The contribution of the placenta to the diagnosis of congenital tuberculosis

Rabie, Ursula (2014-04)

Thesis (MMed)--Stellenbosch University, 2014.

Thesis

ENGLISH ABSTRACT: The aim of this pilot project was to determine whether mothers with laboratory confirmed or clinically suspected tuberculosis (TB) had evidence of TB in the placenta. A secondary objective was to correlate evidence of placental TB with neonatal outcome. A total of 56 placentas were examined to determine if there were any specific histopathological features predictive of tuberculosis together with Ziehl-Neelsen (ZN) staining. A total of 30 cases were positive for maternal TB and one case was a false positive maternal diagnosis of TB, whilst 25 cases were negative for maternal TB. Biopsies from these 56 placentas were collected for conventional PCR from the paraffin embedded tissue blocks. The performance of these two diagnostic modalities (histopathology and PCR) was assessed coll ectively and individually, and compared to the neonatal outcome (presence or absence of active clinical mycobacterial tuberculosis infection) and evidence of maternal pulmonary and extra pulmonary tuberculosis. The recognition of specific sites of lesions in the placenta (e.g. membranes vs. intervillous space) may lead to an understanding of the pathogenic mechanisms involved in matern alfetal transmission of tuberculosis, and thereby pave the way for further studies in understanding the pathogenesis of congenital TB. Invaluable knowledge was obtained in the diagnoses of M.tuberculosis in the placenta as it was found that micro abscesses and intervillositis were strong indicators of TB infection in the placenta, however, ZN staining still remains the gold standard for diagnosing M.tuberculosis infection in the placenta. PCR is found to have limitations, because only M.tuberculosis DNA is amplified and does not distinguish live from dead bacteria. The conclusion reached is that PCR is of limited value in the diagnosis of active M.tuberculosis infection in the placenta using FFPE tissue, while certain histological changes may be indicative of such infection; however confirmation of the organism by ZN staining is still essential.

AFRIKAANSE OPSOMMING: Die hoofdoelwit van hierdie projek was om vas te stel of moeders met bevestigde of vermoedelike TB enige indikasie van TB in die plasenta toon. ‘n Tweede doelwit was om die neonatale uitkoms teenoor die plasentale TB te korreleer. ‘n Totale getal van 56 plasentas is ondersoek om vas te stel of daar enige spesifieke histopatologiese indikasies is van tuberkulose met die hulp van die ZN spesiale kleuring. Die totale getal positiewe vir TB was 30 asook ‘n vals positiewe geval vir TB en daar was 25 TB negatiewe gevalle. Ses en vyftig biopsies is versamel van paraffien in gebedteerde weefsel vir die gebruik in PKR. Die uitvoering van hierdie twee diagnostiese modaliteite is elk individueel ondersoek asook gesamentlik om dit te vergelyk met die neonatale uitkoms (m.a.w die teenwoordigheid of aanwesigheid van mikobakteriale tuberkulose infeksie) asook die teenwoordigheid van moederlike pulmunere en ekstra-pulmunere tuberkulose. Die spesifieke ligging van die letsels in die plasenta (bv. membrane vs. intervillus spasie) kan lei tot verbeterde begrip van die patogeniese meganismes betrokke in die moeder fetale oordrag van tuberkulose en dit kan lei tot toekomstige navorsing. Waardevolle kennis is opgedoen in die diagnose van M.tuberkulose in die plasenta, want die letsels van mikro abbesses en intervillisitus gee ‘n goeie aanduiding van TB infeksie in die plasenta. Die ZN kleuring bly nog steeds die standaard metode om M.tuberculose in die plasenta te diagnoseer. PKR het baie limiete want dit kan slegs die M.tuberkulose DNA vermeningvuldig, maar dit kan nie onderskeid tref tussen lewendige en dooie bakterie nie. The slotsom in hierdie projek is dat PKR ‘n be pperkte waarde het in die diagnose van aktiewe M .tuberkulose in die plasenta, deur die gebruik van formalien gefikseerde paraffien ingebedteerde weefsel nie terwyl sekere histologiese veranderinge ‘n aa nduiding van sodanige infeksie kan wees maar dat dit deur die spesiale kleruring (ZN) bevestig moet word.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/86623
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