Pathology
Overview
 

Pathology is the precise study and diagnosis
Medical diagnosis
Medical diagnosis refers both to the process of attempting to determine or identify a possible disease or disorder , and to the opinion reached by this process...

 of disease
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...

. The word pathology is from Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 , pathos, "feeling, suffering"; and , -logia, "the study of". Pathologization, to pathologize, refers to the process of defining a condition or behavior as pathological, e.g. pathological gambling. Pathologies is synonymous with diseases. The suffix "path" is used to indicate a disease, e.g.
Encyclopedia

Pathology is the precise study and diagnosis
Medical diagnosis
Medical diagnosis refers both to the process of attempting to determine or identify a possible disease or disorder , and to the opinion reached by this process...

 of disease
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...

. The word pathology is from Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 , pathos, "feeling, suffering"; and , -logia, "the study of". Pathologization, to pathologize, refers to the process of defining a condition or behavior as pathological, e.g. pathological gambling. Pathologies is synonymous with diseases. The suffix "path" is used to indicate a disease, e.g. psychopath.

Pathology addresses 4 components of disease: cause/etiology, mechanisms of development (pathogenesis), structural alterations of cells (morphologic changes), and the consequences of changes (clinical manifestations).

Pathology is further separated into divisions, based on either the system being studied (e.g. veterinary pathology and animal disease) or the focus of the examination (e.g. forensic pathology and determining the cause of death).

General pathology

General pathology, also called investigative pathology, experimental pathology, or theoretical pathology, is a broad and complex scientific field
Science
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...

 which seeks to understand the mechanisms of injury to cells
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

 and tissues
Tissue (biology)
Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...

, as well as the body's means of responding to and repairing injury. Areas of study include cellular adaptation to injury, necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...

, inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...

, wound healing
Wound healing
Wound healing, or cicatrisation, is an intricate process in which the skin repairs itself after injury. In normal skin, the epidermis and dermis exists in a steady-state equilibrium, forming a protective barrier against the external environment...

, and neoplasia
Neoplasia
Neoplasm is an abnormal mass of tissue as a result of neoplasia. Neoplasia is the abnormal proliferation of cells. The growth of neoplastic cells exceeds and is not coordinated with that of the normal tissues around it. The growth persists in the same excessive manner even after cessation of the...

. It forms the foundation of pathology, the application of this knowledge to diagnose diseases in humans and animals.

The term general pathology is also used to describe the practice of both anatomical and clinical pathology.

Anatomical pathology

Anatomical pathology (Commonwealth) or anatomic pathology (United States) is a medical specialty that is concerned with the diagnosis of disease based on the gross
Gross examination
Gross examination or "grossing" is the process by which pathology specimens are inspected with the bare eye to obtain diagnostic information, while being processed for further microscopic examination....

, microscopic
Histopathology
Histopathology refers to the microscopic examination of tissue in order to study the manifestations of disease...

, chemical, immunologic and molecular
Molecular pathology
Molecular pathology is an emerging discipline within pathology which is focused in the study and diagnosis of disease through the examination of molecules within organs, tissues or bodily fluids....

 examination of organs, tissues, and whole bodies (autopsy
Autopsy
An autopsy—also known as a post-mortem examination, necropsy , autopsia cadaverum, or obduction—is a highly specialized surgical procedure that consists of a thorough examination of a corpse to determine the cause and manner of death and to evaluate any disease or injury that may be present...

).

Anatomical pathology is itself divided in subspecialties, the main ones being surgical pathology
Surgical pathology
Surgical pathology is the most significant and time-consuming area of practice for most anatomical pathologists. Surgical pathology involves the gross and microscopic examination of surgical specimens, as well as biopsies submitted by non-surgeons such as general internists, medical subspecialists,...

, cytopathology
Cytopathology
Cytopathology is a branch of pathology that studies and diagnoses diseases on the cellular level. The discipline was founded by Rudolf Virchow in 1858. A common application of cytopathology is the Pap smear, used as a screening tool, to detect precancerous cervical lesions and prevent cervical...

, and forensic pathology
Forensic pathology
Forensic pathology is a branch of pathology concerned with determining the cause of death by examination of a corpse. The autopsy is performed by the pathologist at the request of a coroner or medical examiner usually during the investigation of criminal law cases and civil law cases in some...

. To be licensed
Medical license
In most countries, only persons with a medical license bestowed either by a specified government-approved professional association or a government agency are authorized to practice medicine. Licenses are not granted automatically to all people with medical degrees...

 to practice pathology, one has to complete medical school
Medical school
A medical school is a tertiary educational institution—or part of such an institution—that teaches medicine. Degree programs offered at medical schools often include Doctor of Osteopathic Medicine, Bachelor/Doctor of Medicine, Doctor of Philosophy, master's degree, or other post-secondary...

 and secure a license to practice medicine. An approved residency
Residency (medicine)
Residency is a stage of graduate medical training. A resident physician or resident is a person who has received a medical degree , Podiatric degree , Dental Degree and who practices...

 program and certification (in the United States, the American Board of Pathology or the American Osteopathic Board of Pathology) is usually required to obtain employment or hospital privileges.

Anatomical pathology is one of two branches of pathology, the other being clinical pathology, the diagnosis of disease through the laboratory
Medical laboratory
A medical laboratory or clinical laboratory is a laboratory where tests are done on clinical specimens in order to get information about the health of a patient as pertaining to the diagnosis, treatment, and prevention of disease.-Departments:...

 analysis of bodily fluids and tissues. Often, pathologists practice both anatomical and clinical pathology, a combination known as general pathology. The distinction between anatomic and clinical pathology is increasingly blurred by the introduction of technologies that require new expertise and the need to provide patients and referring physicians with integrated diagnostic reports. Similar specialties exist in veterinary pathology.

Clinical pathology

Clinical pathology is a medical specialty that is concerned with the diagnosis of disease based on the laboratory
Medical laboratory
A medical laboratory or clinical laboratory is a laboratory where tests are done on clinical specimens in order to get information about the health of a patient as pertaining to the diagnosis, treatment, and prevention of disease.-Departments:...

 analysis of bodily fluids such as blood and urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...

, and tissues using the tools of chemistry, microbiology, hematology
Hematology
Hematology, also spelled haematology , is the branch of biology physiology, internal medicine, pathology, clinical laboratory work, and pediatrics that is concerned with the study of blood, the blood-forming organs, and blood diseases...

 and molecular pathology. Clinical pathologists work in close collaboration with medical technologist
Medical technologist
A Medical Laboratory Scientist is a healthcare professional who performs chemical, hematological, immunologic, microscopic, and bacteriological diagnostic analyses on body fluids such as blood, urine, sputum, stool, cerebrospinal fluid , peritoneal fluid, pericardial fluid, and synovial...

s, hospital administrations, and referring physicians to ensure the accuracy and optimal utilization of laboratory testing.

Clinical pathology is one of the two major divisions of pathology, the other being anatomical pathology. Often, pathologists practice both anatomical and clinical pathology, a combination sometimes known as general pathology.

Dermatopathology

Dermatopathology is a subspecialty of anatomic pathology that focuses on the skin as an organ. It is unique in that there are two routes which a physician can use to obtain this specialization. All general pathologists and general dermatologists are trained in the pathology of the skin; however, the dermatopathologist is a specialist in this organ. In the USA, either a general pathologist or a dermatologist can undergo a 1 to 2 year fellowship in the field of dermatopathology. The completion of this fellowship allows one to take a subspecialty board examination, and becomes a board certified dermatopathologist.

Hematopathology

Hematopathology is the study of diseases of blood cells (White blood cells, red blood cells, platelets) and cells/tissues/organs comprising the hematopoietic system. The term hematopoietic system refers to tissues and organs that produce and/or primarily host hematopoietic cells and include bone marrow, lymph node, thymus, spleen, and other lymphoid tissues. In the United States, hematopathology is a board certified subspecialty (American Board of Pathology) practiced by those physicians who have completed general pathology residency (anatomic, clinical, or combined) and an additional year of fellowship training in hematology. The hematopathologist reviews biopsies of lymph nodes, bone marrows and other tissues involved by an infiltrate of cells of the hematopoietic system. In addition, the hematopathologist may be in charge of flow cytometric and/or molecular hematopathology studies. After the hematopathologist makes the diagnosis, the hematologist or hemato-oncologist can make a decision about the best course of action.

Oral and Maxillofacial Pathology

Oral and Maxillofacial Pathology is one of nine dental specialties recognized by the American Dental Association. Oral Pathologists must complete three years of post doctoral training in an accredited program and subsequently obtain Diplomate status from the American Board of Oral and Maxillofacial Pathology. The specialty focuses on the diagnosis, clinical management and investigation of diseases that affect the oral cavity and surrounding maxillofacial structures including but not limited to odontogenic, infectious, epithelial, salivary gland, bone and soft tissue pathologies.

Forensic pathology

Forensic pathology is a branch of pathology concerned with determining the cause of death
Cause of Death
Cause of Death is a 1990 album by American death metal band Obituary. Cause of Death is considered a classic album in the history of death metal. The artwork was done by artist Michael Whelan...

 by examination of a cadaver
Cadaver
A cadaver is a dead human body.Cadaver may also refer to:* Cadaver tomb, tomb featuring an effigy in the form of a decomposing body* Cadaver , a video game* cadaver A command-line WebDAV client for Unix....

. The autopsy
Autopsy
An autopsy—also known as a post-mortem examination, necropsy , autopsia cadaverum, or obduction—is a highly specialized surgical procedure that consists of a thorough examination of a corpse to determine the cause and manner of death and to evaluate any disease or injury that may be present...

 is performed by the pathologist at the request of a coroner
Coroner
A coroner is a government official who* Investigates human deaths* Determines cause of death* Issues death certificates* Maintains death records* Responds to deaths in mass disasters* Identifies unknown dead* Other functions depending on local laws...

 usually during the investigation of criminal law
Criminal law
Criminal law, is the body of law that relates to crime. It might be defined as the body of rules that defines conduct that is not allowed because it is held to threaten, harm or endanger the safety and welfare of people, and that sets out the punishment to be imposed on people who do not obey...

 cases and civil law
Civil law (common law)
Civil law, as opposed to criminal law, is the branch of law dealing with disputes between individuals or organizations, in which compensation may be awarded to the victim...

 cases in some jurisdictions. Forensic pathologists are also frequently asked to confirm the identity of a cadaver.

The word forensics
Forensics
Forensic science is the application of a broad spectrum of sciences to answer questions of interest to a legal system. This may be in relation to a crime or a civil action...

is derived from the Latin forēnsis meaning forum.

Veterinary pathology

Veterinary pathologists are doctors of veterinary medicine who specialize in the diagnosis
Medical diagnosis
Medical diagnosis refers both to the process of attempting to determine or identify a possible disease or disorder , and to the opinion reached by this process...

 of diseases through the examination of animal tissue and body fluids. As with medical pathology, veterinary pathology is divided in two branches, anatomical pathology and clinical pathology. Veterinary pathologists are critical participants in the drug development process.

Psychopathology

In psychology
Psychology
Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...

 and psychiatry
Psychiatry
Psychiatry is the medical specialty devoted to the study and treatment of mental disorders. These mental disorders include various affective, behavioural, cognitive and perceptual abnormalities...

, psychopathology is the study of mental illness, mental distress and abnormal, maladaptive behavior. The term is most commonly used within psychiatry where pathology refers to disease processes. Abnormal psychology is a similar term used more frequently in the non-medical field of psychology.

Plant pathology

Plant pathology (also phytopathology) is the scientific study of plant diseases caused by pathogens (infectious diseases) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like organisms, phytoplasmas, protozoa, nematodes and parasitic plants. Not included are insects, mites, vertebrate or other pests that affect plant health by consumption of plant tissues. Plant pathology also involves the study of pathogen identification, disease etiology, disease cycles, economic impact, plant disease epidemiology
Plant disease epidemiology
Plant Disease epidemiology is the study of disease in plant populations. Much like diseases of humans and animals, plant diseases occur due to pathogens such as bacteria, viruses, fungi, oomycetes, nematodes, phytoplasmas, protozoa, and parasitic plants...

, plant disease resistance
Plant disease resistance
Plant disease resistance is crucial to the reliable production of food, and it provides significant reductions in agricultural use of fuel, land, water and other inputs. There are numerous examples of devastating plant disease impacts , as well as recurrent severe plant disease issues...

, how plant diseases affect humans and animals, pathosystem genetics, and management of plant diseases.

The "disease triangle" is a central concept of plant pathology. It is based on the principle that infectious diseases develop, or do not develop, based on three-way interactions between the host, the pathogen, and environmental conditions.

Molecular pathology

Molecular pathology is an emerging discipline within pathology, and focuses in the study and diagnosis of disease through the examination of molecules within organs, tissues or bodily fluids. Molecular pathology shares some aspects of practice with both anatomic pathology and clinical pathology, molecular biology
Molecular biology
Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...

, biochemistry
Biochemistry
Biochemistry, sometimes called biological chemistry, is the study of chemical processes in living organisms, including, but not limited to, living matter. Biochemistry governs all living organisms and living processes...

, proteomics
Proteomics
Proteomics is the large-scale study of proteins, particularly their structures and functions. Proteins are vital parts of living organisms, as they are the main components of the physiological metabolic pathways of cells. The term "proteomics" was first coined in 1997 to make an analogy with...

 and genetics
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....

, and is sometimes considered a "crossover" discipline. It is multi-disciplinary in nature and focuses mainly on the sub-microscopic aspects of disease and unknown illnesses with strange causes.

It is a scientific discipline that encompasses the development of molecular and genetic approaches to the diagnosis and classification of human tumors, the design and validation of predictive biomarkers for treatment response and disease progression, the susceptibility of individuals of different genetic constitution to develop cancer, and the environmental and lifestyle factors implicated in carcinogenesis.

Pathology as a medical specialty

Pathologists are doctors who diagnose and characterize disease in living patients by examining biopsies
Biopsy
A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...

 or bodily fluids. In addition, pathologists interpret medical laboratory tests to help prevent illness or monitor a chronic condition.

The vast majority of cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...

 diagnoses are made by pathologists. Pathologists examine tissue biopsies to determine if they are benign or cancerous. Some pathologists specialize in genetic testing that can, for example, determine the most appropriate treatment for particular types of cancer. In addition, a pathologist analyzes blood samples from a patient's annual physical and alerts their primary care physician to any changes in their health early, when successful treatment is most likely. Pathologists also review results of tests ordered or performed by specialists, such as blood tests ordered by a cardiologist, a biopsy of a skin lesion removed by a dermatologist, or a Pap test performed by a gynecologist, to detect abnormalities.

Pathologists work with other doctors, medical specialty societies, medical laboratory professionals, and health care consumer organizations to set guidelines and standards for medical laboratory testing that help improve a patient's medical care and guide treatment, as well as ensure the quality and safety of domestic and international medical laboratories.

Pathologists may also conduct autopsies to investigate causes of death. Autopsy results can aid living patients by revealing a hereditary disease unknown to a patient's family.

Pathology is a core discipline of medical school
Medical school
A medical school is a tertiary educational institution—or part of such an institution—that teaches medicine. Degree programs offered at medical schools often include Doctor of Osteopathic Medicine, Bachelor/Doctor of Medicine, Doctor of Philosophy, master's degree, or other post-secondary...

 and many pathologists are also teachers. As managers of medical laboratories
Medical laboratory
A medical laboratory or clinical laboratory is a laboratory where tests are done on clinical specimens in order to get information about the health of a patient as pertaining to the diagnosis, treatment, and prevention of disease.-Departments:...

 (which include chemistry, microbiology, cytology, the blood bank, etc.), pathologists play an important role in the development of laboratory information system
Laboratory information system
A lab information system is a class of software that receives, processes, and stores information generated by medical laboratory processes. These systems often must interface with instruments and other information systems such as hospital information systems...

s. Although the medical practice of pathology grew out of the tradition of investigative pathology, most modern pathologists do not perform original research.

Pathology is a unique medical specialty. Pathology touches all of medicine, as diagnosis is the foundation of all patient care. In fact, more than 70 percent of all decisions about diagnosis and treatment, hospital admission, and discharge rest on medical test results.

Pathologists play a critical role on the patient care team, working with other doctors to treat patients and guide care. To be licensed, candidates must complete medical training, an approved residency program, and be certified by an appropriate body. In the US, certification is by the American Board of Pathology or the American Osteopathic Board of Pathology. The organization of subspecialties within pathology varies between nations, but usually includes anatomic pathology and clinical pathology.

See also

  • Surgical pathology
    Surgical pathology
    Surgical pathology is the most significant and time-consuming area of practice for most anatomical pathologists. Surgical pathology involves the gross and microscopic examination of surgical specimens, as well as biopsies submitted by non-surgeons such as general internists, medical subspecialists,...

  • Hematopathology
    Hematopathology
    Hematopathology is the branch of pathology which studies diseases of hematopoietic cells . In the United States, hematopathology is a board certified subspecialty practiced by those physicians who have completed general pathology residency and additional fellowship training in...

  • Telepathology
    Telepathology
    Telepathology is the practice of pathology at a distance. It uses telecommunications technology to facilitate the transfer of image-rich pathology data between distant locations for the purposes of diagnosis, education, and research. Performance of telepathology requires that a pathologist...

  • Important publications in pathology
  • List of pathologists

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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