Successful rapid oral desensitization for dual hypersensitivity to isoniazid and rifampin while treating central nervous system tuberculosis

CNS tuberculoma in an immunocompetent patient: A case report of multi-drug hypersensitivity to RIPE therapy

Background

Tuberculosis (TB) is the second leading cause of death due to an infectious disease worldwide (World Health Organization, 2022 [1]). The first line treatment of TB involves the concurrent use of four drugs: rifampin, isoniazid, pyrazinamide, and ethambutol (RIPE). Given the rising threat of multidrug resistant TB, it is crucial to understand how TB can be treated when first line treatment is not an option.

Case presentation

We report a rare case of multi-drug hypersensitivity to RIPE therapy in an immunocompetent patient with an unusual presentation of CNS tuberculoma. The patient presented to an outside hospital four months prior with weakness, numbness, imbalance, and speech difficulties. A CT of the head revealed a mass in the left parietal lobe that demonstrated chronic necrotizing granulomatous inflammation with positive cultures for M. tuberculosis. The patient was started on a regimen of rifampin 600 mg daily, isoniazid 300 mg daily, pyrazinamide 2000 mg daily, ethambutol 1200 mg daily, and pyridoxine 50 mg daily. However, the patient developed drug hypersensitivity reactions to both rifampin and ethambutol with subsequent failed desensitization to rifabutin. She was ultimately discharged from the hospital on a regimen of isoniazid, pyridoxine, pyrazinamide, and moxifloxacin with plans for outpatient follow-up.

Conclusions

This case highlights a rare clinical presentation of multiple drug hypersensitivity in the setting of a CNS tuberculoma and the importance of identifying the offending agents early in the course of treatment and adjusting the drug regimen accordingly. Desensitization should be attempted, but if ineffective, then alternative drug regimens should be formulated on a case-by-case basis.

'Practical management of suspected hypersensitivity reactions to anti-tuberculosis drugs.'

Tuberculosis (TB) is the commonest cause of death by a single infectious agent globally and ranks amongst the top ten causes of global mortality. The incidence of TB is highest in Low-Middle Income countries (LMICs). Prompt institution of, and compliance with, therapy are cornerstones for a favourable outcome in TB and to mitigate the risk of multiple drug resistant (MDR)-TB, which is challenging to treat. There is some evidence that adverse drug reactions (ADRs) and hypersensitivity reactions (HSRs) to anti-TB drugs occur in over 60% and 3-4% of patients respectively. Both ADRs and HSRs represent significant barriers to treatment adherence and are recognised risk factors for MDR-TB. HSRs to anti-TB drugs are usually cutaneous and benign, occur within few weeks after commencement of therapy and are likely to be T-cell mediated. Severe and systemic T-cell mediated HSRs and IgE mediated anaphylaxis to anti-TB drugs are relatively rare, but important to recognise and treat promptly. T-cell mediated HSRs are more frequent amongst patients with co-existing HIV infection. Some patients develop multiple sensitisation to anti-TB drugs. Whilst skin tests, patch tests and in vitro diagnostics have been used in the investigation of HSRs to anti-TB drugs, their predictive value is not established, they are onerous, require specialist input of an allergist and are resource-dependent. This is compounded by the global, unmet demand for allergy specialists, particularly in low income countries (LICs) / LMICs and now the challenging circumstances of the SARS-CoV-2 pandemic. This narrative review provides a critical analysis of the limited published evidence on this topic and proposes a cautious and pragmatic approach to optimise and standardise the management of HSRs to anti-TB drugs. This includes clinical risk stratification and a dual strategy involving sequential re-challenge and rapid drug desensitisation. Furthermore, a concerted international effort is needed to generate real-time data on ADRs, HSRs, safety and clinical outcomes of these interventions.

Combined administration of rifampicin, ethambutol, and clarithromycin for the treatment of tenosynovitis of the hand caused by Mycobacterium avium complex: Case series and literature review

ABSTRACT

We report the clinical results and problems of combined administration of rifampicin, ethambutol, and clarithromycin (REC) for the treatment of Mycobacterium avium complex (MAC) infection of the hand (hand MAC).Participants included 7 patients with hand MAC. After resection of the infected lesion, REC was prescribed for 12 months. For these patients, the site of infection, clinical course after initiation of REC, adverse drug effects (ADEs), and incidence of recurrence were evaluated.Sites of infection were the flexor tenosynovium in 5 patients, extensor tenosynovium in 1 patient, and both flexor and extensor tenosynovium in 1 patient. ADEs of REC occurred in 5 patients, and included visual disturbance caused by ethambutol in 2 patients, liver function abnormality caused by rifampicin in 2 patients, and fever with diarrhea caused by rifampicin in 1 patient. For 2 of these 5 patients, desensitization therapy was applied and REC was able to be reinstated. In the remaining 3 patients, the causative drugs were discontinued and levofloxacin, a new quinolone, was administered. Complete healing was achieved in 5 patients, and recurrence was observed in 2 patients. These 2 patients with recurrence included 1 patient in whom REC was completed and 1 patient in whom REC therapy was modified due to ADE.REC provided relatively good clinical results as a treatment for hand MAC. However, recurrences were observed even after the completion of REC and the use of an alternative drug. Optimal duration of REC and appropriate alternative drugs need to be identified in the future.

Protocols for drug allergy desensitization in children

Introduction: When a drug hypersensitivity reaction is proven, desensitization protocols allow the reintroduction of the molecule in patients for whom such therapy is essential. Through drug desensitization (DDS), a temporary immune tolerance is maintained for the single course of a specific therapy. In pediatrics, indications for such a procedure include children with chronic diseases, severe infectious diseases and/or malignancies, who have a proven drug hypersensitivity.Areas covered: We ran a search on PubMed and Web of Science for papers on DDS and on DDS in children. Most protocols and recommendations on DDS focus on adults and have been adapted for children. The best candidates for desensitization are children with a history of immediate, IgE-mediated drug allergy, but this therapy may be applied also in nonallergic hypersensitivities and in non-immediate reactions. Most protocols in literature focus on antibiotics, especially beta-lactams, on chemotherapeutic agents, and on monoclonal antibodies.Expert opinion: Pediatric allergists should cooperate with specialists in infectious diseases and onco-hematology to provide DDS to children in need. Standardized protocols and international guidelines are still needed to optimize such treatment and to implement it in clinical daily practice.