Diseases

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).

Hepatoerythropoietic porphyria

Hepatoerythropoietic porphyria: an autosomal recessive disorder in which there is a deficiency or absence of uroporphyrinogen decarboxylase; results in photosensitivity and excessive hepatic production of 8- and 7-carboxylate porphyrins. Source: Stedman's Medical Spellchecker, © 2006 Lippincott Williams & Wilkins. All rights reserved. Hepatoerythropoietic porphyria: An autosomal recessive cutaneous porphyria that is due to a deficiency of UROPORPHYRINOGEN DECARBOXYLASE in both the LIVER and the BONE MARROW. Similar to PORPHYRIA CUTANEA TARDA, this disorder is caused by defects in the fifth enzyme in the 8-enzyme biosynthetic pathway of HEME, but is a homozygous enzyme deficiency with less than 10% of the normal enzyme activity. Cutaneous lesions are severe and mutilating.

Hepatorenal syndrome

Hepatorenal syndrome (often abbreviated HRS) is a life-threatening medical condition that consists of rapid deterioration in kidney function in individuals with cirrhosis or fulminant liver failure. HRS is usually fatal unless a liver transplant is performed, although various treatments, such as dialysis, can prevent advancement of the condition.

HRS can affect individuals with cirrhosis (regardless of cause), severe alcoholic hepatitis, or fulminant liver failure, and usually occurs when liver function deteriorates rapidly because of an acute insult such as an infection, bleeding in the gastrointestinal tract, or overuse of diuretic medications. HRS is a relatively common complication of cirrhosis, occurring in 18% of cirrhotics within one year of their diagnosis, and in 39% of cirrhotics within five years of their diagnosis. Deteriorating liver function is believed to cause changes in the circulation that supplies the intestines, altering blood flow and blood vessel tone in the kidneys. The kidney failure of HRS is a consequence of these changes in blood flow, rather than direct damage to the kidney. The diagnosis of hepatorenal syndrome is based on laboratory tests of individuals susceptible to the condition. Two forms of hepatorenal syndrome have been defined: Type 1 HRS entails a rapidly progressive decline in kidney function, while type 2 HRS is associated with ascites (fluid accumulation in the abdomen) that does not improve with standard diuretic medications.

The risk of death in hepatorenal syndrome is very high; the mortality of individuals with type 1 HRS is over 50% over the short term, as determined by historical case series. The only long-term treatment option for the condition is liver transplantation. While awaiting transplantation, people with HRS often receive other treatments that improve the abnormalities in blood vessel tone, including supportive care with medications, or the insertion of a transjugular intrahepatic portosystemic shunt (TIPS), which is a small shunt placed to reduce blood pressure in the portal vein. Some patients may require hemodialysis to support kidney function, or a newer technique called liver dialysis which uses a dialysis circuit with albumin-bound membranes to bind and remove toxins normally cleared by the liver, providing a means of extracorporeal liver support until transplantation can be performed.

Hereditary amyloidosis

Hereditary amyloidosis is a condition in which abnormal protein deposits (called amyloid) form in almost every tissue in the body. These protein deposits damage the tissues and interfere with the function of the involved organs.

Hereditary angioedema

Hereditary angioedema is an immune disorder characterized by recurrent episodes of severe swelling. The most commonly affected areas of the body are the limbs, face, intestinal tract, and airway. HAE is caused by low levels or improper function of a protein called C1 inhibitor which affects the blood vessels. This condition is inherited in an autosomal dominant pattern.

There are three types of HAE, types I, II, and III. The types can be distinguished by their underlying causes and levels of C1 inhibitor in the blood. Type I and II are caused by mutations in the SERPING1 gene. Some cases of type III are associated with mutations in the F12 gene. Other genes are likely to be identified as the cause of other cases of HAE type III.

Hereditary ataxia

Hereditary ataxia: A group of rare genetic neuromuscular disorder involving degeneration of the brain and spinal cord.

Hereditary ATTR amyloidosis

hATTR amyloidosis is an inherited, rapidly progressive, life-threatening disease.1-3 hATTR amyloidosis is caused by a mutation in the transthyretin (TTR) gene that results in misfolded TTR proteins accumulating as amyloid fibrils in multiple tissues in the body, including the nerves, heart, and gastrointestinal tract.2,4,5

hATTR amyloidosis is an autosomal dominant disease; meaning a person only needs to inherit one copy of the affected gene from one parent in order to develop the condition. When one parent carries an autosomal dominant mutation, any child will have a 50% chance of inheriting that mutation.2,6

hATTR amyloidosis affects an estimated 50,000 people worldwide.5 In the disease continuum of hATTR amyloidosis some individuals present primarily with nerve-related symptoms, historically known as familial amyloidotic polyneuropathy (FAP).5,6 Others present primarily with heart-related symptoms, historically known as familial amyloidotic cardiomyopathy (FAC).5,6 More than half of people with hATTR amyloidosis present with a mix of both types of symptoms.7,8

The symptom presentation of hATTR amyloidosis is highly varied among individuals, even within the same mutation or the same family. In addition to the varied symptom presentation, the age of onset is wide-ranging – the median age is 39 years, with some people presenting as early as their 20s.6,9

Hereditary carnitine deficiency

Hereditary carnitine deficiency: An inherited deficiency of carnitine resulting primarily in muscle problems. Severe symptoms can be triggered by periods of illness or fasting.

Hereditary cerebral hemorrhage with amyloidosis

Cerebral hemorrhage with amyloidosis, hereditary, Dutch type: An inherited condition characterized mainly by brain hemorrhage and amyloid deposits in the brain blood vessels. The size and location of the hemorrhage determines the severity of symptoms. The condition was first described in a Dutch family.

Hereditary deafness

Alternative Names :Hereditary nephritis; Hematuria - nephropathy - deafness; Hemorrhagic familial nephritis; Hereditary deafness and nephropathy. Alport syndrome is an inherited disorder that leads to kidney damage.