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...
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...
Ischiopubic synchondrosis asymmetry 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 cases are thought to be symptomatic and ma...
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 characterised 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 a wide variability in its manifestations. It is thought to have autosomal recessive inheritance.
There is a 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 characterised by the association of the following:
cleft lip and palate
minor vertebral and rib anomalies 4
horseshoe kidneys 4
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.
The cause for t...
Kartagener syndrome is a subset of primary ciliary dyskinesia, an autosomal recessive condition characterised by an abnormal ciliary structure or function, leading to impaired mucociliary clearance.
The prevalence of primary ciliary dyskinesia is approximately 1 in 12,000-60,000 ...
Kasabach-Merritt syndrome, also known as haemangioma thrombocytopenia syndrome, is a rare life-threatening disease found in infants in which a rapidly growing vascular tumour is responsible for thrombocytopenia, microangiopathic haemolytic anaemia and consumptive coagulopathy.
Klinefelter syndrome (KS) is a chromosomal anomaly, which in most cases is characterised 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 testes...
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 recognised 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...
Lambert-Eaton myasthenia syndrome (LEMS) is rare but is still the second most common neuromuscular junction disease after myasthenia gravis. Two-thirds of LEMS present as a paraneoplastic syndrome secondary to malignancy, most commonly lung cancer but is also associated with breast, ovarian and ...
Lane-Hamilton syndrome (LHS) refers to the rare concurrent association of idiopathic pulmonary haemosiderosis and coeliac 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 ...
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, also known as large endolymphatic sac anomaly, refers to the presence of congenital sensorineural hearing loss with an enlarged vestibular aqueduct. It is thought to be one of the most common congenital causes of sensorineural hearing loss.
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 characterised by many features i...
Lateral medullary syndrome (or 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. This syndrome is cha...
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 picture from the involvement of the following pontine stru...
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 oedema.
Pulmonary oedema 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...
Lemierre syndrome refers to thrombophlebitis of the jugular veins with distant metastatic sepsis in the setting of initial oropharyngeal infection such as pharyngitis/tonsillitis with or without peritonsillar or retropharyngeal abscess.
Since the advent of antibiotics, the inciden...
Lemmel syndrome is defined as an obstructive jaundice caused by a periampullary duodenal diverticulum (of the second part of the duodenum) compressing the intrapancreatic part of the common bile duct with resultant upstream dilatation of the extra- and intrahepatic bile ducts.
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...
Lethal omphalocele-cleft palate syndrome is, as the name suggests, characterised 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 calcifications and cysts, also known as Labrune syndrome, is a rare condition that consists of a triad of leukoencephalopathy, cerebral calcifications and oedematous cysts.
Leukoencephalopathy with calcifications and cysts is an extremely rare condition, w...
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 characterised by recurrent pain, pressure or discomfort in the region of the rectum, sac...
Locked-in syndrome is a condition that can occur as a result of a stroke involving the brainstem; the stroke damages the ventral brainstem, corresponding to the pyramidal bundles.
The infarct is pontine; the midbrain is preserved. The oculomotor nerve III is intact so the...
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 ...
Löfgren syndrome is a specific acute clinical presentation of systemic sarcoidosis that usually manifests with lymphadenopathy, fevers, erythema nodosum, and arthritis.
It is important to not confuse this syndrome with Löffler syndrome, as the names are quite similar but the condi...
Lowe syndrome (also known as the the oculocerebrorenal syndrome of Lowe) is a multi-system disorder characterised by anomalies primarily affecting the eyes, nervous system, and kidneys.
It is an extremely rare, pan-ethnic, x-linked disease, with estimated prevalence in the general po...
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...
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 characterised 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 characterised by multiple enchondromas with soft-tissue venous malformations (haemangiomas).
On imaging, it is usually portrayed by a short limb with metaphyseal distortions due to multiple enchondromas, which may appear grote...
Man-in-the-barrel syndrome is a neurological syndrome characterised 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 with autosomal dominant inheritance of a defect in the fibrillin 1 gene. The affected patients are tall with long, disproportionate extremities and have pectus excavatum, arachnodactyly, and may also experience upward and lateral optic l...
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 goitre or nodular Graves disease 1.
The syndrome is rare with reported prevalence somewhere b...
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 consisting of:
fibrous dysplasia: usually polyostotic 2
multiple soft tissue myxomas (intramuscular myxomas): typically in large muscle groups
It is very rare, with only 81 cases in the global literature reported to 2012 13. It is most frequ...
McCune-Albright syndrome (MAS) is a genetic disorder characterised by the association of:
endocrinopathy: precocious puberty
polyostotic fibrous dysplasia: more severe than in sporadic cases
cutaneous pigmentation: coast of Maine 'cafe au lait' spots
Presentation is va...
McKusick Kaufman syndrome (MKS) is an autosomal recessive multiple malformation syndrome primarily characterised by
hydrometrocolpos - vaginal atresia
congenital heart disease
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, represents less than 1% of brainstem stroke syndromes 1,2. Thrombotic or embolic occlusion of small perforating branches from vertebral or proximal basilar artery supplying the medial aspect of medulla oblongata cause this rare syndrome...
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 stress injury that occurs at the medial tibia. This term is often used to indicate any type of tibial stress injury or the earlier manifestations of a tibial stress lesion before a fracture component can be...
Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) (also known as the Berdon syndrome) is a rare congenital disorder characterised by a dilated non-obstructive urinary bladder and hypoperistalsis of the gastrointestinal tract.
There is recognised 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 characterised by early brain overgrowth and body morphogenesis an...
Mendelson syndrome or peptic pneumonia refers to acute chemical pneumonitis caused by the aspiration of stomach contents in patients under general anesthesia.
The etiologic agents is believed to be aspiration of acidic stomach contents, other compounds, e.g. bile, may also play a rol...
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-dependant mitochondrial enzymes.
MERRF (myoclonic epilepsy with red ragged fibres) is a rare, multisystem mitochondrial disorder.
Patients usually present in late adolescence or early adulthood with 1,2,3
vision and/or hearing loss
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 the 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 (MAS) is an uncommon entity affecting children and young adults. It is characterised by progressive narrowing of the abdominal aorta and its major branches.
The onset of symptoms is usually during young adulthood or childhood 2:
hypertension (most comm...
Middle East Respiratory Syndrome coronavirus (MERS-CoV) infection is an uncommon viral 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 its sim...
Mikulicz syndrome was considered a form of Sjögren syndrome (type 1) however more recently it is considered in IgG4 related disease spectrum. It is a non-specific inflammatory enlargement of at least two or more of the salivary and lacrimal glands with xerostomia.
It may also be referred to b...
Milk-alkali syndrome is the combination of:
It is due to the large amounts 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 nephr...
Millard-Gubler syndrome, also known as ventral pontine syndrome, is one of the crossed paralysis syndromes, which are characterised 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...
The Mirizzi syndrome refers to an uncommon phenomenon which 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 ...
Möbius syndrome, also known as congenital facial diplegia syndrome, is a rare congenital condition characterised by the absence or underdevelopment of the abducens nerve (CN VI) and facial nerve (CN VII) nuclei.
Möbius syndrome is rare with an estimated incidence of ~1 case per 10...
Morgagni-Stewart-Morel syndrome consists of the triad of:
hyperostosis frontalis interna
excessive hair growth (virilism/hirsutism)
and along with these metabolic/hormonal disorders is associated with neuropsychiatric conditions. The cause is unclear.
History and etymology
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 females...
Morquio 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. Clinical features:
severe dwarfism (<4 foot)
Morvan syndrome, also known as Morvan fibrillary chorea, is a rare syndrome thought to be either paraneoplastic or autoimmune in origin.
It is characterised by:
Voltage gated pot...
Mucopolysaccharidoses (MPS) constitute a group of hereditary disorders, one of a number of lysosomal storage disorders, having in common an excessive accumulation of mucopolysaccharides secondary to deficiencies in specific enzymes (lysosomal hydrolases) responsible for degradation of mucopolysa...
Multiple endocrine neoplasia type I (MEN1), also known as Wermer syndrome, is an autosomal dominant genetic disease that results in proliferative lesions in multiple endocrine organs, particularly the pituitary gland, islet cells of the pancreas and parathyroid glands.
There are other multiple...
Multiple endocrine neoplasia (MEN) type IIa, also known as Sipple syndrome, accounts for most cases of MEN2 and is characterised by:
pheochromocytomas: in 50% of patients, often bilateral, and can be extra-adrenal
medullary thyroid cancer: 100% of patients, aggressive, and may secrete calciton...
Multiple endocrine neoplasia (MEN) type IIb, also known as MEN type 3 (MEN3) 3 or mucosal neuroma syndrome 2, accounts for only 5% cases of MEN2 and is characterised by:
pheochromocytoma(s): in 50% of patients, often bilateral, and can be extra-adrenal
medullary thyroid cancer: 100% of patient...
Multiple system atrophy (MSA) is a sporadic neurodegenerative disease (one of the synucleinopathies) characterised by varying degrees of cerebellar ataxia, autonomic dysfunction, parkinsonism and corticospinal dysfunction.
Multiple systemic atrophy is a sporadic disease, with a p...
Nail-patella syndrome (also known as Fong disease, osteo-onychodysostosis, Österreicher-Turner syndrome 10, Turner-Kieser syndrome, and Trauner-Rieger syndrome) is a rare autosomal dominant condition which results from symmetrical mesodermal and ectodermal abnormalities.
Neck tongue syndrome (NTS) is rare and comprises altered sensation in one side of the tongue aggravated by neck movement, with ipsilateral neck pain 1.
NTS is seen in a wide range of ages but is more commonly reported in older children and young adults 1-3.
Nelson syndrome is a rare disorder observed in patients with Cushing disease that have undergone bilateral adrenalectomy. It involves enlargement of an existing adrenocorticotropic hormone-secreting pituitary tumour, typically an adenoma, after surgical resection of the adrenal glands.
Nephrotic syndrome (NS) results from loss of plasma proteins in the urine and characterised by hypoalbuminemia, hyperalbuminuria, hyperlipidemia, and oedema. It may be caused by primary (idiopathic) renal disease or by a variety of secondary causes.
Patients present with ...
Neu-Laxova syndrome is a lethal autosomal recessive multiple malformation syndrome with a heterogeneous phenotype.
The clinical spectrum can be quite wide and includes:
dermal / cutaneous
severe skin restriction
decreased fetal movement
marked intrauterine gro...
Neurocutaneous melanosis or neurocutaneous melanomatosis, is a rare sporadic phakomatosis characterised by multiple congenital cutaneous nevi and meningeal melanocytosis / meningeal melanomatosis.
Neurocutaneous melanosis tends to be diagnosed in the first few years of life with ...
Neuroferritinopathy, also known as neurodegeneration with brain iron accumulation type 2 (NBIA type 2), is a disorder of iron metabolism caused by a mutation in the ferritin light chain 1 gene (FTL1) on chromosome 19.
Neuroferritinopathy is a rare disorder first described in 2001 ...
Neurofibromatosis type 1 (NF1), also known as von Recklinghausen disease, is a multisystem neurocutaneous disorder, the most common phakomatosis, and a RASopathy. Additionally, it is also one of the most common inherited CNS disorders, autosomal dominant disorders and inherited tumour syndromes....
Cutaneous manifestations of neurofibromatosis type 1 (NF1), or von Recklinghausen disease, are the heralding features of this multisystem neurocutaneous disorder, which is the most common phakomatosis.
Nowadays genetic testing permits the laboratory diagnosis of NF1 in as many as 95%, although ...
Thoracic manifestations of neurofibromatosis type 1 (NF1), or von Recklinghausen disease, are related to pulmonary and mediastinal features of this multisystem neurocutaneous disorder, which is the most common phakomatosis.
For thoracic manifestations involving the skeleton, such as focal thora...
Niacin (vitamin B3) deficiency, also known as pellagra, is a multisystem disease which involves the skin, gastrointestinal tract and central nervous system.
It use to be widespread until the early twenty century, but after fortification of flour with niacin it was practically era...
Nijmegen breakage syndrome (NBS) (also known as Seemanova syndrome or Berlin breakage syndrome) is a rare autosomal recessive syndrome of chromosomal instability.
Main clinical features are:
microcephaly present at birth and
progressive with age
dysmorphic facial feat...
Nonsteroidal anti-inflammatory drug (NSAID) exacerbated respiratory disease or previously known as Samter syndrome or aspirin or analgesic-induced asthma refers to the constellation of 1-2:
allergy to aspirin
nasal polyposis / rhinosinusitis
In adults, prevalence can ran...
Noonan syndrome with multiple lentigines, previously known as LEOPARD syndrome (LS), is a rare autosomal dominant RASopathy that has many similarities to Noonan syndrome.
Despite a change in formal name, the 'LEOPARD' acronym is still useful to summarise the clinical feat...