Monday, September 28, 2009

3 Hepatic icterus
§ Yellow fever
§ Viral hepatitis A, B, C, D, E
§ Medicinal and alcoholic hepatitis
§ Leptospirosis
§ East African trypanosomiasis
§ Recurrent fever (borreliosis)
§ Q fever (Coxiella burnetii) is a rare cause of jaundice
§ Typhoid fever can in rare cases cause jaundice
§ Liver decompensation due to acute liver failure after consumption of toxic mushrooms, such as Gyromitra sp., Amanita phalloides
§ Budd-Chiari syndrome (occlusion of vena hepatica)
§ Veno-occlusive disease resulting from ingestion of vegetable pyrrolizidine alkaloids (Heliotropium, Crotalaria, Senecio sp). See also Jamaican bush tea.
§ Cosmopolitan diseases, e.g. auto-immune hepatitis, biliary cirrhosis

Cat with noticeable jaundice from Feline Hepatic Lipidosis. Note the ears and eye-membrane.
Hepatic causes include acute hepatitis, hepatotoxicity and alcoholic liver disease, whereby cell necrosis reduces the liver's ability to metabolise and excrete bilirubin leading to a buildup in the blood. Less common causes include primary biliary cirrhosis, Gilbert's syndrome (a genetic disorder of bilirubin metabolism which can result in mild jaundice, which is found in about 5% of the population) and metastatic carcinoma. Jaundice seen in the newborn, known as neonatal jaundice, is common, occurring in almost every newborn as hepatic machinery for the conjugation and excretion of bilirubin does not fully mature until approximately two weeks of age..
Laboratory Findings: Urine: bilirubin present, Urobilirubin > 2 units but variable (Except in children)
Hepatic jaundice
Liver diseases of all kinds threaten the organ's ability to keep up with bilirubin processing. Starvation, circulating infections, certain medications, hepatitis, and cirrhosis can all cause hepatic jaundice, as can certain hereditary defects of liver chemistry, including Gilbert's syndrome and Crigler-Najjar syndrome.
Symptoms and complications associated with jaundice
Certain chemicals in bile may cause itching when too much of them end up in the skin. In newborns, insoluble bilirubin may get into the brain and do permanent damage. Long-standing jaundice may upset the balance of chemicals in the bile and cause stones to form. Apart from these potential complications and the discoloration of skin and eyes, jaundice by itself is inoffensive. Other symptoms are determined by the disease producing the jaundice.
Physical examination
In many cases the diagnosis of jaundice is suggested by the appearance of the patient's eyes and complexion. The doctor will ask the patient to lie flat on the examining table in order to feel (palpate) the liver and spleen for enlargement and to evaluate any abdominal pain. The location and severity of abdominal pain and the presence or absence of fever help the doctor to distinguish between hepatic and obstructive jaundice.
Laboratory tests
Disorders of blood formation can be diagnosed by more thorough examination of the blood or the bone marrow, where blood is made. Occasionally a bone marrow biopsy is required, but usually the blood itself will reveal the diagnosis. The spleen can be evaluated by an ultrasound examination or a nuclear scan if the physical examination has not yielded enough information.
Liver disease is usually assessed from blood studies alone, but again a biopsy may be necessary to clarify less obvious conditions. A liver biopsy is performed at the bedside. The doctor uses a thin needle to take a tiny core of tissue from the liver. The tissue sample is sent to the laboratory for examination under a microscope.
Imaging studies
Disease in the biliary system can be identified by imaging techniques, of which there are many. X rays are taken a day after swallowing a contrast agent that is secreted into the bile. This study gives functional as well as anatomical information. There are several ways of injecting contrast dye directly into the bile ducts. It can be done through a thin needle pushed straight into the liver or through a scope passed through the stomach that can inject dye into the Ampulla of Vater. CT and MRI scans are very useful for imaging certain conditions like cancers in and around the liver or gallstones in the common bile duct.
Hepatic jaundice
Most liver diseases have no specific cure, but the liver is so robust that it can heal from severe damage and regenerate itself from a small remnant of its original tissue.
Erythroblastosis fetalis can be prevented by giving an Rh negative mother a gamma globulin solution called RhoGAM whenever there is a possibility that she is developing antibodies to her baby's blood. G6PD hemolysis can be prevented by testing patients before giving them drugs that can cause it. Medication side effects can be minimized by early detection and immediate cessation of the drug. Malaria can often be prevented by certain precautions when traveling in tropical or subtropical countries. These precautions include staying in after dark; using prophylactic drugs such as mefloquine; and protecting sleeping quarters with mosquito nets treated with insecticides and mosquito repellents. In 2003, new studies showed promise for a possible vaccine against malaria. Early trials showed that vaccination combination might stimulate T-cell activity against malaria, the best type of protection that researchers can hope to find. However, further studies will have to be done.
Jaundice is a condition easily recognized by its symptoms of yellowed skin and sclera (the whites of the eyes), due to an accumulation of bilirubin in the body.
Red blood cells live about 120 days then die and are flushed through the body. In this process, bilirubin is produced when the hemoglobin of red blood cells is broken down in the spleen, then carried to the liver by albumin in the blood. Here most of the bilirubin combines with glucuronide to form conjugated or direct bilirubin, then is absorbed in bile, and excreted in the feces. If a disorder prevents this process from completing itself, the yellow-colored bilirubin builds up in the system until it becomes noticeable in the mucous membranes and skin.
Jaundice is not dangerous in itself but can indicate potentially serious underlying conditions that should be diagnosed and treated by a physician.
Knowing how bilirubin is processed, causes for accumulation can be narrowed to one of three key possibilities, which create the three basic classes of jaundice:
· Pre-hepatic or hemolytic: Too many red blood cells are broken down.
· Hepatic: Liver does not process the bilirubin correctly.
· Post-hepatic or extrahepatic: Bile is unable to pass properly.
Pre-hepatic (hemolytic) jaundice is caused by any condition or disease that accelerates the breakdown of red blood cells. Malaria is one example and certain genetic deficiencies can creates conditions that lead to hemolytic jaundice, as can anemia.
Hepatic jaundice causes range from acute viral hepatitis to liver disease resulting from alcoholism. Neonatal jaundice, common in newborns, is usually brief lasting only a week or so and is thought to be a result of the still-developing physiology. Though it is usually harmless and in most cases passes on its own, any infant displaying signs of jaundice should be seen by a pediatrician. (In newborns the liver sometimes requires a week or so to adjust and jaundice may be present during this time. Though this is not due to disease, it is still considered hepatic because liver function is at the root of the condition.)
Post-hepatic (obstructive) jaundice, occurs when bile cannot drain properly to the feces. Gallstones obstructing the bile duct, other ductal obstructions and certain cancers can cause post-hepatic jaundice marked by pale stools lacking the normal pigment contained in bile.
Anyone displaying symptoms of jaundice should seek medical attention so that the underlying condition can be diagnosed and treated.

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