Point-of-Care Ultrasound Predictors for the Diagnosis of Tuberculosis in HIV-Positive Patients Presenting to an Emergency Center

Comments and Illustrations of Ultrasound Findings in Extrapulmonary Tuberculosis Manifestations

This review describes the appearance of extrapulmonary tuberculosis manifestations in comprehensive and multiparametric ultrasound imaging. The aim is to increase awareness of typical ultrasound findings regarding extrapulmonary tuberculosis, correlate those with pathological features, and facilitate differential diagnosis. Point of care ultrasound protocols can be used as a screening method in high-risk populations, although the negative findings do not exclude tuberculosis. Conversely, the diagnosis of extrapulmonary tuberculosis can never be made using ultrasound alone, as many ultrasound findings in extrapulmonary tuberculosis are non-specific. However, ultrasound-based sampling techniques can significantly facilitate the collection of samples for microbiological or molecular proof of tuberculosis, as well as facilitating the establishment of alternative diagnoses.

Point-of-care ultrasound for tuberculosis and HIV-revisiting the focused assessment with sonography for HIV-associated tuberculosis (FASH) protocol and its differential diagnoses

BACKGROUND

The 'Focused assessment with sonography for HIV-associated tuberculosis' (FASH) protocol has been applied and researched for over a decade in HIV-infected patients with suspected extra-pulmonary tuberculosis. Interpretation of target FASH features may be challenging as they can also indicate alternative opportunistic diseases.

OBJECTIVES

The primary aim of the review was summarizing the accumulated evidence on the diagnostic accuracy of the FASH protocol including description of diagnoses of target FASH features.

SOURCES

Literature was searched using PubMed, Google Scholar, and publications referencing the original FASH publications; data from identified studies were compiled with data from studies identified by a preceding Cochrane review. A meta-analysis was performed based on a generalized linearized mixed model. Data on differential diagnoses were compiled by literature review and retrospective evaluation of clinical data.

CONTENT

We identified ten studies; abdominal target FASH features were most studied. Sensitivity and specificity estimates were 39% (95% CI 25-54) and 89% (95% CI 83-96) for enlarged lymph nodes (ten studies), and 30% (95% CI 16-45%) and 93% (95% CI 89-98%) for hypoechoic spleen lesions (eight studies). In people living with HIV differential diagnoses of target FASH features are multiple and primarily include other opportunistic infections and malignancies such as non-tuberculous mycobacterial infection, bacillary angiomatosis, hepato-splenic brucellosis, meliodiosis, visceral leishmaniasis, invasive fungal infections, and lymphoma as well as Kaposi sarcoma. Ultrasound-guided diagnostic sampling may assist obtention of a definitive diagnosis.

IMPLICATIONS

On the basis of current evidence, although limited by methodology, and personal experience, we recommend basic ultrasound training, including the FASH protocol and ultrasound-guided diagnostic interventions, for all healthcare providers working with people living with HIV in resource-limited settings.

Building Consensus on the Point-of-Care Ultrasound Skills Required for Effective Healthcare Service Delivery at District Hospitals in South Africa: A Delphi Study

BACKGROUND

Despite the widespread availability of ultrasound machines in South African district hospitals, there are no guidelines on the competency in point-of-care ultrasound (POCUS) use required by generalist doctors in this setting. This study aimed to define the required POCUS competencies by means of consensus via the Delphi method.

METHODS

An online Delphi process was initiated in June 2022, using the existing American Academy of Family Physicians' ultrasound curriculum (84 skillsets) as the starting questionnaire. Panelists were selected across the country, including two from district hospitals in each province and two from each academic family medicine department in South Africa (N = 36). In each iterative round, the participants were asked to identify which POCUS skillsets were essential, optional (region-specific), or non-essential for South African district hospitals. This process continued until consensus (>70% agreement) was achieved on all of the skillsets.

RESULTS

Consensus was achieved on 81 of the 84 skillsets after 5 iterative rounds (96.4%), with 3 skillsets that could not achieve consensus (defined as <5% change over more than 2 consecutive rounds). The final consensus identified 38 essential, 28 optional, and 15 non-essential POCUS skillsets for the South African district hospital context.

CONCLUSIONS

The list of essential POCUS skillsets provided by this study highlights the predominance of obstetric- and trauma-based skillsets required for generalist healthcare workers in South African district hospitals. The findings will require priority setting and revalidation prior to their implementation across the country.

Point-of-Care Ultrasound for Tuberculosis Management in Sub-Saharan Africa-A Balanced SWOT Analysis

Point-of-care ultrasound (POCUS) is an increasingly accessible skill, allowing for the decentralization of its use to non-specialist healthcare workers to guide routine clinical decision making. The advent of ultrasound-on-a-chip has transformed the technology into a portable mobile health device. Due to its high sensitivity to detect small consolidations, pleural effusions and sub pleural nodules, POCUS has recently been proposed as a sputum-free likely triage tool for tuberculosis (TB). To make an objective assessment of the potential and limitations of POCUS in routine TB management, we present a Strengths, Weaknesses, Opportunities & Threats (SWOT) analysis based on a review of the relevant literature and focusing on Sub-Saharan Africa (SSA). We idenitified numerous strengths and opportunities of POCUS for TB management e.g.; accessible, affordable, easy to use & maintain, expedited diagnosis, extra-pulmonary TB detection, safer pleural/pericardial puncture, use in children/pregnant women/PLHIV, targeted screening of TB contacts, monitoring TB sequelae, and creating AI decision support. Weaknesses and external threats such as operator dependency, lack of visualization of central lung pathology, poor specificity, lack of impact assessments and data from Sub-Saharan Africa must be taken into consideration to ensure that the potential of the technology can be fully realized in research as in practice.

Resident perception on the impact of point-of-care ultrasound in clinical care at a family medicine training program in Zambia

Background

Patient access to necessary medical imaging in low- and middle-income countries (LMICs) remains a major obstacle, complicating clinician decision-making and compromising patient outcomes.

Methods

We implemented a longitudinal point-of-care ultrasound (POCUS) training program at a new Family Medicine residency in Zambia and subsequently evaluated residents’ perceptions on the impact of POCUS in patient care. Data were documented by the scanning resident via a post-scan survey, which assessed if/how the scan assisted in medical management, and if/how the scan changed that management. The primary endpoint was frequency of scans assisting and changing management. Data were summarized using descriptive statistics.

Results

Over the 1-year study period, 366 patient encounters occurred in which POCUS was utilized, resulting in a total of 542 unique POCUS scans. POCUS assisted in decision-making in 95.6% (350/366) of patient encounters, most commonly by helping to determine a diagnosis. POCUS changed management in 65.8% (235/357) of patient encounters, most commonly leading to a medication change.

Conclusions

Zambian resident physicians perceived POCUS to be very helpful in their clinical decision-making. These data support the need to advance POCUS education at the residency level throughout LMICs, which may be an ideal strategy to promote widespread utilization of POCUS in low-resource settings globally.

A multi-parameter diagnostic clinical decision tree for the rapid diagnosis of tuberculosis in HIV-positive patients presenting to an emergency centre

Background: Early diagnosis is essential to reduce the morbidity and mortality of HIV-associated tuberculosis. We developed a multi-parameter clinical decision tree to facilitate rapid diagnosis of tuberculosis using point-of-care diagnostic tests in HIV-positive patients presenting to an emergency centre. Methods: A cross-sectional study was performed in a district hospital emergency centre in a high-HIV-prevalence community in South Africa. Consecutive HIV-positive adults with ≥1 WHO tuberculosis symptoms were enrolled over a 16-month period. Point-of-care ultrasound (PoCUS) and urine lateral flow lipoarabinomannan (LF-LAM) assay were done according to standardized protocols. Participants also received a chest X-ray. Reference standard was the detection of Mycobacterium tuberculosis using Xpert MTB/RIF or culture. Logistic regressions models were used to investigate the independent association between prevalent microbiologically confirmed tuberculosis and clinical and biological variables of interest. A decision tree model to predict tuberculosis was developed using the classification and regression tree algorithm. Results: There were 414 participants enrolled: 171 male, median age 36 years, median CD4 cell count 86 cells/mm3. Tuberculosis prevalence was 42% (n=172). Significant variables used to build the classification tree included ≥2 WHO symptoms, antiretroviral therapy use, LF-LAM, PoCUS independent features (pericardial effusion, ascites, intra-abdominal lymphadenopathy) and chest X-ray. LF-LAM was positioned after WHO symptoms (75% true positive rate, representing 17% of study population). Chest X-ray should be performed next if LF-LAM is negative. The presence of ≤1 PoCUS independent feature in those with ‘possible or unlikely tuberculosis’ on chest x-ray represented 47% of non-tuberculosis participants (true negative rate 83%). In a prediction tree which only included true point-of-care tests, a negative LF-LAM and the presence of ≤2 independent PoCUS features had a 71% true negative rate (representing 53% of sample). Conclusions: LF-LAM should be performed in all adults with suspected HIV-associated tuberculosis (regardless of CD4 cell count) presenting to the emergency centre.

High sensitivity of ultrasound for the diagnosis of tuberculosis in adults in South Africa: A proof-of-concept study

BACKGROUND

There are limited data on the performance characteristics of ultrasound for the diagnosis of pulmonary tuberculosis in both HIV-positive and HIV-negative persons. The objective of this proof-of-concept study was to determine the sensitivity and specificity of ultrasound for the diagnosis of tuberculosis in adults.

METHODS

Comprehensive thoracic and focused abdominal ultrasound examinations were performed by trained radiologists and pulmonologists on adults recruited from a community multimorbidity survey and a primary healthcare clinic in KwaZulu-Natal Province, South Africa. Sputum samples were systematically collected from all participants. Sensitivity and specificity of ultrasound to detect tuberculosis were calculated compared to a reference standard of i) bacteriologically-confirmed tuberculosis, and ii) either bacteriologically-confirmed or radiologic tuberculosis.

RESULTS

Among 92 patients (53 [58%] male, mean age 41.9 [standard deviation 13.7] years, 49 [53%] HIV positive), 34 (37%) had bacteriologically-confirmed tuberculosis, 8 (9%) had radiologic tuberculosis with negative bacteriologic studies, and 50 (54%) had no evidence of active tuberculosis. Ultrasound abnormalities on either thoracic or abdominal exams were detected in 31 (91%) participants with bacteriologic tuberculosis and 27 (54%) of those without tuberculosis. Sensitivity and specificity of any ultrasound abnormality for bacteriologically-confirmed tuberculosis were 91% (95% confidence interval [CI] 76%-98%) and 46% (95% CI 32%-61%). Sensitivity and specificity of any ultrasound abnormality for either bacteriologically-confirmed or radiologic tuberculosis were 86% (95% CI 71%-95%) and 46% (95% CI 32%-61%). Overall performance did not appear to differ markedly between participants with and without HIV.

CONCLUSION

A comprehensive ultrasound scanning protocol in adults in a high TB burden setting had high sensitivity but low specificity to identify bacteriologically-confirmed tuberculosis.

Chest Imaging in the Diagnosis and Management of Pulmonary Tuberculosis: The Complementary Role of Thoraci Ultrasound

Tuberculosis (TB) is a severe infectious disease that still represents a major cause of mortality and morbidity worldwide. For these reasons, clinicians and radiologists should use all the available diagnostic tools in the assessment of the disease in order to provide precise indications about starting an anti-tubercular treatment and reduce risk of TB transmission and complications especially in developing countries where the disease is still endemic. As TB mycobacteria are mainly transmitted through respiratory droplets, the pulmonary parenchyma is usually the first site of infection. As a result, chest imaging plays a central role in the diagnostic process. Thoracic ultrasound (TUS) is a portable, non-invasive, radiation-free, and cost-contained technology which could be easily available in resource-limited settings. This perspective article focuses on the potential role of TUS in the diagnosis and management of patients with pulmonary TB. Unfortunately, there are still insufficient evidence and too contrasting data to judge TUS as an appropriate diagnostic method for the screening of the disease. Despite this, TUS may have a useful role in identifying pleural and anterior pericardial effusions or in the identification of abscesses of the anterior chest wall and paraspinal collections in low- and middle-income settings. In addition, TUS seems to have a milestone role in guiding minimally invasive interventional procedures, such as placement of chest tubes, drainage of loculated collections, thoracentesis and pericardiocentesis, and percutaneous biopsy of subpleural pulmonary consolidations or pleural plaques.

Demographics and clinical characteristics of hospitalised patients under investigation for COVID-19 with an initial negative SARS-CoV-2 PCR test result

Background

The COVID-19 pandemic is placing abnormally high and ongoing demands on healthcare systems. Little is known about the full effect of the COVID-19 pandemic on diseases other than COVID-19 in the South African setting.

Objective

To describe a cohort of hospitalised patients under investigation for SARS-CoV-2 that initially tested negative.

Methods

Consecutive patients hospitalised at Khayelitsha Hospital from April to June 2020, whose initial polymerase chain reaction test for SARS-CoV-2 was negative were included. Patient demographics, clinical characteristics, ICD-10 (International Statistical Classification of Diseases and Related Health Problems 10th Revision) diagnosis, referral to tertiary level facilities and ICU, and all-cause in-hospital mortality were collected. The 90-day re-test rate was determined and comparisons were made using the χ²-test and the independent samples median test.

Results

Overall, 261 patients were included: median age 39.8 years, 55.6% female (n = 145). Frequent comorbidities included HIV (41.4%), hypertension (26.4%), and previous or current tuberculosis (24.1%). Nine (3.7%) patients were admitted to ICU and 38 (15.6%) patients died. Ninety-three patients (35.6%) were re-tested and 21 (22.6%) were positive for SARS-CoV-2. The top primary diagnoses related to respiratory diseases (n = 82, 33.6%), and infectious and parasitic diseases (n = 62, 25.4%). Thirty-five (14.3%) had a COVID-19 diagnostic code assigned (26 without microbiological confirmation) and 43 (16.5%) had tuberculosis. Older age (p = 0.001), chronic renal impairment (p = 0.03) and referral to higher level of care (all p < 0.001; ICU p = 0.03) were more frequent in those that died.

Conclusion

Patients with tuberculosis and other diseases are still presenting to emergency centres with symptoms that may be attributable to SARS-CoV-2 and requiring admission. Extreme vigilance will be necessary to diagnosis and treat tuberculosis and other diseases as we emerge from the COVID-19 pandemic.

The burden of HIV and tuberculosis on the resuscitation area of an urban district-level hospital in Cape Town

INTRODUCTION

Many patients present to emergency centres with HIV and tuberculosis related emergencies. Little is known about the influence of HIV and tuberculosis on the resuscitation areas of district-level hospitals. The primary objective was to determine the burden of non-trauma patients with HIV and/or tuberculosis presenting to the resuscitation area of Khayelitsha Hospital, Cape Town.

METHODS

A retrospective analysis was performed on a prospectively collected observational database. A randomly selected 12-week sample of data from the resuscitation area was used. Trauma and paediatric (<13 years) cases were excluded. Patient demographics, HIV and tuberculosis status, disease category, investigations and procedures undertaken, disposition and in-hospital mortality were assessed. HIV and tuberculosis status were determined by laboratory confirmation or from clinical records. Descriptive statistics are presented and comparisons were done using the χ2-test or independent t-test.

RESULTS

A total of 370 patients were included. HIV prevalence was 38.4% (n = 142; unknown n = 78, 21.1%), tuberculosis prevalence 13.5% (n = 50; unknown n = 233, 63%), and HIV/tuberculosis co-infection 10.8% (n = 40). HIV and tuberculosis were more likely in younger patients (both p < 0.01) and more females were HIV-positive (p < 0.01). Patients with tuberculosis spend 93 min longer in the resuscitation area than those without (p = 0.02). The acuity of patients did not differ by HIV or tuberculosis status.Infectious-related diseases and diseases of the digestive system occurred significantly more in the HIV-positive group, and endocrine-related diseases and diseases of the nervous system in HIV-negative patients.HIV-positive patients received more abdominal ultrasound examinations (p < 0.01), blood cultures (p < 0.01) and intravenous antibiotics (p < 0.01). In-hospital mortality was 17% and was not influenced by HIV status (p = 0.36) or tuberculosis status (p = 0.29).

CONCLUSION

This study highlights the burden of HIV and tuberculosis on the resuscitation area of a district level hospital. Neither HIV nor tuberculosis status were associated with in-hospital mortality.

A multi-parameter diagnostic clinical decision tree for the rapid diagnosis of tuberculosis in HIV-positive patients presenting to an emergency centre

Background: Early diagnosis is essential to reduce the morbidity and mortality of HIV-associated tuberculosis. We developed a multi-parameter clinical decision tree to facilitate rapid diagnosis of tuberculosis using point-of-care diagnostic tests in HIV-positive patients presenting to an emergency centre. Methods: A cross-sectional study was performed in a district hospital emergency centre in a high-HIV-prevalence community in South Africa. Consecutive HIV-positive adults with ≥1 WHO tuberculosis symptoms were enrolled over a 16-month period. Point-of-care ultrasound (PoCUS) and urine lateral flow lipoarabinomannan (LF-LAM) assay were done according to standardized protocols. Participants also received a chest X-ray. Reference standard was the detection of Mycobacterium tuberculosis using Xpert MTB/RIF or culture. Logistic regressions models were used to investigate the independent association between prevalent microbiologically confirmed tuberculosis and clinical and biological variables of interest. A decision tree model to predict tuberculosis was developed using the classification and regression tree algorithm. Results: There were 414 participants enrolled: 171 male, median age 36 years, median CD4 cell count 86 cells/mm3. Tuberculosis prevalence was 42% (n=172). Significant variables used to build the classification tree included ≥2 WHO symptoms, antiretroviral therapy use, LF-LAM, PoCUS independent features (pericardial effusion, ascites, intra-abdominal lymphadenopathy) and chest X-ray. LF-LAM was positioned after WHO symptoms (75% true positive rate, representing 17% of study population). Chest X-ray should be performed next if LF-LAM is negative. The presence of ≤1 PoCUS independent feature in those with ‘possible or unlikely tuberculosis’ on chest x-ray represented 47% of non-tuberculosis participants (true negative rate 83%). In a prediction tree which only included true point-of-care tests, a negative LF-LAM and the presence of ≤2 independent PoCUS features had a 71% true negative rate (representing 53% of sample). Conclusions: LF-LAM should be performed in all adults with suspected HIV-associated tuberculosis (regardless of CD4 cell count) presenting to the emergency centre.