{"id":287,"date":"2023-09-16T22:20:13","date_gmt":"2023-09-16T21:20:13","guid":{"rendered":"https:\/\/microregistrar.com\/?p=287"},"modified":"2023-09-16T22:20:14","modified_gmt":"2023-09-16T21:20:14","slug":"smi-summary-investigation-of-bone-marrow","status":"publish","type":"post","link":"https:\/\/microregistrar.com\/?p=287","title":{"rendered":"SMI Summary: Investigation of bone marrow"},"content":{"rendered":"\n<p>Because it is an invasive procedure, bone marrow biopsy (typically collected from the posterior iliac crest or the sternum) is rarely used. It\u2019s also proposed that it shouldn\u2019t be done on people who are immune-competent.<br>It may be useful in the diagnosis of infection in immunocompromised patients (HIV, transplant patients, or patients on high-dose steroids), caused by a small number of pathogens (listed below).<\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-28f84493 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<p>Some situations where it can be useful are:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>PUO, when other modalities failed to get a diagnosis.<\/li>\n\n\n\n<li>Infection is a differential diagnosis of a haematological abnormality.<\/li>\n<\/ul>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/microregistrar.com\/wp-content\/uploads\/2022\/03\/220px-Bone_marrow_biopsy.jpg\" alt=\"Bone marrow aspirate\" class=\"wp-image-10346\"\/><figcaption class=\"wp-element-caption\">Bone marrow aspirate&nbsp;<em>(Photographer\u2019s Mate 2nd Class Chad McNeeley&nbsp;\u2013&nbsp;<a href=\"http:\/\/www.news.navy.mil\/view_single.asp?id=4416\">Navy News Service<\/a>, 021204-N-0696M-180)<\/em><\/figcaption><\/figure>\n<\/div>\n<\/div>\n\n\n\n<p>The advantage of bone marrow examination over blood culture:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>It can be positive in both acute and chronic infections. Blood culture is usually positive in acute infection only.<\/li>\n\n\n\n<li>It is more likely to be positive in patients who have been treated with antibiotics.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Organisms for which it is useful:<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>ORGANISM<\/th><th>NOTE<\/th><\/tr><\/thead><tbody><tr><td>Salmonella typhi,<br>Salmonella paratyphi<\/td><td>\u2013 Enteric fever is the only bacterial infection for which bone marrow is routinely recommended.<br>\u2013 The culture of bone marrow is considered to be the \u2018gold standard\u2019 method for the diagnosis of typhoid fever. It has higher sensitivity than both blood culture and serology.<\/td><\/tr><tr><td>Brucella species<\/td><td>\u2013 Usual method of investigation: Culture, NAATs and antibody detection (the presence of antibodies is not always indicative of active brucellosis). Recovery from blood is suboptimal.<br>\u2013 Culture of bone marrow (as well as liver tissue and lymph nodes) may improve the recovery rate within a shorter time frame.<\/td><\/tr><tr><td>Mycobacterium species<\/td><td>\u2013 Culture is considered the \u2018gold standard\u2019 method for laboratory diagnosis, however, incubation times may be long.<br>\u2013 Bone marrow culture assists in aiding diagnosis in uncertain cases of disseminated disease, particularly in those with HIV.<\/td><\/tr><tr><td>Fungi<\/td><td>\u2013 Bone marrow investigation can be performed for Visceral Leishmaniasis.<br>\u2013 Splenic puncture is the most sensitive test, but bone marrow examination is safer and has a sensitivity of around 70 \u2013 80%.<br><br>Following presumptive identification using Giemsa stain to detect amastigotes, send the sample to ref lab for confirmation. Rapid diagnostic tests are direct agglutination and immunochromatographic tests (ICT).<br><br>Serological diagnosis is significantly less sensitive in those with advanced HIV coinfection than for HIV-negative individuals. Negative results should not, therefore, be used to rule out a diagnosis in those with HIV.<\/td><\/tr><tr><td>Leishmania species<\/td><td>\u2013 Bone marrow investigation can be performed for Visceral Leishmaniasis.<br>\u2013 Splenic puncture is the most sensitive test, but bone marrow examination is safer and has a sensitivity of around 70 \u2013 80%.<br><br>Following presumptive identification using Giemsa stain to detect amastigotes, send the sample to ref lab for confirmation. Rapid diagnostic tests are direct agglutination and immunochromatographic tests (ICT).<br><br>Serological diagnosis is significantly less sensitive in those with advanced HIV coinfection than for HIV negative individuals. Negative results should not, therefore, be used to rule out a diagnosis in those with HIV.<\/td><\/tr><tr><td>Virus<\/td><td>Viral detection indicates infection but does not necessarily confirm a diagnosis of disease. The clinical significance of a positive bone marrow result is dependent on the immune status of the patient and the disease\/illness under investigation; positive results from bone marrow samples must therefore be interpreted with caution.<br><br>In the immunocompromised, blood serology results may be negative at the onset of clinical disease. If there is a high clinical suspicion of viral infection, but peripheral blood NAATs results are negative, diagnosis may be confirmed by bone marrow examination.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Specimen<\/h2>\n\n\n\n<p>The specimen should be put in blood culture bottles; additional samples can be put in leakproof sterile containers. The sample should be as large as possible but remember \u2013 volumes of &gt;3mL are likely to be contaminated with peripheral blood which may have a dilution effect.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Safety<\/h2>\n\n\n\n<p>If suspecting hazard group 3 organism process in containment level 3 (TB, Salmonella typhi\/paratyphi, dimorphic fungi, Brucella). If not suspecting ACDP category 3 (or 4) organism process at containment level 2 but perform all the procedures inside a safety cabinet. Pay attention to the travel history when processing fungus. Dimorphic fungi may present as yeast in blood culture bottles but @ 28-30 degrees on a subculture plate, they may present as highly infectious mould.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Stain<\/h2>\n\n\n\n<p>Giemsa, Gram and AFB stain, as and when appropriate.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Culture<\/h2>\n\n\n\n<p>Blood culture bottle \u2013 subcultured onto \u2013 blood agar, chocolate agar, FAA and SAB (when suspecting fungus). Brucella may need 5 days of incubation \u2013 check chocolate agar.<br>Investigation for TB, parasites and Viruses, as appropriate (as per respective SMI).<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Identification<\/h2>\n\n\n\n<p>To species level.<br>Methods like MALDI-ToF or NAAT (PCR) are used.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Notification to public health<\/h2>\n\n\n\n<p>Notify if any of the listed organisms are isolated \u2013 https:\/\/www.gov.uk\/guidance\/notifiable-diseases-and-causative-organisms-how-to-report<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Ref:<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/assets.publishing.service.gov.uk\/government\/uploads\/system\/uploads\/attachment_data\/file\/467492\/B_38i2.pdf\" target=\"_blank\" rel=\"noreferrer noopener\">https:\/\/assets.publishing.service.gov.uk\/government\/uploads\/system\/uploads\/attachment_data\/file\/467492\/B_38i2.pdf<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/www.gov.uk\/guidance\/specialist-and-reference-microbiology-laboratory-tests-and-services\">https:\/\/www.gov.uk\/guidance\/specialist-and-reference-microbiology-laboratory-tests-and-services<\/a><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Because it is an invasive procedure, bone marrow biopsy (typically collected from the posterior iliac crest or the sternum) is [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center 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