SUNScholar - Browsing by Author "Irusen, E. M."

Browsing by Author "Irusen, E. M."

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Asthma control
(Continuing Medical Education, 2008-04) Irusen, E. M.
The SA Thoracic Society and the Global Initiative for Asthma (GINA) have recently published updated guidelines to assist practitioners in the management of asthma. The guidelines were based on reports that asthma management is far from optimal. Despite a wealth of evidence on the inflammatory nature of asthma, inhaled corticosteroids (ICS) are still under-prescribed and even when issued, are under-utilised. Many doctors and patients have also aligned themselves to lower expectations: doctors who allow asthma to be uncontrolled and patients who accept that they will always be symptomatic. The consequences are unnecessary morbidity, exacerbations, time off work or school, and even mortality.
Complete resolution of apparently definite radiological and histological usual interstitial pneumonia
(Health & Medical Publishing Group, 2018-08-30) Simon, D.; Irusen, E. M.; Allwood, Brian W.; Rigby, J.; Koegelenberg, C. F. N.
ENGLISH ABSTRACT: Idiopathic pulmonary fibrosis is considered to be the most common form of pulmonary fibrosis. It is a progressive and irreversible disease with a reported median survival of ~3 years. The pathological correlate is usual interstitial pneumonia (UIP), and although antifibrotic agents can slow down lung function decline, they do not completely reverse the disease process. To date, there have been no case reports describing reversal of UIP. We present a case where both the imaging and histology were compatible with definite UIP, yet it reversed with immunosuppressive therapy without the use of antifibrotic agents.
The current aetiology of malignant pleural effusion in the Western Cape Province, South Africa
(Health & Medical Publishing Group, 2018-04) Koegelenberg, C. F. N.; Bennji, S. M.; Boer, E.; Schubert, P. T.; Shaw, J. A.; Allwood, Brian W.; Irusen, E. M.
Background: Malignant pleural effusion (MPE) represents a very common cause of pleural exudates, and is one of the most challenging pleural disorders to manage. This could be attributed to the paucity of high-quality experimental evidence, and inconsistent practice worldwide. South Africa (SA) currently has no data regarding the aetiology of MPE. Objectives: To identify the most common malignancies causing MPE in a population served by a large tertiary hospital in SA, and specifically the relative contribution of mesothelioma. A secondary objective was to evaluate the efficacy of chemical pleurodesis in a subset of patients. Methods: We retrospectively included all known cases of MPE evaluated at our institution over a 3-year period with a tissue diagnosis of MPE. Results: The most common causes of MPE in a total of 274 patients were lung cancer (n=174, 63.5%), breast cancer (n=32, 11.7%), unknown primary (n=22, 11.7%) and mesothelioma (n=27, 9.9%). Talc pleurodesis was performed in 81 of 194 patients (41.8%) referred to our division, and was radiologically successful in 22 of 25 (88.0%) followed up to 3 months. Conclusions: The main cause of MPE in our setting was lung cancer, followed by breast cancer, unknown primary and mesothelioma. Chemical pleurodesis was a viable palliative measure for MPE in this population.
The diagnostic accuracy of integrated positron emission tomography/computed tomography in the evaluation of pulmonary mass lesions in a tuberculosis-endemic area
(Health and Medical Publishing Group, 2015) Du Toit, R.; Shaw, J. A.; Irusen, E. M.; Von Groote-Bidlingmaier, F.; Warwick, J. M.; Koegelenberg, C. F. N.
Background. Integrated positron emission tomography/computed tomography (PET-CT) is a well-validated modality for assessing pulmonary mass lesions and specifically for estimating risk of malignancy. Tuberculosis (TB) is known to cause false-positive PET-CT findings. Objective. To investigate the utility of PET-CT in the evaluation of pulmonary mass lesions and nodules in a high TB prevalence setting. Methods. All patients referred for the evaluation of a solitary pulmonary nodule or mass and who underwent PET-CT scanning over a 3-year period were included. The PET-CT findings, including maximum standardised uptake value (SUVmax), were compared with the gold standard (tissue or microbiological diagnosis). The sensitivity, specificity, positive and negative predictive values and diagnostic accuracy for malignant disease were calculated according to the SUVmax cut-off of 2.5 and a proposed cut-off obtained from a receiver operating characteristic (ROC) curve. Results. Forty-nine patients (mean (standard deviation) age 60.1 (10.2) years; 29 males) were included, of whom 30 had malignancy. Using an SUVmax cut-off of 2.5, PET-CT had a sensitivity, specificity, positive and negative predictive value and diagnostic accuracy for malignancy of 93.3%, 36.8%, 70.0%, 77.8% and 71.4%, respectively. After a ROC curve analysis, a suggested SUVmax cut-off of 5.0 improved the specificity to 78.9% and the diagnostic accuracy to 86.7%, with a small reduction in sensitivity to 90.0%. Conclusions. The diagnostic accuracy of PET-CT in the evaluation of pulmonary mass lesions using the conventional SUVmax cut-off of 2.5 was reduced in a TB-endemic area. An SUV cut-off of 5.0 has a higher specificity and diagnostic accuracy for malignancy, with a comparable sensitivity.
The impact of an electronic clinical decision support for pulmonary embolism imaging on the efficiency of computed tomography pulmonary angiography utilisation in a resource-limited setting
(Health & Medical Publishing Group, 2016-01) Murthy, C.; Davis, R.; Koegelenberg, C. F. N.; Irusen, E. M.; Pitcher, R. D.
ENGLISH SUMMARY : Background. Pulmonary embolism (PE) is associated with high morbidity and mortality. Effective intervention requires prompt diagnosis. Computed tomography pulmonary angiography (CTPA) is sensitive and specific for PE and is the investigation of choice. Inappropriate CTPA utilisation results in unnecessary high radiation exposure and is costly. Stateoftheart electronic radiology workflow can provide clinical decision support (CDS) for specialised imaging requests, but there has been limited work on the clinical impact of CDS in PE, particularly in resourceconstrained environments. Objective. To determine the impact of an electronic CDS for PE on the efficiency of CTPA utilisation in a resourcelimited setting. Methods. In preparation, a PE diagnostic algorithm was distributed to hospital clinicians, explaining the combined role of the validated modified Wells score and the quantitative Ddimer test in defining the pretest probability of PE. Thereafter, an automated, electronic CDS was introduced for all CTPA requests. Total CTPA referrals and the proportion positive for PE were assessed for three study phases: (i) pre diagnostic algorithm; (ii) postalgorithm, preCDS; and (iii) postCDS. Results. The proportion of CTPAs positive for PE after CDS implementation was almost double that prior to introduction of the diagnostic algorithm (phase 1 v. 3, 17.4% v. 30.7%; p=0.036), with a correspondingly significant decrease in the proportion of nonpositive CTPAs (phases 1 v. 3, 82.6% v. 69.3%; p=0.015) During phases 2 and 3, no CTPAs were requested for patients with a modified Wells score of ≤4 and a documented negative Ddimer, indicating adherence to the algorithm. Conclusion. Implementing an electronic CDS for PE significantly increased the efficiency of CTPA utilisation and significantly decreased the proportion of inappropriate scans.
The impact of HIV infection on the presentation of lung cancer in South Africa
(Health & Medical Publishing Group, 2016) Koegelenberg, C. F. N.; Van Der Made, T.; Taljaard, J. J.; Irusen, E. M.
ENGLISH ABSTRACT: Background. Despite the very high background prevalence of HIV and smoking-related diseases in sub-Saharan Africa, very little is known about the presentation of lung cancer in HIV-infected individuals. Methods. We prospectively compared HIV-positive (n=44) and HIV-negative lung cancer patients (n=425) with regard to demographics, cell type, performance status and umour node metastasis staging at initial presentation. Results. HIV-positive patients were found to be younger than HIV-negative (mean 54.1 (standard deviation (SD) 8.4) years v. 60.5 (10) years, p<0.01), more likely to have squamous cell carcinoma (43.2% v. 30.1%, p=0.07) and significantly more likely to have a poor Eastern Cooperative Oncology Group (ECOG) performance status of ≥3 (47.7% v. 29.4%, p=0.02). In the case of non-small cell-lung cancer, they were also significantly less likely to have early stage lung cancer (0% v. 10.3%, p=0.02) compared with HIV-negative patients. Conclusions. HIV-positive lung cancer patients were younger, significantly more likely to have a poor performance status at presentation and significantly less likely to have early stage lung cancer when compared with HIV-negative patients.
The non-pharmacological management of COPD is a neglected area in the treatment of respiratory diseases
(Health and Medical Publishing Group (HMPG), 2009-04) Irusen, E. M.; Plekker, D.
An almost uniformly neglected area of respiratory disease management is the non-pharmacological component. Most patients with chronic respiratory illnesses will lose their exercise capacity (deconditioning) as the illness progressively limits physical activity. It is usually not appreciated that as medication improves the disease state and static lung function, normalisation of physical activities does not automatically ensue – it has to be re-established. Many patients with obstructive lung disease will inappropriately use rescue bronchodilator therapy when experiencing dyspnoea with exertion, whereas the real problem is that of deconditioning.
The pharmacokinetics of enteral antituberculosis drugs in patients requiring intensive care
(Health and Medical Publishing Group (HMPG), 2013-06) Koegelenberg, C. F. N.; Nortje, A.; Lalla, U.; Enslin, A.; Irusen, E. M.; Rosenkranz, B.; Seifart, H. I.; Bolliger, C. T.
Background. There is a paucity of data on the pharmacokinetics of fixed-dose combination enteral antituberculosis treatment in critically ill patients. Objectives. To establish the pharmacokinetic profile of a fixed-dose combination of rifampicin, isoniazid, pyrazinamide and ethambutol given according to weight via a nasogastric tube to patients admitted to an intensive care unit (ICU). Methods. We conducted a prospective, observational study on 10 patients (mean age 32 years, 6 male) admitted to an ICU and treated for tuberculosis (TB). Serum concentrations of the drugs were determined at eight predetermined intervals over 24 hours by means of highperformance liquid chromatography. Results. The therapeutic maximum plasma concentration (Cmax) for rifampicin at time to peak concentration was achieved in only 4 patients, whereas 2 did not achieve therapeutic Cmax for isoniazid. No patient reached sub-therapeutic Cmax for pyrazinamide (6 were within and 4 above therapeutic range). Three patients reached sub-therapeutic Cmax for ethambutol, and 6 patients were within and 1 above the therapeutic range. Patients with a sub-therapeutic rifampicin level had a higher mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score (p=0.03) and a lower estimated glomerular filtration rate (GFR) (p=0.03). Conclusions. A fixed-dose combination tablet, crushed and mixed with water, given according to weight via a nasogastric tube to patients with TB admitted to an ICU resulted in sub-therapeutic rifampicin plasma concentrations in the majority of patients, whereas the other drugs had a more favourable pharmacokinetic profile. Patients with a sub-therapeutic rifampicin concentration had a higher APACHE II score and a lower estimated GFR, which may contribute to suboptimal outcomes in critically ill patients. Studies in other settings have reported similar proportions of patients with ‘sub-therapeutic’ rifampicin concentrations.
Predictors of treatment success in smoking cessation with varenicline combined with nicotine replacement therapy v. varenicline alone
(Health & Medical Publishing Group, 2018-01) Noor, F.; Koegelenberg, C. F. N.; Esterhuizen, T. M.; Irusen, E. M.
Background. Identification of the predictors of treatment success in smoking cessation may help healthcare workers to improve the effectiveness of attempts at quitting. Objective. To identify the predictors of success in a randomised controlled trial comparing varenicline alone or in combination with nicotine replacement therapy (NRT). Methods. A post-hoc analysis of the data of 435 subjects who participated in a 24-week, multicentre trial in South Africa was performed. Logistic regression was used to analyse the effect of age, sex, age at smoking initiation, daily cigarette consumption, nicotine dependence, and reinforcement assessment on abstinence rates at 12 and 24 weeks. Point prevalence and continuous abstinence rates were self-reported and confirmed biochemically with exhaled carbon monoxide readings. Results. The significant predictors of continuous abstinence at 12 and 24 weeks on multivariate analysis were lower daily cigarette consumption (odds ratio (OR) 1.86, 95% confidence interval (CI) 1.21 - 2.87, p=0.005 and OR 1.83, 95% CI 1.12 - 2.98, p=0.02, respectively) and older age (OR 1.52, 95% CI 1.00 - 2.31, p=0.049 and OR 1.79, 95% CI 1.13 - 2.84, p=0.01, respectively). There was no difference in the predictors of success in the univariate analysis, except that older age predicted point prevalence abstinence at 12 weeks (OR 1.47, 95% CI 1.00 - 2.15, p=0.049). The findings were inconclusive for an association between abstinence and lower nicotine dependence, older age at smoking initiation and positive reinforcement. Conclusion. Older age and lower daily cigarette consumption are associated with a higher likelihood of abstinence in patients using varenicline, regardless of the addition of NRT.
Pulmonary scar carcinoma in South Africa
(Health & Medical Publishing Group, 2017) Jenkins, N.; Irusen, E. M.; Koegelenberg, C. F. N.
Background. The association between lung scarring and the subsequent development of cancer remains controversial. South Africa has one of the highest incidences of tuberculosis in the world, and resultant scarring may predispose to malignancy. The country also carries a very high burden of smoking and smoking-related diseases that may be synergistic in malignant transformation. Objective. To assess the frequency of pulmonary scarring in patients with lung cancer. Methods. All patients with confirmed lung cancer and a staging computed tomography (CT) scan of the chest were included in this 2-year retrospective study. Pulmonary scarring was categorised according to location as present in: (i) the same lobe as the primary tumour, (ii) a different lobe of the same lung, or (iii) the contralateral lung; or (iv) as diffuse. Post-obstructive bronchiectasis and other changes secondary to cancer were considered not to represent scarring. Results. We identified 435 cases of primary lung cancer. In total, 95 patients (21.8%) had CT evidence of pulmonary scarring. Eighty-three of 85 patients (97.6%) had focal scarring in the same lobe as the primary tumour. Of these, 37 (43.5%) also had scarring involving a different lobe of the same lung, whereas only one (1.2%; p<0.001) had scarring isolated to a different lobe of the same lung. Moreover, 21 patients (24.7%) also had scarring of the opposite lung, but only one patient (1.2%; p<0.001) had scarring isolated to the contralateral lung. Ten patients had diffuse scarring, caused by bronchiectasis (n=5), idiopathic pulmonary fibrosis (n=4) and silicosis (n=1). Conclusion. At least one in five patients with lung cancer had scarring, which was significantly more likely to be present in the same lobe as the tumour, suggesting a predisposition to malignancy.
A severity-of-illness score in patients with tuberculosis requiring intensive care
(Health & Medical Publishing Group, 2021-03-02) Lalla, U.; Irusen, E. M.; Allwood, B. W.; Taljaard, J. J.; Koegelenberg, C. F. N.
Background. We previously retrospectively validated a 6-point severity-of-illness score aimed at identifying patients at risk of dying of tuberculosis (TB) in the intensive care unit (ICU). Parameters included septic shock, HIV infection with a CD4 count <200 cells/µL, renal dysfunction, a ratio of partial pressure of arterial oxygen to fraction of inspired oxygen (P/F) <200 mmHg, a chest radiograph demonstrating diffuse parenchymal infiltrates, and no TB treatment on admission. Objectives. To prospectively validate the severity-of-illness scoring system in patients with TB requiring intensive care, and to refine and simplify the score in order to expand its clinical utility. Methods. We performed a prospective observational study with a planned post hoc retrospective analysis, enrolling all adult patients with confirmed TB admitted to the medical ICU of a tertiary hospital in Cape Town, South Africa, from 1 February 2015 to 31 July 2018. The admission data of all adult patients with TB requiring admission to the ICU were used to calculate the 6-point severity-of-illness score and a refined 4-point score (based on the planned post hoc analysis). Descriptive statistics and χ2 or Fisher’s exact tests (where indicated) were performed on dichotomous categorical variables, and t-tests on continuous data. Patients were categorised as hospital survivors or non-survivors. Results. Forty-one of 78 patients (52.6%) died. The 6-point scores of non-survivors were higher than those of survivors (mean (standard deviation (SD)) 3.5 (1.3) v. 2.7 (1.2); p=0.01). A score ≥3 v. <3 was associated with increased mortality (64.0% v. 32.1%; odds ratio (OR) 3.75; 95% confidence interval (CI) 1.25 - 10.01; p=0.01). Post hoc, a P/F ratio <200 mmHg and no TB treatment on admission failed to predict mortality, whereas any immunosuppression did. A revised 4-point score (septic shock, any immunosuppression, acute kidney injury and lack of lobar consolidation) demonstrated higher scores in non-survivors than survivors (mean (SD) 2.8 (1.1) v. 1.6 (1.1); p<0.001). A score ≥3 v. ≤2 was associated with increased mortality (78.4% v. 29.3%; OR 8.76; 95% CI 3.12 - 24.59; p<0.001). Conclusions. The 6-point severity-of-illness score identified patients at increased risk of death. We were able to derive and retrospectively validate a simplified 4-point score with superior predictive power.
The utility of hand-held mobile spirometer technology in a resource-constrained setting
(Health & Medical Publishing Group, 2019) Du Plessis, E.; Swart, F.; Maree, D.; Heydenreich, J.; Van Heerden, J.; Esterhuizen, T. M.; Irusen, E. M.; Koegelenberg, C. F. N.
Background. Mobile phone-linked spirometry technology has been designed specifically for evaluating lung function at primary care level. The Air-Smart Spirometer is the first mobile spirometer accepted in Europe for the screening of patients with chronic respiratory diseases. Objectives. To prospectively assess the accuracy of the device in measuring forced expiratory volume in the first second (FEV1) and forced vital capacity (FVC) in a South African population, and to investigate the ability of the device to detect obstructive ventilatory impairment. Methods. A total of 200 participants were randomly assigned to perform spirometry with either the mobile spirometer connected to a smartphone or the desktop spirometer first, followed by the other. The FEV1/FVC ratio as well as the absolute FEV1 and FVC measurements were compared, using each participant as their own control. A Pearson correlation and Bland-Altman analysis were performed to measure the agreement between the two devices. We defined obstructive ventilatory impairment as FEV1/FVC <0.7 measured by desktop spirometry in order to calculate the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the Air-Smart Spirometer. Results. There was a strong correlation between the absolute FEV1 and FVC values and FEV1/FVC ratio measured with the mobile Air-Smart Spirometer and more conventional pulmonary function testing, with r=0.951, r=0.955 and r=0.898, respectively. The Air-Smart Spirometer had a sensitivity of 97.6%, specificity of 74.4%, PPV of 73.0% and NPV of 97.8% for obstructive ventilatory impairment. Conclusions. The mobile Air-Smart Spirometer compared well with conventional spirometry, making it an attractive and potentially affordable tool for screening purposes in a primary care setting. Moreover, it had a high sensitivity and NPV for obstructive ventilatory impairment.

Browsing by Author "Irusen, E. M."

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