Morning glory disk 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 disk anomaly is rare and is more commonly found in females...
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...
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 characterized 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 characterized 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) characterized by varying degrees of cerebellar ataxia, autonomic dysfunction, parkinsonism and corticospinal dysfunction.
Multiple systemic atrophy is a sporadic disease, with a p...
Muscle-eye-brain disease is a congenital muscular dystrophy with associated progressive eye and brain abnormalities.
There is severe intellectual disability, in combination with seizures. Motor development is usually severely delayed. Eye abnormalities include choroidal h...
Myoclonic epilepsy with red ragged fibers (MERRF) is a rare, multisystem mitochondrial disorder.
Patients usually present in late adolescence or early adulthood with 1-3
vision and/or hearing loss
The Nager syndrome (also known as acrofacial dysostosis) is a rare congenital syndrome primarily characterized by facial and skeletal features
Recognised features include:
lower lid ptosis
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 tumor, typically an adenoma, after surgical resection of the adrenal glands.
Nephrotic syndrome results from loss of plasma proteins in the urine and characterized by hypoalbuminemia, hyperalbuminuria, hyperlipidemia, and edema. It may be caused by primary (idiopathic) renal disease or by a variety of secondary causes.
Patients present with marked...
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
Neurocutaneous melanosis or neurocutaneous melanomatosis, is a rare sporadic phakomatosis characterized 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 tumor 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 ...
Clinical diagnosis requires the presence of at least 2 criteria to confirm the presence of neurofibromatosis type 1 (NF1) 1.
These diagnostic criteria of can be remembered by the mnemonic:
C: café-au-lait spots (>6 evident during one year)
A: axillary or inguinal frecklin...
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, also known as Seemanova syndrome or Berlin breakage syndrome, is a rare autosomal recessive syndrome of chromosomal instability.
microcephaly present at birth and
progressive with age
dysmorphic facial features
mild growth retardation
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 (NS) is a genetically and phenotypically heterogeneous non aneuploidic congenital RASopathy. Affected individuals can bear some clinical features similar to that of Turner syndrome.
The estimated incidence is at ~1 in 1000-2500 10. As individuals have normal numbe...
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 summarize the clinical feat...
Norrie disease is a rare X-linked inherited cause of congenital bilateral blindness. It can present with a retinal mass (pseudoglioma) and cataracts. It is associated with developmental delay and hearing loss.
Nothnagel syndrome is a rare midbrain stroke syndrome that involves the tectum of the midbrain, including the quadrigeminal plate 1-4.
Classically, the syndrome involves the oculomotor nerve fascicles and superior cerebellar peduncle, leading to ipsilateral CN III palsy a...
Nutcracker syndrome is a vascular compression disorder and refers to the compression of the left renal vein between the superior mesenteric artery (SMA) and aorta. This can lead to renal venous hypertension, resulting in rupture of thin-walled veins into the collecting system with resultant hema...
Occipital horn syndrome is a rare X-linked disorder of copper metabolism resulting in connective tissue abnormalities. Menkes disease is the severe form of this disease, with patients rarely surviving past 3 years of age. Occipital horn syndrome (also known as X-linked cutis laxa or Ehlers Danl...
Olecranon bursitis refers to inflammation of the olecranon bursa. The olecranon bursa is a subcutaneous sac that overlies the olecranon process and contains a small amount of fluid to prevent against injury of subcutaneous tissue and skin from the uncovered bony olecranon.
Ophelia syndrome is the association of Hodgkin lymphoma with an autoimmune limbic encephalitis, as a result of anti-metabotropic glutamate receptor 5 antibodies (mGluR5) 1.
Opsomyoclonus (OMS), also known as dancing eyes-dancing feet syndrome, is a clinical syndrome which has a strong association with neuroblastoma.
The “opso-“ refers to the presence of intermittent jerky eye movements (dancing eyes) and the “myoclonus” to myoclonic jerks an...
Organophosphate poisoning is an important cause of acute neurological dysfunction and respiratory distress.
Organophosphate poisoning is common, often as a result of suicidal ingestion (acute high-level exposure) or occupational exposure to pesticides (chronic low-level exposure) ...
Ortner syndrome, also known as cardiovocal syndrome, is characterized by hoarse voice resulting from left recurrent laryngeal nerve palsy secondary to a cardiovascular disorder.
Left recurrent laryngeal nerve palsy in this condition is due to traction or compression of the nerve betw...
Osteopathia striata with cranial sclerosis (OS-CS) is a clinically separate entity from osteopathia striata (Voorhoeve disease). Bony changes on their own are typically incidental and autosomal dominant, whereas OS-CS is a multisystem, X-linked dominant disorder.
OS-CS is extremel...
Osteoporosis pseudoglioma syndrome is a rare autosomal recessive disease that is characterized by severe osteoporosis and blindness. This disease is frequently mistaken for osteogenesis imperfecta.
This disease is encountered in approximately 1 in 2 million births.
Otopalatodigital syndrome type I is a rare genetic disorder marked by the association of
and a characteristic face (with hypertelorism, broad nasal root, prominent supraorbital ridges, small flat nose and downslanted palpebral fissures).
It is ...
Ovarian vein syndrome is a relatively rare condition where a dilated ovarian vein causes notching, dilatation, or obstruction of the ureter. This is usually secondary to varicoses of the ovarian vein or ovarian vein thrombosis and occurs at the point where the ovarian vein crosses the ureter.
Paget-Schrötter syndrome, alternatively spelled Paget-Schroetter syndrome and also known as effort thrombosis, refers to primary thrombosis of the axillary and/or subclavian vein. It can be thought of as a venous equivalent of thoracic outlet syndrome.
It is associated with forced...
Pancoast syndrome results from involvement of the brachial plexus and sympathetic chain by a Pancoast tumor or, less commonly, from other tumors involving the superior pulmonary sulcus.
The syndrome consists of:
C8-T2 radicular pain
Pantothenate kinase-associated neurodegeneration (PKAN), previously known as Hallervorden-Spatz syndrome, is an autosomal recessive disorder causing involuntary spasticity and progressive dementia. It is a subset of neurodegeneration with brain iron accumulation (NBIA).
Paradoxical brain herniation, also known as sinking skin flap syndrome (SSFS) or syndrome of the trephined, is a rare and potentially fatal complication of decompressive craniectomy.
Atmospheric pressure exceeding intracranial pressure at the craniectomy results in displacement of t...
Paraneoplastic syndromes occur secondary to the indirect effects of a malignancy and occur remotely to the primary malignancy. Symptoms are mediated by cytokines, hormones or immune cross-reactivity. These syndromes can cause a diverse range of symptoms and can affect multiple systems.
Parinaud syndrome, also known as the dorsal midbrain syndrome, is a supranuclear vertical gaze disturbance caused by compression of the tectal plate.
It is characterized by a classic triad of findings:
upward gaze palsy, often manifesting as diplopia
pupillary light-near dissociation (pupils ...
Parkinson-plus syndrome refers to a loose group of neurodegenerative disorders that are characterized by features of Parkinson disease but with other neurological symptoms/signs. They have a poor response to levodopa, and mostly have fairly characteristic neuroimaging features.
Parry-Romberg syndrome (PRS), also known as progressive facial hemiatrophy (PFH), is a rare progressive craniofacial disorder (phakomatosis).
It is classically characterized by a slow progressive degeneration (atrophy) of the soft tissues of half of the face (hemifacial atrophy). This involves ...
Parsonage-Turner syndrome is an acute idiopathic brachial neuritis.
There is male predominance (M:F 2:1 to 11.5:1) 1. Patients from 3 months to 85 years old have been reported, but the majority are between 3rd to 7th decade of life.
The presentation is typi...
Patau syndrome (also known as trisomy 13) is considered the 3rd commonest autosomal trisomy.
Patau syndrome along with Down syndrome (trisomy 21) and Edward syndrome (trisomy 18) are the only three trisomies to be compatible with extrauterine life. However, few infants live more than a few days...
Pelvic congestion syndrome (some prefer pelvic venous insufficiency 9) is a condition that results from retrograde flow through incompetent valves in ovarian veins. It is a commonly missed and potentially-treatable cause of chronic abdominopelvic pain.
It tends to be more common ...
PELVIS or LUMBAR syndrome is the combination of pelvic hemangiomas with other extracutaneous abnormalities. The syndrome may be incomplete.
external genital malformations
Pendred syndrome is an autosomal recessively inherited disorder characterized by a euthyroid goiter associated with sensorineural hearing loss.
It is considered the most common form of syndromic hearing loss and accounts for upwards of 10% of hereditary deafness.
Pepper syndrome is of interest only (the term is not readily used in day-to-day practice), and refers to primary adrenal neuroblastoma with extensive liver metastases 1. In essence, it refers to stage 4S neuroblastoma (see staging of neuroblastoma).
Peutz-Jeghers syndrome is one of the polyposis syndromes. It has an autosomal dominant inheritance and is characterized by:
multiple hamartomatous polyps, most commonly involving the small intestine (predominantly the ileum), but also colon and stomach; mouth and esophagus are spared
PHACE syndrome, also known as cutaneous hemangioma–vascular complex syndrome or Pascual-Castroviejo type II syndrome, is a phakomatosis that comprises of:
P: posterior fossa malformations (e.g. Dandy-Walker malformation)
A: arterial anomalies
C: coarctation of the aorta and ca...
Phlegmasia cerulea dolens (PCD) is an uncommon complication of deep venous thrombosis, which results from extensive thrombotic occlusion of the major and collateral veins of an extremity (usually the legs).
Left leg is more commonly affected than the right 4.
Pickwickian syndrome, or obesity hypoventilation syndrome (OHS), comprises the triad of obesity (BMI ≥30 kg/m2), daytime hypoventilation (awake hypercapnia and hypoxemia), and sleep-disordered breathing in the absence of alternative explanations (e.g. severe parenchymal lung disease, mechanical ...
Pinch-off syndrome is a spontaneous catheter fracture, which is seen as a complication of subclavian venous catheterisation.
It is a known complication of central venous catheterisation with a much-reduced incidence in current practice and is generally considered to be rare.
Pituitary stalk transection syndrome, also known as pituitary stalk interruption syndrome, is a syndrome characterized by absent or hypoplastic anterior pituitary gland, thin or absent infundibulum, and ectopic posterior pituitary location.
Patients with pituitary stalk transectio...
Plummer-Vinson syndrome, also known as the Paterson-Brown-Kelly syndrome, predisposes to hypopharyngeal squamous cell carcinoma and consists of four features:
esophageal webs or hypopharyngeal webs
The condition is more common in women.
POEMS syndrome is the acronymic name for a rare multisystem paraneoplastic disorder comprising of a minimum of three of the following features in the setting of a plasma cell dyscrasia:
hepatomegaly, splenomegaly or lymphadenopathy
Poland-Möbius syndrome, is the combination of Möbius syndrome and Poland syndrome, which although very rare, has been well described 1.
Sir Alfred Poland (1822-1872): English surgeon 2
Paul Julius Möbius (1853-1907): German neurologist 3
Poland syndrome refers to a congenital unilateral absence of the pectoralis major and minor muscles and is a recognised cause of unilateral hyperlucent hemithorax.
Poland syndrome is usually sporadic, although rare familial cases have been described 1. It is rare, with an estimat...
Polycystic ovarian syndrome (PCOS), recently referred also as hyperandrogenic anovulation, is a chronic anovulation syndrome associated with androgen excess.
The diagnosis of PCOS generally requires any two of the following three criteria for the diagnosis, as well as the exclusion of other et...
Polydactyly (less commonly called hyperdactyly) refers to the situation where there are more than the usual number of digits (five) in a hand or foot. It can be broadly classified as:
pre-axial polydactyly: extra digit(s) towards the thumb/hallux (radially)
post-axial polydactyly: extra digit(...
Polysplenia syndrome, also known as left isomerism, is a type of heterotaxy syndrome where there are multiple spleens congenitally as part of left-sided isomerism.
Polysplenia is seen predominantly in female patients. It is usually diagnosed in childhood or adulthood, later than a...
Popliteal artery entrapment syndrome (PAES) refers to symptomatic compression or occlusion of the popliteal artery due to a developmentally abnormal positioning of the popliteal artery in relation to its surrounding structures such as with the medial head of gastrocnemius (MHG) or less commonly ...
Post-ablation syndrome occurs from 24 to 48 hours following ablation, and lasts no longer than 10 days1. It is believed to occur following cytokine release and tumor necrosis, causing patient fever and flu-like symptoms.
If symptoms persist following 10 days after the procedure, alternate diagn...
Post-axial polydactyly refers to polydactyly where the additional digit is on the ulnar margin of the hand, or lateral to the 5th toe.
Post-axial polydactyly is more common than pre-axial polydactyly, with an estimated incidence of 1 in 3000.
Post-embolization syndrome (PES) is one of the commonest side effects of transarterial embolization and chemoembolisation. It comprises of a constellation of fever, nausea/vomiting, and pain. It usually occurs within the first 72 hours after embolization (liver lesion or uterine fibroids) and th...
Posterior choroidal artery occlusion uncommonly presents as an isolated stroke syndrome. It usually coexists with posterior cerebral artery and often superior cerebellar artery involvement.
When seen in isolation damage is characteristically limited to the:
lateral geniculate body
Posterior reversible encephalopathy syndrome (PRES) is a neurotoxic state that occurs secondary to the inability of the posterior circulation to autoregulate in response to acute changes in blood pressure. Hyperperfusion with resultant disruption of the blood brain barrier results in vasogenic e...
Posterior semicircular canal dehiscence syndrome (PSCD) is the presence of vestibuloauditory symptoms secondary to absence of the bony covering of the posterior semicircular canal (PSC).
It is thought to be rare: in a case series of 112 patients with a high riding jugular bulb it ...
Posterior spinal artery syndrome is a rare syndrome associated occlusion of the posterior spinal artery and results in a unilateral dorsal cord syndrome (since the posterior arteries are paired) 3.
The syndrome is clinically characterized by isolated loss of proprioception and vibratory sensat...
Post-pneumonectomy syndrome is delayed complication of pneumonectomy characterized by respiratory compromise caused by severe mediastinal shift and counterclockwise rotation of the heart and great vessels.
Rare delayed complication of pneumonectomy, which more commonly involves th...
Post thrombotic syndrome (PTS) is a syndrome of chronic venous insufficiency following deep vein thrombosis (DVT) due to valvular incompetence, which results in chronic reflux and chronic venous hypertension.
PTS is a common complication following extensive DVT of the limbs. Up to...
PPP syndrome is the extremely rare association of pancreatitis, panniculitis, and polyarthritis.
Most commonly affects middle-aged male patients with a history of heavy alcohol use 1,2.
In the majority of cases, abdominal symptoms are mild or absent, makin...
Pre-axial polydactyly refers to polydactyly where the additional digit is towards the first digit of the hand (radial side) or foot (medially).
Pre-axial polydactyly is less common than post-axial polydactyly, with an estimated incidence of 1 in 7000.
Primary progressive aphasia was first described in 1982 and is the umbrella term for the language-variant frontotemporal dementias associated with frontotemporal lobar degeneration (FTLD) 3.
It is an insidious disorder characterized by gradual impairment of speech and lan...
Progeria is a term used for any syndrome in which a person is prematurely aged, however, it most commonly refers to Hutchinson-Gilford progeria syndrome (HGPS).
Although the primary clinical manifestations of progeria include short stature and skin changes, the disease is...
Pronator teres syndrome (also called pronator syndrome) is one of three common median nerve entrapment syndromes; the other two being anterior interosseous nerve syndrome and the far more common carpal tunnel syndrome. Signs and symptoms result from compression of the median nerve in the upper f...
Proteus syndrome is a rare congenital, multisystemic, hamartomatous condition characterized by asymmetrical overgrowth of almost any part of the body and a broad spectrum of manifestations. It can affect tissue from any germinal layer. It is suspected to be a genetic condition, but a particular ...
Pseudoxanthoma elasticum (PXE), also known as Grönblad–Strandberg syndrome, is a systemic condition characterized by the degeneration of elastic fibers. It has multiorgan manifestations.
Its prevalence is estimated to be around 1 in 25,000 9.
Patients may ...
PTEN (phosphatase and tensin homolog) gene mutation is associated with a few conditions known as PTEN-related diseases, with relatively similar clinical and radiological manifestations. They include:
Those not f...
Pulled elbow (also known as nursemaid's elbow) is a subluxation of the radial head into the annular ligament, which usually spontaneously or easily reduces and rarely demonstrates abnormal radiographic features. It should be distinguished from dislocation of the radial head.
Quadrangular space syndrome also known as quadrilateral space syndrome is an uncommon diagnosis mainly because of lack of literature on the subject and possible misdiagnosis.
Quadrangular space syndrome is present on ~1% of shoulder MRIs 6.
Radial tunnel syndrome is an entity that refers to entrapment of the radial nerve in the forearm, as it occurs in the supinator syndrome. Some authors believe this is an early form of the posterior interosseous nerve syndrome 5.
The syndrome is characterized by pain along...
Radiologically isolated syndrome (RIS) is defined by MRI findings suggestive of multiple sclerosis (MS) in asymptomatic ("clinically silent") patients. Radiological progression usually occurs in approximately 66% of patients with RIS, while ~33% per 5-year-period will subsequently develop neurol...
Raghib syndrome is a rare developmental complex. It consists of:
persistence of the left superior vena cava
coronary sinus ostial atresia
atrial septal defect
It has also been associated with other congenital malformations including ventricular septal defects, enlargement of the tricuspid an...
Raine syndrome, also known as lethal osteosclerotic bone dysplasia, is a very rare genetic disorder. Infants with this syndrome present with numerous characteristic craniofacial features as well as cerebral calcifications. Many individuals with this disorder are stillborn or die as neonates 4.
Ramsay Hunt syndrome (RMS), also known as herpes zoster oticus, is shingles of the facial nerve. It is due to reactivation of the varicella zoster virus in the geniculate ganglion.
Ramsay Hunt syndrome classically presents with a triad of 3,4:
facial nerve pal...
Raymond syndrome is a posterior circulatory stroke syndrome due to a lesion in the ventral medial mid-pons. It is an extremely rare condition, with only a handful of cases described in the literature.
Clinically, 2 subtypes have been reported 1: