Initial Investigation of Factors Influencing Radiation Dose to Patients Undergoing Barium-Based Fluoroscopy Procedures in Tanzania.

The aim of this study was to investigate the nature and causes of radiation dose imparted to patients undergoing barium-based X-ray fluoroscopy procedures in Tanzania and to compare these doses to those reported in the literature from other regions worldwide. The air kerma area product (KAP) to patient undergoing barium investigations of gastrointestinal tract system was obtained from four consultant hospitals. The KAP was determined using a flat transparent transmission ionization chamber. Mean values of KAP for barium swallow (BS), barium meal (BM) and barium enema (BE) were 2.79, 2.62 and 15.04 Gy cm2, respectively. The mean values of KAP per hospital for the BS, BM and BE procedures varied by factors of up to 7.3, 1.6 and 2.0, respectively. The overall difference between individual patient doses across the four consultant hospitals investigated differed by factors of up to 53, 29.5 and 12 for the BS, BM and BE procedures, respectively. The majority of the mean values of KAP was lower than the reported values for Ghana, Greece, Spain and the UK, while slightly higher than those reported for India. The observed wide variation of KAP values for the same fluoroscopy procedure within and among the hospitals was largely attributed to the dynamic nature of the procedures, the patient characteristics, the skills and experience of personnel, and the different examination protocols employed among hospitals. The observed great variations of procedural protocols and patient doses within and across the hospitals call for the need to standardize examination protocols and optimize barium-based fluoroscopy procedures.

Survey of Effective Doses to Patients Undergoing Contrast-Based X-ray Fluoroscopy Procedures in Tanzania.

The aim of this study was to assess the radiation burden imparted to patients from contrast-based X-ray fluoroscopy procedures in Tanzania. The effective doses (EDs) to patients from five contrast-based fluoroscopy procedures were obtained from four hospitals. The ED was estimated using the knowledge of the patient characteristics, patient-related exposure parameters, measurements of air kerma area product and PCXCM software. The median EDs for the barium swallow (BS), barium meal (BM), barium enema (BE), hysterosalpingography (HSG) and retrograde urethrography (RUG) were 0.50, 1.43, 2.83, 0.65 and 0.59 mSv, respectively. The median ED per hospital for the BS and BM procedures varied by factors of up to 9.9 and 4.2, respectively, while for the BE, HSG and RUG varied by factors of up to 2.3, 2.4 and 4.3, respectively. The overall differences between individual EDs across the four hospitals varied by factors of up to 53, 58.9 and 11.4 for the BS, BM and BE, respectively, while for the HSG and RUG differed by factors of up to 22 and 46.7, respectively. The mean EDs in this study were mostly lower than reported values from Spain, the UK, Ghana and Greece, while slightly higher than those reported from India. The observed wide variations of procedural protocols and patient doses within and across the hospitals; and the observed high patient doses in this study relative to those from the literature call for the need to standardize procedural protocols and optimize contrast-based fluoroscopy procedures.

Experiences with the European guidelines on quality criteria for radiographic images in Tanzania.

Objective assessment of the quality of radiographic images is practically a difficult task and protocols that address this problem are few. In 1996, the European union published nearly objective image quality criteria to unify the practices in Europe. However, experience with these criteria in countries of lower health care levels is little documented. As a case study in Tanzania, we present the general performance of European guidelines in some Tanzanian hospitals to a total of 200 radiographs obtained from some common x-ray examinations. The results show that more than 70% of chest (PA), lumbar spine (AP), and pelvis AP radiographs passed the quality criteria, while the performance of lumbar spine LAT x-ray examinations was about 50% and therefore less satisfactory. The corresponding mean entrance dose to the patient for specified x-ray techniques was of range 0.08-0.56 mGy, 3.1-7.7 mGy, 2.53-5.4 mGy, and 4.0-16.78 mGy for chest PA, lumbar spine AP, pelvis AP, and lumbar spine LAT x-ray examinations, respectively. Although a good number of observers were not well familiar to the guidelines, the quality criteria have been found useful and their adoption in the country recommended. The need to provide relevant education and training to staff in the radiology departments is of utmost importance.

Myelography with Omnipaque (Iohexol) using basic radiographic facilities: the main adverse effects.

OBJECTIVE: Documentation of main adverse effects, their magnitudes and relationship to contrast concentrations in patients subjected to myelography under basic radiographic facilities. Use of the acquired data for better patient management in the future. DESIGN: In a prospective double blind study consecutive admitted neurological patients of age range seven to 77 years were subjected to myelography with different concentrations of Omnipaque (300* cervical, 240* thoracic and 180* lumbar) under limited radiographic facilities by radiologists (cases). Thirty admitted patients of about the same age range with justified medical problems were subjected to diagnostic lumbar puncture by different physicians (controls). The main adverse effects were assessed in both groups (subjects) by a neuro-physician unaware of subject status. Patients primarily admitted to the hospital with headache, dizziness, nausea, vomiting and convulsions and subjected to lumbar puncture were excluded from the study. SETTING: Cases and controls were derived from patients referred from variable regional hospitals scattered throughout the country. SUBJECTS: 110 consecutive neurological cases referred to the Radiology Department for myelography between December 1989 and January 1991. Thirty consecutive qualifying diagnostic lumbar puncture patients managed at the same period. MAIN OUTCOME MEASURES: Development of symptoms including headache, dizziness, nausea, vomiting and convulsions and evaluation of their magnitude subjectively quantitated from mild (+) and moderate (+2) (tolerable) to severe (+3), (intolerable) among the cases and controls. RESULTS: Overall, symptoms in all magnitudes (mild to severe) occurred in 63.6pc of cases compared to 36.7pc of controls (p < 0.05). Concentrations of 300 and 180 were more associated with the effects (p = 0.017 and 0.016 respectively) while the 240 concentration was relatively safe causing no more adverse effects than a diagnostic lumbar puncture (p = 0.137). In severe magnitudes (intolerable) the same effects occurred in 20.9pc of cases compared to 6.7pc of controls (p < 0.05); differences in contrast concentrations did not significantly feature (p = 0.59: Omnipaque 300; p = 0.063: Omnipaque 240 and p = 0.061; Omnipaque 180). CONCLUSION: Even with limited radiographic facilities, myelography with Omnipaque 240 is relatively safe; being associated with no more adverse effects than a medical diagnostic lumbar puncture; thus the contrast concentration of choice for myelography under sub-optical radiographic set up. With the 180 and 300 concentrations, the procedure is associated with tolerable adverse effects not significantly differing from those arising from the same procedure performed under ideal radiodiagnostic establishments.

Clinical features of HIV seropositive and HIV seronegative patients with tuberculous lymphadenitis in Dar es Salaam.

SETTING: The medical wards of a referral hospital in Dar es Salaam, Tanzania. OBJECTIVE: To investigate the impact of HIV infection on clinical features in tuberculous lymphadenitis. DESIGN: A prospective clinical study of HIV seropositive and HIV seronegative patients with lymphadenopathy. RESULTS: Of 128 patients with peripheral lymphadenopathy, 24 had no tuberculosis (TB) and in 10 patients TB was found only in other organs. The remaining 94 patients, of whom 76% were HIV seropositive, formed our study population. TB lymphadenitis was considered proven in 89 and probable in 5 patients. Disseminated TB (both TB adenitis and TB in other organs) was diagnosed more often in HIV seropositive than in HIV seronegative patients (52% versus 26%, P < 0.03). 59% of the 71 HIV-infected patients compared to only 4% of the 23 patients without HIV infection were over 30 years of age (P < 0.02). The following clinical features were significantly associated with HIV infection: dyspnoea, respiratory rate > 20/min, low motility score (bedridden), neurological abnormalities, hepatomegaly, splenomegaly, lymph node size < 2.5 cm, negative PPD skin test, lymphopenia (< 1000/cm3) and presence of pleural fluid. CONCLUSION: Co-infection with HIV influences several clinical and laboratory features in patients with tuberculous lymphadenitis.

Clinical features of HIV-seropositive and HIV-seronegative patients with tuberculous pleural effusion in Dar es Salaam, Tanzania.

In a prospective study, we investigated whether human immunodeficiency virus (HIV) infection alters the clinical presentation in patients with tuberculous pleuritis. One hundred twelve of 118 patients who presented with pleural effusion suffered from tuberculosis (TB); 65 patients (58%) were HIV seropositive. Evidence of disseminated TB was found more often in HIV-positive than in HIV-negative patients (30.8% vs 10.6%, p < 0.02). Dyspnea, fever, night sweat, fatigue, and diarrhea, severe tachypnea, hepatomegaly, splenomegaly, and lymphadenopathy were significantly more common in HIV-infected than in HIV-negative patients with TB. The same applied to a negative Mantoux reaction, lower hemoglobin, higher beta 2-microglobulin values, and in pleural fluid, lower albumin and higher gamma-globulin levels. Among HIV-infected patients, PPD skin test anergy was significantly associated with relative low albumin and gamma-globulin levels of pleural fluid. However, the radiographic features did not differ with respect to HIV status; they were predominantly those of primary pleuritis (78% in each group). We conclude that coexisting HIV infection affects clinical and laboratory features, but not the radiographic presentation of patients with TB pleuritis in Tanzania.

Diagnosis of tuberculous lymphadenitis in an area of HIV infection and limited diagnostic facilities.

In order to evaluate procedures leading to the diagnosis of tuberculous lymphadenitis, a prospective clinical study was carried out of patients with lymphadenopathy admitted to the medical wards of a referral hospital in Tanzania. The yield of diagnostic procedures (direct auramine/Ziehl-Neelsen (ZN) stained smears, Löwenstein-Jensen (LJ) cultures, cytology and histological examinations of fine needle aspirations (FNA) and biopsy material of lymph nodes, respectively, was compared. We also tried to identify clinical diagnostic markers. One hundred and twenty-eight (99 HIV-seropositive) patients were included. In 89 (67 HIV-positive) patients TB lymphadenitis could be proven. Histology and LJ culture of a lymph node biopsy had the highest diagnostic yield, 85% and 88% respectively, followed by detection of acid-fast bacilli (AFB) in biopsy smear (53%) and in fine-needle aspirations (35%). The diagnostic yield of the several procedures was not affected by associated HIV infection. Macroscopic caseation was 100% predictive for TB with a sensitivity of 69%. Firm and matted lymph nodes, ESR > 100 mm/hr, a positive PPD skin test and pleural opacity on a chest x-ray proved to be independent predictors for TB. Retrospective testing of a stepwise diagnostic approach based on direct smears of FNA, macroscopic visible caseation and direct smear of biopsy tissue, suggests that in 93% of the patients a definite diagnosis of TB lymphadenitis could have been made. Our data suggest that in HIV/TB epidemic areas most of the cases of TB lymphadenitis can be diagnosed correctly by simple and cheap methods which are generally available at district hospitals. Our findings need further prospective validation, however.

PIP: In order to evaluate procedures leading to the diagnosis of tuberculous lymphadenitis, a prospective clinical study was carried out on patients with lymphadenopathy admitted to four medical wards of the Muhibili Medical Center, Dar es Salaam, Tanzania, from January to August 1991. The yield of diagnostic procedures (direct auramine/Ziehl-Neelsen stained smears, Lowenstein-Jensen [LJ] cultures, cytology and histological examinations of fine needle aspirations [FNA], and biopsy material of lymph nodes) was compared. Clinical diagnostic markers were also identified. 128 (99 HIV-seropositive) patients with a mean age of 30 years were included. 41% were male. In 89 (67 HIV-positive) patients, TB lymphadenitis could be demonstrated. 46 (30 HIV-positive) had TB lymphadenitis only and 43 (37 HIV-positive) had disseminated TB. In 10 patients TB was found in specimens other than the lymph node, making the total of TB patients 99. Histology and LJ culture of lymph node biopsy had the highest diagnostic yield, 85% and 88%, respectively, followed by detection of acid-fast bacilli in biopsy smears (53%) and in FNAs (35%). The diagnostic yield of the procedures was not affected by associated HIV infection. Macroscopic caseation was 100% predictive of TB with a sensitivity of 69%. Multivariate logistic regression analysis demonstrated four independent predictors of TB: 1) firm and matted lymph nodes (odds ratio [OR] 11.8); 2) erythrocyte sedimentation rate (ESR) 100 mm/hr (OR 4.6); 3) a positive purified protein derivative (PPD) skin test (OR 10.2); and 4) pleural opacity on a chest X-ray (OR 9.5). Retrospective testing of a stepwise diagnostic approach based on direct smears of FNA, macroscopic visible caseation, and direct smears of biopsy tissue suggests that in 93% of the patients a definite diagnosis of TB lymphadenitis could have been made. These data suggest that in HIV/TB epidemic areas most of the cases of TB lymphadenitis can be diagnosed correctly by simple and cheap methods which are generally available at district hospitals.

Diagnosis of tuberculosis in patients with pleural effusion in an area of HIV infection and limited diagnostic facilities.

In a prospective study of 118 patients with pleural effusion, tuberculosis (TB) was diagnosed in 112. In 84 patients the diagnosis of TB was made by detection of acid-fast bacilli by stain (auramine, Ziehl-Neelsen) or by culture of mycobacteria (Löwenstein-Jensen medium) in pleural fluid or pleural tissue (obtained by closed biopsy) or by the presence of caseating granulomas in histological sections. In 28 patients the diagnosis of TB was considered probable, based on good response to anti-tuberculous therapy. The highest diagnostic yield was obtained by histology (85%), followed by culture of pleural biopsy (37%) and pleural fluid culture (36%). Pulmonary tuberculosis was found in 8 patients and dissemination of TB to other sites in 25 patients of whom 20 were HIV positive. By logistic regression analysis we identified 2 independent diagnostic markers for TB pleuritis: pleural fluid protein > 50 g/l (Odds ratio 12.1, 95% confidence interval (CI): 1.1-128.3) and adenosine deaminase of > 10 U/l (Odds ratio 11.08, 95% CI: 1.3-96.4). We conclude that conventional facilities of a referral hospital are sufficient to diagnose tuberculous pleuritis as well as disseminated tuberculosis irrespective of HIV infection. However, for regions with overstretched health services and high prevalences of tuberculous pleurisy in patients with pleural effusion we suggest a simplified diagnostic approach based on exclusion of other causes of pleural effusion by simple means and use of these diagnostic markers.

PIP: In a prospective study of 118 patients with pleural effusion admitted to four medical wards in Muhimbili Medical Center between January and August 1991, Dar es Salaam, Tanzania, tuberculosis (TB) was diagnosed in 112. In 84 patients the diagnosis of TB was made by detection of acid-fast bacilli by stain (auramine, Ziehl-Neelsen) or by culture of mycobacteria (Lowenstein-Jensen medium) in pleural fluid or pleural tissue obtained by closed biopsy or by the presence of caseating granulomas in histological sections. In 28 patients the diagnosis of TB was considered probable, based on good response to anti-tuberculous therapy. In the remaining 6 non-TB patients adenocarcinoma (1), bacterial infection (2), and aspecific inflammation (3) were diagnosed. 58% of the TB and 3 of the non-TB patients were infected with HIV. The diagnostic procedures were evaluated in 75 patients. The highest diagnostic yield was obtained by histology (85%), followed by culture of pleural biopsy (37%), and pleural fluid culture (36%). Pulmonary tuberculosis was found in 8 (4 HIV-positive) patients and dissemination of TB to other sites in 25 patients, of whom 20 were HIV-positive. By logistic regression analysis, two independent diagnostic markers for TB pleuritis were identified: pleural fluid protein 50 g/l (odds ratio [OR] 12.1) and pleural fluid adenosine deaminase level of 10 U/l (OR 11.08). The sensitivity of these two diagnostic tests was 82% and 97.3%, and the specificity was 83.6% and 50%, respectively. TB was the underlying cause in nearly all patients who presented with pleural effusion (94.9%). TB was confirmed in 75% of these using the referral hospital. Conventional facilities of a referral hospital are sufficient to diagnose tuberculous pleuritis as well as disseminated tuberculosis irrespective of HIV infection. However, in regions with overburdened health facilities and high prevalence of tuberculous pleurisy in patients with pleural effusion, a simplified diagnostic approach is suggested based on exclusion of other causes of pleural effusion by simple use of these diagnostic markers.