It is classified as pulmonary
tuberculosis (PTB), tuberculosis of the lungs or extrapulmonary tuberculosis (EPTB), tuberculosis
of organs, other than lungs. The EPTB sites most commonly involved are the lymph nodes,
pleura, genitourinary tract, bones and joints, meninges, peritoneum, and pericardium.
However, virtually all organ systems may be affected. As a result of hematogenous
dissemination in HIV-infected individuals, EPTB is seen more commonly today than in past.
The most common form of extrapulmonary TB is genitourinary disease, accounting for
27% (range, 14 to 41%) worldwide (9). The global prevalence of GTB is estimated to be 8-10 millions cases, with a
rising incidence in the developing counties partly as a result of its association with HIV virus infection and emergence of
multidrug resistance. However, the actual incidence may be under reported due to asymptomatic presentation of
GUTB and paucity of investigations. In comparison to only pulmonary TB, which comprises around 68.4%, the
incidence of combined pulmonary-extrapulmonary cases and extrapulmonary TB alone comprise 12% and 20-25% of
the total disease burden respectively (8).
The typical presentation of GUTB includes pelvic pain, menstrual irregularity, general malaise and infertility.
Diagnosis of early TB is very difficult. Early diagnosis may be associated with a more favorable result before extensive
genital damage occurs.[1]
Female Genital Tract Tuberculosis (FGTB): It is estimated that 18% of infertile women, aged between 20-40 years in
India suffer from GTB. The genital organs commonly affected are as follows: fallopian tube (95-100%), endometrium
(50-60%), ovaries (20-30%), cervix (5-15%),
myometrium (2.5%) and vulva/vagina (1%). [2]
Male Genital Tuberculosis (MGTB): It is
predominantly associated with tuberculosis of the
kidney and prostate, seminal vesicle, epididymis,
testes as well as scrotum may occasionally be
affected. In men, the sites most commonly
involved are epididymis, followed by the prostate.
Testicular involvement is less common and
usually is the result of direct extension from the
epididymis. Tubercular prostatitis usually results
from antegrade infection within the urinary tract.
Tuberculous epididymo-orchitis has a considerable effect on fertility, the sperm count and motility may be reduced due
to blockage of the vas and/or secondary atrophy. [2]
Diagnosis of GTB
The diagnostic dilemma arises because of varied clinical presentation of the disease confounded by diverse results on
imaging, laparoscopy, histopathology, bacteriological and serological tests, each of which has its limitation in
diagnostic sensitivity and specificity. Diagnosis of GTB has profound implications for asymptomatic women seeking
fertility.
Endometrial TB
Diagnosis of GTB depends on following:
The sensitivity of endometrial biopsy or curetting in the diagnosis of TB is low
 Clinical Symptomatology
(40%), as the granulomas are often focal and the functionalis layer is shed
 CBC, ESR, RFT, CRP
every four weeks (granulomas take two weeks to develop). So, if suspected,
curettage/biopsy should be performed during the late secretory phase of the
 Chest X-ray
menstrual cycle. In a comparative study of sensitivity of detection of
 Pelvic ultrasound / Hystero-salpingography
genitourinary TB, smear microscopy, histopathological examination,
(HSG).
mycobacterial culture, nucleic acid amplification by PCR, or combination of
 Laparoscopy
culture and PCR were 87.5%, 82.3%, 91.6%, 96.4% and 100%
respectively. While the specificity for the same were as follows, 86.36%,
 Histopathology
84.6%, 88.88%, 100% and 100% respectively [2].
 Microbiology
o Mantoux test
o QTG-T
o AFB microscopy / culture
 Endometrial aspiration / Endometrial biopsy/ Endometrial curettage/ Menstrual blood in
females.
August 15, 2011
o
o
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 Urine – 3 consecutive days
Molecular tests
HIV
Photomicrograph of section of endocervix showing
caseating granulomas and Langhans giant cells admist
chronic inflammatory infiltrate. (H&E 400 X).
Source: Journal of Clinical and Diagnostic Research. 2010
Feb;(4):2083-2086.
Interferon Gamma Release Assays (IGRAs)
IGRA is a coupling of the discovery of antigens ESAT-6 and CFP-10, which
are
relatively specific to M. tuberculosis, and the development of simplified technologies of measuring interferon-gamma
(IFN-g) [4]. IGRAs measure a person’s immune reactivity to M. tuberculosis. White blood cells from most persons that
have been infected with M. tuberculosis will release IFN-g when mixed with antigens derived from M. tuberculosis. They
do not help differentiate latent tuberculosis infection from tuberculosis disease [5]. Two IGRAs approved by the U.S.
Food and Drug Administration (FDA) are:
 QuantiFERON®-TB Gold In-Tube test (QFT-GIT) - measures interferon-g in IU/mL using an enzyme-linked
immunosorbent assay (ELISA).
 T-SPOT®.TB test (T-Spot) - Counts the
cells releasing IFN-G visualized as spots
with
the
enzyme-linkedimmunospot
(ELISPOT) technique.
Clinical Utility:
 Can detect both latent and active
pulmonary and extra-pulmonary cases.
 Useful for screening person who has
symptoms of TB.
 Screening suspected Extra-Pulmonary
tuberculosis eg: GTB
Role of Molecular Methods in Diagnosis of GTB
A definite diagnosis can be made by positive mycobacterial culture and by demonstrating specific histopathological
lesion in the specimen of suspected case of GTB. However, these methods have
low detection rates and limitations as GTB is paucibacillary, also substantial
number of TB lesions of the genital tract are bacteriologically mute. The low rate
of positivity in culture may also be due to the presence of a bacteriostatic
substance which inhibits the growth of the bacilli [7]. Hence, no single test can
stand alone as the diagnostic test for genital tuberculsis.
In recent years, PCR technique has evolved as useful and rapid technique for the diagnosis of pulmonary and extrapulmonary tuberculosis. Any method that is used to diagnose GTB should be highly sensitive to diagnose the disease
reliably in its early stage, so that treatment may improve the prospects of cure, and in females before the tubes are
damaged beyond recovery. Fundamentally all the available molecular tests are based on the principle of PCR.
Advantages:
 High specificity and sensitivity, requires only < 10 bacteria/mL of specimen to achieve a positive report.
 Rapid method, results are available within a day of the DNA being extracted from the specimen.
 Can be applied to sterile fluids like peritoneal fluid where the culture is difficult due to a low bacterial load.
Disadvantages:
 False Negative - absence of even a single AFB in the sample collected, and high salt concentration of a
specimen which interferes with the PCR results.
 False Positive- PCR cannot distinguish between live and hiked bacilli and there is a risk of false positive results.
Depending upon the test requests received at SRL, the following can be a suggested step wise guideline for TB
diagnosis in genital tuberculosis
Clinical suspicion of genital TBSite specific sample for TB-PCRif negative, laparoscopic removal of fluid/tissue
for histopathology and or culture.
August 15, 2011
Innersense Voice 122
Case Study - Tubercular Cervicitis Clinically Mimicking As Carcinoma Cervix
A 38 year old female presented in the gynaecology OPD with the complaint of menometrorrhagia. Her pelvic
examination revealed a friable papillary growth on the cervix. Pap smear revealed a mixed inflammatory infiltrate
along with atypical cells of uncertain origin (ASCUS). A punch biopsy was taken for diagnostic confirmation. The
clinical differentials included neoplastic and viral aetiologies. The histopathological examination revealed
endocervicitis with well formed epithelioid cell granulomas along with Langhans giant cell formation and caseation
necrosis. A provisional diagnosis of tuberculosis of the cervix was made. AFB stain did not reveal any bacilli. Further
investigations were done to rule out any comorbid conditions. A re- biopsy of the growth was done and the tissue was
sent for tubercular polymerase reaction (TB-PCR), which was positive for Mycobacterium tuberculosis. The patient was
started on antitubercular therapy. The growth regressed after four months. A repeat biopsy revealed the absence of
granulomatous inflammation. Till the last follow up, the patient was symptom free [6].
As seen by the above case, diagnosis of GTB is based on collective investigations. Clinical symptomatology,
radiography, and laboratory investigations together aid a physician to come a definitive diagnosis. However, early
diagnosis and early treatment is the key to prevent the aftermath.
Frequently Asked Questions (Endometrial Tuberculosis)
1) What is the clinical utility of TB PCR in Gynecological TB?
Ans. TB PCR aids in confirming the diagnosis of genital TB infection in infertile patients with high
index of suspicion.
2) How do TB PCR correlates with other routine diagnostic methods in Gynecological TB cases?
Ans. Various studies have indicated strong association of endoscopic features of genital TB with positive PCR results in
endometrial specimens. Culture methods have limited detection rate (usually < 10%), and therefore they rarely correlate
with TB PCR. Histopathology have higher detection range than culture methods. However due to secondary nature of the
genital tuberculosis, the infecting organisms are sparse in number or in some cases the sample site may not represent the
infected area or sometimes the cellular changes suggestive of TB may be due to certain pyogenic bacteria. In such
scenarios, correlation between histopathology and PCR is very rare. Recent studies have highlighted that positive TB PCR
results should be given due importance particularly in clinically suspected cases. In presence of positive PCR results,
patients with infertility should be considered as having Genital TB and should be treated.
3) What type of gynecological specimens can be processed for TB PCR, which specimen is preferred?
Ans. Endometrial Biopsies, endometrial aspirate (EA), fluid from the pouch of Douglas (POD), and Menstrual Blood are the
most common specimens. In Gynecological TB, fallopian tube is the initial site of involvement, affected in almost all cases,
followed by endometrium in 50-90% of cases. In as many as 50% of cases infection may be limited to the fallopian tube.
Moreover, due to the cyclical shedding of the endometrium, granulomas do not have enough time to form, so the
endometrium may not show evidence of tuberculosis in all the cycles. However despite these facts, endometrial biopsy is the
preferred specimen for Gyecological TB. Though menstrual blood specimen offers a non-invasive means for diagnosis of
Gynecological TB, presently there is limited evidence on its reliability mainly considering the cyclic shedding of TB bacilli.
Tests offered at SRL
Test
Test
Code
GAMMA INTERFERON
(TBFERON)
2405
TB DETECTION by Microscopy
1122
TB SPECIATION by Microbiology tests
2419ID
TB CULTURE POSITIVE
REFLEX MDR BY PCR
SEQUENCING
9215RFX
Test
Test Code
MYCOBACTERIA SPECIATION by PCRsequencing
AFB SUSCEPTIBILITY,
BACTEC : 10 DRUG PANEL
AFB SUSCEPTIBILITY,
BACTEC : 5 DRUG PANEL
1464R2
AFB SUSCEPTIBILITY,
BACTEC : SIRE PANEL
1490
2402
1464R1
August 15, 2011
References:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Innersense Voice 122
TB MONITORING PANEL
(CBC,ESR,SGPT/SGOT/CRE
ATININE,ANA,AFB SMEAR)
5010
AFB SUSCEPTIBILITY,
BACTEC : SIREP PANEL
5649
TB PANEL (MYCO3 PCR,
ADA, GAMMA INTERFERON)
2440
AFB SUSCEPTIBILITY; MIC
TESTING FOR RAPIDLY
GROWING MYCOBACTERIA
1464RGM
TB PCR (MYCOREAL)
2434
TB-Spot
RD1323
TB PCR (MYCOTECT)
2439
AFB Culture (MGIT 960)
1464EP
MYCO3PLEX (AFB Fluorescent Stain, Culture, PCR)
2435
Puri S, Bansal B. Diagnostic Value of Polymerase Chain Reaction in Female Tuberculosis Leading to Infertility and
Conception Rate After ATT. JK Science Journal of Medical Education and Research. Jan-Mar 2009. Vol. 11(1).
Das P, Ahuja A, and Datta-Gupta S . Incidence, etiopathogenesis and pathological aspects of genitourinary tuberculosis in
India: A journey revisited. Indian J Urol. 2008 Jul-Sep; 24(3): 356–361. doi: 10.4103/0970-1591.42618
Jassawalla MJ. Genital tuberculosis - A diagnostic dilemma. J Obstet Gynecol India Vol. 56, No. 3 : May/June 2006 Pg
203-204
Lange C and Mori T. Advances in the diagnosis of tuberculosis. Respirology (2010) 15, 220–240. doi: 10.1111/j.14401843.2009.01692.x
http://www.cdc.gov/tb/publications/factsheets/testing/IGRA.htm. Updated: July 25, 2011
Bhalla A, Mannan R, Khanna M, Bhasin TS. Tubercular Cervicitis Clinically Mimicking As Carcinoma Cervix: Two Case
Reports. Journal of Clinical and Diagnostic Research. 2010 Feb;(4):2083-2086.
Thangappah R, Paramasivan CN, Narayanan S. Evaluating PCR, culture & histopathology in the diagnosis of female
genital tuberculosis. Indian J Med Res [serial online] 2011 [cited 2011 Aug 11];134:40-6. Available from:
http://www.ijmr.org.in/text.asp?2011/134/1/40/83325
Alan JW, Louis RK, Andrew CN, et al., editors. Campbell-Walsh Urology. 9th ed. New York: Saunders, Elsevier; 2006.
Marjorie PG, Holenarasipur RV. Extrapulmonary tuberculosis: An overview. Am Fam Physician. 2005;72:1761–8