Isoniazid-Induced Systemic Lupus Erythematosus: A Case Report

Infant Exposure to Antituberculosis Drugs via Breast Milk and Assessment of Potential Adverse Effects in Breastfed Infants: Critical Review of Data

Infants of mothers treated for tuberculosis might be exposed to drugs via breast milk. The existing information on the exposure of breastfed infants lacks a critical review of the published data. We aimed to evaluate the quality of the existing data on antituberculosis (anti-TB) drug concentrations in the plasma and milk as a methodologically sound basis for the potential risk of breastfeeding under therapy. We performed a systematic search in PubMed for bedaquiline, clofazimine, cycloserine/terizidone, levofloxacin, linezolid, pretomanid/pa824, pyrazinamide, streptomycin, ethambutol, rifampicin and isoniazid, supplemented with update references found in LactMed^®. We calculated the external infant exposure (EID) for each drug and compared it with the recommended WHO dose for infants (relative external infant dose) and assessed their potential to elicit adverse effects in the breastfed infant. Breast milk concentration data were mainly not satisfactory to properly estimate the EID. Most of the studies suffer from limitations in the sample collection, quantity, timing and study design. Infant plasma concentrations are extremely scarce and very little data exist documenting the clinical outcome in exposed infants. Concerns for potential adverse effects in breastfed infants could be ruled out for bedaquiline, cycloserine/terizidone, linezolid and pyrazinamide. Adequate studies should be performed covering the scenario in treated mothers, breast milk and infants.

Disease criteria of systemic lupus erythematosus (SLE); the potential role of non-criteria autoantibodies

Patients with SLE show a broad spectrum of more than 200 autoantibodies. They can be pathogenic, predictive, prognostic or even an epiphenomenon. Here, we discuss different autoantibodies that have not been included in EULAR/ACR 2019 classification criteria. Most of them have been addressed to monitor and detect disease activity and not specifically as classification criteria. Indeed, markers to assess disease activity fluctuate as compared with classification criteria and their validation is different. The development of new methods will probably bring new clinical associations and be evaluated as potential classification criteria.

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Most of the autoantibodies described in SLE are of utility in monitoring disease activity.

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The validation of activity biomarkers is different from classification criteria biomarkers.

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The new methods coming into the clinical routine will bring new associations and potentially classification criteria.

Isoniazid-induced Lupus: When the Cure Can Be Lethal

A 50-year-old female with a past medical history of bone tuberculosis diagnosed nine months ago was admitted in our infirmary for persistent fever with no evident cause. The patient was treated with isoniazid, rifampicin, pyrazinamide, and ethambutol for seven months and for the past two months, she was taking isoniazid and rifampicin. She went to our emergency room (ER) for back pain and fever that she had been experiencing for the last month. She was admitted with suspicion of disseminated tuberculosis that was never confirmed. Physical examination was unremarkable. Blood tests showed an elevation of inflammation parameters. A computed tomography (CT) scan of the chest showed a mild pleural effusion. She remained with fever during the three weeks in the infirmary while undergoing many other studies that were all negative. The back pain would change sides, and three consecutive thoracic radiographies showed a small-sized pleural effusion that was either predominantly right-sided or left-sided. Several differential diagnoses were considered in the process, namely an active infection, neoplasia, or autoimmune disease. The search for circulating lupus anticoagulant was positive. Antinuclear antibodies (ANA) were positive and the anti-histone antibody was strongly positive. At this point, we suspected a drug-induced lupus diagnosis, and isoniazid was discontinued. Following discontinuation of isoniazid, back pain and fever subsided and patient was discharged after one week. This case is a diagnostic challenge because of the rarity and symptom severity of isoniazid-induced lupus. Isoniazid rarely induced this lupus-like syndrome, with an incidence of considerably less than 1%.