Antibiotic scintigraphy in tuberculosis: A new horizon?

Tuberculosis (TB) continues to be a major cause of death worldwide that can be effectively treated with timely diagnosis and treatment. With the advent of nuclear imaging techniques like 18Fluorine Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography (18F-FDG) PET/CT, the diagnosis of tuberculosis, particularly its extrapulmonary forms, has received great impetus in cases where microbiological confirmation cannot be achieved. Although detection of mycobacteria either by staining, culture or nucleic acid amplification techniques still form the gold standard of diagnosis, newer diagnostic techniques are always welcome in the field which can expedite clinical management. Use of radiolabeled antibiotics is one such evolving sphere which needs further research. Moving ahead from radiolabeled leukocytes, antibiotics are being increasingly focused upon to act as a vehicle to locate infectious lesions. Antibiotics like ciprofloxacin have been labeled with diagnostic radionuclides such as Technetium-99m (Tc-99m) and used to image many infectious diseases with encouraging results in TB. However, the nonspecific attributes of ciprofloxacin have hindered its growth to assist the diagnosis of TB. A novel approach would be to utilize ethambutol, a specific antitubercular agent, which has been found to be safe and effective in the diagnosis of TB in the available published studies. Ethambutol is known to be taken up specifically by tubercular lesions. This forms the basis of using Tc-99m labelled ethambutol for imaging TB lesions. An added advantage would be its ability to differentiate tubercular from malignant and fungal lung lesions that are the usual differentials in patients suspected of having TB. Most of the studies involving ethambutol have been done in skeletal TB and its validation in other forms of TB is still awaited. Recently the role of PET-CT has also been explored in human studies using 11C Rifampicin to study the antibiotic uptake in tubercular lesions. This review summarizes the available evidence regarding diagnosis of TB by radiolabeled antibiotic imaging to emphasize the need for accelerated research in the fight against TB.

99mTc-Ethambutol Scintigraphy with Single-Photon Emission Computed Tomography/Computed Tomography in Lymph Node Tuberculosis: An Initial Experience.

Purpose of the Study: The purpose of the study is to evaluate 99mTc-labeled ethambutol (99mTc-EMB) as a potential diagnostic agent in lymph node tuberculosis (LNTB). Materials and Methods: A prospective pilot study was done at All India Institute of Medical Sciences, New Delhi. We included adult consenting patients who were diagnosed with LNTB and were either treatment naïve or had just started treatment. Patients were injected with 10-15 mCi of 99mTc-EMB. Whole-body anteroposterior planar imaging was done from 15 min after injection at serial intervals till 4-6 h along with one single-photon emission computed tomography-computed tomography (SPECT-CT) imaging with the help of a dual-head SPECT-CT gamma camera. The uptake of 99mTc-EMB was analyzed and corroborated with clinicoradiological findings. Results: Between January 2019 and November 2020, we recruited 23 patients who underwent 99mTc-EMB, and 19 scans were interpretable and considered for analysis. Cervical lymphadenopathy was the most common presentation (13, 68.42%), followed by mediastinal (9, 47.36%) and abdominal (4, 21.05%) nodes. Other involvement included pulmonary (8, 42.1%), gastrointestinal (3, 15.78%), and chest wall abscess and bone marrow deposits in 1 patient each. A positive scan was noted in 7 (53.84%) patients with cervical lymphadenopathy, whereas uptake in abdominal and mediastinal lymph nodes was seen in 1 (25%) and 2 (22.22%) cases, respectively. Uptake in pulmonary lesions was noted in 3 (37.5%), but uptake in hepatic and splenic lesions was not seen. Conclusion: 99mTc-EMB scan can demonstrate drug penetrance in vivo in some patients with LNTB and should be explored further with a larger sample size.

Post COVID-19 sequelae: A prospective observational study from Northern India.

Post COVID-19 sequelae are a constellation of symptoms often reported after recovering from COVID-19. There is a need to better understand the clinical spectrum and long-term course of this clinical entity. The aim of this study is to describe the clinical features and risk factors of post COVID-19 sequelae in the North Indian population. This prospective observational study was conducted at a tertiary healthcare centre in Northern India between October 2020 and February 2021. Patients aged >18 years with laboratory-confirmed COVID-19 were recruited after at least two weeks of diagnosis, and details were captured. A total of 1234 patients were recruited and followed up for a median duration of 91 days (IQR: 45-181 days). Among them, 495 (40.1%) had persistent symptoms post-discharge or recovery. In 223 (18.1%) patients, the symptoms resolved within four weeks; 150 (12.1%) patients had symptoms till 12 weeks, and 122 (9.9%) patients had symptoms beyond 12 weeks of diagnosis/symptom-onset of COVID-19. Most common symptoms included myalgia (10.9%), fatigue (5.5%), shortness of breath (6.1%), cough (2.1%), insomnia (1.4%), mood disturbances (0.48%) and anxiety (0.6%). Patients who were hospitalized were more likely to report fatigue as a feature of long COVID. Hypothyroidism (OR: 4.13, 95% CI: 2.2-7.6, p-value < 0.001) and hypoxia (SpO2 ≤ 93%) (OR: 1.7, 95% CI: 1.1-2.4, p-value 0.012) were identified as risk factors for long COVID sequelae. In conclusion, long COVID symptoms were common (22%), and 9.9% had the post COVID-19 syndrome. Myalgias, fatigue and dyspnoea were common symptoms. Patients with hypothyroidism and hypoxia during acute illness were at higher risk of long COVID.

SARS-CoV-2 RT-PCR profile in 298 Indian COVID-19 patients: a retrospective observational study.

BACKGROUND: despite being in the 5th month of pandemic, knowledge with respect to viral dynamics, infectivity and RT-PCR positivity continues to evolve. AIM: to analyse the SARS CoV-2 nucleic acid RT-PCR profiles in COVID-19 patients. DESIGN: it was a retrospective, observational study conducted at COVID facilities under AIIMS, New Delhi. METHODS: patients admitted with laboratory confirmed COVID-19 were eligible for enrolment. Patients with incomplete details, or only single PCR tests were excluded. Data regarding demographic details, comorbidities, treatment received and results of SARS-CoV-2 RT-PCR performed on nasopharyngeal and oropharyngeal swabs, collected at different time points, was retrieved from the hospital records. RESULTS: a total of 298 patients were included, majority were males (75·8%) with mean age of 39·07 years (0·6-88 years). The mean duration from symptom onset to first positive RT-PCR was 4·7 days (SD 3·67), while that of symptom onset to last positive test was 17·83 days (SD 6·22). Proportions of positive RT-PCR tests were 100%, 49%, 24%, 8·7% and 20·6% in the 1st, 2nd, 3rd, 4th and >4 weeks of illness. A total of 12 symptomatic patients had prolonged positive test results even after 3 weeks of symptom onset. Age > = 60 years was associated with prolonged RT-PCR positivity (statistically significant). CONCLUSION: this study showed that the average period of PCR positivity is more than 2 weeks in COVID-19 patients; elderly patients have prolonged duration of RT-PCR positivity and requires further follow up.

Characteristics and outcomes of 231 COVID-19 cases admitted at a tertiary facility in India: An observational cohort study.

BACKGROUND: Ongoing pandemic because of COVID-19 has spread across countries, with varied clinical features and severity. Awareness of clinical course among asymptomatic and symptomatology in symptomatic cases is essential for patients' management as well as optimal utilization of health services (in resource limited settings) based on clinical status and risk factors. This study aimed to describe the clinical characteristics and outcomes of patients admitted with COVID-19 illness in the initial phase of the pandemic in India. METHODS: It was an observational study. Patients aged 18 years or more, with confirmed SARS-CoV-2 infection, asymptomatic or mildly ill, were included. Patients with moderate-severe disease at admission or incomplete clinical symptomatology records were excluded. Data regarding demography, comorbidities, clinical features and course, treatment, results of SARS-CoV-2 RT-PCR, chest radiographs, and laboratory parameters were obtained retrospectively from hospital records. The outcome was noted in terms of course, patients discharged, still admitted (at the time of the study), or death. RESULTS: Out of 231 cases, most were males (78.3%) with a mean age of 39.8 years. Comorbidities were present in 21.2% of patients, diabetes mellitus and hypertension being the most common. The most common symptoms were dry cough (81, 35%), fever (64, 27.7%), sore throat (36, 15.6%); asymptomatic infection noted in 108 (46.8%) patients. The presence of comorbidities was an independent predictor of symptomatic disease (OR-2.66; 95%CI 1.08-6.53, P = 0·03). None of the patients progressed to moderate-severe COVID-19, and there were no deaths. CONCLUSIONS: A large proportion of patients remained asymptomatic whereas those with comorbidities were more likely to be symptomatic. Most with mild disease had a stable disease course, barring few complication in those with comorbidities. The pandemic continues to grow as large number of asymptomatic cases may go undiagnosed.