Pathology (from Greek pathos, suffering; and logos, study of; see also -ology) is the study and diagnosis of disease through examination of organs, tissues, cells and bodily fluids. The term encompasses both the medical specialty which uses tissues and body fluids to obtain clinically useful information, as well as the related scientific study of disease processes.
The histories of both experimental and medical pathology can be traced to the earliest application of the scientific method to the field of medicine, a development which occurred in Western Europe during the Italian Renaissance. Most early pathologists were also practicing physicians or surgeons. Like other medical fields, pathology has become more specialized with time, and most pathologists today do not practice in other areas of medicine.
The concept of studying disease through the methodical dissection and examination of diseased bodies, organs, and tissues may seem obvious today, but there are few if any recorded examples of true autopsies performed prior to the Renaissance. The first physician known to have repeatedly used anatomic dissection to determine cause of death was an Italian, Antonio Benivieni (1443-1502). Perhaps the most famous early gross pathologist was Giovanni Morgagni (1682-1771). His magnum opus, De Sedibus et Causis Morborum per Anatomem Indagatis, published in 1761, describes the findings of over 600 partial and complete autopsies, organised anatomically and methodically correlated with the symptoms exhibited by the patients prior to their demise. Although the study of normal anatomy was already well advanced at this date, De Sedibus was one of the first treatises specifically devoted to the corrolation of diseased anatomy with clinical illness. By the late 1800's, an exhaustive body of literature had been produced on the gross anatomical findings characteristic of known diseases. The extent of gross pathology research in this period can be epitomized by the work of the Viennese pathologist Carl Rokitansky (1804-1878), who is said to have performed 20,000 autopsies, and supervised an additional 60,000, in his lifetime.
The German physician Rudolf Virchow (1821-1902) is generally recognized to be the father of microscopic pathology. While the compound microscope had been invented approximately 150 years prior, Virchow was one of the first prominent physicians to emphasize the study of manifestations of disease which were visible only at the cellular level. A student of Virchow's, Julius Cohnheim (1839-1884) combined histology techniques with experimental manipulations to study inflammation, making him one of the earliest experimental pathologists. Cohnheim also pioneered the use of the frozen section; a version of this technique is widely employed by modern pathologists to render diagnoses and provide other clinical information intraoperatively.
As new research techniques, such as electron microscopy, immunohistochemistry, and molecular biology have expanded the means by which biomedical scientists can study disease, the definition and boundaries of investigative pathology have become less distinct. In the broadest sense, nearly all research which links manifestations of disease to identifiable processes in cells, tissues, or organs can be considered experimental pathology.
Pathology is a broad and complex scientific field which seeks to understand the mechanisms of injury to cells and tissues, as well as the body's means of responding to and repairing injury. Disease processes may be incited or exacerbated by a variety of external and internal influences, including trauma, infection, poisoning, loss of blood flow, autoimmunity, inherited or acquired genetic damage, or errors of development. One common theme in pathology is the way in which the body's responses to injury, while evolved to protect health, can also contribute in some ways to disease processes. Elucidation of general principles underlying pathologic processes, such as cellular adaptation to injury, cell death, inflammation, tissue repair, and neoplasia, creates a conceptual framework with which to analyze and understand specific human diseases.
Cells and tissues may respond to injury and stress by specific mechanisms, which may vary accroding to the cell types and nature of the injury. In the short term, cells may activate specific genetic programs to protect their vital proteins and organelles from heat shock or hypoxia, and may activate DNA repair pathways to fix damage to chromosomes from radiation or chemicals. Hyperplasia is a long-term adaptive response of cell division and multiplication, which can increase the ability of a tissue to compensate for an injury. For example, repeated irritation to the skin can cause a protective thickening due to hyperplasia of the epidermis. Hypertrophy is an increase in the size of cells in a tissue in response to stress, an example being hypertrophy of muscle cells in the heart in response to increased resistance to blood flow as a result of narrowing of the heart's outflow valve. Metaplasia occurs when repeated damage to the cellular lining of an organ triggers its replacement by a different cell type.
Necrosis is the irreversible destruction of cells as a result of severe injury in a setting where the cell is unable to activate the needed metabolic pathways for survival or orderly degeneration. This is often due to external pathologic factors, such as toxins or loss of oxygen supply. Milder stresses may lead to a process called reversible cell injury, which mimics the cell swelling and vacuolization seen early in the necrotic process, but in which the cell is able to adapt and survive. In necrosis, the componants of degenerating cells leak out, potentially contributing to inflammation and further damage. Apoptosis, in contrast, is a regulated, orderly degeneration of the cell which occurs in the settings of both injury and normal physiological processes.
Inflammation is a particularly important and complex reaction to tissue injury, and is particularly important in fighting infection. Acute inflammation is generally a non-specific response triggered by the injured tissue cells themselves, as well as specialized cells of the innate immune system and previously developed adaptive immune mechanisms. A localized acute inflammatory response triggers vascular changes in the injured area, recruits pathogen-fighting neutrophils, and begins the process of developing a new adaptive immune response. Chronic inflammation occurs when the acute response fails to entirely clear the inciting factor. While chronic inflammation can lay a positive role in containing a continuing infectious hazard, it can also lead to progessive tissue damage, as well as predisposing (in some cases) to the development of cancer.
Tissue repair, as seen in wound healing, is triggered by inflammation. The process may proceed even before the resolution of a precipitating insult, through the formation of granulation tissue. Healing involves the proliferation of connective tissue cells and blood vessel-forming cells as a result of hormonal growth signals. While healing is a critical adaptive response, an aberrent healing response can lead to progressive fibrosis, contractures, or other changes which can compromise function.
Neoplasia, or "new growth," is a proliferation of cells which is independent of any physiological process. The most familiar examples of neoplasia are benign tumors and cancers. Neoplasia results from genetic changes which cause cells to activate genetic programs inappropriately. Dysplasia is an early sign of a neoplastic process in a tissue, and is marked by persistance of immature, poorly differentiated cell forms. Interestingly, there are many similarities in the gene pathways activated in cancer cells, and those activated in cells involved in wound healing and inflammation.
Physicians who practice pathology diagnose and characterize disease in living patients by examining biopsies and other specimens. For example, the vast majority of cancer diagnoses are made or confirmed by a pathologist. Pathologists may also conduct autopsies to investigate causes of death. The medical practice of pathology grew out the tradition of investigative pathology, and many of the academic leaders in pathology today are accomplished in both basic science research and diagnostic practice. However, as with other specialties in medicine, most modern physician-pathologists are employed in full-time practice, and do not perform original research.
Pathology is a unique medical specialty in that pathologists typically do not see patients directly, but rather serve as consultants to other physicians (often referred to as "clinicians" within the pathology community). However, in the United States and in many other countries, pathologists receive the same doctorate training, and undergo the same medical licensure process as other physicians. Pathology is a diverse field, and the organization of subspecialties within pathology vary between nations.
Anatomical pathologists diagnose disease and gain other clinically significant information through the examination of tissues and cells. This generally involves gross and microscopic visual examination of tissues, with special stains and immunohistochemistry employed to visualize specific proteins and other substances in and around cells. More recently, anatomical pathologists have begun to employ molecular biology techniques to gain additional clinical information from these same specimens. Anatomic pathologists serve as the definitive diagnosticians for most cancers, as well as numerous other diseases.
Clinical pathology, also known as laboratory medicine, is the medical specialty concerned with diagnosing diseases based on the analysis of body fluids, such as plasma, urine, stool, respiratory or mucosal secretions, inflammatory exudates, and pleural, pericardial, peritoneal, synovial, or cerebrospinal fluid. The practice of clinical pathology is centered around the clinical laboratory. In modern clinical laboratories, many routine studies are largely automated. The clinical pathologist is responsible for overseeing the work of laboratory technicians, performing quality assurance to assure the validity of test results, performing interpretations of more complex studies, and serving as a consultant to clinicians so that the most appropriate studies can be performed for the diagnosis or assessment of an individual patient's condition. In some areas, non-pathologists, such as other physicians or Ph.D.'s may run clinical labs and perform functions within those specific labs which are similar to the role of a board-certified clinical pathologist.
Sub-specialties within clinical pathology include the following:
In the United States, pathologists are medical doctors (M.D.) or doctors of osteopathic medicine (D.O.), that have completed a four-year undergraduate program, four years of medical school training, and three to four years of postgraduate training in the form of a pathology residency. Training may be within two primary specialties, as recognized by the American Board of Pathology: Anatomic Pathology, and Clinical Pathology, each of which requires separate board certification. Many pathologists seek a broad-based training and become certified in both fields. These skills are complementary in many hospital-based private practice settings, since the day-to-day work of many clinical laboratories only requires the intermittent attention of a physician. Thus, pathologists are able to spend much of their time evaluating anatomic pathology cases, while remaining available to cover any special issues which might arise in the clinical laboratories. Pathologists may pursue specialised fellowship training within one or more sub-specialties of either anatomic or clinical pathology. Some of these sub-specialities permit additional board certification, while others do not.
In the UK pathologists are medical doctors registered with the UK General Medical Council. They will have completed an undergraduate medical education which in most countries lasts 4-6 years. The training to become a pathologist is under the oversight of the Royal College of Pathologists. Typically a one year training attachment is followed by an aptitude test. This is followed by further specialist training in surgical pathology, cytopathology, and post mortem pathology. There are two examinations run by the Royal College of Pathologists termed Part 1 and Part 2. The Part 2 examination is designed to test competence to work as an independent practitioner in pathology and is typically taken after 5 years specialist training. All post-graduate medical training and education in the UK is overseen by the Postgraduate Medical Education and Training Board. It is possible to take a specialist part 2 examination in paediatric pathology or neuropathology. It is possible to take a special diploma in dermatopathology or cytopathology, recognising additional specialist training and expertise.
Veterinary pathologists are veterinary practitioners who specialise in the diagnosis and characterization of veterinary diseases through the examination of animal tissue and body fluids.
Plant pathologists are specialized scientists who investigate the causes of diseases in plants.
|Principles of pathology||Disease - Necrosis - Infection - Ischemia - Inflammation - Wound healing - Neoplasia|
|Anatomical pathology||Surgical pathology - Cytopathology - Autopsy - Molecular pathology - Forensic Pathology - Dental pathology
Gross examination - Histopathology - Immunohistochemistry - Electron microscopy - Immunofluorescence - Fluorescent in situ hybridization
|Clinical pathology||Clinical chemistry - Hematopathology - Transfusion medicine - Medical microbiology - Diagnostic immunology
Enzyme assay - Mass spectrometry - Chromatography - Flow cytometry - Blood bank - Microbiological culture - Serology
|General||Advance practice nursing - Chiropractic medicine - Audiology - Dentistry - Dietetics - Emergency medical services - Epidemiology - Medical technology - Midwifery - Nursing - Occupational therapy - Optometry - Osteopathic medicine - Pharmacy - Physical therapy (Physiotherapy) - Physician - Physician assistant - Podiatry - Psychology - Public health - Respiratory therapy - Speech and language pathology|
|Physician specialties||Anesthesiology - Dermatology - Emergency medicine - General practice (Family medicine) - Internal medicine - Neurology - Nuclear medicine - Obstetrics and gynecology - Occupational medicine - Ophthalmology - Pathology - Pediatrics - Physical medicine and rehabilitation (Physiatry) - Preventive medicine - Psychiatry - Radiation oncology - Radiology - Surgery|
|Medical subspecialties||Allergy and immunology - Cardiology - Endocrinology - Gastroenterology - Hematology - Infectious disease - Intensive care medicine (Critical care medicine) - Medical genetics - Nephrology - Oncology - Pulmonology - Rheumatology|
|Surgical subspecialties||Cardiac surgery - General surgery - Hand surgery - Neurosurgery - Oral and maxillofacial surgery - Orthopaedic surgery - Otolaryngology (ENT) - Pediatric surgery - Plastic surgery - Surgical oncology - Thoracic surgery - Transplant surgery - Trauma surgery - Urology - Vascular surgery|
|Anatomy - Astrobiology - Biochemistry - Bioinformatics - Botany - Cell biology - Ecology - Developmental biology - Evolutionary biology - Genetics - Genomics - Marine biology - Human biology - Microbiology - Molecular biology - Origin of life - Paleontology - Parasitology - Pathology - Physiology - Taxonomy - Zoology|
|Benign tumors||Hyperplastic tumor - Cyst - Pseudocyst - Hamartoma - Benign neoplasm|
|Malignant progression||Dysplasia - Carcinoma in situ - Invasive cancer - Metastasis|
|Topography||Anus - Bladder - Bile duct - Bone - Brain - Breast - Cervix - Colon/rectum - Duodenum - Endometrium - Esophagus - Eye - Gallbladder - Head/Neck - Liver - Larynx - Lung - Mediastinum (chest)- Mouth - Pancreas - Penis - Prostate - Kidney - Ovaries - Skin - Stomach - Tailbone - Testicles - Thyroid|
|Morphology||Papilloma/carcinoma - Choriocarcinoma - Endodermal sinus tumor - Teratoma - Adenoma/adenocarcinoma - Soft tissue sarcoma - Melanoma - Fibroma/fibrosarcoma - Lipoma/liposarcoma - Leiomyoma/leiomyosarcoma - Rhabdomyoma/rhabdomyosarcoma - Mesothelioma - Angioma/angiosarcoma - Osteoma/osteosarcoma - Chondroma/chondrosarcoma - Glioma - Lymphoma/leukemia|
|Treatment||Surgery - Chemotherapy - Radiation therapy - Immunotherapy - Experimental cancer treatment|
|Misc.||Tumor suppressor genes/oncogenes - Staging/grading - Carcinogenesis - Carcinogen - Research - Paraneoplastic phenomenon - ICD-O - List of oncology-related terms|
|White blood cells||Lymphoid: Lymphoid leukaemia (ALL, CLL, HCL) • Lymphoma (Hodgkin's disease, NHL) • LPD • Myeloma (Multiple myeloma, Extramedullary plasmacytoma)
Myeloid: Myeloid leukemia (AML, CML) • MPD Ph- (Essential thrombocytosis, Polycythemia vera, Myelofibrosis) • MDS • Neutropenia
|Red blood cells/anemia/hemoglobinopathy||Nutritional anemia: (Iron deficiency anemia, Plummer-Vinson syndrome, Pernicious anemia, Megaloblastic anemia) • Hemolytic anemia: (G6PD Deficiency, Thalassemia, Sickle-cell disease/trait, Hereditary spherocytosis, Hereditary elliptocytosis, Hereditary stomatocytosis, Warm autoimmune hemolytic anemia, Hemolytic-uremic syndrome, Microangiopathic hemolytic anemia, Paroxysmal nocturnal hemoglobinuria) • Aplastic anemia: (Acquired pure red cell aplasia, Fanconi anemia) • Hemochromatosis|
|Coagulation/platelets||DIC • Hemophilia (A, B, C) • Von Willebrand disease • Purpura (Henoch-Schönlein, ITP, TTP)|
|other||Methemoglobinemia - Langerhans cell histiocytosis|
|Thyroid||Hypothyroidism (Iodine deficiency, Cretinism, Congenital hypothyroidism, Goitre) - Hyperthyroidism (Graves-Basedow disease, Toxic multinodular goitre, Teratoma with thyroid tissue or Struma ovarii) - Thyroiditis (De Quervain's thyroiditis, Hashimoto's thyroiditis)|
|Pancreas||Diabetes mellitus (type 1, type 2, coma, angiopathy, ketoacidosis, nephropathy, neuropathy, retinopathy) - Hypoglycemia - Hyperinsulinism - Zollinger-Ellison syndrome|
|Parathyroid||Hypoparathyroidism (Pseudohypoparathyroidism) - Hyperparathyroidism (Primary, Secondary, Tertiary)|
|Pituitary||hyperfunction (Acromegaly, Hyperprolactinaemia, Syndrome of inappropriate antidiuretic hormone) - Hypopituitarism (Sheehan's syndrome, Kallmann syndrome, Simmonds' disease, Growth hormone deficiency) - Diabetes insipidus - Hypothalamic-pituitary dysfunction|
|Adrenal||Cushing's syndrome (Nelson's syndrome, Pseudo-Cushing's syndrome) - Congenital adrenal hyperplasia (due to 21-hydroxylase deficiency) - Hyperaldosteronism (Conn syndrome, Bartter syndrome) - Adrenal insufficiency (Addison's disease) - Hypoaldosteronism|
|Gonads||Polycystic ovary syndrome - 5-alpha-reductase deficiency - Hypogonadism - Delayed puberty - Precocious puberty|
|Other||Autoimmune polyendocrine syndrome - Carcinoid syndrome - Laron syndrome - Psychogenic dwarfism - Androgen insensitivity syndrome - Progeria|
|Malnutrition||Kwashiorkor - Marasmus|
|Other underconsumption||B vitamins: B1: Beriberi/Wernicke's encephalopathy, B2: Ariboflavinosis, B3: Pellagra, B7: Biotin deficiency, B9: Folate deficiency
mineral: Iron deficiency, Magnesium deficiency - Chromium deficiency
|Hyperalimentation||Obesity - Hypervitaminosis A - Hypervitaminosis D|
|Amino acid||Aromatic (Phenylketonuria, Alkaptonuria, Ochronosis, Tyrosinemia, Albinism, Histidinemia) - Branched chain (Maple syrup urine disease, Propionic acidemia, Methylmalonic acidemia, Isovaleric acidemia, 3-Methylcrotonyl-CoA carboxylase deficiency) - Transport (Cystinuria, Cystinosis, Hartnup disease) - Sulfur (Homocystinuria, Cystathioninuria) - Urea cycle (Argininosuccinic aciduria, Citrullinemia, Hyperammonemia) - Glutaric acidemia type 1 - Sarcosinemia|
|Carbohydrate||Lactose intolerance - Glycogen storage disease (type I, type II, type III, type IV, type V, type VI, type VII) - Fructose intolerance - Essential fructosuria - Galactosemia - PCD - PDHA - Pentosuria - Renal glycosuria|
|Lipid storage||Sphingolipidoses/Gangliosidoses: GM2 gangliosidoses (Sandhoff disease, Tay-Sachs disease) - GM1 gangliosidoses - Mucolipidosis type IV - Gaucher's disease - Niemann-Pick disease - Farber disease - Fabry's disease - Metachromatic leukodystrophy - Krabbe disease
Neuronal ceroid lipofuscinosis (Batten disease) - Cerebrotendineous xanthomatosis - Cholesteryl ester storage disease (Wolman disease)
|Other lipid||Lipoprotein/lipidemias: Hyperlipidemia - Hypercholesterolemia - Familial hypercholesterolemia - Xanthoma - Combined hyperlipidemia - Lecithin cholesterol acyltransferase deficiency - Tangier disease - Abetalipoproteinemia
Fatty acid: Adrenoleukodystrophy - Carnitine (Primary, I, II)
|Mineral||Cu Wilson's disease/Menkes disease - Fe Haemochromatosis - Zn Acrodermatitis enteropathica - PO43− Hypophosphatemia/Hypophosphatasia - Mg2+ Hypermagnesemia/Hypomagnesemia - Ca2+ Hypercalcaemia/Hypocalcaemia/Disorders of calcium metabolism|
|Fluid, electrolyte and acid-base balance||Electrolyte disturbance - Na+ Hypernatremia/Hyponatremia - Acidosis (Metabolic, Respiratory, Lactic) - Alkalosis (Metabolic, Respiratory) - Mixed disorder of acid-base balance - H2O Dehydration/Hypervolemia - K+ Hypokalemia/Hyperkalemia - Cl− Hyperchloremia/Hypochloremia|
|Purine and pyrimidine||Hyperuricemia - Lesch-Nyhan syndrome - Xanthinuria|
|Porphyrin||Acute intermittent, Gunther's, Cutanea tarda, Erythropoietic, Hepatoerythropoietic, Hereditary copro-, Variegate|
|Bilirubin||Unconjugated (Gilbert's syndrome, Crigler-Najjar syndrome) - Conjugated (Dubin-Johnson syndrome, Rotor syndrome)|
|Glycosaminoglycan||Mucopolysaccharidosis - 1:Hurler/Hunter - 3:Sanfilippo - 4:Morquio - 6:Maroteaux-Lamy - 7:Sly|
|Glycoprotein||Mucolipidosis - I-cell disease - Pseudo-Hurler polydystrophy - Aspartylglucosaminuria - Fucosidosis - Alpha-mannosidosis - Sialidosis|
|Other||Alpha 1-antitrypsin deficiency - Cystic fibrosis - Amyloidosis (Familial Mediterranean fever) - Acatalasia|
|Eyelid, lacrimal system and orbit||Stye - Chalazion - Blepharitis - Entropion - Ectropion - Lagophthalmos - Blepharochalasis - Ptosis - Xanthelasma - Trichiasis - Dacryoadenitis - Epiphora - Exophthalmos - Enophthalmos|
|Conjunctiva||Conjunctivitis - Pterygium - Subconjunctival hemorrhage|
|Sclera and cornea||Scleritis - Keratitis - Corneal ulcer - Snow blindness - Thygeson's superficial punctate keratopathy - Fuchs' dystrophy - Keratoconus - Keratoconjunctivitis sicca - Arc eye - Keratoconjunctivitis - Corneal neovascularization - Kayser-Fleischer ring - Arcus senilis|
|Iris and ciliary body||Iritis - Uveitis - Iridocyclitis - Hyphema - Persistent pupillary membrane|
|Lens||Cataract - Aphakia|
|Choroid and retina||Retinal detachment - Retinoschisis - Hypertensive retinopathy - Diabetic retinopathy - Retinopathy - Retinopathy of prematurity - Macular degeneration - Retinitis pigmentosa - Macular edema - Epiretinal membrane - Macular pucker|
|Ocular muscles, binocular movement, accommodation and refraction||Strabismus - Ophthalmoparesis - Progressive external ophthalmoplegia - Esotropia - Exotropia - Refractive error - Hyperopia - Myopia - Astigmatism - Anisometropia - Presbyopia - Fourth nerve palsy - Sixth nerve palsy - Kearns-Sayre syndrome - Esophoria - Exophoria - Duane syndrome - Convergence insufficiency - Internuclear ophthalmoplegia - Aniseikonia|
|Visual disturbances and blindness||Amblyopia - Leber's congenital amaurosis - Subjective (Asthenopia, Hemeralopia, Photophobia, Scintillating scotoma) - Diplopia - Scotoma - Anopsia (Binasal hemianopsia, Bitemporal hemianopsia, Homonymous hemianopsia, Quadrantanopia) - Color blindness (Achromatopsia) - Nyctalopia - Blindness/Low vision|
|Commonly associated infectious diseases||Trachoma - Onchocerciasis|
|Other||Glaucoma - Floater - Leber's hereditary optic neuropathy - Red eye - Argyll Robertson pupil - Keratomycosis - Xerophthalmia - Aniridia|
|Hypertension||Hypertensive heart disease - Hypertensive nephropathy - Secondary hypertension - Renovascular hypertension|
|Ischaemic heart disease||Angina pectoris - Prinzmetal's angina - Myocardial infarction - Dressler's syndrome|
|Pulmonary circulation||Pulmonary embolism - Cor pulmonale|
|Pericardium||Pericarditis - Cardiac tamponade|
|Endocardium/heart valves||Endocarditis - Mitral regurgitation - Mitral valve prolapse - Mitral stenosis - Aortic valve stenosis - Aortic insufficiency - Pulmonary valve stenosis|
|Myocardium||Myocarditis - Cardiomyopathy (Dilated cardiomyopathy, Hypertrophic cardiomyopathy, Restrictive cardiomyopathy) - Arrhythmogenic right ventricular dysplasia|
|Electrical conduction system of the heart||AV block (First degree, Second degree, Third degree) - Bundle branch block (Left, Right) - Bifascicular block - Trifascicular block - Wolff-Parkinson-White syndrome - Lown-Ganong-Levine syndrome - Long QT syndrome - Cardiac arrest - Tachycardia (Supraventricular tachycardia, AV nodal reentrant tachycardia, Ventricular tachycardia) - Premature contraction (Atrial, Ventricular) - Sick sinus syndrome|
|Other heart conditions||Heart failure - Cardiomegaly - Ventricular hypertrophy (Left, Right)|
|Arteries, arterioles and capillaries||Atherosclerosis - Aortic dissection - Raynaud's phenomenon/Raynaud's disease - Buerger's disease - Intermittent claudication|
|Veins, lymphatic vessels and lymph nodes||Thrombosis - Phlebitis - Deep vein thrombosis - Portal vein thrombosis - Venous thrombosis - Budd-Chiari syndrome - Thrombophlebitis - Paget-Schroetter disease - Varicose veins - Hemorrhoid - Esophageal varices - Varicocele - Gastric varices - Superior vena cava syndrome - Lymphadenopathy - Lymphedema|
|Acute upper respiratory infections||Upper respiratory tract infection - Common cold - Rhinitis - Sinusitis - Pharyngitis - Tonsillitis - Laryngitis - Tracheitis - Croup - Epiglottitis|
|Influenza and Pneumonia||Influenza - Pneumonia (Viral, Bacterial, Bronchopneumonia)|
|Other acute lower respiratory infections||Bronchitis - Bronchiolitis|
|Other diseases of upper respiratory tract||Vasomotor rhinitis - Hay fever - Atrophic rhinitis - Nasal polyp - Adenoid hypertrophy - Peritonsillar abscess - Vocal fold nodule - Laryngospasm|
|Chronic lower respiratory diseases||Emphysema - COPD - Asthma - Status asthmaticus - Bronchiectasis|
|Lung diseases due to external agents||Coalworker's pneumoconiosis - Pneumoconiosis - Silicosis - Bauxite fibrosis - Berylliosis - Siderosis - Byssinosis - Hypersensitivity pneumonitis (Farmer's lung, Bird fancier's lung)|
|Other, principally affecting the interstitium||Acute respiratory distress syndrome - Pulmonary edema - Hamman-Rich syndrome - Interstitial lung disease|
|Suppurative and necrotic conditions of lower respiratory tract||Lung abscess - Pleural effusion - Empyema|
|Other||Pneumothorax - Respiratory failure - Atelectasis - Mediastinitis|
|Dentofacial Anomalies||Malocclusion - Micrognathism - Prognathism - Retrognathism - Temporomandibular joint disorder|
|Developmental Anomalies||Amelogenesis imperfecta - Anodontia - Concrescence - Dens evaginatus - Dens invaginatus - Dentin dysplasia -
Dentinogenesis imperfecta - Dilaceration - Enamel pearl - Fusion - Gemination - Hyperdontia - Macrodontia - Microdontia - Regional odontodysplasia -
Talon cusp - Taurodontism - Turner's hypoplasia
|Hard, Soft and Periapical Tissues||Attrition - Abrasion - Ankylosis - Dental caries - Denticles - Erosion - External resorption - Fluorosis - Gingivitis - Hypercementosis - Impaction - Internal resorption - Periodontitis - Pulpitis - Pulp stones - Ulcer|
|Maxillomandibular anomalies||Ameloblastoma - Odontogenic keratocyst - Torus mandibularis - Torus palatinus|
|Lip and Oral mucosa||Angular cheilitis - Erythroplakia - Hairy leukoplakia - Leukoplakia|
|Salivary glands||Drooling - Benign lymphoepithelial lesion - Frey's syndrome - Mikulicz's disease - Mucus retention cyst - Mumps -
Necrotizing sialometaplasia - Ranula - Sialadenitis - Sialolithiasis - Sjogren's syndrome - Stomatitis - Xerostomia
|Tongue||Geographic tongue - Fissured tongue - Glossitis - Glossodynia|
|Esophagus||Halitosis - Nausea - Vomiting - Heartburn - GERD - Achalasia - Esophageal cancer - Esophageal varices|
|Stomach||Peptic ulcer - Abdominal pain - Stomach cancer - Non-ulcer dyspepsia - Gastroparesis - Abdominal angina - Malabsorption (e.g. celiac disease, giardiasis) - Pyloric stenosis|
|Small intestine||Peptic ulcer - Intussusception - Malabsorption (e.g. coeliac, lactose intolerance, fructose malabsorption, Whipple's) - Lymphoma|
|Colon||Diarrhea - Appendicitis - Diverticulitis - Diverticulosis - IBD (Crohn's, Ulcerative colitis) - IBS - Constipation - Colorectal cancer - Hirschsprung's - Pseudomembranous colitis|
|Hernia||Inguinal - Femoral - Umbilical - Incisional - Diaphragmatic|
|Liver||Alcoholic liver disease - Cholestasis - Hepatitis - Liver failure - Cirrhosis - NASH - PBC - Budd-Chiari - Hepatocellular carcinoma|
|Accessory digestive||Gallbladder/Biliary tree (Gallstones, Cholecystitis, PSC, Ascending cholangitis) - Pancreas (Acute pancreatitis, Chronic pancreatitis, Pancreatic pseudocyst, Hereditary pancreatitis, Pancreatic cancer)|
|Diseases of the glomerulus||Lupus nephritis | Post-infectious glomerulonephritis | Minimal change disease | Focal segmental glomerulosclerosis | Diabetic nephropathy | IgA nephropathy | Membranous glomerulonephritis | Nephritic syndrome | Nephrotic syndrome|
|Diseases of the proximal convoluted tubules||Fanconi syndrome (Type II renal tubular acidosis) | renal cell carcinoma|
|Diseases of the distal convoluted tubules||pseudohypoaldosteronism (Type IV renal tubular acidosis)|
|Diseases of the collecting duct||Type I renal tubular acidosis|
|Tumours of the kidney||Renal cell carcinoma | Wilms' tumor (children)|
|Diseases of the renal vasculature||renal artery stenosis | vasculitis | atheroembolic disease|
|Tubulointerstitial diseases of the kidney||Drug-induced interstitial nephritis | Obstructive nephropathy | Radiation nephritis | Reflux nephropathy | Sarcoidosis|
|Genetic diseases of the kidney/syndromes associated with kidney dysfunction||Alport syndrome | Polycystic kidney disease | Wilms' tumour (children) | von Hippel-Lindau syndrome | Hereditary papillary renal carcinoma | Birt-Hogg-Dube syndrome | Hereditary renal carcinoma|
|Autosomal trisomies||Down syndrome (21), Edwards syndrome (18), Patau syndrome (13), Trisomy 9, Warkany syndrome 2 (8)|
|Autosomal monosomies/deletions||Wolf-Hirschhorn syndrome, Cri du chat, Angelman syndrome/Prader-Willi syndrome|
|X/Y linked||Turner syndrome, Triple X syndrome, Klinefelter's syndrome, XYY syndrome|
|Translocations||Philadelphia chromosome, Burkitt's lymphoma|