A new understanding of clinical patterns in post-TB lung disease

BACKGROUND

Post-TB lung disease (PTLD) can be categorised based on physiological, radiological, and clinical abnormalities, delineating distinct clinical patterns; however, thus far the importance of this is unknown. People with PTLD have a high morbidity and increased mortality, but predictors of long-term outcomes are poorly understood.

METHODS

We conducted an observational study of PTLD patients attending a tertiary hospital in South Africa between 1 October 2021 and 30 September 2022. Patient demographics, risk factors, symptoms, lung function tests and outcomes were captured.

RESULTS

A total of 185 patients were included (mean age: 45.2 years, SD ±14.3). Half of patients reported only one previous episode of Mycobacterium tuberculosis infection (n = 94, 50.8%). There was a statistically significant association between TB-associated obstructive lung disease (OLD) and dyspnoea (P = 0.002), chest pain (P = 0.014) and smoking (P = 0.005). There were significant associations between haemoptysis and both cavitation (P = 0.015) and fungal-associated disease (P < 0.001). Six patients (3.2%) died by study end.

CONCLUSION

PTLD can affect young people even with only one previous episode of TB, and carries a high mortality rate. For the first time, clinical patterns have been shown to have meaningful differences; TB-related OLD is associated with dyspnoea, chest pain and smoking; while haemoptysis is associated with cavitary and fungal-associated disease..

An outbreak within an outbreak: The impact of Infection Prevention and Control strategies on hospital-acquired infections and the occurrence of multi-drug resistant organisms during the COVID-19 pandemic

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic placed an unprecedented strain on intensive care units (ICUs) in South Africa. Infection prevention and control (IPC) strategies were highlighted to minimise the risk to healthcare workers and for the protection of patients from contracting hospital-acquired infections (HAIs). During the third wave, our institution adopted a shift system to address severe burnout among ICU personnel. We noted an upstroke in the occurrence of HAIs, specifically carbapenem-resistant Enterobacterales (CRE) and multidrug-resistant (MDR) Acinetobacter baumannii.

OBJECTIVES

To report these outbreaks, compare the rate of CRE and A. baumannii infections with the first COVID-19 wave and to analyse its impact on patient outcomes.

METHOD

We retrospectively analysed data from a prospectively collected registry involving all adult patients with severe COVID-19 admitted to the dedicated COVID-19 ICU from May 2021 to September 2021. Information from the admission database, including the patients' demographics, comorbidities, laboratory results and length of ICU stay were extracted.

RESULTS

Ninety patients were admitted with severe COVID-19 during the third wave. There was an outbreak of both CRE (the majority Klebsiella pneumoniae) and A. baumannii. Furthermore, 18 patients cultured the same CRE organism, and 25 patients cultured the environmental organism A. baumannii. The HAI rate was significantly higher compared with the first wave published data: 59/90 (65.6%) v. 73/363 (20.1%, p<0.01). Patients with any HAI had a longer mean stay in ICU (10.1 days v. 6.7 days (p<0.01) and a higher mortality of 48/59 (81%) v. 19/31 (61%) (p=0.05).

CONCLUSION

We observed a very significant rise in HAIs in the COVID-19 ICU during the third wave compared with the first, with almost three times as many patients developing HAIs. Unsurprisingly, it was associated with a longer mean stay in ICU and a higher mortality. The outbreak of both CRE and A. baumannii, and the fact that many patients cultured the same CRE organism and A. baumannii, strongly suggests that a critical breakdown in IPC measures had occurred.

Pulmonary hypertension in adults completing tuberculosis treatment

Background

Pulmonary hypertension (PH) after tuberculosis (TB) is typically not included among the chronic lung diseases causing PH (group 3 PH), with few data available to support the inclusion.

Objectives

To determine the prevalence of PH in an adult population completing TB treatment.

Methods

This single-centre, cross-sectional study only included patients with their first documented episode of TB, and who were in the second half of treatment or had recently completed treatment. PH was assessed using transthoracic echocardiography. Questionnaires were completed, and spirometry and a 6-minute walk test were performed.

Results

One hundred patients were enrolled, with a mean age of 37.1 years, of whom 58% were male and 46% HIV positive. The median time since initiation of TB treatment was 22 weeks. The mean (standard deviation) measured right ventricular systolic pressure (RVSP) was 23.6 (6.24) mmHg. One participant had PH (defined as RVSP ≥40 mmHg; 95% confidence interval (CI) 0.0 - 3.0) and a further 3 had possible PH (RVSP ≥35 and <40 mmHg), with a combined PH prevalence of 4% (95% CI 0.2 - 7.8). Airflow obstruction on spirometry was found in 13.3% of 98 patients, while 25.5% had a reduced forced vital capacity. There was no association between RVSP or PH/possible PH and sex, age, HIV status, systemic hypertension, spirometry measurements or 6-minute walking distance. Smoking status was associated with RVSP, but not with the presence of PH/possible PH.

Conclusion

There was a significant prevalence of PH in this preliminary study of predominantly young patients completing treatment for a first episode of TB. Larger and more detailed studies are warranted.

Study synopsis

What the study adds. Of 100 adult patients with their first episode of tuberculosis (TB) who underwent echocardiograms near the end of treatment completion to determine the prevalence of pulmonary hypertension (PH), 1 (1%) had PH and a further 3 (3%) had possible PH. There was no association between sex, age, HIV status, lung function or 6-minute walking distance and the presence of PH. The study adds to the growing awareness of the association of TB with pulmonary vascular disease. It shows that even in a young population with a first episode of TB treated in an ambulatory setting, there is a significant prevalence of PH on treatment completion.Implications of the findings. Given that 10.6 million people acquire TB annually, the absolute global burden of cases with PH is likely to be high, but is underappreciated to date. Further work is urgently needed in this field.

Chronic thromboembolic pulmonary hypertension: More options, more awareness

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The effect of inhaled nitric oxide on shunt fraction in mechanically ventilated patients with COVID-19 pneumonia

Background

Studies in patients with severe acute respiratory distress syndrome (ARDS) with refractory hypoxaemia suggest that inhaled nitric oxide (iNO) can be added to ventilatory strategies as a potential bridge to clinical improvement. However, the potential role of iNO as a management strategy in severe COVID-19 pneumonia remains unclear. The authors describe their clinical findings of using iNO for severe COVID-19 pneumonia in 10 patients with refractory hypoxaemia in a tertiary respiratory intensive care unit. The results showed an improvement in shunt fraction, P/F ratio, PaO2 and arterial oxygen saturation but the improvements did not translate into a mortality benefit. This report adds to the current body of literature indicating that the correct indications, timing, dose and duration of iNO therapy and how to harness its pleiotropic effects still remain to be elucidated.

What the study adds

This brief report adds to the body of literature exploring the potential use of inhaled nitric oxide as a management strategy in patients with severe COVID-19 pneumonia with refractory hypoxaemia.

What are the implications of the findings

The findings of the report shows that there is a beneficial role of using inhaled nitric oxide to improve respiratory parameters, but that it does not translate to a mortality benefit. It adds to the investigation of establishing which patients, the duration and at what dose, inhaled nitric oxide should be used to gain maximum benefit for this subgroup of patients.

Performance of spirometry assessment at TB diagnosis

BACKGROUND: Spirometry is considered relevant for the diagnosis and monitoring of post-TB lung disease. However, spirometry is rarely done in newly diagnosed TB patients.METHODS: Newly diagnosed, microbiologically confirmed TB patients were recruited for the study. Spirometry was performed within 21 days of TB treatment initiation according to American Thoracic Society/European Respiratory Society guidelines. Spirometry analysis was done using Global Lung Initiative equations for standardisation.RESULTS: Of 1,430 eligible study participants, 24.7% (353/1,430) had no spirometry performed mainly due to contraindications and 23.0% (329/1,430) had invalid results; 52.3% (748/1,430) of participants had a valid result, 82.8% (619/748) of whom had abnormal spirometry. Of participants with abnormal spirometry, 70% (436/619) had low forced vital capacity (FVC), 6.1% (38/619) had a low ratio of forced expiratory volume in 1 sec (FEV1) to FVC, and 19.1% (118/619) had low FVC, as well as low FEV1/FVC ratio. Among those with abnormal spirometry, 26.3% (163/619) had severe lung impairment.CONCLUSIONS: In this population, a high proportion of not performed and invalid spirometry assessments was observed; this was addressed by removing tachycardia as a (relative) contraindication from the study guidance and retraining. The high proportion of patients with severe pulmonary impairment at the time of TB diagnosis suggests a huge morbidity burden and calls for further longitudinal studies on the relevance of spirometry in predicting chronic lung impairment after TB.

Issues in Medicine

Rasmussen aneurysms are abnormalities of the pulmonary arterial system caused by tuberculosis (TB). They are associated with a highmortality rate when they cause life-threatening haemoptysis. High TB-prevalence regions have a large burden of TB-related haemoptysisbut often limited resources. This series of 25 patients who presented with life-threatening haemoptysis from current and/or previous TBwere found to have abnormal pulmonary arteries on computed tomography pulmonary angiogram (CTPA), which were judged to belikely contributors to their bleeding, either in isolation or with concomitant abnormal bronchial or systemic vasculature. These patientsunderwent transcatheter placement of Amplatzer vascular plugs in the feeder pulmonary artery. Bronchial and systemic lesions wereaddressed separately as needed. Immediate technical success was achieved in all patients, but four of them experienced intraoperativehaemoptysis related to dislodgement of the occluding platelet plug by the high-pressure automatic injector and wire. At 48 hours after theprocedure, 18 (72%) remained haemoptysis-free. Six of these experienced recurrence within 1 year of their procedure. Pulmonary arteryplacement of an Amplatzer vascular plug is a feasible option for treating bleeding Rasmussen aneurysms, but should be part of a combinedapproach to addressing suspected culprit vascular lesions in all intrathoracic vascular systems.

Immunologic and imaging signatures in post tuberculosis lung disease

Post Tuberculosis Lung Disease (PTLD) affects millions of tuberculosis survivors and is a global health burden. The immune mechanisms that drive PTLD are complex and have historically been under investigated. Here, we discuss two immune-mediated paradigms that could drive human PTLD. We review the characteristics of a fibrotic granuloma that favors the development of PTLD via an abundance of T-helper-2 and T-regulatory cells and an upregulation of TGF-β mediated collagen deposition. Next, we discuss the post-primary tuberculosis paradigm and the complex mixture of caseous pneumonia, cavity formation and fibrosis that can also lead to PTLD. We review the delicate balance between cellular subsets and cytokines of the innate and adaptive immune system in conjunction with host-derived proteases that can perpetuate the parenchymal lung damage seen in PTLD. Next, we discuss the role of novel host directed therapies (HDT) to limit the development of PTLD and in particular, the recent repurposing of established medications such as statins, metformin and doxycycline. Finally, we review the emerging role of novel imaging techniques as a non-invasive modality for the early recognition of PTLD. While access to computed tomography imaging is unlikely to be available widely in countries with a high TB burden, its use in research settings can help phenotype PTLD. Due to a lack of disease-specific biomarkers and controlled clinical trials, there are currently no evidence-based recommendations for the management of PTLD. It is likely that an integrated antifibrotic strategy that could simultaneously target inflammatory and pro-fibrotic pathways will probably emerge as a successful way to treat this complex condition. In a disease spectrum as wide as PTLD, a single immunologic or radiographic marker may not be sufficient and a combination is more likely to be a successful surrogate that could aid in the development of successful HDTs.

Correlation between lung function tests and peak oxygen consumption in post-TB lung disease

BACKGROUND: After TB treatment, many patients have post-TB lung disease (PTLD), associated with increased mortality and morbidity. Nevertheless, relationships between lung function testing and exercise capacity in people with PTLD are poorly understood.METHODS: This single-centre study investigated the association between lung function testing and peak oxygen consumption (VO₂peak) and percentage-predicted VO₂peak (VO₂peak (%pred)) in adults with PTLD investigated for surgery.RESULTS: Eighty-two patients (52 males, 30 females) with a mean age of 43.2 years (SD 11.3) were included. Spirometric values of forced vital capacity (FVC) percentage predicted (%pred) and forced expiratory volume in 1 sec (FEV₁) %pred suggested significant correlations with VO₂peak (%pred) (P < 0.001 and P < 0.001), whereas FEV₁/FVC did not. Diffusing capacity for carbon monoxide (DL_CO) %pred also correlated significantly with VO₂peak (%pred) (P = 0.002). However, the magnitude of all significant correlation coefficients were weak. No significant correlations for any plethysmographic values with VO₂peak (%pred) could be robustly concluded. Correlations with VO₂peak (ml/kg/min) for most physiological variables were less robust than for VO₂peak (%pred).CONCLUSIONS: Although statistically significant, the correlations between any measure of lung function and VO₂peak or VO₂peak (%pred) were weak, with only FVC correlation coefficient surpassing 0.50.

Position statement for adult and paediatric spirometry in South Africa: 2022 update

Spirometry is required as part of the comprehensive evaluation of both adult and paediatric individuals with suspected or confirmed respiratory diseases and occupational assessments. It is used in the categorisation of impairment, grading of severity, assessment of potential progression and response to interventions. Guidelines for spirometry in South Africa are required to improve the quality, standardisation and usefulness in local respiratory practice. The broad principles of spirometry have remained largely unchanged from previous versions of the South African Spirometry Guidelines; however, minor adjustments have been incorporated from more comprehensive international guidelines, including adoption of the Global Lung Function Initiative 2012 (GLI 2012) spirometry reference equations for the South African population. All equipment should have proof of validation regarding resolution and consistency of the system. Daily calibration must be performed, and equipment quality control processes adhered to. It is important to have standard operating procedures to ensure consistency and quality and, additionally, strict infection control as highlighted during the COVID-19 pandemic. Adequate spirometry relies on a competent, trained operator, accurate equipment, standardised operating procedures, quality control and patient co-operation. All manoeuvres must be performed strictly according to guidelines, and strict quality assurance methods should be in place, including acceptability criteria (for any given effort) and repeatability (between efforts). Results must be categorised and graded according to current guidelines, taking into consideration the indication for the test.

Comparison of patients with severe COVID-19 admitted to an intensive care unit in South Africa during the first and second wave of the COVID-19 pandemic

Background

The second wave of coronavirus disease 2019 (COVID-19), dominated by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Beta variant, has been reported to be associated with increased severity in South Africa (SA).

Objectives

To describe and compare clinical characteristics, management and outcomes of COVID-19 patients admitted to an intensive care unit (ICU) in SA during the first and second waves.

Methods

In a prospective, single-centre, descriptive study, we compared all patients with severe COVID-19 admitted to ICU during the first and second waves. The primary outcomes assessed were ICU mortality and ICU length of stay (LOS).

Results

In 490 patients with comparable ages and comorbidities, no difference in mortality was demonstrated during the second compared with the first wave (65.9% v. 62.5%, p=0.57). ICU LOS was longer in the second wave (10 v. 6 days, p<0.001). More female admissions (67.1% v. 44.6%, p<0.001) and a greater proportion of patients were managed with invasive mechanical ventilation than with non-invasive respiratory support (39.0% v. 14%, p<0.001) in the second wave.

Conclusion

While clinical characteristics were comparable between the two waves, a higher proportion of patients was invasively ventilated and ICU stay was longer in the second. ICU mortality was unchanged.

A position statement and practical guide to the use of particulate filtering facepiece respirators (N95, FFP2, or equivalent) for South African health workers exposed to respiratory pathogens including Mycobacterium tuberculosis and SARS-CoV-2

SUMMARY

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is transmitted mainly by aerosol in particles <10 µm that can remain suspended for hours before being inhaled. Because particulate filtering facepiece respirators ('respirators'; e.g. N95 masks) are more effective than surgical masks against bio-aerosols, many international organisations now recommend that health workers (HWs) wear a respirator when caring for individuals who may have COVID-19. In South Africa (SA), however, surgical masks are still recommended for the routine care of individuals with possible or confirmed COVID-19, with respirators reserved for so-called aerosol-generating procedures. In contrast, SA guidelines do recommend respirators for routine care of individuals with possible or confirmed tuberculosis (TB), which is also transmitted via aerosol. In health facilities in SA, distinguishing between TB and COVID-19 is challenging without examination and investigation, both of which may expose HWs to potentially infectious individuals. Symptom-based triage has limited utility in defining risk. Indeed, significant proportions of individuals with COVID-19 and/or pulmonary TB may not have symptoms and/or test negative. The prevalence of undiagnosed respiratory disease is therefore likely significant in many general clinical areas (e.g. waiting areas). Moreover, a proportion of HWs are HIV-positive and are at increased risk of severe COVID-19 and death.

RECOMMENDATIONS

Sustained improvements in infection prevention and control (IPC) require reorganisation of systems to prioritise HW and patient safety. While this will take time, it is unacceptable to leave HWs exposed until such changes are made. We propose that the SA health system adopts a target of 'zero harm', aiming to eliminate transmission of respiratory pathogens to all individuals in every healthcare setting. Accordingly, we recommend: the use of respirators by all staff (clinical and non-clinical) during activities that involve contact or sharing air in indoor spaces with individuals who: (i) have not yet been clinically evaluated; or (ii) are thought or known to have TB and/or COVID-19 or other potentially harmful respiratory infections;the use of respirators that meet national and international manufacturing standards;evaluation of all respirators, at the least, by qualitative fit testing; andthe use of respirators as part of a 'package of care' in line with international IPC recommendations. We recognise that this will be challenging, not least due to global and national shortages of personal protective equipment (PPE). SA national policy around respiratory protective equipment enables a robust framework for manufacture and quality control and has been supported by local manufacturers and the Department of Trade, Industry and Competition. Respirator manufacturers should explore adaptations to improve comfort and reduce barriers to communication. Structural changes are needed urgently to improve the safety of health facilities: persistent advocacy and research around potential systems change remain essential.

The burden and determinants of post-TB lung disease

BACKGROUND: Post-TB lung disease (PTLD) is an important but under-recognised chronic respiratory disease in high TB burden settings such as Tanzania.METHODS: This was a cross-sectional survey of adults within 2 years of completion of TB treatment in Kilimanjaro, Tanzania. Data were collected using questionnaires (symptoms and exposures), spirometry and chest radiographs to assess outcome measures, which were correlated with daily life exposures, including environment and diet.RESULTS: Of the 219 participants enrolled (mean age: 45 years ± 10; 193 88% males), 98 (45%) reported chronic respiratory symptoms; 46 (22%) had received treatment for TB two or more times; and HIV prevalence was 35 (16%). Spirometric abnormalities were observed in 146 (67%). Chest X-ray abnormalities occurred in 177 (86%). A diagnosis of PTLD was made in 200 (91%), and half had clinically relevant PTLD. The prevalence of mMRC ≥Grade 3 chronic bronchitis and dyspnoea was respectively 11% and 26%. Older age, multiple episodes of TB and poverty indicators were linked with clinically relevant PTLD.CONCLUSIONS: We found a substantial burden of PTLD in adults who had recently completed TB treatment in Tanzania. There is a pressing need to identify effective approaches for both the prevention and management of this disease.

Bacterial infection, antibiotic use and COVID-19: Lessons from the intensive care unit

BACKGROUND

Empirical broad-spectrum antibiotics are frequently prescribed to patients with severe COVID-19, motivated by concern about bacterial coinfection. There is no evidence of benefit from such a strategy, while the dangers of inappropriate antibiotics are well described.

OBJECTIVES

To investigate the frequency, profile and related outcomes of infections by bacterial pathogens in patients admitted to an intensive care unit (ICU) with severe COVID-19 pneumonia.

METHODS

This was a prospective, descriptive study in a dedicated COVID-19 ICU in Cape Town, South Africa, involving all adult patients admitted to the ICU with confirmed COVID-19 pneumonia between 26 March and 31 August 2020. We collected data on patient comorbidities, laboratory results, antibiotic treatment, duration of admission and in-hospital outcome.

RESULTS

We included 363 patients, who collectively had 1 199 blood cultures, 308 tracheal aspirates and 317 urine cultures performed. We found positive cultures for pathogens in 20 patients (5.5%) within the first 48 hours of ICU admission, while 73 additional patients (20.1%) had positive cultures later during their stay. The most frequently isolated pathogens at all sites were Acinetobacter baumannii (n=54), Klebsiella species (n=13) and coagulase-negative staphylococci (n=9). Length of ICU stay (p&lt;0.001) and intubation (p&lt;0.001) were associated with positive cultures on multivariate analysis. Disease severity (p=0.5), early antibiotic use (p=0.5), diabetes mellitus (p=0.1) and HIV (p=0.9) were not associated with positive cultures. Positive cultures, particularly for tracheal aspirates (p&lt;0.05), were associated with longer ICU length of stay and mortality. Early empirical antibiotic use was not associated with mortality (odds ratio 2.5; 95% confidence interval 0.95 - 6.81).

CONCLUSIONS

Bacterial coinfection was uncommon in patients at the time of admission to the ICU with severe COVID-19. Avoiding early empirical antibiotic therapy is therefore reasonable. Strategies to avoid coinfection and outbreaks in hospital, such as infection prevention and control, as well as the strict use of personal protective equipment, are important to improve outcomes.

Corticosteroids in critical COVID-19: Are all corticosteroids equal?

The hyperinflammation seen as part of a dysregulated immune response to SARS-CoV-2 in its most severe form leads to acute respiratory distress syndrome (ARDS), multiorgan failure and death. Corticosteroid therapy targets this hyperinflammation, otherwise known as a cytokine storm. It is the only therapeutic agent to date with a mortality benefit, with clear guidelines from national and international health authorities guiding its use. Objectives. To compare severity-of-illness indices, survival, length of intensive care unit (ICU) stay and potential ICU complications in patients treated with different corticosteroid regimens (high-dose hydrocortisone, high-dose methylprednisolone and lower-dose dexamethasone). Methods. In this single-centre descriptive retrospective observational study of a cohort of patients with severe COVID-19 admitted to a COVID-dedicated ICU, we compared patients treated with the three different corticosteroid regimens. Results. In 242 cases we could not demonstrate any statistically or clinically significant difference in the outcome of patients with critical COVID-19 treated with high-dose intravenous hydrocortisone (n=88) or methylprednisolone (n=46) compared with a relatively lower dose of dexamethasone (n=108). The survival rates were 38.6%, 39.1% and 33.3%, respectively (p=0.68). Patients treated with methylprednisolone tended to have a shorter length of ICU stay (median (interquartile range) 6 (4 - 10), 4 (2 - 8) and 5 (2 - 8) days; p=0.015) and fewer episodes of nosocomial sepsis (47.7%, 32.6% and 48.1%; p=0.01). Conclusions. Hydrocortisone or methylprednisolone can be given as an alternative to dexamethasone in the management of critical COVID-19, and this is a feasible alternative, especially in resource-constrained settings.

Persistent chronic respiratory symptoms despite TB cure is poorly correlated with lung function

BACKGROUND: Persistent respiratory symptoms and lung function deficits are common after patients with TB. We aimed to define the burden of post-TB lung disease (PTLD) and assess associations between symptoms and impairment in two high TB incidence communities.METHODS: This was a cross-sectional survey of adults in Cape Town, South Africa who completed TB treatment 1-5 years previously. Questionnaires, spirometry and 6-minute walking distance (6MWD) were used to assess relationships between outcome measures and associated factors.RESULTS: Of the 145 participants recruited (mean age: 42 years, range: 18-75; 55 [38%] women), 55 (38%) had airflow obstruction and 84 (58%) had low forced vital capacity (FVC); the mean 6MWD was 463 m (range: 240-723). Respiratory symptoms were common: chronic cough (n = 27, 19%), wheeze (n = 61, 42%) and dyspnoea (modified MRC dyspnoea score 3 or 4: n = 36, 25%). There was poor correlation between FVC or obstruction and 6MWD. Only low body mass index showed consistent association with outcomes on multivariable analyses. Only 19 (13%) participants had a diagnosis of respiratory disease, and 16 (11%) currently received inhalers.CONCLUSION: There was substantial burden of symptoms and physiological impairment in this "cured" population, but poor correlation between objective outcome measures, highlighting deficits in our understanding of PTLD.

COVID-19 and the renin-angiotensin system (RAS): A spark that sets the forest alight?

The coronavirus disease 2019 (COVID-19) pandemic has increased exponentially in numbers with more than 20 million people infected around the globe. It is clear that COVID-19 is not a simple viral pneumonia, but presents with unusual pathophysiological effects. Of special interest is that SARS-CoV-2 utilises the angiotensin-converting enzyme-2 (ACE2) for cell entry and therefore has a direct effect on the renin angiotensin system (RAS). The RAS is primarily responsible for blood pressure control via the classic pathway. Recently numerous other pathological processes have been described due to stimulation of this classic pathway. There is also a protective RAS pathway medicated by ACE2 which may be suppressed in COVID-19. This leads to overstimulation of the classic pathway with adverse cardiovascular and respiratory effects, hypercoagulation, endothelial dysfunction, inflammation and insulin resistance. We hypothesize that overreaction of the renin-angiotensin-aldosterone may account for the myriad of unusual biochemical and clinical abnormalities noted in patients infected with SARS-CoV-2.

Post-tuberculosis lung health: perspectives from the First International Symposium

ALTHOUGH CURABLE, TB frequently leaves the individual with chronic physical and psycho-social impairment, but these consequences have been largely neglected. The 1^st International Post-Tuberculosis Symposium (Stellenbosch, South Africa) was held to discuss priorities and gaps in addressing this issue. A barrier to progress has been the varied terminology and nomenclature, so the Delphi process was used to achieve consensus on definitions. Lack of sufficient evidence hampered definitive recommendations in most domains, including prevention and treatment of post-TB lung disease (PTLD), but the discussions clarified the research needed. A consensus was reached on a toolkit for future PTLD measurement and on PTLD patterns to be considered. The importance of extra-pulmonary consequences and progressive impairment throughout the life-course was identified, including TB recurrence and increased mortality. Patient advocates emphasised the need to address the psychological and social impacts post TB and called for clinical guidance. More generally, there is an urgent need for increased awareness and research into post-TB complications.

Consent for critical care research after death from COVID-19: Arguments for a waiver

Pandemics challenge clinicians and scientists in many ways, especially when the virus is novel and disease expression becomes variable or unpredictable. Under such circumstances, research becomes critical to inform clinical care and protect future patients. Given that severely ill patients admitted to intensive care units are at high risk of mortality, establishing the cause of death at a histopathological level could prove invaluable in contributing to the understanding of COVID-19. Postmortem examination including autopsies would be optimal. However, in the context of high contagion and limited personal protective equipment, full autopsies are not being conducted in South Africa (SA). A compromise would require tissue biopsies and samples to be taken immediately after death to obtain diagnostic information, which could potentially guide care of future patients, or generate hypotheses for finding needed solutions. In the absence of an advance written directive (including a will or medical record) providing consent for postmortem research, proxy consent is the next best option. However, obtaining consent from distraught family members, under circumstances of legally mandated lockdown when strict infection control measures limit visitors in hospitals, is challenging. Their extreme vulnerability and emotional distress make full understanding of the rationale and consent process difficult either before or upon death of a family member. While it is morally distressing to convey a message of death telephonically, it is inhumane to request consent for urgent research in the same conversation. Careful balancing of the principles of autonomy, non-maleficence and justice becomes an ethical imperative. Under such circumstances, a waiver of consent, preferably followed by deferred proxy consent, granted by a research ethics committee in keeping with national ethics guidance and legislation, would fulfil the basic premise of care and research: first do no harm. This article examines the SA research ethics framework, guidance and legislation to justify support for a waiver of consent followed by deferred proxy consent, when possible, in urgent research after death to inform current and future care to contain the pandemic in the public interest.

Histologically confirmed tuberculosis-associated obstructive pulmonary disease

Although chronic airflow limitation (CAL) is an important long-term consequence of tuberculosis (TB), little is known about the disease process. We present what we believe to be the first case of histologically confirmed residual TB-associated obstructive pulmonary disease (TOPD) in a 23-year-old non-smoking man who developed severe CAL after one episode of TB, with no other plausible risk factors. Lung biopsies identified residual post-TB pathology affecting the small airways and vessels throughout his lung; this has not been reported previously. These findings strengthen the argument that TOPD may be a phenotype of CAL distinct from both smoking-related chronic obstructive pulmonary disease and bronchiectasis.

Assessment of previous tuberculosis status using questionnaires, chest X-rays and computed tomography scans

SETTING

Accurate diagnosis of previous pulmonary tuberculosis disease (PPTB) status is important clinically and in research. Reliable records of bacteriologically confirmed tuberculosis (TB) are frequently unavailable.

OBJECTIVES

To evaluate the use of questionnaires and chest imaging to determine PPTB status in a high TB prevalence population.

DESIGN

PPTB status was assessed using two questionnaires, chest X-ray (CXR) and high-resolution chest computed tomography (CT) scans reported by experienced readers. The study population comprised adults aged >40 years diagnosed with obstructive lung disease in a community-based prevalence survey.

RESULTS

The Burden of Obstructive Lung Disease (BOLD) questionnaire and a second comprehensive questionnaire (PTbQ) provided a history of PPTB in respectively 38% (n = 41) and 36.4% (n = 39) of 107 participants. On CXR, 43.3% (45/104) had evidence of PPTB, with good inter-reader agreement (κ = 0.73). Changes compatible with PPTB were identified on chest CT in 68.3% (71/104) of the subjects. Questionnaire and CXR had negative predictive values for PPTB of 48% and 47%, respectively, compared to a composite definition.

CONCLUSION

Both questionnaire and CXR markedly underestimate the prevalence of previous TB in patients with chronic obstructive pulmonary disease. The combination of a structured questionnaire and CT scan is more useful when a diagnosis of PPTB needs to be ruled out.