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.

451 results found
Article

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...
Article

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...
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Ischiopubic synchondrosis asymmetry

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...
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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 characterised 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 a wide variability in its manifestations. It is thought to have autosomal recessive inheritance. Clinical presentation There is a wide variability in the clinical presentation, but common features are: low birth weight hyp...
Article

Juberg-Hayward syndrome

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:  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. Pathology The cause for t...
Article

Kartagener syndrome

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.  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 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. Pathology Vascul...
Article

Klinefelter syndrome

Klinefelter syndrome (KS) is a chromosomal anomaly, which in most cases is characterised 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 testes...
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 recognised 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 myasthenia syndrome

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 ...
Article

Lane-Hamilton syndrome

Lane-Hamilton syndrome (LHS) refers to the rare concurrent association of idiopathic pulmonary haemosiderosis and coeliac 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 ...
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, 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.  Clinical presenta...
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 characterised by many features i...
Article

Lateral medullary syndrome

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...
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...
Article

Lateral pontine syndrome

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. Clinical presentation There is a characteristic clinical picture from the involvement of the following pontine stru...
Article

Laurin-Sandrow syndrome

Laurin-Sandrow syndrome is a rare disorder characterized by tetrameric polysyndactlyly. Radiographic features polysyndactyly of the hands (both post-axial and pre-axial) "cup-shaped" hands mirror polysyndactyly of the feet ulnar dimelia absence of the radius and tibia possible hypertelori...
Article

Leaky lung syndrome

Leaky lung syndrome refers to a form of non-cardiogenic pulmonary oedema. Pathology Pulmonary oedema due to increased capillary permeability.   Radiographic features 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...
Article

Lemierre syndrome

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. Epidemiology Since the advent of antibiotics, the inciden...
Article

Lemmel syndrome

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. Clinical presenta...
Article

Leontiasis ossea

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...
Article

Leprosy

Leprosy, previously known as Hansen's disease, is a chronic infectious disease caused by Mycobacterium leprae and presents mainly in tropical developing countries. Epidemiology It is most common in tropical developing countries and is endemic in over 100 countries. Worldwide, there is a preval...
Article

Lethal omphalocele-cleft palate syndrome

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...
Article

Leukoencephalopathy with calcifications and cysts

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. Epidemiology Leukoencephalopathy with calcifications and cysts is an extremely rare condition, w...
Article

Levator ani syndrome

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. Clinical presentation Levator ani syndrome is characterised by recurrent pain, pressure or discomfort in the region of the rectum, sac...
Article

Locked-in syndrome

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. Clinical presentation The infarct is pontine; the midbrain is preserved. The oculomotor nerve III is intact so the...
Article

Löffler syndrome

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. Pathology Aetiology The cause is not usually ...
Article

Löfgren syndrome

Löfgren syndrome is a specific acute clinical presentation of systemic sarcoidosis that usually manifests with lymphadenopathy, fevers, erythema nodosum, and arthritis.  Terminology It is important to not confuse this syndrome with Löffler syndrome, as the names are quite similar but the condi...
Article

Lowe syndrome

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. Pathology It is an extremely rare, pan-ethnic, x-linked disease, with estimated prevalence in the general po...
Article

Low phospholipid-associated cholelithiasis syndrome

Low phospholipid-associated cholelithiasis (LPAC) syndrome is one of the syndromes associated with ABCB4/MDR3 mutation. Characteristics of this syndrome include 1,2: intrahepatic microlithiasis/sludge symptomatic cholesterol stones with early onset (<40 years) recurrent symptoms post cholecys...
Article

Lutembacher syndrome

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.
Article

Madelung disease

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 ...
Article

Maffucci syndrome

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...
Article

Man-in-the-barrel syndrome

Man-in-the-barrel syndrome is a neurological syndrome characterised by bilateral brachial muscular weakness. Pathology This syndrome is usually caused by bilateral cerebral lesions in the border zone between the anterior and middle cerebral arteries. Aetiology The syndrome has been described...
Article

Marchiafava-Bignami disease

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.  Epidemiology MBD is in most instances seen in chronic alcoholics, and as such the epidem...
Article

Marfan syndrome

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...
Article

Marine-Lenhart syndrome

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.  Epidemiology The syndrome is rare with reported prevalence somewhere b...
Article

May-Thurner syndrome

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...
Article

Mazabraud syndrome

Mazabraud syndrome is a rare syndrome consisting of: fibrous dysplasia: usually polyostotic 2 multiple soft tissue myxomas (intramuscular myxomas): typically in large muscle groups Epidemiology It is very rare, with only 81 cases in the global literature reported to 2012 13. It is most frequ...
Article

McCune-Albright syndrome

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 Clinical presentation Presentation is va...
Article

McKusick Kaufman syndrome

McKusick Kaufman syndrome (MKS) is an autosomal recessive multiple malformation syndrome primarily characterised by hydrometrocolpos - vaginal atresia post-axial polydactyly congenital heart disease
Article

Meconium plug syndrome

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. Pat...
Article

Medial medullary 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...
Article

Medial patellar plica 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. Epidemiology While it can affect those of any age, it typically involves the young...
Article

Medial tibial stress syndrome

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...
Article

Megacystis microcolon intestinal hypoperistalsis syndrome

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. Epidemiology There is recognised strong female predi...
Article

Megalencephaly-capillary malformation syndrome

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...
Article

Mendelson syndrome

Mendelson syndrome or peptic pneumonia refers to acute chemical pneumonitis caused by the aspiration of stomach contents in patients under general anesthesia. Pathology The etiologic agents is believed to be aspiration of acidic stomach contents, other compounds, e.g. bile, may also play a rol...
Article

Menkes disease

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.  Epidemiology Menk...
Article

MERRF

MERRF (myoclonic epilepsy with red ragged fibres) is a rare, multisystem mitochondrial disorder.  Clinical presentation Patients usually present in late adolescence or early adulthood with 1,2,3 myoclonus epilepsy cerebellar ataxia intellectual disability vision and/or hearing loss cardi...
Article

Metabolic syndrome

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. Clinical presentation There are five central components of the metabolic syndrome: hyperinsulinaemia impaired glucose tolerance dys...
Article

Metaphyseal chondrodysplasia

Metaphyseal chondrodysplasia (also known as metaphyseal dysplasia or dysostosis) is a type of skeletal dysplasia. Pathology Classification Schmid type - mild type, due to mutation in type X collagen (COL10A1 gene), metaphyses are cupped resembling rickets Pena and Vaandrager type - intermedi...
Article

Metronidazole central nervous system toxicity

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. Epidemiology In a review of the case literature 1, affected patients range widely in age, with the peak incidence occurring in the...
Article

Midaortic syndrome

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. Clinical presentation The onset of symptoms is usually during young adulthood or childhood 2: hypertension (most comm...
Article

Middle East Respiratory Syndrome coronavirus (MERS-CoV)

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...
Article

Mikulicz syndrome

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...
Article

Milk-alkali syndrome

Milk-alkali syndrome is the combination of: hypercalcaemia renal failure metabolic alkalosis 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...
Article

Millard-Gubler syndrome

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. Clinical presentation ipsilateral facial and contralateral body he...
Article

Milwaukee shoulder

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. Epidemiology Milwaukee shoulder frequently affects older women, often with a history of trauma t...
Article

Mirizzi syndrome

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 ...
Article

Möbius syndrome

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. Epidemiology Möbius syndrome is rare with an estimated incidence of ~1 case per 10...
Article

Morgagni-Stewart-Morel syndrome

Morgagni-Stewart-Morel syndrome​ consists of the triad of: hyperostosis frontalis interna obesity excessive hair growth (virilism/hirsutism) and along with these metabolic/hormonal disorders is associated with neuropsychiatric conditions. The cause is unclear.  History and etymology It wa...
Article

Morning glory syndrome (eye)

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. Epidemiology Morning glory disc anomaly is rare and is more commonly found in females...
Article

Morquio syndrome

Morquio syndrome is an autosomal recessive mucopolysaccharidosis (MPS), type IV. Epidemiology Incidence estimated at ~1:40,000. Clinical presentation Many cases present at ~2 years of age and have normal intelligence. Clinical features: severe dwarfism (<4 foot) joint laxity corneal opaci...
Article

Morvan syndrome

Morvan syndrome, also known as Morvan fibrillary chorea, is a rare syndrome thought to be either paraneoplastic or autoimmune in origin. Clinical presentation It is characterised by: neuromyotonia pain hyperhydrosis weight loss severe insomnia hallucinations Pathology Voltage gated pot...
Article

Mucopolysaccharidoses

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...
Article

Multiple endocrine neoplasia type I

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...
Article

Multiple endocrine neoplasia type IIa

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...
Article

Multiple endocrine neoplasia type IIb

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...
Article

Multiple system atrophy

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.  Epidemiology Multiple systemic atrophy is a sporadic disease, with a p...
Article

Nail-patella syndrome

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. Clinical presentation ...
Article

Neck tongue syndrome

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.  Epidemiology NTS is seen in a wide range of ages but is more commonly reported in older children and young adults 1-3.  Clinical presentatio...
Article

Nelson syndrome

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.  Epidemi...
Article

Nephrotic syndrome

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. Clinical presentation Patients present with ...
Article

Neu-Laxova syndrome

Neu-Laxova syndrome is a lethal autosomal recessive multiple malformation syndrome with a heterogeneous phenotype. Clinical features The clinical spectrum can be quite wide and includes: dermal / cutaneous severe skin restriction ichthyosis decreased fetal movement marked intrauterine gro...
Article

Neurocutaneous melanosis

Neurocutaneous melanosis or neurocutaneous melanomatosis, is a rare sporadic phakomatosis characterised by multiple congenital cutaneous nevi and meningeal melanocytosis / meningeal melanomatosis.  Epidemiology Neurocutaneous melanosis tends to be diagnosed in the first few years of life with ...
Article

Neuroferritinopathy

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. Epidemiology Neuroferritinopathy is a rare disorder first described in 2001 ...
Article

Neurofibromatosis type 1

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....
Article

Neurofibromatosis type 1 (cutaneous manifestations)

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 ...
Article

Neurofibromatosis type 1 (thoracic manifestations)

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...
Article

Niacin deficiency

Niacin (vitamin B3) deficiency, also known as pellagra, is a multisystem disease which involves the skin, gastrointestinal tract and central nervous system.  Epidemiology It use to be widespread until the early twenty century, but after fortification of flour with niacin it was practically era...
Article

Nijmegen breakage syndrome

Nijmegen breakage syndrome (NBS) (also known as Seemanova syndrome or Berlin breakage syndrome) is a rare autosomal recessive syndrome of chromosomal instability.  Clinical presentation Main clinical features are: microcephaly present at birth and progressive with age dysmorphic facial feat...
Article

Nonsteroidal anti-inflammatory drug (NSAID) exacerbated respiratory disease

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 asthma Epidemiology In adults, prevalence can ran...
Article

Noonan syndrome with multiple lentigines

Noonan syndrome with multiple lentigines, previously known as LEOPARD syndrome (LS), is a rare autosomal dominant RASopathy that has many similarities to Noonan syndrome. Clinical presentation Despite a change in formal name, the 'LEOPARD' acronym is still useful to summarise the clinical feat...

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