Amyloidosis Health Dictionary

Nephrotic syndrome is one of PROTEINURIA, hypo-albuminaemia and gross OEDEMA. The primary cause is the leak of albumin (see ALBUMINS) through the GLOMERULUS. When this exceeds the liver’s ability to synthesise albumin, the plasma level falls and oedema results. The nephrotic syndrome is commonly the result of primary renal glomerular disease (see KIDNEYS, DISEASES OF – Glomerulonephritis). It may also be a result of metabolic diseases such as diabetic glomerular sclerosis and AMYLOIDOSIS. It may be the result of systemic autoimmune diseases such as SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) and POLYARTERITIS NODOSA. It may complicate malignant diseases such as MYELOMATOSIS and Hodgkin’s disease (see LYMPHOMA). It is sometimes caused by nephrotoxins such as gold or mercury and certain drugs, and it may be the result of certain infections such as MALARIA and CROHN’S DISEASE.... nephrotic syndrome

Any disease of the heart muscle that weakens the force of cardiac contractions, thereby reducing the efficiency of blood circulation. Cardiomyopathies may have an infectious, metabolic, nutritional, toxic, autoimmune, or degenerative cause. However, in many cases the cause is unknown.

There are 3 main types. In hypertrophic cardiomyopathy, which is usually inherited, the heart muscle is abnormally thickened. In dilated cardiomyopathy, metabolism of the heart muscle cells is abnormal and the walls of the heart tend to balloon out under pressure. Restrictive cardiomyopathy is caused by scarring of the endocardium (the inner lining of the heart) or by amyloidosis.

Symptoms of cardiomyopathy include fatigue, chest pain, and palpitations. The condition may lead to heart failure, symptoms of which include breathing difficulty and oedema. A chest X-ray may show enlargement of the heart, and echocardiography may show thickened heart muscle. A biopsy of heart muscle may reveal muscle cell abnormalities.

Symptoms may be treated with diuretic drugs to control heart failure and antiarrhythmic drugs to correct abnormal heart rhythm. In many cases, heart muscle function deteriorates, and the only remaining option is a heart transplant.... cardiomyopathy

Characteristic waxy deposits of amyloid found in primary AMYLOIDOSIS, the cause of which is unknown.... amyloid plaques

A procedure used to ?lter o? waste products from the blood and remove surplus ?uid from the body in someone who has kidney failure (see KIDNEYS, DISEASES OF). The scienti?c process involves separating crystalloid and COLLOID substances from a solution by interposing a semi-permeable membrane between the solution and pure water. The crystalloid substances pass through the membrane into the water until a state of equilibrium, so far as the crystalloid substances are concerned, is established between the two sides of the membrane. The colloid substances do not pass through the membrane.

Dialysis is available as either haemodialysis or peritoneal dialysis.

Haemodialysis Blood is removed from the circulation either through an arti?cial arteriovenous ?stula (junction) or a temporary or permanent internal catheter in the jugular vein (see CATHETERS). It then passes through an arti?cial kidney (‘dialyser’) to remove toxins (e.g. potassium and urea) by di?usion and excess salt and water by ultra?ltration from the blood into dialysis ?uid prepared in a ‘proportionator’ (often referred to as a ‘kidney machine’). Dialysers vary in design and performance but all work on the principle of a semi-permeable membrane separating blood from dialysis ?uid. Haemodialysis is undertaken two to three times a week for 4–6 hours a session.

Peritoneal dialysis uses the peritoneal lining (see PERITONEUM) as a semi-permeable membrane. Approximately 2 litres of sterile ?uid is run into the peritoneum through the permanent indwelling catheter; the ?uid is left for 3–4 hours; and the cycle is repeated 3–4 times per day. Most patients undertake continuous ambulatory peritoneal dialysis (CAPD), although a few use a machine overnight (continuous cycling peritoneal dialysis, CCPD) which allows greater clearance of toxins.

Disadvantages of haemodialysis include cardiovascular instability, HYPERTENSION, bone disease, ANAEMIA and development of periarticular AMYLOIDOSIS. Disadvantages of peritoneal dialysis include peritonitis, poor drainage of ?uid, and gradual loss of overall e?ciency as endogenous renal function declines. Haemodialysis is usually done in outpatient dialysis clinics by skilled nurses, but some patients can carry out the procedure at home. Both haemodialysis and peritoneal dialysis carry a relatively high morbidity and the ideal treatment for patients with end-stage renal failure is successful renal TRANSPLANTATION.... dialysis

Diseases affecting the kidneys can be broadly classi?ed into congenital and genetic disorders; autoimmune disorders; malfunctions caused by impaired blood supply; infections; metabolic disorders; and tumours of the kidney. Outside factors may cause functional disturbances – for example, obstruction in the urinary tract preventing normal urinary ?ow may result in hydronephrosis (see below), and the CRUSH SYNDROME, which releases proteins into the blood as a result of seriously damaged muscles (rhabdomyolosis), can result in impaired kidney function. Another outside factor, medicinal drugs, can also be hazardous to the kidney. Large quantities of ANALGESICS taken over a long time damage the kidneys and acute tubular NECROSIS can result from certain antibiotics.

K

Diagram of glomerulus (Malpighian corpuscle).

Fortunately the body has two kidneys and, as most people can survive on one, there is a good ‘functional reserve’ of kidney tissue.

Symptoms Many patients with kidney disorders do not have any symptoms, even when the condition is quite advanced. However,

others experience loin pain associated with obstruction (renal colic) or due to infection; fevers; swelling (oedema), usually of the legs but occasionally including the face and arms; blood in the urine (haematuria); and excess quantities of urine (polyuria), including at night (nocturia), due to failure of normal mechanisms in the kidney for concentrating urine. Patients with chronic renal failure often have very di?use symptoms including nausea and vomiting, tiredness due to ANAEMIA, shortness of breath, skin irritation, pins and needles (paraesthesia) due to damage of the peripheral nerves (peripheral neuropathy), and eventually (rarely seen nowadays) clouding of consciousness and death.

Signs of kidney disease include loin tenderness, enlarged kidneys, signs of ?uid retention, high blood pressure and, in patients with end-stage renal failure, pallor, pigmentation and a variety of neurological signs including absent re?exes, reduced sensation, and a coarse ?apping tremor (asterixis) due to severe disturbance of the body’s normal metabolism.

Renal failure Serious kidney disease may lead to impairment or failure of the kidney’s ability to ?lter waste products from the blood and excrete them in the urine – a process that controls the body’s water and salt balance and helps to maintain a stable blood pressure. Failure of this process causes URAEMIA – an increase in urea and other metabolic waste products – as well as other metabolic upsets in the blood and tissues, all of which produce varying symptoms. Failure can be sudden or develop more slowly (chronic). In the former, function usually returns to normal once the underlying cause has been treated. Chronic failure, however, usually irreparably reduces or stops normal function.

Acute failure commonly results from physiological shock following a bad injury or major illness. Serious bleeding or burns can reduce blood volume and pressure to the point where blood-supply to the kidney is greatly reduced. Acute myocardial infarction (see HEART, DISEASES OF) or pancreatitis (see PANCREAS, DISORDERS OF) may produce a similar result. A mismatched blood transfusion can produce acute failure. Obstruction to the urine-?ow by a stone (calculus) in the urinary tract, a bladder tumour or an enlarged prostate can also cause acute renal failure, as can glomerulonephritis (see below) and the haemolytic-uraemia syndrome.

HYPERTENSION, DIABETES MELLITUS, polycystic kidney disease (see below) or AMYLOIDOSIS are among conditions that cause chronic renal failure. Others include stone, tumour, prostatic enlargement and overuse of analgesic drugs. Chronic failure may eventually lead to end-stage renal failure, a life-threatening situation that will need DIALYSIS or a renal transplant (see TRANSPLANTATION).

Familial renal disorders include autosomal dominant inherited polycystic kidney disease and sex-linked familial nephropathy. Polycystic kidney disease is an important cause of renal failure in the UK. Patients, usually aged 30–50, present with HAEMATURIA, loin or abdominal discomfort or, rarely, urinary-tract infection, hypertension and enlarged kidneys. Diagnosis is based on ultrasound examination of the abdomen. Complications include renal failure, hepatic cysts and, rarely, SUBARACHNOID HAEMORRHAGE. No speci?c treatment is available. Familial nephropathy occurs more often in boys than in girls and commonly presents as Alport’s syndrome (familial nephritis with nerve DEAFNESS) with PROTEINURIA, haematuria, progressing to renal failure and deafness. The cause of the disease lies in an absence of a speci?c ANTIGEN in a part of the glomerulus. The treatment is conservative, with most patients eventually requiring dialysis or transplantation.

Acute glomerulonephritis is an immune-complex disorder due to entrapment within glomerular capillaries of ANTIGEN (usually derived from B haemolytic streptococci – see STREPTOCOCCUS) antibody complexes initiating an acute in?ammatory response (see IMMUNITY). The disease affects children and young adults, and classically presents with a sore throat followed two weeks later by a fall in urine output (oliguria), haematuria, hypertension and mildly abnormal renal function. The disease is self-limiting with 90 per cent of patients spontaneously recovering. Treatment consists of control of blood pressure, reduced ?uid and salt intake, and occasional DIURETICS and ANTIBIOTICS.

Chronic glomerulonephritis is also due to immunological renal problems and is also classi?ed by taking a renal biopsy. It may be subdivided into various histological varieties as determined by renal biospy. Proteinuria of various degrees is present in all these conditions but the clinical presentations vary, as do their treatments. Some resolve spontaneously; others are treated with steroids or even the cytotoxic drug CYCLOPHOSPHAMIDE or the immunosuppressant cyclosporin. Prognoses are generally satisfactory but some patients may require renal dialysis or kidney transplantation – an operation with a good success rate.

Hydronephrosis A chronic disease in which the kidney becomes greatly distended with ?uid. It is caused by obstruction to the ?ow of urine at the pelvi-ureteric junction (see KIDNEYS – Structure). If the ureter is obstructed, the ureter proximal to the obstruction will dilate and pressure will be transmitted back to the kidney to cause hydronephrosis. Obstruction may occur at the bladder neck or in the urethra itself. Enlargement of the prostate is a common cause of bladder-neck obstruction; this would give rise to hypertrophy of the bladder muscle and both dilatation of the ureter and hydronephrosis. If the obstruction is not relieved, progressive destruction of renal tissue will occur. As a result of the stagnation of the urine, infection is probable and CYSTITIS and PYELONEPHRITIS may occur.

Impaired blood supply may be the outcome of diabetes mellitus and physiological shock, which lowers the blood pressure, also affecting the blood supply. The result can be acute tubular necrosis. POLYARTERITIS NODOSA and SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) may damage the large blood vessels in the kidney. Treatment is of the underlying condition.

Infection of the kidney is called pyelonephritis, a key predisposing factor being obstruction of urine ?ow through the urinary tract. This causes stagnation and provides a fertile ground for bacterial growth. Acute pyelonephritis is more common in women, especially during pregnancy when bladder infection (CYSTITIS) spreads up the ureters to the kidney. Symptoms are fever, malaise and backache. Antibiotics and high ?uid intake are the most e?ective treatment. Chronic pyelonephritis may start in childhood as a result of congenital deformities that permit urine to ?ow up from the bladder to the kidney (re?ux). Persistent re?ux leads to recurrent infections causing permanent damage to the kidney. Specialist investigations are usually required as possible complications include hypertension and kidney failure.

Tumours of the kidney are fortunately rare. Non-malignant ones commonly do not cause symptoms, and even malignant tumours (renal cell carcinoma) may be asymptomatic for many years. As soon as symptoms appear – haematuria, back pain, nausea, malaise, sometimes secondary growths in the lungs, bones or liver, and weight loss – urgent treatment including surgery, radiotherapy and chemotherapy is necessary. This cancer occurs mostly in adults over 40 and has a hereditary element. The prognosis is not good unless diagnosed early. In young children a rare cancer called nephroblastoma (Wilm’s tumour) can occur; treatment is with surgery, radiotherapy and chemotherapy. It may grow to a substantial size before being diagnosed.

Cystinuria is an inherited metabolic defect in the renal tubular reabsorption of cystine, ornithine, lysine and arginine. Cystine precipitates in an alkaline urine to form cystine stones. Triple phosphate stones are associated with infection and may develop into a very large branching calculi (staghorn calculi). Stones present as renal or ureteric pain, or as an infection. Treatment has undergone considerable change with the introduction of MINIMALLY INVASIVE SURGERY (MIS) and the destruction of stone by sound waves (LITHOTRIPSY).... kidneys, diseases of

Conditions of the tongue At rest, the TONGUE touches all the lower teeth and is slightly arched from side to side. It has a smooth surface with a groove in the middle and an even but de?nite edge. It is under voluntary control and the tip can be moved in all directions.

Ankyloglossia or tongue-tie is a rare disorder in which the frenum or band connecting the lower surface of the tongue to the ?oor of the mouth is so short or tight that the tongue cannot be protruded. Surgery can remedy the defect. It is easy to overdiagnose and is not a common cause of di?culty in feeding at birth or speech defects in infancy.

Gross enlargement of the tongue can make speech indistinct or make swallowing and even breathing di?cult. This is known as macroglossia and may be such that the tongue is constantly protruded from the mouth. The cause may be CONGENITAL, as in severe cases of DOWN’S (DOWN) SYNDROME, or it may occur as a result of ACROMEGALY or be due to abnormal deposits as in AMYLOIDOSIS.

A marked tremor of the tongue when protruded may be seen in various neurological diseases, but may be caused by alcoholism.

After a STROKE involving the motor nerve centre, the control of one side of the tongue musculature will be lost. This will result in the protruded tongue pointing to the side of the body which is paralysed. The sense of taste on one side of the tongue may also be lost in some diseases of the brain and facial nerve.

The presence of fur on the tongue may be obvious and distressing. This is due to thickening of the super?cial layers of the tongue which may appear like hairs which trap food debris and become discoloured. Furring is common during fever and as a result of mouth-breathing and smoking.

In some conditions the tongue may appear dry, red and raw (GLOSSITIS). An in?amed beefy tongue is characteristic of pellagra, a disease caused by de?ciency of NICOTINIC ACID in the diet. A magenta-coloured tongue may be seen when there is a lack of RIBOFLAVIN.

Ulcers of the tongue are similar to those elsewhere in the mouth. The most common are aphthous ulcers which are small, red and painful and last for about ten days. They are associated with stress, mild trauma (such as from jagged teeth), and occasionally with folic acid and vitamin B12 de?ciency. Ulcers of the tongue are sometimes found in patients with chronic bowel disease.... tongue, disorders of

n. a *glycoprotein, resembling starch, that is deposited in the internal organs in amyloidosis. ?-amyloid protein has been found in the brains of Alzheimer’s patients but the significance of this is unclear.... amyloid

a dark-red or reddish-brown pigment that becomes blue in acidic conditions. It is used as a histological *stain. *Amyloidosis is indicated if over 60% of the dye disappears from the blood within one hour of injection.... congo red

adj. resembling lard: often applied to tissue infiltrated with the starchlike substance amyloid (see amyloidosis).... lardaceous

An inherited condition that affects certain Sephardic Jewish, Armenian, and Arab families. Its cause is unknown. Symptoms usually begin between the ages of 5 and 15 years, and include recurrent episodes of fever, abdominal and chestpain, and arthritis. Red skin swellings sometimes occur, and affected people may also suffer psychiatric problems. Attacks usually last from 24–48 hours but may be longer. Between attacks there are usually no symptoms. Although there is no specific treatment for familial Mediterranean fever, known sufferers can reduce the incidence of attacks by taking colchicine. Death may eventually occur from amyloidosis, which is a complication of the condition.... familial mediterranean fever

A rare form of arthritis affecting children. Juvenile chronic arthritis occurs more often in girls, and usually develops between 2 and 4 years of age or around puberty. There are 3 main types. Still’s disease (systemic onset juvenile arthritis) starts with fever, rash, enlarged lymph nodes, abdominal pain, and weight loss. These symptoms last for a period of several weeks. Joint pain, swelling, and stiffness may develop after several months. Polyarticular juvenile arthritis causes pain, swelling, and stiffness in many joints. Pauciarticular juvenile arthritis affects 4 joints or fewer.

Possible complications include short stature, anaemia, pleurisy, pericarditis, and enlargement of the liver and spleen. Uveitis may develop, which, if untreated, may damage vision. Rarely, amyloidosis may occur or kidney failure may develop. Diagnosis is based on the symptoms, together with the results of X-rays and blood tests, and is only made if the condition lasts for longer than 3 months.

Treatment may include antirheumatic drugs, corticosteroid drugs, nonsteroidal anti-inflammatory drugs, or aspirin. Splints may be worn to rest inflamed joints and to reduce the risk of deformities. Physiotherapy reduces the risk of muscle wasting and deformities.

The arthritis usually clears up after several years. However, in some children, the condition remains active into adult life.

– kala-azar A form of leishmaniasis that is spread by insects. Kala-azar occurs in parts of Africa, India, the Mediterranean, and South America.... juvenile chronic arthritis

Impaired absorption of nutrients by the lining of the small intestine. Malabsorption may be caused by many conditions, including lactase deficiency, cystic fibrosis, chronic pancreatitis, coeliac disease, Crohn’s disease, amyloidosis, giardiasis, Whipple’s disease, and lymphoma. The removal of some of the small intestine, and certain operations on the stomach, may also result in malabsorption.

Common symptoms are diarrhoea and weight loss; and in severe cases, there may also be malnutrition (see nutritional disorders), vitamin deficiency, mineral deficiency, or anaemia. Diagnosis may be made by tests on faeces, blood tests, barium X-ray examination and jejunal biopsy. In most cases, dietary modifications or supplements are successful in treating the disorder. In severe cases, intravenous infusion of nutrients is needed (see feeding, artificial).... malabsorption

n. inflammation of the membranes that line the chest, abdomen, and joints, with accumulation of fluid in the cavities. Commonly the condition is inherited and intermittent and is termed familial Mediterranean fever. If complicated by infiltration of major organs by a glycoprotein (see amyloidosis) the disease usually proves fatal. Regular administration of colchicine will prevent the attacks in 95% of patients.... polyserositis

Infection, usually by bacteria, of bone and bone marrow. It is relatively rare in developed countries but is more common in children, most often affecting the long arm and leg bones and vertebrae; in adults, it usually affects the pelvis and vertebrae. In acute osteomyelitis, the infection (usually STAPHYLOCOCCUS AUREUS) enters the bloodstream via a skin wound or as a result of infection elsewhere in the body. The infected bone and marrow become inflamed, and pus forms, causing fever, severe pain and tenderness in the bone, and inflammation and swelling of the skin over the affected area.

Prompt treatment over several weeks or months with high doses of antibiotic drugs usually cures acute osteomyelitis. If the condition fails to respond, surgery is performed to expose the bone, clean out areas of infected and dead bone, and drain the pus.

Chronic osteomyelitis may develop if acute osteomyelitis is neglected or fails to respond to treatment; after a compound fracture; or, occasionally, as a result of tuberculosis spreading from another part of the body.

The condition causes constant pain in the affected bone.

Complications include persistent deformity and, in children, arrest of growth in the affected bone.

In the later stages of the disease, amyloidosis may develop.

Chronic osteomyelitis requires surgical removal of all affected bone, sometimes followed by a bone graft; antibiotic drugs are also prescribed.... osteomyelitis

(polyneuropathy, peripheral neuritis) any of a group of disorders affecting the sensory and/or motor nerves in the peripheral nervous system. They tend to start distally, in the fingers and toes, and progress proximally. Symptoms include pins and needles, stabbing pains and a numbness on the sensory side, and weakness of the muscles. The most common causes of peripheral neuropathy are diabetes, alcohol, certain drugs, and such infections as HIV; genetic causes of peripheral neuropathy include amyloidosis and *Charcot-Marie-Tooth disease. The diagnosis may be established by neurophysiological tests, blood tests, and occasionally a nerve biopsy.... peripheral neuropathy