Rhabdomyolysis secondary to immune reconstitution inflammatory syndrome: case report A 46-year-old woman developed rhabdomyolysis secondary to immune reconstitution inflammatory syndrome following treatment with paclitaxel for breast cancer [route, dosage and time to reaction onset not stated]. The woman, who had been diagnosed with breast cancer in September 2019, was receiving neoadjuvant chemotherapy with paclitaxel. She received her sixth cycle of paclitaxel on 3 rd April 2020. Prior to the next paclitaxel cycle, she underwent SARS-CoV-2 PCR screening test which showed positive result. She was asymptomatic. She was admitted to the isolation ward of a hospital in Portugal. During the first 15 days of hospital stay, she complained of occasional nausea and diffuse myalgia. On 2 nd May, she presented with vomiting, abdominal pain and new-onset fever. Laboratory investigations revealed elevated levels of CRP, amylase, transaminases, lactate dehydrogenase and γ glutamyltrasferase. Concurrent de novo lymphopenia and slight thrombocytopenia were also observed. Urine sediment analysis revealed unspecific alterations. The woman was treated with paracetamol and metoclopramide. Symptomatic relief was noted. Over the following two days, she developed diarrhoea and dry cough. On 5 th May, 19 days after admission, chest X-ray showed a COVID-19 related significant bilateral infiltrate with upper left lung consolidations. Laboratory investigation revealed marked increase in levels of creatine kinase, lactate dehydrogenase, ferritin and IL-6. Her CRP , transaminases, γ glutamyltrasferase, amylase and lipase levels also increased further. She was diagnosed with rhabdomyolysis related to COVID-19. Serology for SARS-CoV-2 showed antibody response. Nasopharyngeal swab was still positive for SARS-CoV-2 RNA. One month had passed since her last paclitaxel cycle. Metoclopramide was discontinued. A cytokine-mediated response in the wake of post-chemotherapy immune reconstitution was strongly suspected, based on the laboratory results and signs of multiorgan damage. She was initiated on methylprednisolone, hydroxychloroquine and bicarbonate. Over the following 48 hours, marked relief of myalgia, diarrhoea and asthenia were observed. Her cough became less intense and her fever resolved. Laboratory investigation revealed recovery of lymphocyte counts as well as decreasing in levels of creatine kinase, lactate dehydrogenase, CRP, liver enzymes and ferritin. She was diagnosed with immune reconstitution inflammatory syndrome secondary to paclitaxel therapy. Methylprednisolone was weaned off and then switched to prednisolone. Hydroxychloroquine was also discontinued. After 10 days of methylprednisolone therapy, a deltoid muscle biopsy performed. No viral RNA was detected in the muscle sample. Pathology did not show any inflammatory infiltrates or signs of muscle damage. The immune reconstitution inflammatory syndrome was suspected to have contributed in the development of rhabdomyolysis. She was discharged on the 10 th day of corticosteroids ...