Diseases

Hemophilia B

Hemophilia is a bleeding disorder that slows the blood clotting process. People with this condition experience prolonged bleeding or oozing following an injury, surgery, or having a tooth pulled. In severe cases of hemophilia, continuous bleeding occurs after minor trauma or even in the absence of injury (spontaneous bleeding). Serious complications can result from bleeding into the joints, muscles, brain, or other internal organs. Milder forms of hemophilia do not necessarily involve spontaneous bleeding, and the condition may not become apparent until abnormal bleeding occurs following surgery or a serious injury.

The major types of this condition are hemophilia A (also known as classic hemophilia or factor VIII deficiency) and hemophilia B (also known as Christmas disease or factor IX deficiency). Although the two types have very similar signs and symptoms, they are caused by mutations in different genes. People with an unusual form of hemophilia B, known ashemophilia B Leyden, experience episodes of excessive bleeding in childhood but have few bleeding problems after puberty.

Hemophilic arthropathy

Hemophilic arthropathy: Joint destruction associated with hemophilia. The knees, ankles, elbows, hip and shoulders are the most common joints involved. Symptoms are progressive and often surgical intervention is required to prevent total loss of joint function.

Hemorrhagic fevers

Hemorrhagic fevers also called Viral hemorrhagic fevers (VHFs) are a diverse group of animal and human illnesses in which fever and hemorrhage are caused by a viral infection. VHFs may be caused by five distinct families of RNA viruses: the families Arenaviridae, Filoviridae, Bunyaviridae, Flaviviridae, and Rhabdoviridae. All types of VHF are characterized by fever and bleeding disorders and all can progress to high fever, shock and death in many cases. Some of the VHF agents cause relatively mild illnesses, such as the Scandinavian nephropathia epidemica (a Hantavirus), while others, such as Ebola virus, can cause severe, life-threatening disease.

Hemorrhagic shock and encephalopathy syndrome

Hemorrhagic shock and encephalopathy syndrome: A very rare severe condition characterized by sudden severe shock, brain disease and liver and kidney dysfunction which occurs in infants. The cause is unknown.

Hemorrhagiparous thrombocytic dystrophy

Hemorrhagiparous thrombocytic dystrophy (medical condition): A rare inherited blood coagulation disorder caused by blood platelet abnormalities which results in easy bruising and excessive bleeding. Hemorrhagiparous thrombocytic dystrophy: Another name for Bernard-Soulier Syndrome (or close medical condition association).

Hemosiderosis

Hemosiderosis: A rare lung condition where bleeding into the lungs causes lung damage due to the accumulation of iron. The severity of the condition is determined by the amount of bleeding.

Hendra virus disease

Hendra virus (formerly called equine morbillivirus) is a member of the family Paramyxoviridae. The virus was first isolated in 1994 from specimens obtained during an outbreak of respiratory and neurologic disease in horses and humans in Hendra, a suburb of Brisbane, Australia.

Hennekam Beemer syndrome

Hennekam-Beemer syndrome (medical condition): A very rare syndrome characterized mainly by short stature, abnormal skin pigmentation, small ears and hearing impairment. Hennekam-Beemer syndrome: Another name for Mastocytosis, cutaneous, with short stature, conductive hearing loss and microtia (or close medical condition association).

Hennekam Koss de Geest syndrome

Hennekam koss de geest syndrome (medical condition): A very rare syndrome characterized mainly by reduced muscle tone, short stature and contractures. Hennekam koss de geest syndrome: Another name for Short stature - contractures - hypotonia (or close medical condition association). Short stature - contractures - hypotonia: A very rare syndrome characterized mainly by reduced muscle tone, short stature and contractures.

Hennekam lymphangiectasia lymphedema syndrome

Hennekam lymphangiectasia lymphedema syndrome (medical condition): A rare disorder characterized by buildup of lymphatic fluid in the limbs, face and genitals, seizures and mental and growth retardation. Hennekam lymphangiectasia lymphedema syndrome: Another name for Lymphangiectasies and lymphedema Hennekam type (or close medical condition association). Lymphangiectasies and lymphedema Hennekam type: A rare disorder characterized by buildup of lymphatic fluid in the limbs, face and genitals, seizures and mental and growth retardation.

Hennekam syndrome

Hennekam syndrome is an inherited disorder resulting from malformation of the lymphatic system, which is part of both the circulatory system and immune system. The lymphatic system consists of a network of vessels that transport lymph fluid and immune cells throughout the body.

Henoch-Schonlein purpura

Alternative Names: Anaphylactoid purpura; Vascular purpura. Henoch-Schonlein purpura is a disease that involves purple spots on the skin, joint pain, gastrointestinal problems, and glomerulonephritis (a type of kidney disorder).

Hepadnavirus infection

The recent isolation of a nonhuman primate hepadnavirus from woolly monkeys prompted an examination of other primates for potentially new hepadnaviruses. A serological analysis of 30 captive gibbons revealed that 47% were positive for at least one marker of ongoing or previous infection with a hepatitis B virus (HBV). The amino acid sequences of the core and surface genes of human and gibbon virus isolates were very similar. Phylogenetic analysis indicated that the gibbon isolates lie within the human HBV family, indicating that these HBV isolates most likely stem from infection of gibbons from a human source. Chronic infection with the hepatitis B virus (HBV) is a major health problem worldwide. The only established therapy is alpha-interferon with an efficacy of only 30-40% in highly selected patients. Major theoretical problems of therapeutical strategies against hepadnaviral infections are the limited immune response and the presence of covalently closed HBV DNA in the nucleus. Many nucleoside analogues and inhibitors of viral reverse transcriptases were tested in vitro and in vivo with transient effects and often severe side effects. Molecular therapeutic strategies include antisense DNA/RNA and ribozymes. In vitro antisense oligodeoxynucleotides could be shown to inhibit viral replication and gene expression in human hepatoma cell lines. In vivo an antisense oligodeoxynucleotide directed against the 5'-region of the preS gene of the duck hepatitis B virus inhibited the viral replication and gene expression in ducks. These results demonstrate the potential clinical use of antisense DNA/ RNA as antiviral therapeutics.

Heparane sulfamidase deficiency

Heparane sulfamidase deficiency (medical condition): A rare inherited biochemical disorder characterized by the accumulation of mucopolysaccharides (glycosaminoglycans). This occurs due to there being not enough of the enzyme called N-acetyl-alpha-glucosaminidase (B) which is needed to break down the mucopolysacharides. The mucopolysaccharides are then deposited in various tissues. Heparane sulfamidase deficiency: Another name for Mucopolysaccharidosis type 3 (or close medical condition association). Mucopolysaccharidosis type 3: A rare inherited biochemical disorder characterized by the accumulation of mucopolysaccharides (glycosaminoglycans). This occurs due to there being not enough of the enzyme called N-acetyl-alpha-glucosaminidase (B) which is needed to break down the mucopolysacharides. The mucopolysaccharides are then deposited in various tissues.

Heparin induced thrombocytopenia

Heparin-induced thrombocytopenia (HIT) is an adverse reaction to the drug heparin resulting in an abnormally low amount of platelets (thrombocytopenia). HIT is usually an immune response which typically occurs 4-10 days after exposure to heparin; it can lead to serious complications and be life-threatening. This condition occurs in up to 5% of those who are exposed to heparin. Characteristic signs of HIT are a drop in platelet count of  greater than 50% and/or the formation of new blood clots during heparin therapy.  The first step of treatment is to discontinue and avoid all heparin products immediately. Often, affected individuals require another medicine to prevent blood clotting (anticoagulants).

Hepatic encephalopathy

Hepatic encephalopathy is a syndrome observed in some patients with cirrhosis. It is defined as a spectrum of neuropsychiatric abnormalities in patients with liver dysfunction, when other known brain disease has been excluded. Signs and symptoms may be debilitating, and they can begin mildly and gradually, or occur suddenly and severely. They may include personality or mood changes, intellectual impairment, abnormal movements, a depressed level of consciousness, and other symptoms. There are several theories regarding the exact cause, but development of the condition is probably at least partially due to the effect of substances that are toxic to nerve tissue (neurotoxic), which are typically present with liver damage and/or liver disease. Treatment depends upon the severity of mental status changes and upon the certainty of the diagnosis.

Hepatic fibrosis

Hepatic fibrosis is overly exuberant wound healing in which excessive connective tissue builds up in the liver. The extracellular matrix is either overproduced, degraded deficiently, or both. The trigger is chronic injury, especially if there is an inflammatory component. Fibrosis itself causes no symptoms but can lead to portal hypertension (the scarring distorts blood flow through the liver) or cirrhosis (the failure to properly replace destroyed liver cells results in liver dysfunction). Diagnosis is based on liver biopsy. Treatment involves correcting the underlying condition when possible.

Hepatic fibrosis renal cysts mental retardation

Unusual facies, hepatic fibrosis, renal cysts and mental retardation: A rare syndrome characterized mainly by liver fibrosis, unusual facial appearance, kidney cysts and mental retardation.

Hepatic venoocclusive disease

Hepatic veno-occlusive disease or veno-occlusive disease (VOD) or  Sinusoidal Obstruction Syndrome (SOS) is a condition in which some of the small veins in the liver are obstructed. It is marked by weight gain due to fluid retention, increased liver size, and raised levels of bilirubin in the blood.

The name sinusoidal obstruction syndrome is now preferred if VOD happens as a result of chemotherapy or bone marrow transplantation.

Apart from chemotherapy, VOD may also occur after ingestion of certain plant alkaloids such as pyrrolizidine alkaloids (in some herbal teas), and has been described as part of a rare hereditary disease called hepatic venoocclusive disease with immunodeficiency (which results from mutations in the gene coding for a protein called SP110).

Along with graft versus host disease (GVHD) and cytomegalovirus (CMV) infection, veno-occlusive disease (VOD) is one of the most frequently encountered serious complications after stem cell transplantation. The reported overall incidence rate of veno-occlusive disease ranges from 5% to more than 60% in children who have undergone stem cell transplantation, and similar rates have been reported in adults.

Hepatic venoocclusive disease with immunodeficiency

Hepatic Venoocclusive Disease with immunodeficiency: An inherited disorder characterized by the association of immunodeficiency and liver disease involving the blockage of small veins in the liver due to swelling and fibrosis.

Hepatitis D

Hepatitis D virus (HDV) is an RNA virus that is structurally unrelated to hepatitis A, hepatitis B, or hepatitis C virus. It was discovered in 1977. HDV causes a unique infection that requires the assistance of viral particles from hepatitis B virus (HBV) to replicate and infect other hepatocytes. Its clinical course is varied and ranges from acute, self-limited infection to acute, fulminant liver failure. Chronic liver infection can lead to end-stage liver disease and associated complications.

Hepatitis E

Hepatitis E is a viral hepatitis (liver inflammation) caused by infection with a virus called hepatitis E virus (HEV). It is one of five known human hepatitis viruses: A, B, C, D, and E. HEV is a positive-sense single-stranded RNA icosahedral virus with a 7.5 kilobase genome. HEV has a fecal-oral transmission route. Infection with this virus was first documented in 1955 during an outbreak in New Delhi, India.

Hepatitis X (non-A–B–C–D–E)

Hepatitis X (non-A,-B,-C,-D,-E): Viral liver inflammation that cannot be determined to be one of the existing types of viral hepatitis - A,B,C,D and E.

Hepatoblastoma

Hepatoblastoma: A primary malignant liver tumor which is rare in infants and children.

Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a malignant tumor that arises from hepatocytes in the liver. Hepatocellular carcinoma is relatively rare in the United States but very common in the sub-Sahara African countries and in Southeast Asia. Most cases are seen in patients over the age of 50 years, but this tumor can also occur in younger individuals and even in children. Hepatocellular carcinoma is more common in males than females and is associated with hepatitis B, hepatitis C, chronic alcohol abuse and cirrhosis. Serum elevation of alpha-fetoprotein occurs in a large percentage of patients with hepatocellular carcinoma. Grossly, hepatocellular carcinoma may present as a single mass, as multiple nodules, or as diffuse liver involvement. Microscopically, there is a wide range of differentiation from tumor to tumor (well differentiated to poorly differentiated tumors).