Practice EssentialsAn immunocompromised host is a patient who does not have the ability to respond normally to an infection because of an impaired or weakened immune system. This inability to fight infection can be caused by a number of conditions, including diseases (eg, diabetes, human immunodeficiency virus [HIV] infection), malnutrition, and drugs. [1] Show
Immunocompromising conditionsCongenital conditions Congenital conditions most commonly affect the fetus and newborn. Classes of congenital conditions include the following:
Acquired conditions These conditions may interfere directly with the immune system or may disrupt barrier function. Types of acquired conditions include the following:
Infectious complicationsImmunocompromised patients are susceptible to bacterial, fungal, viral, and parasitic infections that healthy immune systems usually overcome. They are also more susceptible to complications from common infections. B-cell defects predispose patients to frequent sinopulmonary and respiratory tract infections and infections with nonenveloped viruses, parvovirus B19, and rotavirus. Almost any organism can cause infection in patients with combined B-cell and T-cell defects. These patients often present with failure to thrive, thrush, and Pneumocystis jirovecii infection. Other commonly seen pathogens include Streptococcus pneumoniae, Pseudomonas aeruginosa, Legionella pneumophila, Listeria monocytogenes, Nocardia species, Mycobacterium species, fungi, varicella-zoster virus (VZV), herpes simplex virus (HSV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), viruses that cause respiratory tract infections, Toxoplasma species, cryptosporidia, Strongyloides species, and other encapsulated bacteria. T-cell defects predispose to infections with Candida species, Mycobacterium avium-intracellulare complex, herpesviruses, and P jirovecii. Phagocyte deficiency or dysfunction predisposes patients to infections with Staphylococcus aureus, Nocardia species, P aeruginosa, Serratia species, streptococci, other enteric organisms, and Candida, Burkholderia, Aspergillus, and Chromobacterium species. Complement deficiency is associated with recurrent sinopulmonary infections and invasive infections due to encapsulated bacteria such as S pneumoniae, Haemophilus influenzae, and Neisseria meningitidis. Infectious diarrhea, pneumonia, tuberculosis, measles, malaria, salmonellosis, P jirovecii infection, and HIV infection are common causes of death among malnourished infants and children. In immunosuppression due to HIV infection, a myriad of opportunistic infections may occur, particularly as immune function deteriorates in the absence of antiretroviral treatment. IDSA guidelines recommend vaccination for immunocompromised patientsAccording to guidelines from the Infectious Diseases Society of America (IDSA), most immunocompromised patients should be vaccinated. These guidelines are designed for health care professionals who care for patients with compromised immune systems due to HIV infection or acquired immunodeficiency syndrome (AIDS), cancer, solid organ transplantation, stem cell transplantation, sickle cell disease or asplenia, congenital immune deficiencies, chronic inflammatory conditions, cochlear implants, or cerebrospinal fluid leaks. [2, 3] Specific recommendations include the following:
OverviewMuch of the practice of pediatric infectious diseases now focuses on the treatment of the fetus, neonate, infant, child, and adolescent who have infections in the context of immunocompromise. [4] Because of the vast scope of this topic, the interested reader is referred to appropriate reviews for exhaustive treatment of specific immunologic and immune-compromising disorders and infections. [5, 6] Further information is also available in textbooks of pediatric infectious diseases (some of which are devoted exclusively to this topic) as cited in the bibliography. This review focuses on evaluation of the child with frequent infections (who likely has no immunocompromise), conditions leading to immunocompromise (congenital, acquired, and iatrogenic in broad terms), and the particular infections associated with these conditions. Most children who have a series of frequent, benign, self-limited, mostly viral infections are examined in the office in the context of parental or familial concern for an underlying immune problem or perception that the child is sickly. The patient often seems to get sick more often than siblings and peers. Nevertheless, most children with frequent infections are immunologically healthy. Careful questioning and evaluation frequently reveal previous events or problems that predispose the patient to such concerns (eg, the vulnerable child syndrome). Thorough history taking and physical examination, with a review of laboratory and radiographic results (which generally accompany the patient), almost always help in excluding clinically significant immunologic disorders. In rare cases, Munchausen syndrome or Munchausen syndrome by proxy manifests as frequent or obscure infections (or suspicion of such infections). Secondary or acquired immunodeficiency is more common than primary immunodeficiency. Children who require hospitalization for management of a common infection should raise suspicion of an immunocompromising condition. The Child with Frequent InfectionsHistoryFor the outpatient with frequent infections, a thorough history should be obtained. In particular, the following should be identified [1] :
A complete history should be obtained for all patients, with attention to the following:
Physical examinationA thorough physical examination should be performed for the outpatient with frequent infections, with particular attention to the following:
Thorough physical examination often provides clues to the presence and etiology of infectious complications of immunocompromise. Immunocompromising ConditionsCongenital conditionsCongenital conditions most commonly affect the fetus and newborn. Syndromes
B-cell defects [12]
Combined B-cell and T-cell defects
T-cell defects
Macrophage, cytokine, and miscellaneous defects
Phagocyte deficiency or dysfunction
Complement deficiencies [45]
Other conditions
Acquired conditionsAcquired conditions may interfere directly with the immune system or may disrupt barrier function.
Iatrogenic or self-inflicted conditionsIatrogenic or self-inflicted conditions may directly interfere with the immune system or may disrupt barrier function. Use of certain drugs or therapies (eg, radiation therapy) may interfere with normal flora, decrease gastric acidity and ciliary motility, and also may be directly immunomodulating. [52] Trauma
Treatment
Alternate DiagnosesTable. Differential Diagnoses (Open Table in a new window)
InfectionsIn general, infectious complications can be seen with almost any immune-compromising condition. The following discussion includes infections most frequently associated with the immunocompromising conditions enumerated above, with particular attention to the distinctive infections for each condition. Refer to the reviews of the specific infections for further details. Fetal and neonatal immune systemsThe fetal and neonatal immune systems are not fully developed, [56] and the aggressive measures frequently needed to care for young patients may predispose them to various infections with the following agents:
Hemoglobinopathies and other predisposing conditionsHemoglobinopathies predispose patients to infections that are also seen in those with congenital or acquired asplenia. Some infectious agents associated with hemoglobinopathies include encapsulated organisms such as Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria species. Other organisms include Salmonella species, E coli, K pneumoniae, and Edwardsiella species. Asplenia (congenital or acquired) predisposes patients to parasitic infections, such as malaria and babesiosis, and also to infections by encapsulated organisms, such as S pneumoniae, H influenzae, E coli, K pneumoniae, Neisseria meningitidis, and Capnocytophaga canimorsus. [49] Iron overload increases the susceptibility of patients to Yersinia, Vibrio, and Capnocytophaga infections. Leukemia and lymphoma predispose patients to infections with S aureus, coagulase-negative staphylococci, Pseudomonas aeruginosa, enteric organisms, fungi, [58] S pneumoniae, H influenzae, mycobacteria, and viruses. Transfusions may increase the susceptibility of patients to infections caused by Babesia, Plasmodium, [59] and Trypanosoma species. Humoral deficiencyB-cell defects may predispose patients to frequent sinopulmonary and respiratory tract infections. Common causes of infections are nonenveloped viruses, parvovirus B19, and rotavirus. Patients are also at risk for infections with S pneumoniae, H influenzae, S aureus, P aeruginosa, M pneumoniae, and enteric pathogens such as Giardia lamblia and Salmonella, Shigella, and Campylobacter species. Specific B-cell defects and their associated pathogens and conditions are listed below [12] :
Combined humoral and cellular deficiencyAlmost any organism can cause infection in patients with combined B-cell and T-cell defects. These patients often present with failure to thrive, thrush, and P jirovecii infection. Other commonly seen pathogens include S pneumoniae, P aeruginosa, Legionella pneumophila, L monocytogenes, Nocardia species, Mycobacterium species, fungi, VZV, HSV, CMV, Epstein-Barr virus (EBV), viruses that cause recurrent respiratory tract infections, [61] Toxoplasma species, cryptosporidia, Strongyloides species, and encapsulated bacteria. Types of combined B-cell and T-cell defects and their associated conditions and pathogens include the following:
Cellular deficiencyT-cell defects predispose to infections with Candida, Mycobacterium avium-intracellulare complex, herpesviruses, and P jiroveci. Specific T-cell defects and their associated conditions and pathogens are as follows:
Macrophage, cytokine, and miscellaneous deficienciesMacrophage, cytokine, and miscellaneous defects are associated with mycobacterial infections and infections with Salmonella and Listeria species. Specific defects and their associated conditions and pathogens are as follows:
Autoimmune and inflammatory disorders predispose patients to infections with P jirovecii and Candida, Aspergillus, and Mucor species. Congenital or acquired lymphedema increases the susceptibility of patients to Streptococcus pyogenes infections. Midline dermal sinuses, Mondini defects of the inner ear, and meningeal defects predispose patients to recurrent meningitis. Disorders of ciliary function predispose patients to frequent sinopulmonary and other respiratory tract infections. [91] Geosmithia argillacea is a mold of significance for those with cystic fibrosis. [92] Decreased sensation can contribute to recurrent skin and soft tissue infections. Trisomy 21 and other genetic disorders are linked to otitis media and upper respiratory tract infections, as well as to infections with Candida organisms. Hemorrhagic hereditary telangiectasia (Osler-Weber-Rendu disease) predisposes patients to brain abscesses and S aureus infections. Rubinstein-Taybi syndrome increases the susceptibility of patients to recurrent respiratory tract infections, apparently because of deficient polysaccharide antibody responses. CHARGE (coloboma, heart defect, atresia choanae, retarded growth and development, genital hypoplasia, ear anomalies/deafness) syndrome may have a presentation similar to that of severe combined immunodeficiency. [10] Phagocyte deficiencyPhagocyte deficiency [93] or dysfunction predisposes patients to infections with S aureus, Nocardia species, P aeruginosa, Serratia species, streptococci, other enteric organisms, Candida, Burkholderia, Aspergillus, and Chromobacterium species. Immunocompromising conditions and associated pathogens and infections are as follows:
Complement deficiencyComplement deficiencies and their associated conditions and infections are as follows [45] :
Nutritional deficiencyMalnutrition is a significant condition that leads to immunocompromise and reduces the ability of those affected to manage infections. Infectious processes that cause diarrhea, pneumonia, tuberculosis, measles, malaria, salmonellosis, and P jirovecii infection are common causes of death among malnourished infants and children. Galactosemia predisposes patients to infections with E coli. Human immunodeficiency virusIn immunosuppression due to human immunodeficiency virus (HIV) infection a myriad of infections occur, particularly as the immune function deteriorates in patients without antiretroviral treatment. Conditions and organisms related to HIV infection are as follows:
Barrier deficiencyAny break in the barrier function of the skin and other epithelium predisposes to wound infections and complications, such as tetanus; wound botulism; P aeruginosa infection; and infection with staphylococci, streptococci, gram-negative bacilli, and Mycobacterium marinum. The following medical conditions lead to infectious complications with the agents listed below:
Skin and mucous membrane complications increase the susceptibility of patients to infections with S aureus, S pyogenes, corynebacteria, and other pathogens. Injections predispose to skin and soft tissue infections. Contamination while obtaining intravenous (IV) access may lead to intravascular infections. Wound infections may complicate incisions and other breaks in the skin. Intravascular or drainage devices predispose patients to infections with coagulase-negative staphylococci, S aureus, viridans streptococci, enteric organisms, Corynebacterium species, Bacillus species, Malassezia furfur, Acinetobacter species, P aeruginosa, Candida species, Gemella species, and mycobacteria. Internal foreign bodies predispose to infections with coagulase-negative staphylococci; diphtheroids; corynebacteria; and Leuconostoc, Tsukamurella, and Pediococcus species. Human, animal, and insect bites or scratches may transmit systemic diseases, such as tick- and arthropod-borne infections, or may become complicated by infections with Pasteurella multocida, C canimorsus, Bartonella species, S aureus, S pyogenes, Eikenella corrodens, gram-negative bacilli, anaerobes, and rabies virus. [116] Pathogens that cause infections in burn wounds vary according to the body tissue and location and the hospital environment. Pathogens that have been implicated in burn wound infections include the following:
Complications from medicationDrugs that interfere with the normal flora may predispose patients to candidiasis and Clostridioides difficile infection. Drugs that decrease gastric acidity predispose to infections with Salmonella species and Vibrio cholerae, other enteric infections, and community-acquired pneumonia. [102] Other treatments and medications may interfere directly with immune function. For example, neutropenic patients are particularly at risk for infections with bacteria such as E coli, K pneumoniae, Enterobacter species, Citrobacter species, P aeruginosa, S aureus, Clostridium septicum, coagulase-negative staphylococci, streptococci, enterococci, anaerobes, and a variety of yeasts and fungi (especially Candida and Aspergillus). [117] Corticosteroid therapy predisposes patients to infections with many organisms, including S aureus, S pneumoniae, Legionella species, Listeria species, P jirovecii, Nocardia species, Strongyloides species, and VZV. Inhaled corticosteroid therapy increases the susceptibility of patients to thrush and community-acquired pneumonia. [102] Inhibitors of tumor necrosis factor (TNF) predispose to tuberculosis, [55] atypical mycobacterial infections, HSV encephalitis and infections, [118] histoplasmosis, [119] Listeria infection, [120] and severe Plasmodium falciparum malaria. [121] Other monoclonal antibodies and related small molecules have been associated with numerous infections. [122] For example, therapy with eculizumab, a C5 inhibitor, is associated with invasive meningococcal infection. Similarly, treatment with natalizumab (for multiple sclerosis) is associated with progressive multifocal leukoencephalopathy. [123, 124] Treatment with infliximab has been associated with disseminated cutaneous VZV infection. [121, 125] Transplant complicationsBone marrow or stem cell transplant predisposes to infections with multiple organisms. [126] The pre-engraftment period poses the highest risk of bacterial bloodstream infections. [1] Among the pathogens that have caused infections after bone marrow or stem cell transplant are the following:
Solid organ transplant predisposes to infections with the following organisms [136] :
EvaluationLaboratory studies at initial presentationObtain a complete blood cell count, chemistry profile, and erythrocyte sedimentation rate or C-reactive protein level. Order other diagnostic tests as directed by the presentation and underlying condition. Blood cultures may be indicated depending on the patient's illness. Initial and serial cultures might be performed by using samples obtained from peripheral sites and from an access device. Obtain routine aerobic and anaerobic, fungal, viral, and mycobacterial stains and cultures of samples of various sources or locations: blood, urine, cerebrospinal fluid (CSF), throat, wound, synovial fluid, pleural fluid, peritoneal fluid, genitourinary tract, conjunctiva, nares, or skin. The patient's presenting infection and underlying immunocompromise dictate the tests and samples needed. Order rapid antigen or molecular testing as appropriate. These may include tests for group A streptococci, pneumococci, C difficile, Cryptococcus species, RSV, influenza virus, adenovirus, parainfluenza, human metapneumovirus, and rotavirus. Laboratory studies of immune functionEvaluation of numbers and function of B cells includes the following:
Evaluation of numbers and function of T cells includes the following:
Evaluation of phagocyte numbers and function includes the following:
Evaluation of complement status includes the following:
Imaging studies at initial presentationChest radiography may demonstrate infiltrates or other pulmonary disease. [141] Other radiographic studies should be performed as warranted. Imaging studies of immune system anatomy and functionChest radiography or computed tomography of the chest can be used to identify the thymus or lymphoid tissue. Other imaging studies are indicated by the particular immunocompromising conditions and infectious complications. Therapeutics for Empiric UseTable. Empiric Antimicrobials for Common Pathogens in Immunocompromised Children (Open Table in a new window)
Author Fernando J Bula-Rudas, MD, FAAP Assistant Professor of Pediatrics, Pediatric Infectious Diseases Specialist, Sanford Children's Hospital/Specialty Clinic; Director of Pediatric Infectious Diseases Rotation, Pediatrics Residency Program, Pediatric Clerkship Director, Sanford School of Medicine, The University of South Dakota Fernando J Bula-Rudas, MD, FAAP is a member of the following medical societies: American Academy of Pediatrics, American Medical Association, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, Society for Healthcare Epidemiology of America, South Dakota State Medical Association Disclosure: Nothing to disclose. Specialty Editor Board Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference Disclosure: Nothing to disclose. Joseph Domachowske, MD Professor of Pediatrics, Microbiology and Immunology, Department of Pediatrics, Division of Infectious Diseases, State University of New York Upstate Medical University Joseph Domachowske, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, American Society for Microbiology, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, Phi Beta Kappa Disclosure: Received research grant from: Pfizer;GlaxoSmithKline;AstraZeneca;Merck;American Academy of Pediatrics, Novavax, Regeneron, Diassess, Actelion<br/>Received income in an amount equal to or greater than $250 from: Sanofi Pasteur. Chief Editor Russell W Steele, MD Clinical Professor, Tulane University School of Medicine; Staff Physician, Ochsner Clinic Foundation Russell W Steele, MD is a member of the following medical societies: American Academy of Pediatrics, American Association of Immunologists, American Pediatric Society, American Society for Microbiology, Infectious Diseases Society of America, Louisiana State Medical Society, Pediatric Infectious Diseases Society, Society for Pediatric Research, Southern Medical Association Disclosure: Nothing to disclose. Additional Contributors Itzhak Brook, MD, MSc Professor, Department of Pediatrics, Georgetown University School of Medicine Itzhak Brook, MD, MSc is a member of the following medical societies: American Association for the Advancement of Science, American College of Physicians-American Society of Internal Medicine, American Medical Association, American Society for Microbiology, Association of Military Surgeons of the US, Infectious Diseases Society of America, International Immunocompromised Host Society, International Society for Infectious Diseases, Medical Society of the District of Columbia, New York Academy of Sciences, Pediatric Infectious Diseases Society, Society for Experimental Biology and Medicine, Society for Pediatric Research, Southern Medical Association, Society for Ear, Nose and Throat Advances in Children, American Federation for Clinical Research, Surgical Infection Society, Armed Forces Infectious Diseases Society Disclosure: Nothing to disclose. Archana Chatterjee, MD, PhD Professor and Chair, Department of Pediatrics, Senior Associate Dean for Faculty Development, Sanford School of Medicine, The University of South Dakota Archana Chatterjee, MD, PhD is a member of the following medical societies: American Academy of Pediatrics, American Society for Microbiology, Infectious Diseases Society of America, International Society for Infectious Diseases, Pediatric Infectious Diseases Society, Society for Pediatric Research Disclosure: Nothing to disclose. Rebecca Schreier, DO Resident Physician, Department of Pediatrics, Sanford Children’s Hospital Disclosure: Nothing to disclose. What is a factor that increases a host's susceptibility in the chain of infection?Factors that increase the susceptibility of a host to the development of a communicable disease are called risk factors. Some risk factors arise from outside the individual – for example, poor personal hygiene, or poor control of reservoirs of infection in the environment.
Which of the following is the most important procedure in the prevention of disease transmission in health care institutions?Hand Hygiene. Hand hygiene has been cited frequently as the single most important practice to reduce the transmission of infectious agents in healthcare settings 559, 712, 713 and is an essential element of Standard Precautions.
Which of the following is designed to reduce the risk of transmission of micro organisms from both recognize an unrecognized sources of infection in healthcare facilities?Standard precautions are meant to reduce the risk of transmission of bloodborne and other pathogens from both recognized and unrecognized sources. They are the basic level of infection control precautions which are to be used, as a minimum, in the care of all patients.
Which of the following is commonly identified pathogenic microorganism that causes healthcare associated skin infections?The most common bacterial skin pathogens are Staphylococcus aureus and group A β-hemolytic streptococci.
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