Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

580 results found
Article

Fowler syndrome

Fowler syndrome, also known as proliferative vasculopathy and hydranencephaly-hydrocephaly syndrome (PVHH), is a rare inherited condition. Terminology Not to be confused with Fowler syndrome of urinary retention, a condition caused by primary failure of urethral sphincter relaxation resulting ...
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F P Weber syndrome

F P Weber syndrome (FPWS) is a traditional eponymous denomination of a certain type of angiodysplasia, that would nowadays rather be called a mixed hemolymphatic congenital vascular malformation (CVM) with arteriovenous (AV) shunting, based on the Hamburg classification of CVMs. In his original...
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Fraser syndrome

Fraser syndrome is an extremely rare congenital syndromic anomaly.  Epidemiology The estimated incidence is at around 0.04:10,000 live-born infants and 1:10,000 stillbirths. Clinical spectrum The syndromic spectrum can comprise of: cryptophthalmos syndactyly: often cutaneous tracheal atre...
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Freeman Sheldon syndrome

Freeman Sheldon syndrome (FSS), also known as distal arthrogryposis type IIa, is a congenital condition where multiple joint contractures are a key feature. Affected individuals are known to have a characteristic facial expression resembling that of a whistling face and hence the syndrome is als...
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Frey syndrome

Frey syndrome (also known as Baillarger syndrome, Dupuy syndrome and auriculotemporal syndrome) is a complication of parotid surgery. It clinically manifests as sweating and reddening in the region of the face supplied by the auriculotemporal nerve. The symptoms typically occur when tasting food...
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Frontonasal dysplasia

Frontonasal dysplasia, also known as median cleft face syndrome, is a rare disorder characterized by midline defects involving the face, head, and central nervous system. Epidemiology Frontonasal dysplasia is considered to be a very rare condition, with approximately 100 cases having been repo...
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Functional gastrointestinal disorders

The functional gastrointestinal disorders (FGIDs) are a set of conditions characterized by their chronic GI manifestations, in the absence of structural abnormality of the gut. These conditions are common and may be disabling in nature. The understanding of their pathogenesis is incomplete, comp...
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Galloway-Mowat syndrome

Galloway-Mowat syndrome (GAMOS) is a rare autosomal recessive disorder characterized by nephrotic syndrome and central nervous system (CNS) abnormalities, namely microcephaly. Epidemiology Galloway-Mowat syndrome is considered extremely rare. Approximately 40 cases have been reported worldwide...
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Gasperini syndrome

Gasperini syndrome is a rare pontine stroke syndrome that involves the caudal pons tegmentum. Clinical presentation Classically, the syndrome presents with 1-3: involvement of the CN V nucleus: ipsilateral facial sensory loss involvement of the CN VI nucleus: ipsilateral impaired eye abducti...
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GATA2 deficiency

GATA2 deficiency is a germ-line disease expressed as a wide spectrum of phenotypes, including monocytopenia, myelodysplasia, myeloid leukaemias, and lymphedema. It is a rare cause of pulmonary alveolar proteinosis. Clinical presentation GATA2 deficiency has considerably variable clinical manif...
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Gerstmann-Straussler-Scheinker disease

Gerstmann-Straussler-Scheinker disease is a very rare type of human transmissible spongiform encephalopathy. It manifests with dementia and/or ataxia and is due to a mutation in the prion protein (PRNP) gene, which is inherited in an autosomal dominant pattern.  History and etymology It is nam...
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Gerstmann syndrome

Gerstmann syndrome, also known as angular gyrus syndrome, is a dominant hemisphere stroke syndrome affecting the left parietal lobe in the region of the angular gyrus, consisting of four components:  agraphia or dysgraphia acalculia or dyscalculia finger agnosia left-right disorientation Pu...
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Giant axonal neuropathy

Giant axonal neuropathy is a rare, autosomal recessive neurodegenerative disease of both the peripheral nervous system (PNS) and the central nervous system (CNS). It is one of the inherited leukodystrophies.  Epidemiology Approximately 50 affected families have been reported in the literature;...
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Gillespie syndrome

Gillespie syndrome is a rare genetic condition presenting as a mydriasis, secondary to an omnipresent partial aniridia. The abnormal iris is bilateral, with a highly-specific scalloped inner margin, due to hypoplasia of the central constrictor pupillae fibers. Associated features include an unch...
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Glycogen storage disease

Glycogen storage disease (GSD) refers to a number of syndromes which are characterized by a defect in synthesis, metabolism or storage of glycogen. Pathology There are many types of GSD: type I: von Gierke disease type II: Pompe disease type III: Cori or Forbes disease type IV: Andersen di...
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Glycogen storage disease type I

Glycogen storage disease type I (GSD-I), also known as von Gierke disease, is a type of glycogen storage disease where there is excess deposition of glycogen primarily in the liver, but also in the kidney and small bowel. Epidemiology It occurs approximately one in every 100,000 live births 2,...
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Goldenhar syndrome

Goldenhar syndrome, also known as oculo-auriculo-vertebral spectrum (OAVS), Goldenhar-Gorlin syndrome or facio-auriculo-vertebral dysplasia, is a complex congenital anomaly characterized by abnormalities of the ears, eyes and vertebrae. Epidemiology The estimated incidence is at 1 in 3000-5000...
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Gomez-Lopez-Hernandez syndrome

Gomez-Lopez-Hernandez syndrome, also known as cerebellotrigeminal-dermal dysplasia, is a rare phakomatosis characterized by rhombencephalosynapsis, parietal-occipital scalp alopecia, brachycephaly, facial malformations and trigeminal anesthesia.  History and etymology It is named after Manuel ...
Article

Goodman syndrome

Goodman syndrome is a type of acrocephalopolysyndactyly (often considered type IV). It is an extremely rare genetic disorder characterized by marked malformations of the head and face, abnormalities of the hands and feet, and congenital heart disease. The syndrome is inherited as an autosomal re...
Article

Goodpasture syndrome

Goodpasture syndrome, also referred as antiglomerular basement membrane (anti-GBM) antibody disease, is an autoimmune disease characterized by damage to the alveolar and renal glomerular basement membranes by a cytotoxic antibody. It is a type of pulmonary-renal syndrome. Goodpasture syndrome i...
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Good syndrome

Good syndrome is a rare paraneoplastic syndrome in which a thymoma causes hypogammaglobulinemia and humoral immunodeficiency. It has been estimated to occur in 0.2%–2% of thymomas 2. thymoma low to absent B-cells T-cell mediated defects CD4 T-cell lymphopenia inverted CD4/CD8+ T-cell ratio ...
Article

Gradenigo syndrome

Gradenigo syndrome consists of the triad of: petrous apicitis abducens nerve palsy, secondary to involvement of the nerve as it passes through Dorello canal retro-orbital pain, or pain in the cutaneous distribution of the frontal and maxillary divisions of the trigeminal nerve, due to extensi...
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Greig cephalopolysyndactyly syndrome

The Greig cephalopolysyndactyly syndrome (GCPS) is a rare pleiotropic, multiple congenital anomaly syndrome. It is primarily characterized by: polydactyly-polysyndactyly: preaxial polydactyly (most common 2) or mixed pre- and postaxial polydactyly true ocular hypertelorism macrocephaly fro...
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Grisel syndrome

Grisel syndrome is a rare cause of torticollis that involves subluxation of atlanto-axial joint from inflammatory ligamentous laxity following an infectious process in the head and neck, usually a retropharyngeal abscess. Epidemiology It usually occurs in infants or young children. Clinical p...
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Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is defined as a heterogeneous group of autoimmune polyradiculopathies, involving sensory, motor and autonomic nerves. It is the most common cause of rapidly progressive flaccid paralysis. It is believed to be one of a number of related conditions, sharing a similar ...
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Gullo syndrome

Gullo syndrome, also known as benign pancreatic hyperenzymaemia, is characterized by the abnormal elevation of the serum levels of most or all of the pancreatic enzymes without any evidence of underlying pancreatic pathology. All other laboratory assays and imaging studies are unremarkable. Cli...
Article

Hemoglobinopathies

A hemoglobinopathy is a genetic disorder which alters the structure of hemoglobin 1. The result is reduced oxygen-carrying capacity of the blood to the tissues, and other sequelae. Clinical presentation Clinical presentation varies, is related to hypoxia, and characteristically includes the fo...
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Hemolytic uremic syndrome

Hemolytic uremic syndrome (HUS) is a multisystem thrombotic microangiopathic disease characterized by the triad of renal failure, hemolytic anemia and thrombocytopenia. It is the most common cause of renal failure in infancy and childhood requiring dialysis.  There are two forms of this syndrom...
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Hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH), also known as macrophage activation syndrome when occurring in the setting of a rheumatologic disorder, is a non-malignant but often-fatal disorder of immune dysregulation affecting multiple organs. Epidemiology It typically affects infants and young c...
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Haglund syndrome

Haglund syndrome refers to the triad (Haglund triad) of: insertional Achilles tendinopathy retrocalcaneal bursitis Haglund deformity (i.e. posterosuperior calcaneal exostosis) This results in pain at the back of the heel. It is associated with calcaneal spurs, and the wearing of high heels (...
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Hajdu-Cheney syndrome

Hajdu-Cheney syndrome is a very rare connective tissue disorder with only 50 cases reported in the literature 7. Clinical presentation It is mostly diagnosed in adulthood or adolescence with the presence of a positive family history. There has been no link between severity of disease and age o...
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Hamatolunate impingement syndrome

Hamatolunate impingement is an uncommon cause of ulnar-sided wrist pain. The condition occurs most commonly in wrists where there is type II lunate morphology (existence of a medial facet on the distal lunate for articulation with the hamate). Repeated impaction of the opposing articular surface...
Article

Hamman syndrome

Hamman syndrome, also known as Macklin syndrome, refers to spontaneous pneumomediastinum along with subcutaneous emphysema. Epidemiology It is a rare entity most often encountered in young adults. It is a known entity peri- and postpartum 3. Clinical presentation The condition is most common...
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Hand-foot syndrome (chemotherapy)

Hand-foot syndrome, also known as palmar-plantar erythrodysaesthesia or Burgdorf reaction, is a benign, aseptic, self-limiting complication of many chemotherapeutic agents characterized by a widespread erythema, edema and ulceration of the hands and feet.  Causative drugs Many chemotherapeutic...
Article

Heerfordt syndrome

Heerfordt syndrome, also known as Heerfordt-Waldenström syndrome or uveoparotid fever, is a variant of sarcoidosis, comprising of: fever parotid enlargement facial palsy ocular involvement (anterior uveitis) Epidemiology The exact prevalence is unknown, as only isolated case reports exist....
Article

Heiner syndrome

The Heiner syndrome is a rare form of primary pulmonary hemosiderosis associated with an allergy to cow's milk. The syndrome includes: rectal blood loss with hypochromic microcytic anemia pulmonary infiltrates (often recurrent) hypoproteinemia See also pulmonary hemosiderosis
Article

HELLP syndrome

HELLP syndrome is a pregnancy-related condition and is an abbreviation for: haemolysis elevated liver enzymes and  low platelets It is considered a severe and life-threatening form of pre-eclampsia although it can occur without co-existing pre-eclampsia.  Epidemiology The estimated inciden...
Article

Hemiconvulsion-hemiplegia epilepsy syndrome

Hemiconvulsion-hemiplegia epilepsy syndrome (HHE) is a clinical syndrome of infancy or early childhood that is associated with seizures, cerebral hemiatrophy and transient or permanent epilepsy. It refers to the characteristic holohemispheric global atrophy of one hemisphere, that is independen...
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Hemifacial microsomia

Hemifacial microsomia (HFM) is the second most common congenital facial anomaly after cleft lip/palate. The condition may vary from mild to severe. Goldenhar syndrome has been described as a variant of HFM, in which vertebral anomalies and epibulbar dermoids were present. Terminology HFM is al...
Article

Hemihyperplasia

Hemihyperplasia, also known as hemihypertrophy, is asymmetry in size between the right and left of the body, more than can be attributed to normal variation. Terminology Hemihyperplasia is more scientifically correct than hemihypertrophy as the cells are hyperplastic rather than hypertrophied ...
Article

Hemimedullary syndrome

Hemimedullary syndrome, also known as Reinhold syndrome, occurs as a result of the occlusion of the ipsilateral vertebral artery proximal to the posterior inferior cerebellar artery and its anterior spinal artery branches 1-3. This situation causes lateral medullary infarct and medial medullary ...
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Hepatopulmonary syndrome

Hepatopulmonary syndrome (HPS) refers to the combination of hepatic dysfunction (cirrhosis) hypoxemia (alveolar-arterial O2 gradient of >15 mmHg; >20 mmHg in >64 years old patients) peripheral pulmonary arterial dilatation (due to right to left micro-shunts) Epidemiology It is estimated to ...
Article

Hereditary angiopathy with nephropathy, aneurysms, and muscle cramps syndrome

Hereditary angiopathy with nephropathy, aneurysms, and muscle cramps (HANAC) syndrome is an autosomal dominant monogenic COL4A1-related disorder. Epidemiology The exact prevalence is unknown. Clinical presentation The cardinal features of HANAC syndrome are helpfully described in the name of...
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Hereditary breast and ovarian cancer syndrome

Hereditary breast and ovarian cancer (HBOC) syndrome is caused by a mutation to either BRCA1 or BRCA2 genes. These patients have an increased risk of breast cancer, ovarian cancer, pancreatic cancer and prostate cancer. However, these gene mutations are not the only cause of hereditary breast ca...
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Hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is a rare inherited disorder characterized by abnormal blood vessel formation in the skin, mucous membranes, and organs including the lungs, liver, and central nervous system. Epidemiology Worldwide prevalen...
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Hereditary multiple exostoses

Hereditary multiple exostoses, also known as diaphyseal aclasis or osteochondromatosis is an autosomal dominant condition, characterized by the development of multiple osteochondromas. Epidemiology Hereditary multiple exostoses demonstrate an autosomal dominant inheritance pattern, with incomp...
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Hereditary non-polyposis colorectal cancer

Hereditary non-polyposis colorectal cancer (HNPCC), also known as Lynch syndrome, is an inherited condition which predisposes to a host of malignancies, including colorectal carcinoma. It is considered the most frequent form of hereditary colorectal cancer. Diagnosis requires evaluation using cl...
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Herlyn-Werner-Wunderlich syndrome

Herlyn-Werner-Wunderlich (HWW) syndrome, is a rare anomaly characterized by Müllerian duct anomalies (MDA) associated with mesonephric duct anomalies 3. This entity is also known as obstructed hemivagina and ipsilateral renal anomaly (OHVIRA). It is not to be confused with the Wunderlich syndrom...
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Hermansky-Pudlak syndrome

Hermansky-Pudlak syndrome (HPS) is a rare syndrome which consists of: oculocutaneous hypopigmentation (albinism) platelet dysfunction  abnormal storage of autofluorescent pigment (ceroid or lipofuscin)  typically occurs within lysosomal organelles of the cells of multiple organs and the reti...
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Heterotaxy syndrome

Heterotaxy syndrome or situs ambiguus (also commonly, but etymologically less correctly, spelled situs ambiguous) is a disturbance in the usual left-right distribution of the thoracic and abdominal organs that does not entirely correspond to the complete mirror image (situs inversus). It occurs...
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Heyde syndrome

Heyde syndrome is an association between aortic valve stenosis and gastrointestinal hemorrhage. The etiology of the gastrointestinal bleeding in this setting is uncertain, but it is thought to be related to intestinal angiodysplasia. The strength of this association independent of age-related d...
Article

HIV-associated nephropathy

HIV-associated nephropathy (HIVAN) is commonly seen in patients with HIV/AIDS and leads to end-stage renal disease (ESRD). The diagnosis is not imaging-based and must be confirmed by renal biopsy. Epidemiology HIVAN is seen in patients at advanced stages of HIV and AIDS, but it can also be see...
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Horizontal gaze palsy with progressive scoliosis

Horizontal gaze palsy with progressive scoliosis (HGPPS) is a rare autosomal recessive disease. Clinical presentation Abnormal horizontal gaze while normal vertical gaze and kyphoscoliosis. Horizontal gaze requires the action of ipsilateral abducent nerve and contralateral oculomotor nerve and...
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Hurler syndrome

Hurler syndrome is one of the mucopolysaccharidoses (MPS type I). Epidemiology The estimated incidence is ~1:100,000. Clinical presentation It manifests in the first years of life with intellectual disability, corneal clouding, deafness, and cardiac disease. Death usually occurs within the f...
Article

Hydrolethalus syndrome

Hydrolethalus syndrome is a rare lethal genetic syndrome characterized by multiple developmental defects of fetus which include  midline malformations cleft lip + / - palate CNS malformations fetal hydrocephalus agenesis of the corpus callosum Dandy-Walker malformation absent midline stru...
Article

Hyperimmunoglobulin IgE syndrome

Hyperimmunoglobulin E (hyper IgE) syndrome (HIES), also known as Job syndrome, consists of a heterogeneous group of complex hereditary combined B- and T-cell immune deficiency diseases characterized by recurrent Staphylococcus aureus chest infections, characteristic coarse facial appearance and ...
Article

Hyperparathyroidism-jaw tumor syndrome

Hyperparathyroidism-jaw tumor syndrome is an extremely rare condition where a gene mutation results in hyperparathyroidism in association with both benign and malignant tumors, most notably, tumors in the mandible or maxilla 2. Epidemiology Approximately 200 cases have been reported in the med...
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Hyperperfusion syndrome after carotid endarterectomy

Hyperperfusion syndrome after carotid endarterectomy (CEA) or carotid artery stenting (CAS) is a rare complication.  Epidemiology Hyperperfusion occurs in ~7.5% (range 1-14%) of patients but only a minority (~1.5%) of patients are symptomatic 1,2, with incidence being reported slightly more af...
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Hypomelanosis of Ito

Hypomelanosis of Ito, also known as incontinentia pigmenti achromians, is the third most frequent phakomatosis, involving a wide spectrum of defects in multiple organ systems. Epidemiology The prevalence is unknown, being reported as between 1 per 8000 patients in a general pediatric hospital ...
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Hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) is a cyanotic congenital cardiac anomaly where affected individuals can have profound cyanosis and cardiac failure. It is one of the commonest causes for a neonate to present with congestive cardiac failure and the 4th most frequent cardiac anomaly to mani...
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Hypothenar hammer syndrome

Hypothenar hammer syndrome occurs from trauma to the distal ulnar artery or proximal portion of superficial palmar arch as a result of repetitive trauma to the hypothenar eminence. Originally described in patients using hammers and screwdrivers, it is also seen in various athletes such as basket...
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Hypothyroidism

The clinical syndrome of hypothyroidism is marked by inadequate thyroid hormone production, resulting in a decreased rate of cellular metabolism. It may be primary, in which the dysfunction pertains to the thyroid gland itself, or secondary, due to hypothalamic or pituitary dysfunction 1. Epide...
Article

Idiopathic pneumonia syndrome

Idiopathic pneumonia syndrome (IPS) refers to diffuse lung injury which can occur following haematopeotic stem cell transplantation where neither an infectious nor non-infectious etiology can be found. Epidemiology The incidence of IPS is thought to be around 12% following haematopoetic stem c...
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Idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a clinical syndrome and considered the most common and the most lethal form of pulmonary fibrosis corresponding to the histologic and imaging pattern of UIP. It is more common in elderly men and diagnosed by:  histological or imaging pattern of usual inter...
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Iliotibial band syndrome

Iliotibial band (friction) syndrome is a common cause of lateral knee pain related to intense physical activity resulting in chronic inflammation. Epidemiology Commonly affect young patients who are physically active, most often long distance runners or cyclists. The exact prevalence is unknow...
Article

Immune reconstitution inflammatory syndrome

Immune reconstitution inflammatory syndrome (IRIS) is paradoxical deterioration of a pre-existing illness following abrupt improvement in an individual's immune function. It is classically seen in HIV/AIDS patients following initiation of highly active anti-retroviral therapy (HAART). Increasing...
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Incontinentia pigmenti

Incontinentia pigmenti, also known as Bloch-Sulzberger syndrome, is a rare condition that can affect many body systems, especially the skin. As an X-linked dominant genetic disorder, it occurs much more often in females than in males. Epidemiology Incontinentia pigmenti is rare and the true pr...
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Inferior medial pontine syndrome

Inferior medial pontine syndrome, also known as Foville syndrome, is one of the brainstem stroke syndromes occurring when there is infarction of the medial inferior aspect of the pons due to occlusion of the paramedian branches of the basilar artery 1-3. This infarction involves the following 1-...
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Internuclear ophthalmoplegia

Internuclear ophthalmoplegia (INO) describes a clinical syndrome of impaired adduction in one eye with dissociated horizontal nystagmus of the other abducting eye, due to a lesion in the medial longitudinal fasciculus (MLF) ipsilateral to the eye unable to adduct. It is a common finding in multi...
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Irritable bowel syndrome

Irritable bowel syndrome (IBS) is the commonest of the functional gastrointestinal disorders (FGIDs). Its key presenting features are recurrent abdominal pain and change in bowel habit (diarrhea and/or constipation), which may be severe, such that for an individual, there may be a marked negativ...
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Ischiofemoral impingement

Ischiofemoral impingement refers to the impingement of soft tissues between the ischial tuberosity and lesser trochanter of the femur, primarily the quadratus femoris muscle. Narrowing of the distance between these two osseous landmarks (ischiofemoral space) predisposes for and correlates with i...
Article

Ischiopubic synchondrosis asymmetry

Ischiopubic synchondrosis asymmetry (also known as van Neck-Odelberg disease) is characteristic enlargement of one of the ischiopubic synchondroses. It is largely considered an anatomic variant of skeletal developmental, given that it is a common and usually asymptomatic finding. However, some ...
Article

Jacobsen syndrome

Jacobsen syndrome (also known as the chromosome 11q deletion syndrome) is a rare chromosomal anomaly that results from deletion of the terminal region of chromosome 11. It results in intellectual disabilities, a distinctive facial appearance and a variety of physical problems including heart def...
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Jaffe-Campanacci syndrome

Jaffe-Campanacci syndrome is characterized by: multiple non-ossifying fibromas of the long bones and jaw café au lait spots intellectual disability kyphoscoliosis hypogonadism or cryptorchidism ocular malformations cardiovascular malformations giant cell granuloma of the jaw History and...
Article

Jarcho-Levin syndrome

The Jarcho-Levin syndrome (JLS) or spondylothoracic dysostosis is a rare autosomal recessive heterogeneous disorder that can occur with variable severity. Previously the condition spondylocostal dysostosis was also considered as part of the JLS spectrum but is now considered a distinct pathologi...
Article

Johanson-Blizzard syndrome

Johanson-Blizzard syndrome is a disorder of ectodermal dysplasia with wide variability in its manifestations. It is thought to have an autosomal recessive inheritance. Clinical presentation There is wide variability in the clinical presentation, but common features are: low birth weight hypo...
Article

Juberg-Hayward syndrome

Juberg-Hayward syndrome (JHS), also known as the oro-cranio-digital syndrome, is a rare autosomal recessive syndrome characterized by the association of the following:  growth retardation microcephaly cleft lip and palate minor vertebral and rib anomalies 4 horseshoe kidneys 4 thumb anomal...
Article

Juvenile polyposis syndrome

Juvenile polyposis syndrome, also referred as familial juvenile polyposis, is one of the polyposis syndromes and consists of hundreds of juvenile polyps. Epidemiology Presentation in the second decade is most common 2. Clinical presentation Rectal bleeding, bowel obstruction and intussuscept...
Article

Kabuki syndrome

Kabuki syndrome (Niikawa-Kuroki syndrome) is a rare polydysplasia that is thought to be more common in Japan. Epidemiology Estimated incidence of 1:32,000 in Japan. Sporadically seen elsewhere in the world. The reason for the disparity in incidence is controversial. Clinical presentation cha...
Article

Kartagener syndrome

Kartagener syndrome is a subset of primary ciliary dyskinesia, an autosomal recessive condition characterized by an abnormal ciliary structure or function, leading to impaired mucociliary clearance.  Epidemiology The prevalence of primary ciliary dyskinesia is approximately 1 in 12,000-60,000 ...
Article

Kasabach-Merritt syndrome

Kasabach-Merritt syndrome, also known as hemangioma thrombocytopenia syndrome, is a rare life-threatening disease found in infants in which a rapidly growing vascular tumor is responsible for thrombocytopenia, microangiopathic hemolytic anemia and consumptive coagulopathy. Pathology Vascular t...
Article

Klinefelter syndrome

Klinefelter syndrome (KS) is a sex chromosomal anomaly, which in most cases is characterized by 47 chromosomes instead of the usual 46. Epidemiology The estimated incidence is 0.15-0.2% of live births. Clinical presentation the testes are normal prior to puberty and small in post pubertal te...
Article

Klippel-Feil syndrome

Klippel-Feil syndrome is a complex heterogeneous entity that results in cervical vertebral fusion. Two or more non-segmented cervical vertebrae are usually sufficient for diagnosis. Epidemiology There is a recognized female predilection 1. Klippel-Feil syndrome has an incidence of 1:40,000-42,...
Article

Klippel-Trénaunay-Weber syndrome

Klippel-Trénaunay-Weber syndrome (KTWS) is a syndrome combination of capillary malformations, soft-tissue or bone hypertrophy, and varicose veins or venous malformations. It is considered an angio-osteo-hypertrophic syndrome. KTS classically comprises a triad of: port wine nevi bony or soft t...
Article

Kyphomelic dysplasias

Kyphomelic dysplasias (also known as "pseudocampomelia") is thought to be a heterogeneous class of "bent bone" skeletal dysplasias. Entities included in a differential for the class are: congenital bowing of the long bones cartilage-hair hypoplasia (CHH; metaphyseal dysplasia, McKusick type) ...
Article

Lacunar stroke syndrome

Lacunar stroke syndrome (LACS) is a description of the clinical syndrome that results from a lacunar infarct.  Each of the five classical lacunar syndromes has a relatively distinct symptom complex. Symptoms may occur suddenly, progressively, or in a fluctuating manner (e.g. the capsular warnin...
Article

Lambert-Eaton myasthenic syndrome

Lambert-Eaton myasthenic syndrome (LEMS) is a rare neuromuscular junction disorder of paraneoplastic or primary autoimmune etiology. Epidemiology LEMS is the second most common neuromuscular junction disease after myasthenia gravis.  Two-thirds of LEMS present as a paraneoplastic syndrome sec...
Article

Lane-Hamilton syndrome

Lane-Hamilton syndrome (LHS) refers to the rare concurrent association of idiopathic pulmonary hemosiderosis and celiac disease 1. Epidemiology It is typically seen in children under the age of 15 but can occasionally be seen in adults. History and etymology It was originally described by D ...
Article

Langer-Giedion syndrome

Langer-Giedion syndrome, also known as trichorhinophalangeal syndrome type II, is an extremely rare autosomal dominant genetic disorder. Pathology The effects are seen mainly on the skeletal system and primarily involves hair: tricho nose: rhino digits of the hands and feet: phalangeal The...
Article

Large vestibular aqueduct syndrome

Large vestibular aqueduct syndrome (LVAS), also known as large endolymphatic sac anomaly (LESA), refers to the presence of congenital sensorineural hearing loss with an enlarged vestibular aqueduct due to enlargement of the endolymphatic duct. It is thought to be one of the most common congenita...
Article

Larsen syndrome

Larsen syndrome (LS) is an extremely rare disorder, often classified as a type of osteochondrodysplasia. Epidemiology The estimated incidence is thought to be at ~ 1 in 100,000 people. There may be an increased female predilection. Clinical presentation It is characterized by many features i...
Article

Lateral medullary syndrome

Lateral medullary syndrome, also known as Wallenberg syndrome, is a clinical syndrome caused by an acute ischemic infarct of the lateral medulla oblongata. This is most commonly due to occlusion of the intracranial portion of the vertebral artery followed by PICA and its branches 1-3.  Epidemio...
Article

Lateral meningocele syndrome

Lateral meningocele syndrome is an extremely rare hereditary connective tissue disorder characterized by multiple lateral lumbar meningoceles, distinctive facial features, joint hypermobility, hypotonia, skeletal abnormalities, congenital cardiovascular malformations, urogenital anomalies and ne...

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