Infectious disease (medical specialty)

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Infectious disease (infectiology)
Gram stain 01.jpg
Gram stain of bacteria: a test frequently performed in infectiology
SynonymsInfectious diseases, infectious medicine, infectious disease medicine, infectiology
Significant diseases Infections, e.g. osteomyelitis, pneumonia, tuberculosis, HIV/AIDS, influenza, also public health issues e.g. epidemics, antimicrobial resistance, bioterrorism
Significant tests Gram staining, microbiological cultures (including blood cultures), serological tests, genotyping, polymerase chain reaction (PCR), medical imaging
SpecialistInfectious disease specialist, Infectiologist
Glossary Glossary of medicine

Infectious disease, also known as infectiology, is a medical specialty dealing with the diagnosis, control and treatment of infections. An infectious disease (ID) specialist's practice may consist largely of managing nosocomial (hospital-acquired) infections, or it may be out-patient based.

A medical speciality is a branch of medical practice that is focused on a defined group of patients, diseases, skills, or philosophy. Examples include children (paediatrics), cancer (oncology), laboratory medicine (pathology), or primary care. After completing medical school, physicians or surgeons usually further their medical education in a specific specialty of medicine by completing a multiple-year residency to become a medical specialist.

Hospital-acquired infection

A hospital-acquired infection (HAI), also known as a nosocomial infection, is an infection that is acquired in a hospital or other health care facility. To emphasize both hospital and nonhospital settings, it is sometimes instead called a health care–associated infection. Such an infection can be acquired in hospital, nursing home, rehabilitation facility, outpatient clinic, or other clinical settings. Infection is spread to the susceptible patient in the clinical setting by various means. Health care staff can spread infection, in addition to contaminated equipment, bed linens, or air droplets. The infection can originate from the outside environment, another infected patient, staff that may be infected, or in some cases, the source of the infection cannot be determined. In some cases the microorganism originates from the patient's own skin microbiota, becoming opportunistic after surgery or other procedures that compromise the protective skin barrier. Though the patient may have contracted the infection from their own skin, the infection is still considered nosocomial since it develops in the health care setting.

Contents

Scope

ID specialists typically serve as consultants to other physicians in cases of complex infections, and often manage patients with HIV/AIDS and other forms of Immunodeficiency. [1] Although many common infections are treated by physicians without formal expertise in ID, the ID specialist may be consulted for cases where an infection is difficult to diagnose. They may also be asked to help determine the cause of a fever of unknown origin. [2] [1]

HIV/AIDS Spectrum of conditions caused by HIV infection

Human immunodeficiency virus infection and acquired immune deficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV). Following initial infection, a person may not notice any symptoms or may experience a brief period of influenza-like illness. Typically, this is followed by a prolonged period with no symptoms. As the infection progresses, it interferes more with the immune system, increasing the risk of developing common infections such as tuberculosis, as well as other opportunistic infections, and tumors that rarely affect people who have uncompromised immune systems. These late symptoms of infection are referred to as acquired immunodeficiency syndrome (AIDS). This stage is often also associated with unintended weight loss.

ID specialists can practice both in hospitals (inpatient) and clinics (outpatient). In hospitals, ID specialists help ensure the timely diagnosis and treatment of acute infections by recommending the appropriate diagnostic tests to identify the source of the infection and by recommending the appropriate antibiotic to treat the infection. For certain types of infections, involvement of an ID specialists may improve patient outcomes. [3] In clinic, ID specialists can provide long-term care to patients with chronic infections such as HIV.

History

ID is historically associated with travel medicine and tropical medicine, as many diseases acquired in tropical and subtropical areas are infectious in nature. [4]

Travel medicine branch of medicine that deals with the prevention and management of health problems of international travelers

Travel medicine or emporiatrics is the branch of medicine that deals with the prevention and management of health problems of international travelers.

Tropical medicine medical specialty

Tropical medicine is an interdisciplinary branch of medicine that deals with health issues that occur uniquely, are more widespread, or are more difficult to control in tropical and subtropical regions.

Investigations

ID specialists employ a variety of diagnostic tests to help identify the pathogen that is causing an infection. Common tests include Gram staining, blood cultures, serological tests, genotyping, and polymerase chain reaction (PCR).

Serology is the scientific study of serum and other bodily fluids. In practice, the term usually refers to the diagnostic identification of antibodies in the serum. Such antibodies are typically formed in response to an infection, against other foreign proteins, or to one's own proteins.

Genotyping is the process of determining differences in the genetic make-up (genotype) of an individual by examining the individual's DNA sequence using biological assays and comparing it to another individual's sequence or a reference sequence. It reveals the alleles an individual has inherited from their parents. Traditionally genotyping is the use of DNA sequences to define biological populations by use of molecular tools. It does not usually involve defining the genes of an individual.

Polymerase chain reaction method for amplifying DNA

Polymerase chain reaction (PCR) is a method widely used in molecular biology to make many copies of a specific DNA segment. Using PCR, a single copy of a DNA sequence is exponentially amplified to generate thousands to millions of more copies of that particular DNA segment. PCR is now a common and often indispensable technique used in medical laboratory and clinical laboratory research for a broad variety of applications including biomedical research and criminal forensics. PCR was developed by Kary Mullis in 1983 while he was an employee of the Cetus Corporation. He was awarded the Nobel Prize in Chemistry in 1993 for his work in developing the method.

Treatments

ID specialists employ a variety of antimicrobial agents to help treat infections. The type of agent used depends on the organism that is causing the infection. Antibiotics are used to treat bacterial infections; antiviral agents treat viral infections; and antifungal agents treat fungal infections.

Training

Occupation
NamesDoctor, Medical Specialist, Infectious diseases Consultant
Occupation type
Specialty
Activity sectors
Medicine
Description
Education required
Doctor of Medicine (M.D.) or
Doctor of Osteopathic Medicine (D.O.) or
Bachelor of Medicine, Bachelor of Surgery
Fields of
employment
Hospitals, Clinics

United States

In the United States, ID is a subspecialty of internal medicine or pediatrics [5] (i.e., an internist or pediatrician trains for an additional 2 years as a medical fellow to qualify as an ID specialist and sit for the ID boards).

Internal medicine or general medicine is the medical specialty dealing with the prevention, diagnosis, and treatment of adult diseases. Physicians specializing in internal medicine are called internists, or physicians in Commonwealth nations. Internists are skilled in the management of patients who have undifferentiated or multi-system disease processes. Internists care for hospitalized and ambulatory patients and may play a major role in teaching and research.

Pediatrics field of medicine dealing with the care of children

Pediatrics is the branch of medicine that involves the medical care of infants, children, and adolescents. The American Academy of Pediatrics recommends people be under pediatric care up to the age of 21. A medical doctor who specializes in this area is known as a pediatrician, or paediatrician. The word pediatrics and its cognates mean "healer of children"; they derive from two Greek words: παῖς and ἰατρός. Pediatricians work both in hospitals, particularly those working in its subspecialties such as neonatology, and as primary care physicians.

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Medicine The science and practice of the diagnosis, treatment, and prevention of physical and mental illnesses

Medicine is the science and practice of establishing the diagnosis, prognosis, treatment, and prevention of disease. Medicine encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness. Contemporary medicine applies biomedical sciences, biomedical research, genetics, and medical technology to diagnose, treat, and prevent injury and disease, typically through pharmaceuticals or surgery, but also through therapies as diverse as psychotherapy, external splints and traction, medical devices, biologics, and ionizing radiation, amongst others.

Neurology medical specialty dealing with disorders of the nervous system

Neurology is a branch of medicine dealing with disorders of the nervous system. Neurology deals with the diagnosis and treatment of all categories of conditions and disease involving the central and peripheral nervous systems, including their coverings, blood vessels, and all effector tissue, such as muscle. Neurological practice relies heavily on the field of neuroscience, the scientific study of the nervous system.

Pelvic inflammatory disease infection of uterus, fallopian tubes, ovaries or the inner surface of pelvis

Pelvic inflammatory disease, also known as pelvic inflammatory disorder (PID), is an infection of the upper part of the female reproductive system, namely the uterus, fallopian tubes, and ovaries, and inside of the pelvis. Often, there may be no symptoms. Signs and symptoms, when present, may include lower abdominal pain, vaginal discharge, fever, burning with urination, pain with sex, bleeding after sex, or irregular menstruation. Untreated PID can result in long-term complications including infertility, ectopic pregnancy, chronic pelvic pain, and cancer.

Syphilis sexually transmitted infection

Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum subspecies pallidum. The signs and symptoms of syphilis vary depending in which of the four stages it presents. The primary stage classically presents with a single chancre but there may be multiple sores. In secondary syphilis, a diffuse rash occurs, which frequently involves the palms of the hands and soles of the feet. There may also be sores in the mouth or vagina. In latent syphilis, which can last for years, there are few or no symptoms. In tertiary syphilis, there are gummas, neurological problems, or heart symptoms. Syphilis has been known as "the great imitator" as it may cause symptoms similar to many other diseases.

Infection invasion of a host by disease-causing organisms

Infection is the invasion of an organism's body tissues by disease-causing agents, their multiplication, and the reaction of host tissues to the infectious agents and the toxins they produce. Infectious disease, also known as transmissible disease or communicable disease, is illness resulting from an infection.

Pathology study and diagnosis of disease

Pathology is the study of the causes and effects of disease or injury. The word pathology also refers to the study of disease in general, incorporating a wide range of bioscience research fields and medical practices. However, when used in the context of modern medical treatment, the term is often used in a more narrow fashion to refer to processes and tests which fall within the contemporary medical field of "general pathology," an area which includes a number of distinct but inter-related medical specialties that diagnose disease, mostly through analysis of tissue, cell, and body fluid samples. Idiomatically, "a pathology" may also refer to the predicted or actual progression of particular diseases, and the affix path is sometimes used to indicate a state of disease in cases of both physical ailment and psychological conditions. A physician practicing pathology is called a pathologist.

Infectious mononucleosis common viral infectious disease

Infectious mononucleosis, also known as glandular fever, is an infection usually caused by the Epstein–Barr virus (EBV). Most people are infected by the virus as children, when the disease produces few or no symptoms. In young adults, the disease often results in fever, sore throat, enlarged lymph nodes in the neck, and tiredness. Most people recover in two to four weeks; however, feeling tired may last for months. The liver or spleen may also become swollen, and in less than one percent of cases splenic rupture may occur.

<i>Clostridioides difficile</i> infection colitis characterized by an overgrowth of Clostridium difficile bacteria

Clostridioides difficile infection, also known as Clostridium difficile infection, is a symptomatic infection due to the spore-forming bacterium, Clostridioides difficile. Symptoms include watery diarrhea, fever, nausea, and abdominal pain. It makes up about 20% of cases of antibiotic-associated diarrhea. Complications may include pseudomembranous colitis, toxic megacolon, perforation of the colon, and sepsis.

Strongyloidiasis Human helminthiasis

Strongyloidiasis is a human parasitic disease caused by the nematode called Strongyloides stercoralis, or sometimes S. fülleborni which is a type of helminth. It belongs to a group of nematodes called roundworms. This intestinal worm can cause a number of symptoms in people, principally skin symptoms, abdominal pain, diarrhea and weight loss, among many other specific and vague symptoms in disseminated disease, and severe life threatening conditions through hyperinfection. In some people, particularly those who require corticosteroids or other immunosuppressive medication, Strongyloides can cause a hyperinfection syndrome that can lead to death if untreated. The diagnosis is made by blood and stool tests. The medication ivermectin is widely used to treat strongyloidiasis.

Infection control is the discipline concerned with preventing nosocomial or healthcare-associated infection, a practical sub-discipline of epidemiology. It is an essential, though often underrecognized and undersupported, part of the infrastructure of health care. Infection control and hospital epidemiology are akin to public health practice, practiced within the confines of a particular health-care delivery system rather than directed at society as a whole. Anti-infective agents include antibiotics, antibacterials, antifungals, antivirals and antiprotozoals.

The Infectious Diseases Society of America (IDSA) is a medical association representing physicians, scientists and other health care professionals who specialize in infectious diseases. It was founded in 1963 and is based in Arlington, Virginia. As of 2013, IDSA had more than 9,000 members from across the United States and nearly 100 other countries on six different continents. IDSA's purpose is to improve the health of individuals, communities, and society by promoting excellence in patient care, education, research, public health, and prevention relating to infectious diseases.

Medical microbiology medical specialty

Medical microbiology , the large subset of microbiology that is applied to medicine, is a branch of medical science concerned with the prevention, diagnosis and treatment of infectious diseases. In addition, this field of science studies various clinical applications of microbes for the improvement of health. There are four kinds of microorganisms that cause infectious disease: bacteria, fungi, parasites and viruses, and one type of infectious protein called prion.

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Gonorrhea sexually transmitted infection

Gonorrhea, colloquially known as the clap, is a sexually transmitted infection (STI) caused by the bacterium Neisseria gonorrhoeae. Many of those infected have no symptoms. Men may have burning with urination, discharge from the penis, or testicular pain. Women may have burning with urination, vaginal discharge, vaginal bleeding between periods, or pelvic pain. Complications in women include pelvic inflammatory disease and in men include inflammation of the epididymis. If untreated, gonorrhea can spread to joints or heart valves.

Sexually transmitted infection Infection transmitted through human sexual behavior

Sexually transmitted infections (STI), also referred to as sexually transmitted diseases (STD), are infections that are commonly spread by sexual activity, especially vaginal intercourse, anal sex and oral sex. Many times STIs initially do not cause symptoms. This results in a greater risk of passing the disease on to others. Symptoms and signs of disease may include vaginal discharge, penile discharge, ulcers on or around the genitals, and pelvic pain. STIs can be transmitted to an infant before or during childbirth and may result in poor outcomes for the baby. Some STIs may cause problems with the ability to get pregnant.

African tick bite fever spotted fever that has material basis in Rickettsia africae, which is transmitted by ticks

African tick bite fever (ATBF) is a bacterial infection spread by the bite of a tick. Symptoms may include fever, headache, muscles pains, and a rash. At the site of the bite there is typically a red skin sore with a dark center. Onset usually occur 4–10 days after the bite. Complications are rare, however may include joint inflammation. Some people do not develop symptoms.

Infectious diseases within American correctional settings are a concern within the public health sector. The corrections population is susceptible to infectious diseases through, exposure to blood and other bodily fluids, drug injection, poor health care, prison overcrowding, demographics, security issues, lack of community support for rehabilitation programs, and high-risk behaviors. The spread of infectious diseases, such as HIV/AIDS and other sexually transmitted diseases, hepatitis C (HCV), hepatitis B (HBV), and tuberculosis result largely from needle-sharing, drug use, and consensual and nonconsensual sex among prisoners. HIV/AIDS and hepatitis C need specific attention because of the specific public health concerns and issues they raise.

Chronic Lyme disease is a generally rejected diagnosis that encompasses "a broad array of illnesses or symptom complexes for which there is no reproducible or convincing scientific evidence of any relationship to Borrelia burgdorferi infection." Despite numerous studies, there is no clinical evidence that "chronic" Lyme disease is caused by a persistent infection. It is distinct from post-treatment Lyme disease syndrome, a set of lingering symptoms which may persist after successful treatment of infection with Lyme spirochetes. The symptoms of "chronic Lyme" are generic and non-specific "symptoms of life".

Antimicrobial stewardship (AMS) is the systematic effort to educate and persuade prescribers of antimicrobials to follow evidence-based prescribing, in order to stem antibiotic overuse, and thus antimicrobial resistance. AMS has been an organized effort of specialists in infectious diseases, both in Internal Medicine and Pediatrics with their respective peer-organizations, hospital pharmacists, the public health community and their professional organizations since the late 1990s. It has first been implemented in hospitals. In the U.S., within the context of physicians' prescribing freedom, AMS has largely been voluntary self-regulation in the form of policies and appeals to adhere to a prescribing self-discipline. At hospitals, this may take the form of an antimicrobial stewardship program. As of 2014, only the state of California has made this type of AMS mandatory by law. Within the context of commercial and over-the-counter use of antimicrobials, legally mandated AMS has begun with FDA rules that triclosan be phased out of consumer-grade soaps due to lack of good evidence that such use improves public health.

References

  1. 1 2 "IDSA : What is an ID Specialist". www.idsociety.org. Retrieved 2015-10-27.
  2. "ABMS Guide to Medical Specialties" (PDF).
  3. "The Value of an Infectious Diseases Specialist | Safe HealthcareSafe Healthcare | Blogs | CDC". blogs.cdc.gov. Retrieved 2015-11-14.
  4. Joint Royal Colleges Postgraduate Training Board. "Infectious Diseases" . Retrieved 2013-12-12.
  5. "Infectious Disease, Internal Medicine". American Association of Medical Colleges. Archived from the original on 2015-02-06.

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