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.

Create new article

Filtered (1)Done (clear)

+Systems

+Article Sections

+Sort By

ADVERTISEMENT: Supporters see fewer/no ads

274 results found

Acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia (ALL) is a malignant disorder of the bone marrow characterised by the proliferation of the lymphoid progenitor cells. Epidemiology ALL is the commonest form of childhood leukaemia, accounting for ~80% of paediatric leukaemia cases 1. In adults, ALL corresponds to ...

Acute myeloid leukaemia

Acute myeloid leukaemia (AML), also referred to as acute myelogenous leukaemia, is a haematological malignancy characterised by the abnormal clonal proliferation of immature myeloid precursors (myeloblasts) or poorly differentiated cells of the haematopoietic system. It primary infiltrates the b...

Acute promyelocytic leukaemia

Acute promyelocytic leukaemia (APML) is a distinct subtype of acute myeloid leukaemia. Pathology Genetics It is defined by a balanced translocation between chromosomes 15 and 17 resulting in fusion of the promyelocytic leukaemia gene (PML) on chromosome 15 with the retinoic acid receptor alph...

Adenoid tonsil

The adenoid tonsils, or often just simply the adenoids (also known as the nasopharyngeal or pharyngeal tonsils), are paired foci of lymphatic tissue located on the superoposterior wall of the nasopharynx and form part of Waldeyer's ring.

Afibrinogenaemia

Afibrinogenaemia, also called congenital afibrinogenaemia, is a rare autosomal recessive inherited blood disorder due to deficiency of the clotting protein fibrinogen. The disorder is associated with increased risk of spontaneous haemorrhage1. Epidemiology Afibrinogenaemia has an estimated pre...

Agranulocytosis

Agranulocytosis refers to a situation where the absolute neutrophil count (ANC) falls to less than 100 neutrophils per microlitre of blood. It predisposes to a very high risk of severe infection. Pathology It can be hereditary or acquired. hereditary: usually due to genetic mutations in the ...

AIDS-defining illness

AIDS-defining illnesses are conditions that in the setting of a HIV infection confirm the diagnosis of AIDS and do not commonly occur in immunocompetent individuals 2. According to the CDC surveillance case definition 1, they are: Infectious bacterial infections: multiple or recurrent candidi...

AIDS-related pulmonary lymphoma

AIDS-related pulmonary lymphoma (ARPL) is classified as a distinct form of pulmonary lymphoma. Pulmonary involvement is a common extranodal site in AIDS-related NHL. Pathology ARPL is typically a high-grade B-cell non-Hodgkin's lymphoma and the majority of patients have advanced HIV infection,...

All-trans retinoic acid syndrome

All-trans retinoic acid (ATRA) syndrome, more recently known as differentiation syndrome (DS) 8, is a condition that can occur with patients with acute promyelocytic leukaemia who are on therapeutic all-trans-retinoic acid (ATRA). All-trans-retinoic acid (ATRA) is a normal constituent of plasma...

Anaemia

Anaemia is the presence of reduced haemoglobin in the blood. Formally, the World Health Organisation (WHO) defines anaemia by the haemoglobin concentration in the blood according to age and sex 1: adult men: <130 g/L adult women: <120 g/L Values for pregnant women and children are different. ...

Anaplastic large cell lymphoma

Anaplastic large cell lymphoma (ALCL) is a form of haematological malignancy. It as first described in 1985 as a large-cell neoplasm with anaplastic morphology immunostained by the Ki-1 antibody, which recognises CD30. There are two main sub types anaplastic large-cell lymphoma, ALK-positive ...

Anaplastic lymphoma kinase (ALK) gene rearrangements

Anaplastic lymphoma kinase (ALK) gene rearrangements are known to occur in association with several tumours. The genes codes for an enzyme called anaplastic lymphoma kinase (ALK) or ALK tyrosine kinase receptor / CD246 which is thought o play a role in the brain development and exerts its effect...

Anatomy curriculum

The anatomy curriculum is one of our curriculum articles and aims to be a collection of articles that represent the core anatomy knowledge for radiologists and imaging specialists. General anatomy Neuroanatomy Head and neck anatomy Thoracic anatomy Abdominal and pelvic anatomy Spinal anat...

Angioimmunoblastic T cell lymphoma

Angioimmunoblastic T-cell lymphoma (AITL) (previously known as angioimmunoblastic lymphadenopathy with dysproteinemia (AILD)) is a rare, aggressive (fast-growing) form of peripheral T-cell lymphoma. It only accounts for around 1-2% of all non-Hodgkin lymphoma. It is one of the more common subtyp...

Ann Arbor staging system

The Ann Arbor staging system was the landmark lymphoma staging classification system for both Hodgkin lymphoma and non-Hodgkin lymphoma. It is named after the town of Ann Arbor in the US state of Michigan where the Committee on Hodgkin's Disease Staging Classification met in 1971 to agree on it....

Antiphospholipid syndrome

Antiphospholipid syndrome is a systemic autoimmune disorder. It is usually defined as the clinical complex of vascular occlusion and ischaemic events occurring in patients who have circulating antiphospholipid antibodies. Clinical presentation Antiphospholipid syndrome is characterised by veno...

Antithrombin III deficiency

Antithrombin (AT) III deficiency (now simply called antithrombin deficiency) refers to a congenital lack of the endogenous anticoagulant antithrombin. Epidemiology Antithrombin deficiency is considered the least common of the three main anticoagulant deficiencies (the other two being protein C...

Aplastic anaemia

Aplastic anaemia is a rare haematopoietic stem-cell disorder. The condition results in pancytopenia and hypocellular bone marrow. Most cases are acquired, however, there are unusual inherited forms. Pathology Aplastic anaemia manifests as a marked reduction in the number of pluripotent haemato...

Ariboflavinosis

Ariboflavinosis is the term given to riboflavin (vitamin B2) deficiency. Epidemiology Ariboflavinosis has been seen in both developed and developing countries, and across the socioeconomic spectrum. It is usually present in the context of other hypovitaminoses. It has been found to more comm...

Autoimmune lymphoproliferative syndrome

Autoimmune lymphoproliferative syndrome (ALPS) is a rare lymphoproliferative condition. Clinical presentation It presents with chronic lymphadenopathy, splenomegaly, and symptomatic multilineage cytopenias in an otherwise healthy child. Pathology It represents a failure of apoptotic mechanis...

Autosplenectomy

Autosplenectomy denotes spontaneous infarction of the spleen with resulting hyposplenism. Epidemiology Autosplenectomy is most frequently encountered in patients with homozygous sickle cell disease, although it has also been reported in pneumococcal septicaemia 1, and systemic lupus erythemato...

BALT lymphoma

BALT lymphoma is an abbreviated term for bronchus-associated lymphoid tissue lymphoma. These neoplasms fall under the broader umbrella of mucosa associated lymphoid tissue (MALT) lymphomas. It is sometimes considered a type of primary pulmonary lymphoma. Clinical presentation Up to half of pat...

Binet staging system for chronic lymphocytic leukaemia

The Binet staging system is one of the two staging systems currently adopted in assessment of chronic lymphocytic leukaemia (CLL). It classifies CLL according to the number of lymphoid tissues that are involved (i.e. the spleen and the lymph nodes of the neck, groin, and underarms), as well as ...

Bing-Neel syndrome

Bing-Neel syndrome is an extremely rare neurological complication of Waldenström macroglobulinaemia where there is malignant lymphocyte infiltration into the central nervous system (CNS). Epidemiology The exact incidence is unknown, however, in one study of patients with Waldenström macroglobu...

Blastic plasmacytoid dendritic cell neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare haematological malignancy. It was previously termed as blastic natural-killer lymphoma or agranular CD4+ natural killer cell leukaemia. Epidemiology It only represent a very small proportion (~0.44%) of all haematological malignanc...

Blood

Blood comprises a fluid component called plasma, in which lies the cellular component, comprising several cell lineages, primarily the white blood cells, red blood cells and platelets. In an average adult male the total volume of blood is ~5.5 L.

Bone marrow

Normal bone marrow is divided into red and yellow marrow, a distinction made on the grounds of how much fat it contains. Gross anatomy Red marrow is composed of: haematopoietic cells supporting stroma reticulum (phagocytes and undifferentiated progenitor cells) scattered fat cells a rich ...

Breast lymphoma

Breast lymphoma refers to the involvement of the breast with lymphoma and may be primary or secondary. Epidemiology Both primary and secondary breast lymphomas are rare. Breast lymphoma accounts for <1% of all breast malignancies and <2% of all extranodal non-Hodgkin lymphoma 11. Secondary lym...

B symptoms

The B symptoms (a.k.a. inflammatory symptoms) are a triad of systemic symptoms associated with more advanced disease and a poorer outcome in lymphoma 1,2: weight loss >10% unintentional decrease in body weight in the 6 months preceding the diagnosis fever: >38°C night sweats B symptoms are ...

Burkitt lymphoma

Burkitt lymphoma is an aggressive B-cell lymphoma predominantly affecting children. Epidemiology Burkitt lymphoma is the most common (40%) type of non-Hodgkin lymphoma in childhood. Median age is eight years with a male predominance (M:F = 4:1) 1. It is less common in adults, accounting for 1-...

Capillary leak syndrome

Capillary leak syndrome is a situation characterised by the escape of blood plasma through capillary walls, from the blood vessels to surrounding tissues, muscle compartments, organs or body cavities. Clinical presentation The idiopathic form of the syndrome is characterised by three phases 1,...

Carbon monoxide poisoning

Carbon monoxide (CO) poisoning may result in an anoxic-ischaemic encephalopathy, with acute as well as delayed effects. Epidemiology Carbon monoxide poisoning is mostly preventable with common causes including malfunctioning heating systems, improperly ventilated motor vehicles, and residentia...

Catheter-directed thrombolysis

Catheter-directed thrombolysis (CDT) is an endovascular approach to the treatment of acute iliofemoral deep vein thrombosis. It involves the administration of a lytic agent directly into a thrombus. Indications precise diagnosis of iliofemoral deep vein thrombosis first episode of acute ili...

Chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is a haematological malignancy characterised by the proliferation of mostly mature but abnormal leucocytes. Epidemiology Chronic lymphocytic leukaemia is considered the most common type of leukaemia in the Western hemisphere; its prevalence in Europe and No...

Chronic myeloid leukaemia

Chronic myeloid leukaemia (CML), also known as chronic myelogenous leukaemia, is a myeloproliferative neoplasm characterised by the overproduction of granulocytes with fairly normal differentiation. Epidemiology The annual incidence is about 1 per 100,000 1,3. The typical age at presentation i...

Chronic myelomonocytic leukaemia

Chronic myelomonocytic leukaemia (CMML) is a relatively rare clonal haematologic disorder. In the World Health Organisation classification, it is listed as a disorder with features of both myelodysplastic syndromes and myeloproliferative neoplasms. Clinical presentation Can be variable but man...

CNS lymphoma

CNS lymphoma refers to the involvement of the central nervous system with lymphoma. It can be broadly divided into primary and secondary, with a number of special types of also recognised. primary CNS lymphoma (PCNSL) intravascular lymphoma MALT lymphoma of the dura 5 secondary CNS lymphoma...

Common variable immunodeficiency (hepatic manifestations)

Hepatic manifestations of common variable immunodeficiency are not uncommon and can be primarily related to nodular regenerative hyperplasia. For a general discussion of the underlying condition, please refer to the article on common variable immunodeficiency (CVID). Epidemiology General liv...

Concentric target sign (cerebral toxoplasmosis)

The concentric target sign is a typical sign for cerebral toxoplasmosis. It is seen on T2 weighted MR imaging as a deep parenchymal lesion showing a series of concentric rings with hyperintense and hypointense/isointense signal alternatingly. Strong perifocal oedema is usually visible on T2/FLAI...

Copper deficiency

Copper deficiency (also known as hypocupraemia) is unusual due to the ubiquity of copper in the normal diet. Epidemiology Copper deficiency is thought to be rare, but exact numbers are difficult to ascertain. Clinical presentation The typical presentation of copper deficiency mimics the more...

Cotswolds-modified Ann Arbor classification

The Cotswolds-modified Ann Arbor classification is a lymphoma staging classification system for both Hodgkin lymphoma and non-Hodgkin lymphoma. They came about in 1988 following recommended modifications to the Ann Arbor staging system after a meeting in Cotswold, England. This classification h...

Cryoglobulinaemic vasculitis

Cryoglobulinaemic vasculitis (CV) is a form of immune mediated primary vasculitis involving small to medium sized vessels. It may involve multiple organs and can have a range of clinical presentations. Terminology There are three main types of cryoglobulinaemia which are grouped, as per the Br...

Deauville five-point scale

The Deauville five-point scale (Deauville 5PS) is an internationally-recommended scale for routine clinical reporting and clinical trials using FDG PET-CT in the initial staging and assessment of treatment response in Hodgkin lymphoma (HL) and certain types of non-Hodgkin lymphomas (NHL). Incl...

Diamond-Blackfan anaemia

Diamond-Blackfan anaemia (DBA) (previously known as congenital hypoplastic anaemia) is the primary congenital form of pure red cell aplasia. It is a rare sporadic genetic form of anaemia that typically presents in the first few years of life, and usually only affects cells of the erythroid linea...

Diathesis

Diathesis (plural: diatheses) is a term used to describe a state in which there is an increased chance of something happening. Contemporaneously, the word is used as a synonym for the word predisposition; however the term predates a modern understanding of genetics or pathology 1. Most commonly...

Diffuse large B cell lymphoma

Diffuse large B cell lymphoma is the most common subtype of non-Hodgkin lymphoma. Epidemiology Associations Diffuse large B cell lymphoma is sometimes associated with immunodeficiency, including acquired immunodeficiency syndrome. Pathology Classification In 2016 WHO classification of lymp...

Diffuse T1 bone marrow signal loss

Diffuse T1 vertebral bone marrow signal loss is associated with replacement of fatty marrow by oedema or cellular tissue. T1-weighted imaging without fat suppression is one of the most important sequences for distinguishing between normal and abnormal bone marrow. In the case of homogenous invol...

Disseminated intravascular coagulation

Disseminated intravascular coagulation (DIC), also known as consumption coagulopathy or defibrination syndrome, refers to a systemic phenomenon of overactivation of coagulation and fibrinolysis resulting in widespread clots forming inside blood vessels. Clinical presentation Patients present w...

Dyscrasia

Dyscrasia (plural: dyscrasias) was used historically in medicine to refer to an imbalance of the four bodily humours 1. It is now used as a synonym for disease, and is only found as part of the terms "blood dyscrasia" or "plasma cell dyscrasia". Blood dyscrasia refers to any disease of the bloo...

Ebola virus disease

Ebola virus disease (EVD) (also known as Ebola haemorrhagic fever (EHF) or simply Ebola) is a viral haemorrhagic disease caused by the Ebola filovirus. Ebola is an extremely virulent virus with a case fatality rate of ~70% 1. Epidemiology First recognised in 1967 after polio vaccine laboratory...

Engraftment syndrome

Engraftment syndrome (ES) refers to a potential early complication of haematopoetic stem cell transplantation. It is thought to be related to increased capillary permeability and comprises of a combination of symptoms and signs which include fever erythrodermatous skin rash noncardiogenic pul...

Eosinophil

Eosinophils, also less commonly known as acidophils, are myeloid granulocytes and form one of the main types of white blood cells. Their counts are routinely measured as part of a full blood count. They have important roles in fighting parasitic infections, but are increasingly recognised as hav...

Eosinophilia

Eosinophilia is defined as an abnormally high level of eosinophils in the blood, this is usually defined as >500 cells/μL (normal eosinophil level: <450 cells/μL). Hypereosinophilia is defined as >1500 cells/μL and is usually due to haematological malignancy 1,2. This article includes recommend...

Episodic angioedema with eosinophilia

Episodic angioedema with eosinophilia (EAE), also known as Gleich syndrome, is a rare condition presenting as a self-limiting cyclic urticaria, fever, angioedema, weight gain and marked eosinophilia, with 3-4 weekly episodes 1. Epidemiology Episodic angioedema with eosinophilia is rare, only a...

Erythrocyte sedimentation rate

Erythrocyte sedimentation rate (ESR) is a non-specific marker of acute inflammation which is seen in a very wide spectrum of pathologies. In recent years it has been sidelined by the use of C-reactive protein and other acute phase markers but it still has an important role to play in the managem...

Erythrocytosis

Erythrocytosis (or polycythaemia) is the presence of an excessive number of red blood cells in the circulation. It can be primary or arise secondarily to another pathology. Definition Absolute erythrocytosis is defined as a red cell mass which is >125% predicted for sex and age 2. Although th...

Essential thrombocythaemia

Essential thrombocythaemia (ET) is a myeloproliferative neoplasm characterised by an expansion of the megakaryocytic lineage, leading to an isolated elevation of platelets. It increases the risk of both thrombosis and haemorrhage. Pathology The disease has traditionally been a diagnosis of ex...

Extramedullary haematopoiesis

Extramedullary haematopoiesis is a response to the failure of erythropoiesis in the bone marrow. This article aims to a general approach on the condition, for a dedicated discussion for a particularly involved organ, please refer to the specific articles on: extramedullary haematopoiesis in t...

Extramedullary haematopoiesis in the adrenal gland

Extramedullary haematopoiesis in the adrenal gland is a rare physiologic compensatory event in many haematologic diseases. For a general discussion on this subject, please refer to the main article on extramedullary haematopoiesis. Epidemiology Extramedullary haematopoiesis in the adrenal gla...

Extramedullary plasmacytoma

Extramedullary plasmacytoma, also known as extraosseous plasmacytoma, are the less common form of solitary plasmacytoma, manifesting as isolated plasma cell tumours located at a non-osseous site. In contrast to multiple myeloma (MM), solitary plasmacytoma have little or no systemic bone marrow i...

Extranodal extension

Extranodal extension refers to the growth of a nodal cancer metastasis beyond the confines of the capsule of a lymph node into adjacent tissues. Less preferred synonyms include extranodal spread, extracapsular extension, or extracapsular spread. This finding holds prognostic implications. For e...

Factor V Leiden

Factor V Leiden is a primary hypercoagulable state due to a variant (mutated form) of human factor V. Factor V is one of several coagulation factors that assist in the clotting pathway. Epidemiology Heterozygous factor V Leiden may be present is around 5% of the European population and is most...

Fanconi anaemia

Fanconi anaemia is a rare disorder characterised by progressive bone marrow failure, various congenital abnormalities, and predisposition to malignancies (often acute myeloid leukaemia). Bone marrow failure usually results in decreased production of all blood cells. It is considered the commones...

Felty syndrome

Felty syndrome is a rare haematological syndrome in rheumatoid arthritis. Epidemiology It is thought to occur in ~ 1% of patients with rheumatoid arthritis 2. Clinical presentation Felty syndrome comprises of the triad of: rheumatoid arthritis typically with severe articular and extra-art...

Fetal anaemia

Fetal anaemia is a characterised by inadequate erythrocytes being delivered to the fetus and can result from many causes. Pathology Aetiology haemolytic disease of the newborn fetomaternal ABO incompatibility fetomaternal rhesus (Rh) incompatibility fetal infections fetal parvovirus B19 i...

Folate deficiency

Folate deficiency (hypovitaminosis B9) is the most common vitamin deficiency in the Western world. It is especially important in pregnant women and common amongst alcoholics. Epidemiology Deficiency arises in two distinct populations: increased demand (pregnancy and lactation) decreased abs...

Follicular lymphoma

Follicular lymphoma is the most common subtype of non-Hodgkin lymphoma (NHL) Epidemiology Estimated to account for ~45% of all NHL cases 1. Higher rates in North America and Europe 4. Pathology Nodal effacement by closely packed follicles containing small cleaved cells without nucleoli (cen...

Gallbladder cholesterol polyps

Gallbladder cholesterol polyps are the most common subtype of gallbladder polyps, representing more than 50% of all polyps. They are frequently seen in middle-aged women and are benign lesions, with no malignant potential. For further details, please refer to the parental article on gallbladde...

Gaucher disease

Gaucher disease (GD) is the most common lysosomal storage disorder in humans. It is an autosomal recessive, multisystem disease arising from a deficiency of glucocerebrosidase or beta-glucosidase activity, resulting in the accumulation of a glycolipid (glucocerebroside) within the lysosomes of m...

Graft versus host disease (pulmonary manifestations)

Pulmonary graft versus host disease (GvHD) is one of the thoracic manifestations that can complicate haematopoietic stem cell transplantation. Pulmonary GvHD can be broadly divided into acute and chronic disease 1-4: acute pulmonary GvHD pulmonary involvement is rare the median time of onset ...

Haematinics

The haematinics are nutrients that are required by the body for erythropoiesis, i.e. the production of red blood cells 1,2. List of haematinics Clinically, the most important haematinics are vitamin B12, iron and folic acid because deficiency states of these three substances are much more comm...

Haematopoietic stem cell transplantation

Haematopoietic stem cell transplantation (HSCT) (encompasses bone marrow transplantation (BMT)) is a relatively common procedure used to treat a wide spectrum of conditions 1,2: lymphoproliferative disorders, e.g. multiple myeloma (most common indication), lymphoma, leukaemia solid tumours, ...

Haematopoietic stem cell transplantation (abdominal complications)

Abdominal complications of haematopoietic stem cell transplantation can occur early (0-100 days) or late (>100 days) post-transplant. Complications Early bacterial infections, e.g. pseudomembranous colitis fungal infections, often affecting the oesophagus or as hepatic/splenic microabscesse...

Haemochromatosis

Haemochromatosis is an iron overload disorder characterised by a progressive increase in total body iron stores and deposition of iron in some non-reticuloendothelial system (RES) body organs which results in some instances in organ dysfunction. This article focus on the general principles of h...

Haemochromatosis (cardiac manifestations)

Cardiac involvement in haemochromatosis typically occurs with primary haemochromatosis, as the organ is usually spared in the secondary form of the disease. For a general discussion, and for links to other system specific manifestations, please refer to the article on haemochromatosis. Epidem...

Haemochromatosis (CNS manifestations)

Central nervous system manifestations of haemochromatosis are uncommon and can occur in either primary or secondary haemochromatosis. For a general discussion, and for links to other system specific manifestations, please refer to the article on haemochromatosis. Epidemiology Studies reportin...

Haemochromatosis (pancreatic manifestations)

Pancreatic manifestations of haemochromatosis typically occur with primary haemochromatosis, as the organ is usually spared in the secondary form of the disease. For a general discussion, and for links to other system specific manifestations, please refer to the article on haemochromatosis. Cl...

Haemochromatosis (skeletal manifestations)

Haemochromatosis is a systemic disease which affects many organs systems, including the joints, characterised by haemosiderin and calcium pyrophosphate deposition. For a general discussion, and for links to other system specific manifestations, please refer to the article on haemochromatosis. ...

Haemoglobin

Haemoglobin (Hb) is the oxygen-carrying molecule in red blood cells. Structure Haemoglobin is a tetrameric protein molecule composed of four subunits. Each subunit consists of an iron-containing cyclic haem component linked to a polypeptide chain, the polypeptides are together known as globin....

Haemoglobinopathies

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

Haemoglobin SC disease

Haemoglobin SC (HbSC) disease is a haemoglobinopathy, and a common variant of sickle cell disease (SCD). There is coinheritance of one HbS gene and one HbC gene, resulting in a milder phenotype than full-blown sickle cell disease. It most commonly manifests with a proliferative retinopathy. Pain...

Haemolytic anaemia

Haemolytic anaemia is a form of anaemia where red blood cells are destroyed faster than they can be replaced. This may happen either intravascularly or extravascularly. Clinical presentation The patient presents with anaemia and jaundice. Diagnosis is based on several laboratory parameters 1: ...

Haemolytic uraemic syndrome

Haemolytic uraemic syndrome (HUS) is a multisystem thrombotic microangiopathic disease characterised by the triad of renal failure, haemolytic anaemia and thrombocytopenia. It is the most common cause of renal failure in infancy and childhood requiring dialysis. There are two forms of this syn...

Haemophagocytic lymphohistiocytosis

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

Haemophilia

Haemophilia is an inherited bleeding disorder which is mainly X-linked recessive and therefore occurs almost exclusively in males. There are two main subtypes - haemophilia A (80%) and haemophilia B (20%). Epidemiology The incidence of haemophilia A is around 1 in 5000 male births, and the in...

Haemophilic arthropathy

Haemophilic arthropathy refers to permanent joint disease occurring in haemophilia sufferers as a long-term consequence of repeated haemarthrosis. Epidemiology Around 50% of patients with haemophilia will develop a severe arthropathy. Clinical presentation Presents similarly to osteoarthrit...

Haemosiderosis

Haemosiderosis (plural: haemosideroses) is a general term referring to the accumulation of haemosiderin, which particularly occurs in the reticuloendothelial system (RES) and does not cause organ damage. Pathology Some causes include: frequent transfusions mainly depositional siderosis in re...

Hand-foot syndrome (sickle cell disease)

Hand-foot syndrome, also simply referred to as dactylitis, is a self-limiting manifestation of a vaso-occlusive crisis in individuals with sickle cell anaemia. Terminology Dactylitis is not a specific finding in sickle cell disease, therefore cautious usage is advised if one chooses to employ ...

Hand-Schüller-Christian disease

Hand-Schüller-Christian disease is a clinically intermediate form of a spectrum of histiocytic disorders, which ranges from acute fulminant to chronic indolent disease. It primarily affects children, less often young adults, and rarely older adults. Hand-Schüller-Christian disease has been desc...

Haematopoietic stem cell transplantation (thoracic complications)

There are many thoracic complications that can occur following haematopoietic stem cell transplantation. These can precipitate during various stages following transplantation and can be either infectious or noninfectious. Complications Early pulmonary oedema engraftment syndrome diffuse alv...

Heparin-induced thrombocytopenia

Heparin-induced thrombocytopenia (HIT) is a paradoxical thrombotic state resulting from an immune response to heparin. Epidemiology Occurs in 1:5000 patients who have received heparin, most commonly unfractionated heparin. Pathology HIT is induced by IgG antibodies. Clinical presentation T...

Hepatic lymphoma

Hepatic lymphoma is a term given to any form of hepatic involvement with lymphoma. This can be broadly divided into: secondary hepatic involvement with lymphoma: most common by far, many tend to be non-Hodgkin lymphoma (NHL) 1 primary hepatic lymphoma: extremely rare Pathology Risk factors f...

Hepatic myeloid sarcoma

Hepatic myeloid sarcomas, also referred to as hepatic granulocytic sarcoma or hepatic chloromas, are rare neoplasms comprised of myeloid precursor cells happening in the liver. They are a unique presentation of acute myeloid leukaemia (AML). Please refer to the main article on myeloid sarcoma/...

Updating… Please wait.

Unable to process the form. Check for errors and try again.

Thank you for updating your details.