ELDER TIP As the body ages, the cells become more resistant to insulin, thus reducing the older adult’s ability to metabolize glucose. In addition, the release of insulin from the pancreatic beta cells is reduced and delayed. These combined processes result in hyperglycemia. In the older patient, sudden concentrations of glucose cause increased and more prolonged hyperglycemia.
The “other specific types” of DM result from various conditions (such as a genetic defect of the beta cells or endocrinopathies) or from use of or exposure to certain drugs or chemicals. GDM is considered present whenever a patient has any degree of abnormal glucose during pregnancy. This form may result from weight gain and increased levels of estrogen and placental hormones, which antagonize insulin.
Insulin transports glucose into the cell for use as energy and storage as glycogen. It also stimulates protein synthesis and free fatty acid storage in the fat deposits. Insulin deficiency compromises the body tissues’access to essential nutrients for fuel and storage.
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Source: Professional Guide to Diseases (Eighth Edition), 2005
Introduction: Malignant Neoplasms:
What causes cancer?
(Professional Guide to Diseases (Eighth Edition))
Researchers have found that cancer develops from mutations within the genes of cells. Thus, cancer is a genetic disease. Cancer susceptibility genes are of two types. Some are oncogenes, which activate cell division and influence embryonic development, and some are tumor suppressor genes, which halt cell division.
These genes are typically found in normal human cells, but certain kinds of mutations may transform the normal cells. Inherited defects may cause a genetic mutation, whereas exposure to a carcinogen may cause an acquired mutation. Current evidence indicates that carcinogenesis results from a complex interaction of carcinogens and accumulated mutations in several genes.
In animal studies of the ability of viruses to transform cells, some human viruses exhibit carcinogenic potential. For example, the Epstein-Barr virus, the cause of infectious mononucleosis, has been linked to Burkitt's lymphoma and nasopharyngeal cancer.
High-frequency radiation, such as ultraviolet and ionizing radiation, damages the genetic material known as deoxyribonucleic acid (DNA), possibly inducing genetically transferable abnormalities. Other factors, such as a person's tissue type and hormonal status, interact to potentiate radiation's carcinogenic effect. Examples of substances that may damage DNA and induce carcinogenesis include:
❑alkylating agents — leukemia
❑aromatic hydrocarbons and benzopyrene (from polluted air) — lung cancer
❑asbestos — mesothelioma of the lung
❑tobacco — cancer of the lung, oral cavity and upper airways, esophagus, pancreas, kidneys, and bladder
❑vinyl chloride — angiosarcoma of the liver.
Diet has also been implicated, especially in the development of GI cancer as a result of a high animal fat diet. Additives composed of nitrates and certain methods of food preparation — particularly charbroiling — are also recognized factors.
The role of hormones in carcinogenesis is still controversial, but it seems that excessive use of some hormones, especially estrogen, produces cancer in animals. Also, the synthetic estrogen diethylstilbestrol causes vaginal cancer in some daughters of women who were treated with it. It's unclear, however, whether changes in human hormonal balance retard or stimulate cancer development.
Some forms of cancer and precancerous lesions result from genetic predisposition either directly (as in Wilms' tumor and retinoblastoma) or indirectly (in association with inherited conditions such as Down syndrome or immunodeficiency diseases). Expressed as autosomal recessive, X-linked, or autosomal dominant disorders, their common characteristics include:
❑early onset of malignant disease
❑increased incidence of bilateral cancer in paired organs (breasts, adrenal glands, kidneys, and eighth cranial nerve [acoustic neuroma])
❑increased incidence of multiple primary malignancies in nonpaired organs
❑abnormal chromosome complement in tumor cells.
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Diseases (Eighth Edition), 2005
Malignant spinal neoplasms:
Causes and incidence
(Professional Guide to Diseases (Eighth Edition))
Primary tumors of the spinal cord may be extramedullary (occurring outside the spinal cord) or intramedullary (occurring within the cord itself). Extramedullary tumors may be intradural (meningiomas and schwannomas), which account for 60% of all primary malignant spinal cord neoplasms, or extradural (metastatic tumors from breasts, lungs, prostate, leukemia, or lymphomas), which account for 25% of these malignant neoplasms.
Intramedullary tumors, or gliomas (astrocytomas or ependymomas), are comparatively rare, accounting for only about 10%. In children, they're low-grade astrocytomas.
Spinal cord tumors are rare compared with intracranial tumors (ratio of 1:4). They occur equally in men and women, with the exception of meningiomas, which occur mostly in women. Spinal cord tumors can occur anywhere along the length of the cord or its roots.
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Diseases (Eighth Edition), 2005
Pancreatic cancer:
Causes and incidence
(Professional Guide to Diseases (Eighth Edition))
Evidence suggests that pancreatic cancer is linked to inhalation or absorption of the following carcinogens, which are then excreted by the pancreas:
❑cigarettes
❑food additives
❑industrial chemicals, such as beta-naphthalene, benzidine, and urea.
Possible predisposing factors are chronic pancreatitis, diabetes mellitus, and chronic alcohol abuse (both pancreatitis and diabetes mellitus may be early manifestations of the disease as well).
Pancreatic cancer incidence increases with age, peaking between ages 60 and 70. Geographically, the incidence is highest in Israel, the United States, Sweden, and Canada.
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Diseases (Eighth Edition), 2005
Diabetes mellitus:
Causes
(Handbook of Diseases)
The effects of diabetes mellitus result from insulin deficiency. Insulin transports glucose into the cell for use as energy and storage as glycogen. It also stimulates protein synthesis and free fatty acid storage. Insulin deficiency or resistance compromises the body tissues’access to essential nutrients for fuel and storage.
Type 1A results from autoimmune beta-cell destruction, resulting in insulin deficiency. Type 1B leaves these immunologic markers but results in insulin deficiency and kerosis.
Other risk factors include the following:
❑ Obesity contributes to the resistance to endogenous insulin.
❑ Physiologic or emotional stress can cause prolonged elevation of stress hormone levels (cortisol, epinephrine, glucagon, and growth hormone). This raises blood glucose levels, which, in turn, places increased demands on the pancreas.
❑ Pregnancy causes weight gain and increases levels of estrogen and placental hormones, which antagonize insulin.
❑ Some medications can antagonize the effects of insulin, including thiazide diuretics, adrenal corticosteroids, and hormonal contraceptives.
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Source: Handbook of Diseases, 2003
Pancreatic cancer:
Causes
(Handbook of Diseases)
Pancreatic cancer, the fourth leading cause of cancer-related death in the United States, is slightly more common in men than in women; risk increases with age. Almost one-third of cases result from cigarette smoking; some cases are related to hereditary syndromes.
Possible predisposing factors are chronic pancreatitis, diabetes mellitus, and chronic alcohol abuse.
» READ BOOK EXCERPT ONLINE »
Source: Handbook of Diseases, 2003
Pancreatitis:
Causes
(Handbook of Diseases)
The most common causes of pancreatitis are biliary tract disease and alcoholism; however, it can also result from pancreatic cancer, trauma, or certain drugs, such as glucocorticoids, sulfonamides, chlorothiazide, azathioprine, excessive use of acetaminophen, and hormonal contraceptives.
This disease may also develop as a complication of peptic ulcer, mumps, or hypothermia. Rarer causes are stenosis or obstruction of the sphincter of Oddi, hypercalcemia, duodenal obstruction, hyperlipemia, ischemia from vasculitis or vascular disease, viral infections, mycoplasmal pneumonia, scorpion venom, and pregnancy. The disease may also be familial or idiopathic.
AGE ALERT: In children, pancreatitis may coincide with abdominal trauma, cystic fibrosis, hemolytic uremic syndrome, Kawasaki disease, mumps, Reye’s syndrome, viral illness, or medications the child may be taking.
Pancreatitis may also develop in a patient after surgery. This occurrence has the highest morbidity and mortality. Whatever the cause, complications from acute pancreatitis are possible.
CLINICAL TIP: Determining the cause of pancreatitis is useful for managing and predicting complications.
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Source: Handbook of Diseases, 2003
Pancreatic Pseudocyst:
Pancreatic Pseudocyst - risk factors
(The 5-Minute Pediatric Consult)
Acute or chronic pancreatitis
Pancreatic Pseudocyst - pathophysiology
- Pancreatic pseudocysts develop shortly after an attack of acute pancreatitis or insidiously in chronic pancreatitis.
- Disruption in the pancreatic ductular system result in the extravasation of pancreatic enzymes evoking an inflammatory response.
- The inflammatory reaction leads to a fluid collection that is rich in pancreatic enzymes and is termed “acute pancreatic fluid collection” (PFC).
- If the duration of the fluid collection is >4 weeks, becomes localized (intrapancreatic or extrapancreatic), and develops a fibrin capsule, it is called as a “pseudopancreatic cyst.”
- The pseudocyst does not have a true epithelial lining.
- If there is communication between the pseudocyst and the pancreatic duct, the enzyme level in the fluid remains elevated, and if there is no communication, the enzyme level falls with time.
» READ BOOK EXCERPT ONLINE »
Source: The 5-Minute Pediatric Consult, 2008
Pancreatitis:
Pancreatitis - etiology
(The 5-Minute Pediatric Consult)
- Idiopathic (20–25%)
- Trauma:
- Bicycle handle injuries
- Motor vehicle collisions
- Child abuse
- Postoperative:
- Endoscopic retrograde cholangiopancreatography (ERCP)
- Scoliosis surgery
- Transplantation
- Infections:
- Bacterial:
- Viral: Measles, mumps, Epstein-Barr virus, Coxsackie B, rubella, influenza, echovirus, hepatitis A and B
- Parasites (Ascaris lumbricoides, Echinococcus granulosus, Cryptosporidium parvum, Plasmodium falciparum)
- Biliary tract disease:
- Gallstones
- Sclerosing cholangitis
- Congenital anomalies:
- Pancreatic divisum
- Annular pancreas
- Anomalous choledochopancreaticoduodenal junction
- Biliary tract malformations
- Duplication cyst of the duodenum/gastropancreatic/common bile duct
- Metabolic:
- Hyperlipidemia
- Hypercalcemia
- Uremia
- Inborn errors of metabolism
- Systemic disease:
- Shock/Hypoxemia
- Hemolytic uremic syndrome
- Crohn disease
- Celiac disease
- Malnutrition: Anorexia nervosa, bulimia, and refeeding syndrome
- Diabetes mellitus
- Mitochondropathy
- Hemochromatosis
- Vasculitis: Systemic lupus erythematosus (SLE), Henoch-Schönlein purpura, Kawasaki disease
- Drugs: L-asparaginase, azathioprine/6-MP, mesalamine, sulfonamides, thiazides, furosemide, tetracyclines, valproic acid, corticosteroids, estrogens, procainamide, ethacrynic acid, and others
- Toxins:
- Alcohol, organophosphates, scorpion poison, snake poison
- Hereditary:
- Cystic fibrosis: CFTR mutations
» READ BOOK EXCERPT ONLINE »
Source: The 5-Minute Pediatric Consult, 2008
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