LITERATURE UPDATE
absent skin lesions and negative skin smears. Diagnosing PNL is an uphill task as most of these patients have non- specific changes on nerve biopsy. In such circumstances, additional molecular diagnostic tools like the polymerase chain reaction (PCR) have proven to be useful in diagnosing leprosy. The present study was planned to evaluate the role of PCR in nerve biopsy specimens of patients with PNL.
Patients attending the neuromuscular
clinic from January 2013 to June 2014 with mononeuropathy multiplex underwent detailed diagnostic evaluation to ascertain the cause of neuropathy. Patients where this evaluation failed to establish an aetiology underwent a nerve biopsy. Nerve biopsy was done in 52 patients, of which 35 were diagnosed as pure neuritic leprosy. Definite leprosy with positive Wade-Fite staining for lepra bacilli was seen in 13 patients, and 22 biopsies revealed a probable leprosy without lepra bacilli being identified. PCR for Mycobacterium leprae was positive in 22 patients (62%). Twelve of the 13 cases with definite leprosy on histopathology were PCR-positive while, in the AFB-negative group, PCR was positive in 10 cases. PCR had a sensitivity of 92.3%, and specificity of 54.5%. The positive and negative predictive value of PCR was 54.5% and 92.3%, respectively.
PCR helps in diagnosing PNL in doubtful cases. A positive PCR increases the sensitivity of detection of M. leprae especially in cases of probable PNL where AFB cannot be demonstrated on histopathology.
Disseminated Mycobacterium simiae infection in a patient with adult-onset immunodeficiency due to anti- interferon-gamma antibodies – a case report
Keragala BSDP, Gunasekera CN, Yesudian PD et al. BMC Infect Dis 2020; 20 (1): 258. doi: 10.1186/s12879-020-04984-x.
Mycobacterial species other than Mycobacterium tuberculosis and M. leprae are generally free-living organisms and M. simiae is one of the slowest growing non-tuberculous mycobacteria. This is the first case report of M. simiae infection in Sri Lanka, and only very few cases with extrapulmonary manifestation are reported in the literature. A 24-year-old, previously healthy Sri Lankan male presented with generalised lymphadenopathy with discharging sinuses, evening pyrexia, weight loss, poor appetite and splenomegaly. Lymph node biopsies showed sheets of macrophages packed with organisms in the absence of granulomata. Ziehl-
62
Modified AFB staining showing the presence of leprosy bacilli (Wade-Fite stain).
Neelsen, Wade-Fite and Giemsa stains revealed numerous red coloured acid- fast bacilli within foamy histiocytes. Slit skin smear for leprosy was negative and tuberculosis, fungal and bacterial cultures of the lymph node and bone marrow did not reveal any growth. Later he developed watery diarrhoea and colonoscopy revealed multiple small polyps and ulcers throughout the colon extending up to the ileum, which was confirmed to be due to cytomegalovirus confirmed by PCR and successfully treated with ganciclovir. Positron emission tomography scan- guided biopsies of the intestine and lymph nodes confirmed the presence of mycobacterial spindle cell pseudo- tumours and PCR assays revealed positive HSP65. The culture grew M. simiae. Flow cytometry analysis on the patient’s blood showed extremely low T- and B-cell counts and immunofixation revealed low immunoglobulin levels. His condition was later diagnosed as adult-onset immunodeficiency due to anti-interferon-gamma autoantibodies. He was initially commenced on empirical anti-TB treatment with atypical mycobacterial coverage. He is currently on a combination of daily clarithromycin, ciprofloxacin, linezolid with monthly 2 g/kg intravenous immunoglobulin, to which he had a remarkable clinical response with complete resolution of lymphadenopathy and healing of sinuses. This infection is considered to be
restricted to certain geographic areas such as mainly Iran, Cuba, Israel and Arizona, and this is the first case report from Sri Lanka. Even though the infection is mostly seen in elderly patients, this patient was only 24 years old. In the literature pulmonary involvement
was a common presentation, but in this case the patient had generalised lymphadenopathy and colonic involvement without pulmonary involvement.
An interesting finding of multiple calcified pulmonary nodules in a patient with rheumatoid arthritis Alfahad A, Jennings P, Smith S, Niktash N, Curtin J. BJR Case Rep 2015; 2 (1): 20150116. doi: 10.1259/bjrcr.20150116. eCollection 2016.
Calcified pulmonary (lung parenchymal) densities can occur in a number of conditions. A patient with rheumatoid arthritis presented with new right lung base nodules and left long base soft- tissue densities on his chest X-ray. These findings did not exist on his chest X-ray performed two years earlier. A subsequent thoracic computed tomography (CT) scan showed multiple pleural-based irregular nodules of soft- tissue density that were partially calcified. There was also mediastinal and hilar lymphadenopathy. Following a discussion at the respiratory multidisciplinary team meeting, a CT-guided nodal biopsy was performed that showed necrotic lung tissue with palisaded histiocytes and fibrosis with chronic inflammation. No vasculitis or granulomata were seen and there was no evidence of malignancy. Appearances were consistent with a rheumatoid nodule. No mycobacteria or fungi were seen on Ziehl-Neelsen, Wade-Fite or periodic acid-Schiff stains. The authors concluded that this patient had unusual calcified rheumatoid lung nodules. Previously, calcified pulmonary nodules have been reported in the setting of Caplan’s syndrome in miners.
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