Anatomical Pathology

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Browsing Anatomical Pathology by Subject "AIDS"

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    The contribution of fine needle aspiration biopsy in the diagnosis of Mycobacterial Lymphadenopathy with particular reference to children
    (Stellenbosch : University of Stellenbosch, 2009-12) Wright, Colleen Anne; Warren, R. M.; Marais, B. J.; University of Stellenbosch. Faculty of Health Sciences. Dept. of Pathology. Anatomical Pathology.
    ENGLISH ABSTRACT: Expediting a diagnosis of tuberculosis in children, particularly those who are immunocompromised due to HIV/AIDS, is essential, as they are vulnerable to develop severe forms of disease due to their immature or compromised immune systems. A significant percentage of children (8 to 10%) with TB have TB lymphadenitis, in isolation, or in combination with other disease manifestations. Fine needle aspiration biopsy (FNAB) is a simple and minimally invasive procedure well tolerated by children. It may be performed as an outpatient procedure by clinicians as well as nurses, and excellent results can be achieved with training in the correct procedure. The aim of this dissertation was to demonstrate that FNAB may contribute significantly to the diagnosis of mycobacterial lymphadenitis, with particular reference to children TB suspects. We first established that TB lymphadenitis is a common clinical problem in children in TB endemic areas and that FNAB is an efficient simple and effective diagnostic modality in children with peripheral lymphadenopathy. We then proceeded to document the diagnostic yield and time to diagnosis of FNAB compared to conventional laboratory specimens collected in children. We investigated the value of additional diagnostic modalities such as autofluorescence in improving the ability of cytology to make a definitive diagnosis of mycobacterial infection based on cytomorphology and identification of the organism. In countries where organisms such as Mycobacterium bovis BCG and nontuberculous mycobacteria are prevalent, culture with subsequent speciation is essential. The amount of material harvested during FNAB is minuscule, and requires immediate bedside inoculation for optimal yields. We developed an inexpensive and effective transport medium to facilitate mycobacterial culture from FNAB, even if this is collected at an outside facility. It is ideally suited for use in clinics and rural hospitals as it is stable at room temperature, maintains viability of the organism for seven days, and the closed lid format reduces contamination. Mycobacterial culture even using liquid-based media, takes up to 6 weeks, and this delay is unacceptable particularly in children. We developed a Nucleic Acid Amplification Technique (NAAT) using High Resolution Melt Analysis and applied this novel technique to FNAB specimens submitted in transport medium. Although sensitivity remained suboptimal, the technique is highly specific, simple and rapid. Its use could be incorporated into routine microbiology laboratories, to assist with rapid diagnosis while cultures are pending. We collected a solid body of evidence, which will promote the use of FNAB in suspected mycobacterial lymphadenopathy, particularly in children in resource-limited countries. The utilisation of the diagnostic methods identified will expedite speciation and allow early and appropriate initiation of therapy. This is in keeping with Millennium Development Goal 6: to combat TB by early detection of new cases and effective treatment.