Interstitial cystitis (or painful bladder syndrome) refers to an inflammatory condition affecting the bladder. It is usually defined as urinary bladder pain and irritative symptoms of more than six months' duration. It usually represents a diagnosis of exclusion. Traditionally, it has been defin...
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...
Ischiofemoral impingement refers to the impingement of soft tissues between the ischial tuberosity and lesser trochanter of the femur.
Ischiofemoral impingement is a rare cause of buttock pain, groin pain, or a snapping hip 6,7.
Females are more affected t...
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 ...
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...
Jaffe-Campanacci syndrome is characterized by:
multiple non-ossifying fibromas of the long bones and jaw
café au lait spots
hypogonadism or cryptorchidism
giant cell granuloma of the jaw
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...
Johanson-Blizzard syndrome is a disorder of ectodermal dysplasia with wide variability in its manifestations. It is thought to have an autosomal recessive inheritance.
There is wide variability in the clinical presentation, but common features are:
low birth weight
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:
cleft lip and palate
minor vertebral and rib anomalies 4
horseshoe kidneys 4
Juvenile hyaline fibromatosis is a rare autosomal recessive syndrome outlined by painful, abnormal, often deforming deposits of hyalinized fibrous material in the extracellular matrix of the skin, subcutaneous soft tissues and gums. It is listed under fibroblastic and myofibroblastic tumors in t...
Juvenile polyposis syndrome, also referred as familial juvenile polyposis, is one of the polyposis syndromes and consists of hundreds of juvenile polyps.
Presentation in the second decade is most common 2.
Rectal bleeding, bowel obstruction and intussuscept...
Kabuki syndrome (Niikawa-Kuroki syndrome) is a rare polydysplasia that is thought to be more common in Japan.
Estimated incidence of 1:32,000 in Japan. Sporadically seen elsewhere in the world. The reason for the disparity in incidence is controversial.
Kallmann syndrome is a rare genetic disorder characterized by hypogonadotropic hypogonadism associated with anosmia or hyposmia. When anosmia is absent, a similar syndrome is referred to as normosmic idiopathic hypogonadotropic hypogonadism.
It is a rare disorder with an estimate...
Kartagener syndrome (also known as Kartagener-Afzelius syndrome) is a subset of primary ciliary dyskinesia, an autosomal recessive condition characterized by abnormal ciliary structure or function, leading to impaired mucociliary clearance.
The prevalence of primary ciliary dyski...
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.
Keutel syndrome is an extremely rare inherited condition characterized by
cartilage calcification which include
trachea - with resultant tracheobronchial stenosis
pulmonary arterial stenoses
brachytelephalangism (short fingers and nails that resemble drumsticks)
Klinefelter syndrome (KS) is a sex chromosomal anomaly, which in most cases is characterized by 47 chromosomes instead of the usual 46.
The estimated incidence is 0.15-0.2% of live births.
the testes are normal prior to puberty and small in post pubertal te...
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.
There is a recognized female predilection 1. Klippel-Feil syndrome has an incidence of 1:40,000-42,...
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...
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)
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...
Lady Windermere syndrome refers to a pattern of pulmonary Mycobacterium avium complex (MAC) infection seen typically in elderly white women who chronically suppress the normal cough reflex. A fastidious nature and a reticence to expectorate are believed to predispose such persons to infections w...
Lambert-Eaton myasthenic syndrome (LEMS) is a rare neuromuscular junction disorder of paraneoplastic or primary autoimmune etiology.
LEMS is the second most common neuromuscular junction disease after myasthenia gravis.
Two-thirds of LEMS present as a paraneoplastic syndrome sec...
Lane-Hamilton syndrome (LHS) refers to the rare concurrent association of idiopathic pulmonary hemosiderosis and celiac disease 1.
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 ...
Langer-Giedion syndrome, also known as trichorhinophalangeal syndrome type II, is an extremely rare autosomal dominant genetic disorder.
The effects are seen mainly on the skeletal system and primarily involves
digits of the hands and feet: phalangeal
Large vestibular aqueduct syndrome (LVAS), also known as enlarged vestibular aqueduct (EVA) or 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 ...
Larsen syndrome (LS) is an extremely rare disorder, often classified as a type of osteochondrodysplasia.
The estimated incidence is thought to be at ~ 1 in 100,000 people. There may be an increased female predilection.
It is characterized by many features i...
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.
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...
Lateral pontine syndrome, also known as Marie-Foix syndrome or Marie-Foix-Alajouanine syndrome, refers to one of the brainstem stroke syndromes of the lateral aspect of the pons.
There is a characteristic clinical picture1,2,4:
limb ataxia: cerebellar tracts...
Laurin-Sandrow syndrome is a rare disorder characterized by tetrameric polysyndactlyly.
polysyndactyly of the hands (both post-axial and pre-axial)
mirror polysyndactyly of the feet
absence of the radius and tibia
Leaky lung syndrome refers to a form of non-cardiogenic pulmonary edema.
Pulmonary edema due to increased capillary permeability.
Leaky lung syndrome is considered a mild form of a part of the spectrum of acute lung injury with ARDS at the other end of the s...
Legius syndrome is characterized by multiple café-au-lait spots, with or without freckles and macrocephaly.
More than 200 cases were reported between 2007 and 2013 1,3.
Although rare, it is estimated that up to 2% of patients fulfilling diagnostic criteria for neurofibromatosis-1...
Leigh syndrome, also known as subacute necrotizing encephalomyelopathy (SNEM), is a mitochondrial disorder with progressive neurodegeneration that invariably leads to death, usually in childhood.
Leigh syndrome is encountered in approximately 1 in 40,000 births, although some popu...
Lemierre syndrome (also known as postanginal septicemia) refers to thrombophlebitis of the internal jugular vein(s) with distant metastatic sepsis in the setting of initial oropharyngeal infection such as pharyngitis/tonsillitis with or without peritonsillar or retropharyngeal abscess.
Lemmel syndrome is defined as obstructive jaundice caused by a periampullary duodenal diverticulum compressing the intrapancreatic common bile duct with resultant bile duct dilatation.
Patients may present with recurrent episodes of jaundice, pancreatitis and/or cholangit...
Lennox-Gastaut syndrome is a form of refractory childhood-onset epilepsy and is often accompanied by developmental delay and psychological/ behavioral problems. An electroencephalogram (EEG) often shows a slow spike and wave pattern.
It often appears between the 2nd and 6th years ...
Leontiasis ossea is largely a historical term used to describe a number of conditions that result in the affected patient's face resembling that of a lion. Although it is most frequently associated with craniofacial fibrous dysplasia, it has a broader meaning encompassing other lesions that have...
Leprosy, previously known as Hansen's disease, is a chronic infectious disease caused by Mycobacterium leprae and presents mainly in tropical developing countries.
It is most common in tropical developing countries and is endemic in over 100 countries. Worldwide, there is a preval...
Lesch-Nyhan syndrome is a rare X-linked genetic disease caused by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT).
Affects 1 per 380,000 individuals, which are nearly all male given the X-linked inheritance 1.
Lethal omphalocele-cleft palate syndrome is, as the name suggests, characterized by the association of omphalocele and cleft palate.
Prevalence is assumed to be <1 per 1,000,000. It has been postulated that this syndrome is likely to be an autosomal recessive condition 1.
History and etymolog...
Leukoencephalopathy with calcification and cysts, also known as Labrune syndrome, is a rare condition that consists of a triad of leukoencephalopathy, cerebral calcification and edematous cysts.
Leukoencephalopathy with calcification and cysts is an extremely rare condition, with ...
Levator ani syndrome (LAS) is a musculoskeletal pain syndrome involving the pelvic floor, thought to be caused by spasm or scarring of the levator ani muscles.
Levator ani syndrome is characterized by recurrent pain, pressure or discomfort in the region of the rectum, sac...
Li-Fraumeni syndrome is a hereditary cancer syndrome due to mutations in the tumor suppressor gene TP53. Approximately half of affected individuals are thought to develop invasive cancer by 30 years of age 1.
Little league shoulder is thought to occur due to overuse damage of the proximal humeral epiphysis/metaphysis, seen typically in young baseball players, especially pitchers.
Although it is most commonly seen in baseball players particularly in pitchers, it also presents in adolesc...
Locked-in syndrome is one of the brainstem stroke syndromes and can occur as a result of a pontine stroke that damages the ventral brainstem, pyramidal bundles and corticobulbar tracts 5.
Individuals who are "locked-in" are conscious with preserved cognitive function but ...
Simple pulmonary eosinophilia (also known as Löffler syndrome) is a type of pulmonary eosinophilia that typically presents with transient radiographic infiltrates, minimal constitutional upset, and an elevated eosinophil count in peripheral blood.
The cause is not usually i...
Löfgren syndrome is a specific acute clinical presentation of systemic sarcoidosis that usually manifests with lymphadenopathy, fevers, erythema nodosum, and polyarticular arthritis.
It is important to not confuse this syndrome with Löffler syndrome, as the names are quite similar...
Lowe syndrome, also known as the oculocerebrorenal syndrome of Lowe, is a multisystem disorder characterized by anomalies primarily affecting the eyes, nervous system, and kidneys.
It is an extremely rare, pan-ethnic disease, with an estimated prevalence in the general population ...
Low phospholipid-associated cholelithiasis (LPAC) syndrome is one of the syndromes associated with ABCB4/MDR3 mutation. Characteristics of this syndrome include 1,2:
symptomatic cholesterol stones with early onset (<40 years)
recurrent symptoms post cholecys...
LUMBAR, PELVIS, or SACRAL syndrome is the association of infantile hemangiomas in the lower body with other extracutaneous congenital abnormalities in the region. The syndrome may be incomplete.
lower body hemangiomas
urogenital anomalies and ulceration
Lutembacher syndrome refers to the association of an atrial septal defect (ASD) with mitral stenosis. Both the defects can be either congenital or acquired.
History and etymology
It is named after Rene Lutembacher 4.
Madelung disease, also known as Madelung-Launois-Bensaude syndrome or neck lipomatosis or multiple symmetric lipomatosis, is a rare benign entity clinically characterized by the presence of multiple and symmetric, non-encapsulated masses of fatty tissue, usually involving the neck and the upper ...
Maffucci syndrome is a congenital nonhereditary mesodermal dysplasia characterized by multiple enchondromas with soft-tissue venous malformations (hemangiomas).
On imaging, it is usually portrayed by a short limb with metaphyseal distortions due to multiple enchondromas, which may appear grotes...
Mainzer-Saldino syndrome (also known as conorenal syndrome (CRS)) is a rare condition and is one of the ciliopathies. It is due to mutations in the IFT140 gene, whose protein product is one of the six parts of the intraflagellar transport complex A.
The syndrome's key characteristics are:
Manganism (also known as acquired hypermanganesemia) is the clinical syndrome resulting from acute or chronic overexposure to the transition metal manganese, one of the essential trace elements. It primarily manifests as parkinsonism and is frequently clinically, radiologically and histopatholog...
Man-in-the-barrel syndrome is a neurological syndrome characterized by bilateral brachial muscular weakness.
This syndrome is usually caused by bilateral cerebral lesions in the border zone between the anterior and middle cerebral arteries.
The syndrome has been described ...
Marchiafava-Bignami disease (MBD) is a rare CNS disorder usually seen in the context of alcoholism and malnutrition. The condition classically involves the corpus callosum with necrosis and demyelination.
MBD is in most instances seen in chronic alcoholics, and as such the epidem...
Marfan syndrome is a multisystem connective tissue disease caused by a defect in the protein fibrillin 1, encoded by the FBN1 gene. Cardiovascular involvement with aortic root dilatation and dissection is the most feared complication of the disease.
The estimated prevalence is aro...
Marine-Lenhart syndrome refers to a variant of Graves disease where there are coexistent autonomous thyroid nodules. It is better described as Graves disease with coexistent multinodular goiter or nodular Graves disease 1.
The syndrome is rare with reported prevalence somewhere b...
Marshall-Smith syndrome (MSS) is a rare genetic syndrome primarily comprising the triad of facial dysmorphism, failure to thrive and accelerated osseous maturation 5. Many cases, however, have a wider clinical spectrum.
failure to thrive
May-Thurner syndrome refers to a chronic compression of the left common iliac vein (CIV) against the lumbar vertebrae by the overlying right common iliac artery (CIA), with or without deep venous thrombosis 2.
Although both left and right CIVs lie deep to the right common iliac artery, the left...
Mazabraud syndrome is a rare syndrome characterized by skeletal fibrous dysplasia and intramuscular myxomas 1-3.
Only 107 cases have been reported in the global literature (as of 2019) 1,3-5,15. The prevalence is ~ 1 in 1,000,000 3 with a strong female predilection (68-84%) 1,3. T...
McCune-Albright syndrome (MAS) (also known as McCune-Albright-Sternberg syndrome) is a genetic disorder characterized by the association of:
endocrinopathy: precocious puberty
polyostotic fibrous dysplasia: more severe than in sporadic cases
cutaneous pigmentation: coast of Maine 'café au lai...
McKusick Kaufman syndrome (MKS) is an autosomal recessive multiple malformation syndrome primarily characterized by
hydrometrocolpos - vaginal atresia
congenital heart disease
Meckel-Gruber syndrome (MGS) is classically characterized by the triad of:
renal cystic dysplasia: multiple renal cysts (present most cases)
occipital encephalocoele/holoprosencephaly (~70%)
postaxial polydactyly: usually hexadactyly (~65%)
Additional hepatic developmental defects and hepati...
Meconium plug syndrome refers to a functional colonic obstruction in a newborn due to an obstructing meconium plug. It is usually transient and affects the left colon with meconium plugging the bowel distal to this segment. In this situation, it is also termed the small left colon syndrome.
Medial medullary syndrome, also known as Déjerine syndrome, is secondary to thrombotic or embolic occlusion of small perforating branches from vertebral or proximal basilar artery supplying the medial aspect of medulla oblongata1,2.
Represents less than 1% of brainstem stroke sy...
Medial patellar plica syndrome is one of the conditions that can be associated with the presence of synovial plicae of the knee (in this instance a medial plica). It can be a common source of anterior knee pain.
While it can affect those of any age, it typically involves the young...
Medial tibial stress syndrome (MTSS), also known as shin splints, describes a spectrum of exercise-induced stress injury that occurs at the medial tibial mid-to-distal shaft. This term is often incorrectly used to indicate any type of tibial stress injury but more correctly refers to the earlier...
Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) (also known as the Berdon syndrome) is a rare congenital disorder characterized by a dilated non-obstructive urinary bladder and hypoperistalsis of the gastrointestinal tract.
There is recognized strong female predi...
Megalencephaly-capillary malformation (MCAP) syndrome, also known as macrocephaly-capillary malformation syndrome, is a rare and well described genetic disorder caused by somatic mutations in the PIK3CA gene on chromosome 3q26 and characterized by early brain overgrowth and body morphogenesis an...
Megalocornea is a rare bilateral congenital ocular defect characterized by a corneal diameter of more than 13 mm with the deep anterior chamber and normal intraocular pressure 1-3.
Megalcornea is associated with Chordin-like 1 (CHRDL1) gene mutation 1,2. It is associated with mult...
MEGDEL syndrome (3-MEthylGlutaconic aciduria, Deafness, Encephalopathy, Leigh-like syndrome) is a recently described syndrome with infantile onset. These patients typically initially receive a diagnosis of Leigh syndrome, based on clinical and biochemical features and an abnormal basal ganglia s...
Mendelson syndrome or peptic pneumonia refers to acute chemical pneumonitis caused by the aspiration of stomach contents in patients under general anesthesia.
This syndrome develops rapidly (2-12 hours after aspiration) and within hours the patient may become
Menkes disease, also known as trichopoliodystrophy or kinky hair kinky vessel syndrome, is an X-linked recessive disorder that results in a derangement in copper handling. It results in low copper levels and subsequently, deficiency in copper-dependent mitochondrial enzymes.
Mercedes Benz pattern craniosynostosis also known as pure bilateral lambdoid and sagittal synostosis (BLSS) is a pattern of craniosynostosis. 1-2
The estimated incidence is at around 0.3 - 0.7 % 3.
Cognitive function is grossly normal. Dolichocephalic head...
The metabolic syndrome, also known as syndrome X, is a set of five conditions, which together increase a patient's risk of developing cardiovascular disease 1.
There are five central components of metabolic syndrome:
impaired glucose tolerance
Metaphyseal chondrodysplasia (also known as metaphyseal dysplasia or dysostosis) is a type of skeletal dysplasia.
Schmid type - mild type, due to mutation in type X collagen (COL10A1 gene), metaphyses are cupped resembling rickets
Pena and Vaandrager type - intermedi...
Metronidazole, which is used to treat a wide variety of bacterial and protozoal infections can, in exceedingly rare cases, lead to central nervous system toxicity.
In a review of the case literature 1, affected patients range widely in age, with the peak incidence occurring in the...
Midaortic syndrome is an uncommon entity affecting children and young adults. It is characterized by progressive narrowing of the abdominal aorta and its major branches.
The onset of symptoms is usually during childhood or young adulthood 2:
hypertension (most common)
Middle East respiratory syndrome coronavirus (MERS-CoV) infection is an uncommon coronavirus infection (<1000 cases) with the first case reported in Saudi Arabia in 2012. It most commonly causes pneumonia and acute renal failure with a mortality rate of ~40%. MERS-CoV raises concern because of i...
Mikulicz syndrome was considered a form of Sjögren syndrome (type 1), however, more recently it is considered to be on the IgG4-related disease spectrum.
It may also be referred to by numerous other eponyms as well as the rather verbose: sicca syndrome without a connective tissue ...
Milk-alkali syndrome is the combination of:
It is due to a large amount of calcium and alkali being ingested (e.g. milk and antacids for peptic ulcer disease treatment or calcium carbonate for osteoporosis). It is a cause of medullary nephrocal...
Millard-Gubler syndrome, also known as ventral pontine syndrome, is one of the crossed paralysis syndromes, which are characterized by cranial nerves VI and VII palsies with contralateral body motor or sensory disturbances 1-3.
ipsilateral facial and contralateral body he...
Milwaukee shoulder refers to a destructive shoulder arthropathy due to deposition of hydroxyapatite crystals, and identification of these crystals in synovial fluid is the cornerstone of diagnosis.
Milwaukee shoulder frequently affects older women, often with a history of trauma t...
Mirizzi syndrome refers to an uncommon phenomenon that results in extrinsic compression of an extrahepatic biliary duct from one or more calculi within the cystic duct or gallbladder. It is a functional hepatic syndrome but can often present with biliary duct dilatation and can mimic other hepat...
Möbius syndrome, also known as congenital facial diplegia syndrome, is a rare congenital condition characterized by the absence or underdevelopment of the nuclei of the abducens (CN VI) and facial nerve (CN VII).
Möbius syndrome is rare with an estimated incidence of ~1 case per 1...
Morgagni-Stewart-Morel syndrome consists of the triad of:
hyperostosis frontalis interna
excessive hair growth (virilism/hirsutism)
and is also associated with neuropsychiatric conditions. The cause is unclear.
History and etymology
It was first described in 1765 by the Italian ...
Morning glory disc anomaly (MGDA), also known as morning glory syndrome, is a rare congenital malformation of the optic nerve which is frequently associated with midline abnormalities of the brain and skull 1.
Morning glory disc anomaly is rare and is more commonly found in female...
Morquio syndrome (in older literature it is sometimes called Morquio-Brailsford syndrome) is an autosomal recessive mucopolysaccharidosis (MPS) type IV.
Incidence estimated at ~1:40,000.
Many cases present at ~2 years of age and have normal intelligence. Cl...
Morvan syndrome, also known as Morvan fibrillary chorea, is a rare syndrome thought to be either paraneoplastic or autoimmune in origin.
It is characterized by:
Voltage gated pot...
Moyamoya syndrome, also termed the moyamoya pattern or phenomenon, is due to numerous conditions that can cause arterial occlusion of the circle of Willis, with resultant collaterals, and appearances reminiscent of moyamoya disease. These conditions include 1-4 :
vessel wall abnormalities