Starting with A for "ACE inhibitor" and continuing through to Y for "Yolk Sac Tumour", we give you succinct explanations for scientific and medical terms in clear and simple words.
- LactateSalt of lactic acid. Arises in lactic fermentation, e.g. in muscular work at low oxygen levels. Cf. lactate acidosis, glycolysis.
- Lactate acidosisalso known as metabolic acidosis
Lactate acidosis is caused by increased levels of lactate in the blood.
Lack of oxygen: glycolysis is activated at low levels of oxygen and leads to lactate fermentation, particularly in life threatening situations, such as pulmonary emboli, shock or operations. Also in type 2 diabetes or type 1 diabetes, neurological disease and intense muscular work. Lactate acidosis used to occur frequently during treatment with biguanides, drugs for the treatment of type 2 diabetes, particularly in the presence of liver or kidney failure, heart failure, hyperventilation, alcoholism or liver cirrhosis.
Nausea, abdominal pain, hyperventilation, occasionally sudden blindness, also lightheadedness, lactic acidotic coma.
- Large intestineThe large intestine (Intestinum crassum) is about 1.5 m long and consists of the 6-8 cm long caecum, which lies under the site of entry of the small intestine, with the 5-8 cm long appendix, and the colon. The colon is the main portion of the large intestine. It begins above the entry of the small intestine and is subdivided into ascending (Colon ascendens), transverse (Colon transversum) and descending sections (Colon descendens). No further digestion occurs in the colon, but water and electrolytes are removed from the content of the intestine. The end of the large intestine continues into the rectum.
- Large-for-date babyNew born baby with high weight at birth. Typical finding in badly controlled diabetes mellitus in pregnancy. As a result of excessively high maternal blood sugar, the unborn baby receives excessive levels of glucose, which lead to excessive growth and increased production of insulin. Early feeding after birth is therefore necessary to avoid low blood sugar concentrations (hypoglycaemia). Cf. gestational diabetes
- Late RelapseRecurrence of a disease after a long period without illness (see Relapse). In oncology this term is used for a tumour which recurs at least 5 years after the primary tumour has been successfully treated.
- Latency PeriodInterval between the action of a carcinogenic factor or toxic substance (poison, carcinogenic substance or radiation) on the body and the development of recognisable symptoms or consequences (poisoning, malignant tumour, radiation damage).
- Law on Protection against InfectionA law which serves to prevent and fight infectious diseases in man. One of its regulations is that infectious diseases must be reported (by name or anonymously), to prevent the spread of dangerous diseases.
- Laxativesalso known as purgatives
Drugs which encourage and ease the emptying of the bowels, particularly by increasing peristaltic movements (constricting downwards motion of the intestine wall in the direction of the transport of the intestinal content).
Single or short term use to empty the bowel for diagnostic investigation, for painful anal conditions, after operations, for constipation (obstipation), sometimes also for detoxication.
Flatulence or gastric pain from substances which swell up. Long term use or higher doses can lead to loss of electrolytes (particularly of potassium, which increases the severity of the constipation), bloody intestinal inflammation and grave hypersensitivity reactions.
- LDLAbbreviation for low density lipoproteins
Lipoproteins of low density, which arise from VLDL (very low density lipoproteins). 75 % of LDLs consist of fat (lipids) and 25 % of proteins. LDL transport cholesterol to peripheral cells.
A form of cholesterol that circulates in the blood; LDL is commonly called bad cholesterol because high blood levels increase the risk of heart disease; the normal range for LDL cholesterol in adults is 60 to 180 mg/dl
- LDL receptor geneGene which influences the ability of the receptors to bind LDL (lipoproteins of low density). Changes in the LDL receptor gene can lead to the presence of so-called membrane receptor defects, in which the LDL receptors cannot bind enough LDL. This leads to raised blood levels of cholesterol, which corresponds to primary or familial hypercholesterolaemia.
- LDL/HDL ratioRatio of the blood concentrations of the lipoproteins LDL (low density lipoproteins) and HDL (high density lipoproteins) which mediate the transport of cholesterol in blood. The LDL/HDL ratio is determined to assess the risk of arteriosclerosis, which is clearly higher at values of more than 5.
- Left heart failureForm of heart failure in which the functional capacity of the left heart chamber is inadequate as a result of functional weakness of the heart muscle tissue and which can lead to volume overloading of the lesser (pulmonary) circulation.
Disease of the heart muscle, coronary heart disease, myocardial infarction, high blood pressure (hypertension), congenital or acquired heart defect.
Breathing problems, blue-red discolouration of the skin and mucous membranes as a result of low blood levels of oxygen and congestive bronchitis with dry cough, so-called cardiac asthma, pulmonary oedema (water collects in the lungs) and increased heart rate with a third heart sound (third sound gallop).
- Left ventricular hypertrophyEnlargement of the left heart with increase in muscle mass with unchanged cell number, e.g. in high blood pressure (hypertension). Cf. cardiac hypertrophy.
- left ventricular hypertrophy (LVH)thickening of the wall of the left ventricle of the heart; causes include high blood pressure, heart valve disease and anemia
- LeiomyosarcomaA leiomyosarcoma is a malignant tumour originating in smooth muscle fibres (cf. Myoma, Sarcoma). A leiomyoma is a benign tumour of smooth muscle fibres.
- LeptinHormone which is formed exclusively in fat tissue and which functions as a signal for the mass of fat stored in the body. Individuals with a high proportion of fat normally form more leptin than those with small fat depots. Leptin regulates weight, as it decreases food intake by reducing appetite and increases energy consumption. In cases of pathological overweight it is presumed that either too little leptin is produced or that the target cells in the hypothalamus are insensitive to leptin activity.
- LeukaemiaMalignant disease of the white blood cells in which there is uncontrolled division of immature precursor cells.
Causes: The exact causes have not been clarified. It is thought that there is an interaction between several factors which can increase the risk of disease, predominantly chemicals (e.g. benzene), radioactivity, cytostatic drugs, carcinogenic viruses (e.g. the human T-cell leukaemia virus, Abb. HTLV 1; cf. Viruses, oncogenic). There may also be a familial susceptibility to the development of leukaemia.
Frequency: About 50 persons per million fall ill each years, including more men than women. Leukaemia makes up about 45% of cancers in children, so that it is the most frequent malignant disease.
Classification: The classification of leukaemia is based on the following criteria:
1. The clinical course, so that there is acute and chronic leukaemia.
2. The maturity of the cancer cells, so that there is mature cell and immature cell leukaemia.
3. The origin of the cells, so that there is lymphatic leukaemia, where the precursor cells are lymphocytes, and myeloid leukaemia, where the precursor cells are granulocytes.
4. The number of leukaemia cells in the blood, so that there is aleukaemic leukaemia (no leukaemia cells in the blood), subleukaemic leukaemia (few leukaemia cells in the blood) and leukaemic leukaemia (many leukaemic cells in the blood).
- Leukaemia, AcuteMalignant disease of the white blood cells (see Leukaemia) which progresses rapidly. If untreated, leads to death within weeks or a few months.
Diagnosis: Blood investigation with smear and investigation of the cancer cells, bone marrow investigation (bone marrow biopsy: sample taken from the bone marrow).
Symptoms: Susceptibility to infection, bleeding tendency, signs of blood deficiency (anaemia), sometimes symptoms when individual organs are affected.
The following forms are distinguished:
1. acute lymphatic leukaemia (Abb. ALL): The cancer cells are derived from the precursor cells of lymphocytes, which are a type of white blood cell, which, for example, produce antibodies. This is the predominant form of leukaemia in children (80%). Therapy: Chemotherapy with very powerful chemotherapeutic agents (the so-called aggressive chemotherapy). Prognosis: With aggressive chemotherapy, 80% of affected children survive five years and 50% ten years. Chemotherapy can prolong the life of affected adults, although cure is rarely achieved.
2. acute myeloid leukaemia (Abb. AML): The cancer cells originate from the precursors of granulocytes, which are a type of white blood cell, which can, for example, destroy foreign bodies. This mainly occurs in adults. Therapy: Chemotherapy. Prognosis: In 25-50% of cases, chemotherapy and other measures can make the disease vanish for a few months, although it usually recurs later and then leads to death.
- Leukaemia, ChronicMalignant disease of the white blood cells (see Leukaemia), with slowly progressive course.
The following forms are distinguished:
1. Chronic myeloid leukaemia (Abb. CML): The cancer cells originate from precursors of the granulocytes. These are special white blood cells which can, for example, destroy foreign bodies. The cancer cells grow in the bone marrow, the blood (which explains the tendency to blood aggregation, so-called thrombosis) and in several organs, including the liver and spleen.
Therapy: Chemotherapy with cytostatics and interferons, additionally allopurinol.
Prognosis: If treated, the disease lasts an average of two to three years. Death occurs either from a sudden increase in the number of cancer cells or from the side-effects of chemotherapy.
2. Chronic lymphatic leukaemia (Abb. CLL): The cancer cells originate from precursor cells of the lymphocytes. These are special white blood cells which can, for example, produce antibodies. The patients are usually older people.
Symptoms: Frequent swelling of the lymph nodes, enlargement of the liver and spleen, rarely affects the skin
Therapy: Chemotherapy can help, but should only be used in certain cases, as it sometimes does not improve the clinical course and numerous side-effects must be put up with.
Prognosis: Very different clinical courses may occur.
- Leukaemia, Hairy CellOne form of leukaemia* (blood cancer). The name is derived from the abnormal lymph cells which occur in blood, which have hair-shaped attachments.
In the course of the disease, the spleen is enlarged and there is a general deficiency in functionally intact white blood cells, accompanied by deterioration in the immune defences of the body. The diagnosis is made on the basis of the detection of certain enzymes in the hairy cells. The therapy consists in the removal of the spleen and interferons may also be given (cf. alpha-Interferon). The clinical course of the disease is often protracted and with few symptoms. There may be frequent infections because of the impaired immune system (particularly inflammation of the lung).
- leukocyteswhite blood cells
- libidosexual urge or desire
- Light therapyTherapeutic use of ultraviolet light. The aim of the treatment is the prevention of osteomalacia, ostopenia and osteoporosis, strengthening of the immune system and improvement in the regulation of the vegetative nervous system, especially the cardiovascular system.
Use of 1. natural solar radiation (heliotherapy); 2. artificial sources of radiation, particularly with wavelengths from the UV B range (280-315 nm).
1. Stimulation of the natural production of vitamin D: a) positive action on calcium metabolism and bone growth (cf. Calcium); b) Increased natural defence to infection; 2. Stimulation of the formation of immune mediators in the skin, with effects in the whole body; 3. Positive effect on the regulation of organ systems; 4. UV B radiation stimulates the growth of the skin cells which form pigment (melanocytes) and of the horny cell layer (stratum corneum) (actinic skin thickening).
1. In skin diseases, such as psoriasis; 2. for osteoporosis, osteomalacia, to prevent osteopenia in healthy people who are at risk; 3. in chronic or recurrent infections; 4. in disturbances cardiovascular functions regulated by the vegetative system.
Allergic and toxic reactions to sunlight, acute feverish infectious diseases, cancer, marked general weakness and others.
- Lipase inhibitorSubstances which partially inhibit the activity of the enzyme lipase in the gastrointestinal tract. As lipase is responsible for breaking down triglycerides (fats) in the intestine, these can then not be absorbed into the body. Lipase inhibitors are used to support weight reduction in nutritionally related cases of overweight.
Reduced absorption of fat soluble vitamins, flatulence (wind) in the intestine or stomach, with a lot of gas release, faecal incontinence (inability to retain the faeces), gastric pain, headache.
- LipasesLipases are enzymes, which split triglycerides (fats). They are formed, for example, in the (pancreas). Lipase activity is the precondition for absorption by the body of fat in food. Lipases can only split fat when it is in very fine particles, i.e. emulsified by bile acids. Cf. digestion of neutral fats, lipolysis.
- Lipid metabolismalso known as fat metabolism
Strictly speaking, lipid metabolism means the metabolism of neutral fats, triglycerides. Fat in food must first be brought into an emulsion with bile acids if it is to be absorbed from the stomach into the blood. Only then can they be split by enzymes in the stomach, small intestine and pancreas into fatty acids and glycerol. Fatty acids with fewer than 12 carbon atoms are transported as free fatty acids bound to albumin. Fatty acids with more than 12 carbon atoms are, together with glycerol, reincorporated into triglycerides in the intestinal mucous membrane, transported into the lymph as chylomicrons (small lipoprotein particles) and bound to lipoproteins in the blood serum. Triglycerides are stored with cholesterol esters in fat tissue and released as required. The synthesis of triglycerides in the body occurs particularly in the liver, fat, kidneys, lungs and mammary glands. The required fatty acids are produced from acetyl-CoA, which mostly comes from the metabolism of glucose. The fatty acids which are released during the metabolism of triglycerides in fat tissue (lipolysis) are then subject to further cellular metabolism, which finally leads to energy production. Cf. digestion of neutral fats. Disturbances in lipid metabolism: see hyperlipoproteinaemias, hypolipoproteinaemias.
- Lipid metabolismOverall synthesis, metabolism and conversion of lipids in the organism; see fat metabolism.
- Lipid sinkersalso known as anitlipidaemic drugs
Drugs to decrease blood fat values in the treatment of hyperlipoproteinaemia (particularly hypercholesterolaemia).
1. Anion exchangers: These bind bile acids, so that these are excreted. This increases both the excretion of bile acids and their regeneration. The concentration of cholesterol in the liver is reduced. This causes an increase in LDL receptors and more LDL is taken up from the blood, i.e. blood fat values sink. Side-effects: digestive problems and weakened action of some drugs. 2. HMG-CoA reductase inhibitors (also known as CSE inhibitors or statins): These inhibit the activity of a key enzyme in the formation of cholesterol in the body, which reduces the concentration of cholesterol in cells. Counter-regulation then leads to the formation of more cellular LDL receptors. This leads to a drop in LDL and total cholesterol, because more cholesterol is taken up from the blood. Side-effects: Gastrointestinal problems, headache, rashes, disturbances in liver function, muscle disease. 3. Fibrates: These inhibit the formation of lipoproteins, particularly VLDL, and may activate their metabolism. Side-effects: Gastrointestinal problems, headache, tendency to form gallstones, rarely allergy and muscle disease. 4. Nicotinic acid and derived substances: These inhibit fat breakdown (lipolysis) by inhibiting the enzymes involved. Less VLDL and therefore less LDL is formed in the liver. In addition, the enzyme lipoprotein lipase is activated. Side-effects: attacks of reddening of the skin with feelings of warmth (flush), gastrointestinal problems, at higher doses disturbances in liver function, reduced glucose tolerance, increase in the blood concentration of uric acid. 5. Sitosterol inhibits the intestinal uptake of cholesterol from food. Side-effects: Gastrointestinal problems. 6. Probucol influences LDL metabolism and increases the removal of LDL. The concentrations of LDL and HDL are lowered. Side-effects: Gastrointestinal problems, headache, occasionally disturbances in the action of the heart. 7. Omega-fatty acids mostly reduce the concentrations of triglycerides, presumably through a reduction in VLDL formation.
- LipidsBiomolecules which are highly soluble in fat and which can be of very different chemical structure. The term lipid includes saponifiable and non-saponifiable lipids. Saponfiiable lipids can be split chemically or by enzymes in a certain way (e.g. triglycerides, waxes). Non-saponifiable lipids cannot be split in this way. They include, for instance, long chain alcohols, sterols (e.g. cholesterol), fatty acids and other natural products.
Lipids occur in all organisms. In man they occur as the so-called serum lipids in blood (free fatty acids, lipoproteine), as structural components in cell membranes, as cholesterol and in depot fat. The term can be extended to include fat soluble hormones. Cf. fat metabolism.
- LipolysisSplitting of triglycerides from fat tissue by enzymes and release into the blood of the products of this splitting, (glycerol and fatty acids). Fat is broken down by lipolysis (see Fat Metabolism). Lipolysis is activated by the hormones adrenaline, noradrenaline, glucagon, TSH and ACTH. Lipolysis is inhibited by insulin, prostaglandin E1 and nicotinic acid.
- LipoproteinsHigh molecular weight water soluble complexes of proteins and fat components (lipids), which are bound to them and which can have different compositions. Lipoproteins are formed in the liver and intestine. Their main purpose is the blood transport of cholesterol and cholesterol esters, phospholipids, triglycerides and fat-soluble vitamins.
Lipoproteins are classified according to their density as chylomicrons, VLDL, IDL, LDL and HDL.
- LiposarcomaRare malignant tumour of fat tissue (cf. sarcoma). It is mostly situated in the deep soft tissue of the limbs, more often in the legs than arms, and in the abdominal cavity. Therapy: Surgical removal, radiotherapy after the operation.
- LiposuctionRemoval by suction of deposits of depot fat, mostly for cosmetic reasons. After injection of sodium chloride solution containing a local anaesthetic and adrenalin, destroyed fat tissue is sucked away. Ultrasound may be used to help liquefy the fat.
- LiverThe liver is the largest organ in the human body. It lies in the right upper abdomen under the ribs and partially adheres to the diaphragm. It is not palpable in healthy individuals. The liver can be felt under the right costal arch, but only when it is pathologically enlarged.
Function: The liver produces and secretes bile. The liver is also the central metabolic organ in the human body, in which metabolic products are synthesised, utilised, broken down and stored.
- Liver BiopsyExtraction of a sample from the liver for microscopic examination, exact diagnosis of the disease and control of the clinical course of liver disease (e.g. inflammation of the liver, fatty liver).
- Liver carcinomaDesignation for Primary Liver Cell Carcinoma or bile duct carcinoma (cholangiocellular liver cell carcinoma).
- Liver Cell AdenomaSmall benign tumour of the liver and liver cells, originating from liver cells and special liver vessels. Liver cell adenoma can be diagnosed on the basis of ultrasound, scintigraphy (an imaging technique with radioactive substances) and possibly magnetic resonance tomography. Operative removal is only necessary when the tumour presses on other organs.
- Liver Cell Carcinoma, PrimaryAlso hepatocellular carcinoma or malignant hepatoma
Malignant tumour of the liver cells. Usually forms numerous daughter tumour (metastases), within the liver or in other organs, such as the lymph nodes, lungs and bones
Cause: In 60-80% of cases the development of liver cell carcinoma is supported by liver cirrhosis, hepatitis B or hepatitis C. Other possible causes include some fungal poisons (aflatoxins) and chemicals (vinyl chloride, arsenic).
Occurrence: Rare in Europe, more frequent in Asia and Africa; occurs more often in men,
Symptoms: Diffuse feeling of pressure and fullness, pain in the upper abdomen which can extend into the right shoulder, loss of energy, loss of weight.
Diagnosis: Laboratory tests: Determination of alpha-foetoprotein. Imaging procedures: Ultrasound investigation, magnetic resonance tomography, laparoscopy with tissue sampling, examination of the blood vessels in the liver (angiography)
Therapy: Operative removal of the affected section of the liver is possible in ca. 25% of cases. Liver transplantation may be possible for single tumours which are smaller than 3.5 cm and which have not formed metastases. If an operation is not possible, chemotherapy or radiotherapy can slow the progression of the disease.
Prognosis: The average time of survival is 6 months without an operation. About 20% of patients survive 5 years after an operation.
- Liver CirrhosisLiver cirrhosis is a chronic disease of the whole liver, in which liver tissue is gradually destroyed and replaced with scar tissue. Restoration of normal liver structure is not possible, so that there is increasing restriction to kidney function, as a result of the lack of healthy liver tissue.
Causes: Liver cirrhosis can occur as the result of alcohol abuse, inflammation of the liver, metabolic abnormalities or diseases of the bile ducts or cardiovascular system. Liver cirrhosis also occurs without known cause; this is the so-called cryptogenic cirrhosis.
Symptoms: Liver cirrhosis can be present for an extended period without there being severe physical symptoms. This is so-called compensated liver cirrhosis. In this phase, subjective symptoms occur as in chronic hepatitis, including tiredness, nausea, constipation, flatulence, fat intolerance or pressure under the right costal arch. After this, skin changes develop, such as the so-called starburst varices, which are spider-shaped small blood vessels under the skin and palmar erythema. The liver and spleen are enlarged and hardened and can be palpated. As a result of the progressive transformation of the liver, the liver perfusion deteriorates and this can lead to ascites (accumulation of water in the belly). In addition, varicose veins develop in the oesophagus (Oesophageal Varices) and in the abdominal wall and haemorrhoids occur.
Diagnosis: Clinical chemistry: Low levels of blood platelets and of red and white blood cells, raised sedimentation rate, changed liver values (cf. Probes of Liver Function), changes in blood proteins, abnormal coagulation and often low potassium. The diagnosis is confirmed by ventroscopy and by tissue sampling from the liver (Liver Biopsy).
Complications: Bleedings from the varicose veins in the oesophagus (most frequent cause of death), hepatic coma, liver cancer (Primary Carcinoma of Liver Cells).
- Liver Drugsalso known as hepatica or drugs to protect the liver
Drugs used in the treatment or prophylaxis of toxic or infectious liver damage (e.g. Hepatitis, Liver Cirrhosis). A great variety of drugs belong to this group, including vitamins, lecithin, sugars such as inositol and lactulose, herbal remedies with a special affinity for the liver (hepatotropic remedies), some hormones, immunosuppressive drugs (mercaptopurine, azathioprine), bile acids and many others.
- Liver FunctionCollective term for the metabolic functions of the liver. These are mainly:
1. Formation of bile
2. Interconversions in sugar metabolism
3. Modification of nutrients taken up from the intestine
4. Formation of specific substances in the immune and clotting systems
5. Breakdown of certain fats
6. Breakdown of certain poisons
The function of the liver is tested with the help of liver function probes.
- Liver Necrosis, AcuteAcute liver necrosis means massive disintegration of the liver in the fulminating course of acute hepatitis or in severe liver diseases, for example, from fungal poisoning.
Symptoms: Hepatic coma; if the patient survives the coma, a scarred liver is retained.
Therapy: Liver Transplantation.
- Liver Perfusion, Extracorporealalso extracorporeal liver dialysis
In extracorporeal liver perfusion, an animal liver (baboon) or a technical membrane system, as a liver substitute, is perfused with the blood of the patient for a limited period of time. The blood is detoxified in this way. This procedure is used in endogenous hepatic coma, e.g. in fulminant hepatitis or death-head intoxication.
- Liver TransplantationTransfer of the liver of a deceased person to a patient with liver failure, liver tumours and other severe liver diseases, such as for example severe cases of acute and chronic hepatitis*. After he has received the liver, the immune system of the recipient must be suppressed by drugs for the rest of his life, so that the liver is not rejected.
Prognosis: The chances of success depend on the underlying disease. After 5 years, an average of 60-70% of the patients are still alive. The prognosis is most favourable if the transplantation occurs because of liver cirrhosis.
- Liver Tumours1. Benign liver tumours: Benign tumours of the liver are usually tumours of the blood vessels (haemangiomas), more rarely of the lymph ducts (lymphangiomas), embryonic cells (teratoma, hamartoma), adenoma (liver cell adenomas) or specific changes in the liver as a result of the intake of hormonal contraceptives (focal nodular hyperplasia).
2. Malignant liver tumours: Malignant liver tumours can originate from the liver itself and are mostly carcinoma of the cells of the liver or bile ducts (see primary liver cell carcinoma and bile duct carcinoma). They are however more often tumours with a primary site in other organs or organ systems. This includes metastases of tumours from distant organs (e.g.colorectal carcinomas), tumour which have spread from neighbouring organs (e.g. gallbladder carcinoma) or tumours of the lymphatic system (lymphoma).
- Looser transformation zonesLight stripes which are visible in the X-ray of the bone. They are caused by a reduction in the chalk in the bone (demineralisation) and the compensatory formation of uncalcified bone ground substance. They can lead to bone fractures (fatigue fracture). Looser transformation zones occur in, for example, alimentary osteopathy, rickets and osteomalacia.
- Loss of EnergyLoss of physical or mental energy which may occur within days or weeks. This may be unpleasant for the affected person, although sometimes only the friends or relatives notice it. Loss of energy can be a sign of various diseases, including severe infections (e.g. tuberculosis), tumours or depression.
- LumpectomyForm of operation for breast cancer which retains the breast. This is possible when there is only a single tumour in the breast and when this is small, far enough removed from the nipple (more than 2 cm) and surrounded by a layer of healthy tissue which is at least 1 cm wide. No metastases may be present. The tumour is removed during the operation and the lymph nodes in the arm pit are removed by a second incision. After the operation, radiation therapy of the breast is performed.
- Lung embolismClosure of the arterial circulation in the lungs when a thrombus, or more rarely air, tissue fragments or fat, is washed up, mostly from the veins of the (lower) thigh or pelvis. The symptoms are largely dependent on the size of the blood clot which has been washed up. Lung embolism is a dangerous complication after operation or birth.
Massive lung embolisms involve the blockage of more than half of the lung circulation and make up about 5-10 % of all lung embolisms. The patients generally exhibit the whole range of symptoms, including a feeling of being threatened, sudden difficulties in breathing, increased rate of breathing, low levels of blood oxygen, right heart failure and dilatation, cardiac arrythmia, decrease in arterial blood pressure, possibly shock. The further clinical course depends on whether the thrombus dissolves or whether the vessels remains closed.
- Lung TumoursFormation of new tissue in the lung (neoplasm). A distinction is made between benign and malignant lung tumours.
1. Benign lung tumours: Benign lung tumours do not form daughter growths (metastases), grow slowly and do not penetrate into neighbouring tissue. They mostly come from proliferation of connective tissue, fat tissue, cartilage, bone or from embryonic cells. They are usually asymptomatic and are discovered by chance during X-ray investigation of the lungs.
2. Malignant lung tumours: Malignant lung tumours may originate in the cells of the lung or alveolar sacs. They may however also be tumours which originally grew in other organs and which have migrated into the lung through the blood vessels (metastases) or tumours which have spread into the lung from neighbouring organs. For example, lung metastases are frequent from kidney, breast (see Mammary Tumours), prostate or gastric carcinomas. Tumours from the lining of the lung (see Pleural Mesothelioma), the oesophagus (Oesophageal Carcinoma) or the breast may also grow directly into the lung.
- lupus erythematosusa chronic inflammatory autoimmune disorder that may affect the skin, joints, kidneys and other organs; also called systemic lupus erythematosus or SLE; it affects nine times as many women as men
- lupus nephritisglomerulonephritis associated with systemic lupus erythematosus that is typically characterised by proteinuria and hematuria and that often leads to renal failure
- LymphFluid in the lymph vessels which contains lymphocytes and which is formed when blood passes from the smallest blood vessels into tissue. Lymph first flows into the gaps between tissue and is then collected in the lymph vessels*. It then passes from these into the blood stream.
- Lymph NodesLentil to bean sized organs which are connected to the system of lymph vessels. The lymph fluid is filtered in the lymph nodes and damaging substances, such as microorganisms or antigens are broken down by specialised cells (cf. phagocytes).
- Lymph VesselIn the lymph vessels, the lymph is passed through the lymph nodes into the blood circulation. Lymph is formed when fluid passes from the smallest blood vessels (capillaries) into the surrounding tissue. Lymph cells are present in lymph.
- LymphocytesImportant cells of the immune system, which are formed in the bone marrow, the lymph nodes, the thymus and in the spleen. The lymphocytes are a type of white blood cell (leukocytes). A distinction is made between the B-lymphocytes, which are responsible for the formation of antibodies, T-lymphocytes*, which are responsible for the destruction of foreign or sick cells and for the regulation of the immune system, and natural killer cells (NK cells, which are responsible for the destruction of infected cells and cancer cells).
About 4% of lymphocytes are in blood and the remainder are at their site of formation or in other organs.
- LymphokinesLymphokines are the so-called messenger proteins, which are predominantly formed and secreted by T-lymphocytes and which stimulate other cells to form specific proteins or to replicate (cf. Cytokines).
- LymphomaAlso Swelling of the Lymph Nodes
General term for enlargement of the lymph nodes for different reasons.
1. Benign enlargement of the lymph nodes during infectious diseases (e.g. mononucleosis, toxoplasmosis, lymph node tuberculosis)
2. Malignant enlargement of the lymph nodes accompanying tumours of the lymph nodes (e.g. leukaemia, malignant lymphoma, lymph node metastases).
- LymphopeniaReduction in the number of white blood cells (lymphocytes) in the blood. Occurs in the acute phase of many infectious diseases, in one form of tuberculosis (disseminated tuberculosis) and in advanced HIV disease.
- LymphosarcomaMalignant growth (neoplasm) which originates in the lymphatic tissue of the lymph nodes, tonsils, spleen or other organs. 5-10 per 100,000 population develop lymphosarcoma, particularly between 60 and 70 years of age. It has recently become more frequent in HIV patients. A distinction is made between Hodgkins disease (or lymphogranulomatosis) and non-Hodgkins disease (Abb. NHL). The tumours originate from lymphocytes (immune cells) and are of different types and maturity. Hodgkins disease is classified according to the composition of the tumour:
2. Nodular sclerotic, i.e. forming nodes
3. Mixed cell type
Symptoms: The symptoms include swelling of the lymph nodes and possibly enlargement of the spleen. Depending on the site of the tumour, there may be pressure on other organs.
Diagnosis: Examination of tissue from lymph nodes and bone marrow
Therapy: Depending on the type and stage of the tumour, the treatment includes chemotherapy with various drugs and possibly also radiation therapy.
Prognosis: Even without treatment, the clinical course of the disease may be protracted, without much exacerbation of the disease. The main complications are infections and increasing impairment of bone marrow function, resulting in anaemia and bleeding. Cf. Lymphoma, Brain Tumours.
Glossary entries: Roche and Walter de Gruyter, Berlin