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.

A point-prevalence study of body mass indices in HIV-positive and HIV-negative patients admitted to hospital with COVID-19 in South Africa

Background

Obesity is now well recognised as a risk factor for severe COVID-19, but the true prevalence of obesity in hospitalised adults with COVID-19 remains unclear because formal body mass indices (BMIs) are not routinely measured on admission.

Objectives

To describe the true prevalence of obesity measured by the BMI, and associated comorbidities, in patients hospitalised with severe COVID-19, including people with HIV (PWH).

Methods

We conducted a point-prevalence study of measured BMI in consecutive patients with severe COVID-19 admitted to the medical COVID-19 wards in a tertiary academic hospital in Cape Town, South Africa (SA). Patients were enrolled over a 2-week period during the peak of the first COVID-19 wave in SA.

Results

We were able to measure the BMI in 122 of the 146 patients admitted during the study period. The prevalence of HIV was 20% (n=24/122). Most of the participants were overweight or obese (n=104; 85%), and 84 (68.9%) met criteria for obesity. The mean (standard deviation) BMI was 33 (7.5), and 34.5 (9.1) in PWH. Of PWH, 83% (n=20/24) were overweight or obese and 75% (n=18) met criteria for obesity. Multimorbidity was present in 22 (92%) of PWH.

Conclusion

We found that most patients, including PWH, met criteria for being overweight or obese. The high prevalence of obesity in PWH and severe COVID-19 reinforces the need for targeted management of non-communicable diseases, including obesity, in PWH.

Study synopsis

What the study adds. We found that the true prevalence of obesity, including in people with HIV (PWH), measured with the formal body mass index in hospitalised patients with severe COVID-19 was much higher than reported previously.Multimorbidity was present in over half of all patients, and in 92% of PWH. Implications of the findings. Urgent public health measures are required to tackle the rise in obesity, including in low- and middle-income countries.HIV care must integrate management of non-communicable diseases, including obesity.The pathogenic mechanism of the link between obesity and severe COVID-19 needs further research.

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.

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.

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.

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.

New insights into spontaneous pneumothorax: A review

A spontaneous pneumothorax is a pneumothorax that does not arise from trauma or an iatrogenic cause. Although the traditional classification of either primary or secondary spontaneous pneumothorax based on the absence or presence of overt underlying lung disease is still widely used, it is now well recognised that primary spontaneous pneumothorax is associated with underlying pleuropulmonary disease. Current evidence indicates that computed tomography screening for underlying disease should be considered in patients who present with spontaneous pneumothorax. Recent evidence suggests that conservative management has similar recurrence rates, less complications and shorter hospital stay compared with invasive interventions, even in large primary spontaneous pneumothoraces of >50%. A more conservative approach which is based on clinical assessment rather than pneumothorax size can thus be followed during the acute management in selected stable patients. The purpose of this review is to revisit the aetiology of spontaneous pneumothorax, identify which patients should be investigated for secondary causes and to give an overview of the management strategies at initial presentation as well as secondary prevention.

South African Thoracic Society statement on obstructive airways disease and COVID-19

Asthmatics do not appear to have increased susceptibility to COVID-19.Uncontrolled severe asthma may be associated with worsened COVID-19 outcomes, especially in asthmatics managed with oral corticosteroids. Risk mitigation measures such as hand hygiene, social distancing and wearing of face masks must be observed at all times. Asthma should be managed as outlined in local and international guidelines.Ensure an adequate supply of medication, and inhaled corticosteroids should not be withdrawnChronic obstructive pulmonary disease (COPD) is associated with severe COVID-19 disease and poor outcomes. Maintenance of background medication is important to avoid exacerbations of COPD.Vaccination against influenza is strongly advised for all patients with asthma and COPDVaccination against pneumococcal infection is advisable for patients with COPD. Patients with obstructive airway disease on oral corticosteroids and/or with impaired lung function should take stringent safety precautions. This statement will be updated when more data become available Asthma and COPD occur commonly in South Africa. SARS-CoV-2 is a novel coronavirus, which can result in COVID-19-associated severe respiratory infection with respiratory failure and the need for mechanical ventilation. The South African Thoracic Society has prepared a guidance statement to assist clinicians and patients with asthma and COPD during the current epidemic.

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.

The Role of 18F-FDG PET/CT in Suspected Intraocular Sarcoidosis and Tuberculosis

Purpose: To determine the utility of fluorine-18 fluorodeoxyglucose Positron Emission Tomography Computed Tomography (FDG PET/CT) in patients with suspected ocular sarcoidosis (OS) or intraocular tuberculosis (IOTB) in a resource-constrained, TB endemic area.Methods: Independent review of the FDG PET/CTs, Computed Tomography (CT) scans and chest radiographs (CXRs) of patients with suspected OS or IOTB and inconclusive conventional workup.Results: Twenty-nine PET/CTs and CXRs were reviewed, with 38% of PET/CTs and CTs demonstrating evidence of TB or sarcoidosis, compared to 21% of CXRs. The sensitivity, specificity, positive and negative predictive values for PET/CT and CT were similar - 85.7%, 95.5%, 85.7% and 95.5% for OS, and 33.3%, 100%, 100% and 68% for IOTB respectively and for CXR, 57.1%, 100%, 100% and 88% for OS, and 16.7%, 100%, 100% and 63% for IOTB.Conclusion: PET/CT added no significant additional benefit over Chest CT in patients with suspected OS or IOTB.

Pharmacokinetics of rifampicin in adult TB patients and healthy volunteers: a systematic review and meta-analysis

Objectives

The objectives of this study were to explore inter-study heterogeneity in the pharmacokinetics (PK) of orally administered rifampicin, to derive summary estimates of rifampicin PK parameters at standard dosages and to compare these with summary estimates for higher dosages.

Methods

A systematic search was performed for studies of rifampicin PK published in the English language up to May 2017. Data describing the C_max and AUC were extracted. Meta-analysis provided summary estimates for PK parameter estimates at standard rifampicin dosages. Heterogeneity was assessed by estimation of the I² statistic and visual inspection of forest plots. Summary AUC estimates at standard and higher dosages were compared graphically and contextualized using preclinical pharmacodynamic (PD) data.

Results

Substantial heterogeneity in PK parameters was evident and upheld in meta-regression. Treatment duration had a significant impact on the summary estimates for rifampicin PK parameters, with C_max 8.98 mg/L (SEM 2.19) after a single dose and 5.79 mg/L (SEM 2.14) at steady-state dosing, and AUC 72.56 mg·h/L (SEM 2.60) and 38.73 mg·h/L (SEM 4.33) after single and steady-state dosing, respectively. Rifampicin dosages of at least 25 mg/kg are required to achieve plasma PK/PD targets defined in preclinical studies.

Conclusions

Vast inter-study heterogeneity exists in rifampicin PK parameter estimates. This is not explained by the available modifying variables. The recommended dosage of rifampicin should be increased to improve efficacy. This study provides an important point of reference for understanding rifampicin PK at standard dosages as efforts to explore higher dosing strategies continue in this field.

Utility of routine chest radiography in ocular tuberculosis and sarcoidosis

BACKGROUND

Tuberculosis (TB) and sarcoidosis commonly present with pulmonary and ocular involvement. Routine chest radiography (CXR) is recommended in the workup for suspected intraocular TB (IOTB) or intraocular sarcoidosis (IOS); however, data on the utility of CXR in this setting are lacking.

METHODS

A post-hoc analysis was performed of a prospectively collected data set comprising 104 patients with uveitis of unknown cause. A pulmonologist and thoracic radiologist, blinded to the final diagnosis, independently reported these CXRs as being in keeping with TB or sarcoidosis.

RESULTS

CXRs were reported as normal/indeterminate (n = 88), probable/previous TB (n = 9) or possible/probable sarcoidosis (n = 8), with a 96% inter-observer concordance. CXRs were more often abnormal in IOS than in IOTB (5/8 vs. 5/34, P = 0.01). CXR had a sensitivity of 14.7%, specificity of 94.3%, positive predictive value (PPV) of 55.6% and negative predictive value (NPV) of 69.5% for IOTB, compared with a sensitivity of 62.5%, specificity of 96.9%, PPV of 62.5% and NPV of 96.9% for IOS. Overall diagnostic accuracy was 54.5% (58.1% in human immunodeficiency virus [HIV] positive participants) in the case of IOTB and 79.9% for IOS.

CONCLUSION

CXR had high specificity and NPV for IOS, and poor overall diagnostic accuracy for IOTB, including in the HIV-positive population.

Direct comparison of liquid-based and smear-based cytology with and without rapid on-site evaluation for fine needle aspirates of thoracic tumors

BACKGROUND

Liquid-based cytology (LBC) and rapid on-site evaluation (ROSE) are proposed to improve the quality of fine needle aspirates (FNA) and their diagnostic yield compared with conventional smear cytology (CSC). This prospective study directly compared outcomes of sonar-guided FNA of thoracic tumors supported by LBC, CSC, or CSC with ROSE.

METHODS

Three aspirates each for both LBC and CSC with separate 22G spinal needles in a randomized, alternating sequence during 64 transthoracic FNA of thoracic tumors were collected. Smears were prepared by cytology staff on site but evaluated with ROSE only when all six samples had been collected. If no diagnostic material was found on the first three CSC additional needle passes guided by ROSE were performed.

RESULTS

Final diagnoses were non-small cell lung cancer in 50 (78.1%), small cell lung cancer in 11 (17.2%), mesothelioma in 1 (1.6%), and inflammation in 2 cases (3.1%), respectively. LBC and CSC were diagnostic in 42 (65.6%) and 49 (76.6%) cases, respectively (P = 0.039), with both methods diagnostic in 41 cases (64.1%). Fifteen cases (23.4%) remained undiagnosed following three passes for CSC but 9 (14.1%) of these were diagnosed using FNA and ROSE with a total yield of 58 cases (90.6%; P < 0.001).

CONCLUSION

The diagnostic yield of transthoracic FNA submitted for LBC is significantly lower than with CSC when slides are prepared professionally. ROSE significantly increases the yield of transthoracic FNA.

Impact of routine sputum cytology in a population at high risk for bronchial carcinoma

SETTING

Sub-Saharan Africa carries a high burden of lung cancer, with limited access to specialised health care.

OBJECTIVE

To investigate the diagnostic value of sputum cytology and its potential in reducing the need for invasive diagnostic procedures in a high-risk population.

DESIGN

We collected spontaneously expectorated sputum from 108 patients referred for a diagnostic procedure for suspected lung cancer between June 2010 and June 2012, and examined the diagnostic yield of sputum cytology for malignant cells as well as factors predicting a positive result.

RESULTS

Bronchial carcinoma was diagnosed in 90 patients (83.3%), of whom 35 (38.9%) had sputum cytology positive for malignant cells with 100% diagnostic accuracy. Positive sputum cytology was significantly associated with endobronchial tumour and obstruction seen during bronchoscopy (OR 4.69 and OR 8.89, respectively), and with a histology of squamous cell carcinoma (OR 1.9). All but one patient with positive sputum were inoperable (97.1%), and we estimated that up to a third of all invasive procedures could be avoided if sputum cytology was used for triage.

CONCLUSION

Sputum cytology had a high yield and accuracy in this high-risk group. Its routine use in selected patients is likely to result in reduced costs and less patient risk and discomfort.

Transthoracic ultrasonography in respiratory medicine

Transthoracic ultrasonography (US) has become an essential modality for the evaluation of a wide range of thoracic pathologies by respiratory, emergency and critical care physicians. It can be performed with entry-level equipment and by personnel with minimal training. Its advantages include low cost, lack of radiation and immediate application at the point of care. The main indications for transthoracic US are the qualitative and quantitative assessment of pleural effusions, pleural thickening, diaphragmatic pathology, and chest wall and pleural tumours. US may also be used to visualise pulmonary pathologies that abutt the pleura, including consolidation and the interstitial syndrome. Transthoracic US is at least as sensitive as chest radiographs in the detection of pneumothoraces, and is useful in diagnosing skeletal abnormalities like rib fractures. It is the ideal tool to guide transthoracic procedures, including thoracocentesis and pleural biopsy. Moreover, US-assisted procedures can be performed by a single clinician with no sedation and minimal monitoring. US-assisted fine needle aspiration and/or cutting needle biopsy of extrathoracic lymph nodes, lesions arising from the chest wall, pleura, peripheral lung and mediastinum are safe and have a high yield in the of hands of clinicians. US can potentially also guide aspiration and biopsy of diffuse pulmonary infiltrates, consolidations and lung abscesses. Transthoracic US may also be used for the detection of pulmonary embolism.

Toxic epidermal necrolysis and Stevens-Johnson syndrome in South Africa: a 3-year prospective study

BACKGROUND

Toxic Epidermal Necrolysis (TEN) and Stevens-Johnson syndrome (SJS) remain feared medication-related reactions. HIV infection and tuberculosis predispose to drug eruptions, yet there is a paucity of data on TEN/SJS in populations with high prevalences of both diseases.

AIM

The aim of this prospective observational study was to describe the features and outcomes of patients admitted with TEN/SJS at a large academic hospital in South Africa. We aimed to identify poor prognostic indicators and to validate the use of the TEN-specific severity-of-illness score (SCORTEN) in this population.

METHODS

All patients admitted with TEN/SJS over a 3-year period were enrolled. Disease severity was graded according to percentage skin involved and SCORTEN. Co-morbid diagnoses, clinical features, investigations, complications and outcomes were noted.

RESULTS

75 patients (39.9 ± 10.6 years, 16 males, 59 HIV positive) were classified as TEN (n  = 42), TEN/SJS overlap (n = 11) and SJS (n = 22). Twenty-four percent died, most from refractory septic shock. Non-survivors had a higher mean SCORTEN on Days 1 and 3 (1.89 vs. 1.04, P = 0.006 and 2.27 vs. 0.90, P < 0.001). A SCORTEN ≥2 on Days 1 and 3 predicted non-survival (OR = 2.94, P = 0.047; OR = 7.45, P < 0.001). Other predictors of non-survival included HIV infection (OR = 6.01, P = 0.058), HIV-tuberculosis co-infection (OR = 8.5, P < 0.001), ≥40% skin involvement (OR = 20.27, P < 0.001), anaemia (OR = 4.68, P = 0.005), hypoalbuminemia (OR = 8.5, P = 0.001) and severe sepsis (OR = 71.09, P < 0.001).

CONCLUSION

Most patients with TEN/SJS were HIV positive and female. We validated the use of SCORTEN and identified several prognostic indicators, most significant being HIV-tuberculosis co-infection, ≥40% skin involvement and severe sepsis.

Transbronchial fine needle aspiration biopsy and rapid on-site evaluation in the setting of superior vena cava syndrome

There is a paucity of prospective data on flexible bronchoscopy with rapid on-site evaluation (ROSE) in the setting of superior vena cava (SVC) syndrome. The aims of this prospective study were to assess the diagnostic yield and safety of these investigations and specifically to evaluate the role of ROSE in limiting the need for tissue biopsies. Over a 5-year period 48 patients (57.4 ± 9.7 years) with SVC syndrome secondary to intrathoracic tumors underwent flexible bronchoscopy with TBNA and ROSE. Endobronchial Forceps biopsy was reserved for visible endobronchial tumors with no on-site confirmation of diagnostic material. ROSE confirmed diagnostic material in 41 cases (85.4%), and in only one of the remaining cases did the addition of a forceps biopsy increase the diagnostic yield (overall diagnostic yield of 87.5%). No serious complications were noted. The final diagnoses made included nonsmall lung cancer (n = 27), small cell lung cancer (n = 16), and metastatic carcinoma (n = 3). Two undiagnosed cases died of suspected advanced neoplasms (unknown primary tumors). We conclude that TBNA has a high diagnostic yield and is safe in the setting of SVC syndrome. With the addition of ROSE, tissue biopsy is required in the minority of cases.

High mortality from respiratory failure secondary to swine-origin influenza A (H1N1) in South Africa

BACKGROUND

The novel influenza A (H1N1) pandemic affected South Africa late during the 2009 Southern hemisphere winter and placed an extra burden on a health care system already dealing with a high prevalence of chronic lung diseases and human immunodeficiency virus (HIV) infection.

AIM

The aim of this study was to describe the epidemiological characteristics, clinical features, management and outcomes of patients with confirmed influenza A (H1N1) infection complicated by respiratory failure.

METHODS

We included all adult patients with confirmed influenza A (H1N1) infection that were referred to the medical intensive care unit of a large academic hospital in Cape Town for ventilatory support in this prospective observational study.

RESULTS

A total of 19 patients (39.5 +/- 14.8 years) needed ventilatory support over a 6-week period. Of these, 15 were female and 16 had identifiable risk factors for severe disease, including pregnancy (n = 6), type 2 diabetes mellitus (n = 6), obesity (n = 4), HIV infection (n = 3), immunosuppressive therapy (n = 3) and active pulmonary tuberculosis (n = 2). The most frequent complications were acute renal failure (n = 13), acute respiratory distress syndrome (n = 12) and ventilator associated pneumonia (n = 10). Thirteen patients died (mortality: 68.4%). Fatal cases were significantly associated with an APACHE II score >or=20 (P = 0.034), but not with a P(a)O(2)/F(I)O(2) <200 (P = 0.085) and a chest radiograph score >or=12 (P = 0.134).

CONCLUSION

The majority of patients with respiratory failure secondary to influenza A (H1N1) infection were young females and had an underlying risk factor for severe disease. The condition had a high mortality, particularly amongst patients with an APACHE II score >or=20.

Infective endocarditis: improving the diagnostic yield

INTRODUCTION

Isolating aetiological agents in patients with infective endocarditis (IE) remains problematical. We postulated that the high local incidence of culture-negative IE resulted from antibiotic exposure prior to blood cultures and that a structured delay in therapy in the subacute presentation would improve the diagnostic yield.

AIM

We aimed to prospectively observe the diagnostic approach and give an overview of supplementary laboratory tests.

STUDY DESIGN

Patients with suspected IE were enrolled into this analytical observational study and followed up for six months (n = 92). We compared the diagnostic yield and outcome in cases where antibiotics were withheld for 72 hours, with those cases who received early antimicrobials, despite being deemed safe for delayed therapy.

RESULTS

Definitive diagnoses (definite or excluded IE) were made in 92.8% of patients where antibiotics were delayed, compared to 60% of patients who received empirical treatment (p = 0.08). The mortality rates were 18.4% and 30.0% (p = 0.18). Twenty-three of 26 patients with definite culture-negative IE received antibiotics during the 48 hours preceding cultures, compared to eight of 21 culture-positive patients (P < 0.001). Screening for atypical bacteria did not improve the yield. C-reactive protein (CRP) had a sensitivity of 97.0% (negative predictive value 87.5%), whereas a positive rheumatoid factor (RF) had a specificity of 93.8% (positive predictive value 91.7%).

CONCLUSIONS

We observed tendencies towards a greater diagnostic yield and lower mortality where antibiotics were initially withheld. Antibiotic prior to blood cultures were an important cause of culture-negative IE. A normal CRP proved useful in excluding IE; a positive RF strongly favoured IE.

Infective endocarditis in the Western Cape Province of South Africa: a three-year prospective study

BACKGROUND

The last 50 years have seen major changes in the epidemiology of infective endocarditis (IE).

AIM

To evaluate local patient characteristics, risk factors, clinical sequelae, microbiology, morbidity and mortality in patients with definite IE.

DESIGN

Prospective observational study.

METHODS

Over a three-year period, patients referred with probable IE were prospectively enrolled. All received a standardized diagnostic evaluation. Epidemiological data were documented; underlying risk factors for IE were sought. Initial evaluation and follow-up (to 6 months) included the documentation of vascular or immunological phenomena, morbidity and mortality.

RESULTS

Of 92 patients referred with probable IE, 47 had definite IE. These patients had a mean age of 37.7 years with a male predominance (1.6:1). Rheumatic heart disease was present in 36 (76.6%). Eight had prosthetic valves. Three had congenital heart disease, mitral valve prolapse or multiple central intravascular catheters, respectively. All denied the use of intravenous recreational drugs and only one tested seropositive for HIV. Renal involvement (59.6%) and clubbing (29.8%) were commonly observed. The 6-month mortality rate was 35.6%, while 44.7% needed valvular replacement. An aetiological diagnosis was made in 21, with viridans streptococci the most common isolate.

DISCUSSION

Infective endocarditis in the Western Cape of South Africa is a disease of younger adults, with a male predominance. Rheumatic heart disease is the major predisposing factor. Degenerative heart disease and intravenous drug abuse are not important risk factors. Our data do not support the notion that HIV infection is an independent risk factor for IE. Local mortality rates are much higher than recent international figures, as is the proportion of 'culture-negative' IE.