Current updates on HIV-related pulmonary disease in children: What do radiologists and clinicians need to know?

Page 1 of 5 Review Article Current updates on HIV-related pulmonary disease in children: What do radiologists and clinicians need to know? Authors: Tracy Kilborn1 Winnie C.W. Chu2 K.M. Das3 Bernard Laya4 Edward Y. Lee5 Affiliations: 1 Department of Paediatric Radiology, Red Cross War Memorial Children’s Hospital, University of Cape Town, Cape Town, South Africa Department of Imaging and Interventional Radiology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong 2 Department of Radiology, College of Medicine and Health Sciences, United Arab Emirates (UAE) University, Al Ain, United Arab Emirates 3 Institute of Radiology, St. Luke’s Medical Center – Quezon City and Global City, Philippines 4 Department of Radiology, Boston Children’s Hospital and Harvard Medical School, United States of America 5 Correspondence to: Edward Y. Lee Email: edward.lee@childrens. harvard.edu Postal address: 300 Longwood Avenue, Boston, MA 02115, United States of America Dates: Received: 14 Aug. 2015 Accepted: 09 Oct. 2015 Published: 11 Dec. 2015 Read online: Scan this QR code with your smart phone or mobile device to read online. Despite substantial advances in diagnosis and treatment, pulmonary human immunodeficiency virus (HIV) infection continues to be a major cause of morbidity and mortality in infants and children particularly those who live in developing countries. This article provides an up-to-date review on underlying etiology, often characteristic imaging findings and current management of pulmonary HIV infection in infants and children. Increased understanding of clinical and unique imaging findings of pulmonary HIV infection has a great potential for early and accurate diagnosis which, in turn, can eventually improve pediatric patient care. Introduction Despite substantial advances in diagnosis and treatment, pulmonary human immunodeficiency virus (HIV) infection continues to be a major cause of morbidity and mortality in infants and children particularly those who live in developing countries. This article provides an up-to-date review on etiology, imaging findings and management of pulmonary HIV infection in infants and children. Increased understanding of clinical and imaging findings of pulmonary HIV infection has a great potential for early and accurate diagnosis which, in turn, can eventually improve pediatric patient care. Human immunodeficiency virus (HIV) pulmonary infection Etiology The Joint United Nations Programme on HIV/AIDS (UNAIDS) 2013 global report identifies 2.9 million children infected with HIV living in sub-Saharan Africa, which is the highest incidence in the world.1 The hallmark of HIV infection is the progressive depletion of CD4+ T lymphocytes as a result of reduced production and increased destruction.2 Within the lung, direct infection of pulmonary macrophages and lymphocytes plays an important role in the pathogenesis of pulmonary disease as does an increase in immune activation.2 In addition to T cell destruction and impaired cell-mediated immune response, HIV infection is also associated with defects in humoral (B cell) immunity leading to an impaired ability to generate antigen specific response.3 HIV leads to progressive immunodeficiency, opportunistic infection, AIDS related malignancy and ultimately death. The prognosis of children infected with HIV has improved since the advent of highly active antiretroviral therapy (HAART) with the emerging problem of chronic lung disease. Clinical presentation The HIV epidemic has resulted in an increase in childhood respiratory disease related morbidity and mortality.3,4 This is particularly evident in Africa where it is compounded by poorly implemented preventative strategies and limited access to Highly Active Antiretroviral Therapy (HAART).1 Six major respiratory disorders related to HIV infection in the pediatric patient population include: (1) pneumonia; (2) tuberculosis (TB); (3) lymphocytic interstitial pneumonia (LIP); (4) Immune Reconstitution Inflammatory Syndrome (IRIS); (5) malignancy; and (6) chronic lung disease, which are discussed in the following section. Pneumonia remains the most common cause of hospital admission in African children infected with HIV. Pneumonia related mortality in children infected with HIV is currently 3–6 times that of non-HIV infected patients.5 Pneumocystis jirovecii (PCP) pneumonia remains a frequent underlying infectious cause in infants infected with HIV. These affected infants typically present with mild to severe acute respiratory distress and hypoxia.5 Superimposed infection with Cytomegalovirus How to cite this article: Kilborn T, Chu, W.C.W, Das KM, Laya BF, Lee EY. Current updates on HIV-related pulmonary disease in children: What do radiologists and clinicians need to know? S Afr J Rad. 2015;19(2); Art. #928, 5 pages. http://dx.doi.org/10.4102/sajr.v19i2.928 Copyright: © 2015. The Authors. Licensee: AOSIS OpenJournals. This work is licensed under the Creative Commons Attribution License. http://www.sajr.org.za doi:10.4102/sajr.v19i2.928 Page 2 of 5 (CMV) in HIV infected infants with PCP pneumonia is common and results in more rapid progression of underlying HIV disease.5,6 The common respiratory viruses of childhood (respiratory syncytial virus, influenza, parainfluenza and adenovirus) are more common in older children with HIV and are more likely to be complicated by bacterial pneumonia.4 Outside of infancy, Streptococcus pneumoniae is the most common cause of bacterial infection and may be recurrent in pediatric patients with HIV infection. Other frequent pathogens include Hemophilus influenzae, Staphlococcus aureus (including methicillin resistant strains), Klebsiella pneumoniae, Salmonella spp. and Eschericia coli.5,6 Factors complicating treatment of bacterial infection include reduced efficacy of vaccines and reduced antibiotic susceptibility in children infected with HIV.7,8 In areas with a high incidence of tuberculosis such as Africa, Mycobacterium tuberculosis (TB) is an important cause of acute and chronic respiratory infection in HIV- infected children. They have an increased risk of developing complicated or disseminated disease.5 Standard TB therapy is less efficacious with lower cure rates and higher mortality.9 Co-infection with TB and HIV results in more rapid deterioration in immune function, viral replication and eventually HIV progression.9 Other fungal infection such as chronic oropharyngeal, laryngeal or oesophageal Candida albicans infection is also common and may result in dysmotility, gastro-oesophageal reflux disease and/ or aspiration and present with respiratory symptoms.10 Lymphocytic interstitial pneumonia (LIP) can still occur in HIV-infected children who have limited access to HAART (30%–40%).11,12 Co-infection with Epstein Barr virus and HIV is thought to cause a lymphoproliferative response in multiple organs including the lungs.5 Affected children typically present with cough, tachypnea, a (...truncated)