Obesity / Over-Weight & Under-Weight:

Obesity / Over-Weight / Under-Weight:

Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems.^[1][2] Body mass index (BMI), a measurement which compares weight and height, defines people as overweight (pre-obese) if their BMI is between 25 kg/m² and 30 kg/m², and obese when it is greater than 30 kg/m².^[3]

Obesity increases the likelihood of various diseases, particularly heart disease, type 2 diabetes, breathing difficulties during sleep, certain types of cancer, and osteoarthritis.^[2] Obesity is most commonly caused by a combination of excessive dietary calories, lack of physical activity, and genetic susceptibility, although a few cases are caused primarily by genes, endocrine disorders, medications or psychiatric illness. Evidence to support the view that some obese people eat little yet gain weight due to a slow metabolism is limited; on average obese people have a greater energy expenditure than their thin counterparts due to the energy required to maintain an increased body mass.^[4][5]

Dieting and physical exercise are the mainstays of treatment for obesity. Moreover, it it important to improve diet quality by reducing the consumption of energy-dense foods such as those high in fat and sugars, and by increasing the intake of dietary fiber (Bhargava and Guthrie, 2002; Bhargava, 2006). To supplement this, or in case of failure, anti-obesity drugs may be taken to reduce appetite or inhibit fat absorption. In severe cases, surgery is performed or an intragastric balloon is placed to reduce stomach volume and/or bowel length, leading to earlier satiation and reduced ability to absorb nutrients from food.^[6][7]

Obesity is a leading preventable cause of death worldwide, with increasing prevalence in adults and children, and authorities view it as one of the most serious public health problems of the 21st century.^[8] Obesity is stigmatized in much of the modern world (particularly in the Western world), though it was widely perceived as a symbol of wealth and fertility at other times in history, and still is in some parts of the world.^[2][9]

Classification

Main article: Classification of obesity

Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health.^[1] It is defined by body mass index (BMI) and further evaluated in terms of fat distribution via the waist–hip ratio and total cardiovascular risk factors.^[10][11] BMI is closely related to both percentage body fat and total body fat.^[12]

 

A “super obese” male with a BMI of 47 kg/m²: weight 146 kg (322 lb), height 177 cm (5 ft 10 in)

In children, a healthy weight varies with age and sex. Obesity in children and adolescents is defined not as an absolute number, but in relation to a historical normal group, such that obesity is a BMI greater than the 95th percentile.^[13] The reference data on which these percentiles are based are from 1963 to 1994, and thus have not been affected by the recent increases in weight.^[14]

BMI	Classification
< 18.5	underweight
18.5–24.9	normal weight
25.0–29.9	overweight
30.0–34.9	class I obesity
35.0–39.9	class II obesity
≥ 40.0	class III obesity

BMI is calculated by dividing the subject’s mass by the square of his or her height, typically expressed either in metric or US “customary” units:

Metric: BMI = kilograms / meters²

US customary and imperial: BMI = lb * 703 / in²

where lb is the subject’s weight in pounds and in is the subject’s height in inches.

The most commonly used definitions, established by the World Health Organization (WHO) in 1997 and published in 2000, provide the values listed in the table at right.^[3]

Some modifications to the WHO definitions have been made by particular bodies. The surgical literature breaks down “class III” obesity into further categories whose exact values are still disputed.^[15]

• Any BMI ≥ 35 or 40 is severe obesity
• A BMI of ≥ 35 or 40–44.9 or 49.9 is morbid obesity
• A BMI of ≥ 45 or 50 is super obese

As Asian populations develop negative health consequences at a lower BMI than Caucasians, some nations have redefined obesity; the Japanese have defined obesity as any BMI greater than 25^[16] while China uses a BMI of greater than 28.^[17]

 

Effects on health

Excessive body weight is associated with various diseases, particularly cardiovascular diseases, diabetes mellitus type 2, obstructive sleep apnea, certain types of cancer, and osteoarthritis.^[2] As a result, obesity has been found to reduce life expectancy.^[2]

Mortality

Relative risk of death for men (left) and women (right) in the United States by BMI.[18]

Obesity is one of the leading preventable causes of death worldwide.^[8][19][20] Large-scale American and European studies have found that mortality risk is lowest at a BMI of 22.5–25 kg/m^2[21] in non-smokers and at 24–27 kg/m² in current smokers, with risk increasing along with changes in either direction.^[22][23] A BMI above 32 has been associated with a doubled mortality rate among women over a 16-year period.^[24] In the United States obesity is estimated to cause an excess 111,909 to 365,000 death per year,^[2][20] while 1 million (7.7%) of deaths in the European Union are attributed to excess weight.^[25][26] On average, obesity reduces life expectancy by six to seven years:^[2][27] a BMI of 30–35 reduces life expectancy by two to four years,^[21] while severe obesity (BMI > 40) reduces life expectancy by 10 years.^[21]

 

 

See also

• Maternal obesity

Notes

1. ^ ^{a b} WHO 2000 p.6
2. ^ ^{a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai} Haslam DW, James WP (2005). “Obesity”. Lancet 366 (9492): 1197–209. doi:10.1016/S0140-6736(05)67483-1. PMID 16198769.
3. ^ ^{a b} WHO 2000 p.9
4. ^ Kushner, Robert (2007). Treatment of the Obese Patient (Contemporary Endocrinology). Totowa, NJ: Humana Press. pp. 158. ISBN 1-59745-400-1. http://books.google.com/?id=vWjK5etS7PMC&pg=PA121&lpg=PA121&dq=measurement+of+metabolism+in+obese+Bessesen. Retrieved April 5, 2009.
5. ^ ^{a b} Adams JP, Murphy PG (July 2000). “Obesity in anaesthesia and intensive care”. Br J Anaesth 85 (1): 91–108. doi:10.1093/bja/85.1.91. PMID 10927998. http://bja.oxfordjournals.org/cgi/content/full/85/1/91.
6. ^ NICE 2006 p.10–11
7. ^ ^{a b} Imaz I, Martínez-Cervell C, García-Alvarez EE, Sendra-Gutiérrez JM, González-Enríquez J (July 2008). “Safety and effectiveness of the intragastric balloon for obesity. A meta-analysis”. Obes Surg 18 (7): 841–6. doi:10.1007/s11695-007-9331-8. PMID 18459025.
8. ^ ^{a b} Barness LA, Opitz JM, Gilbert-Barness E (December 2007). “Obesity: genetic, molecular, and environmental aspects”. Am. J. Med. Genet. A 143A (24): 3016–34. doi:10.1002/ajmg.a.32035. PMID 18000969.
9. ^ ^{a b c d e} Woodhouse R (2008). “Obesity in art: A brief overview”. Front Horm Res 36: 271–86. doi:10.1159/000115370. ISBN 9783805584296. PMID 18230908. http://books.google.com/?id=nXRU4Ea1aMkC&pg=PA271&lpg=PA271&dq=Obesity+in+art:+a+brief+overview.
10. ^ Sweeting HN (2007). “Measurement and definitions of obesity in childhood and adolescence: A field guide for the uninitiated”. Nutr J 6: 32. doi:10.1186/1475-2891-6-32. PMID 17963490. PMC 2164947. http://www.nutritionj.com/content/6/1/32.

 

Colon Cancer

Colon Cancer (Colorectal Cancer):

Colorectal cancer, also called colon cancer or large bowel cancer, includes cancerous growths in the colon, rectum and appendix. With 655,000 deaths worldwide per year, it is the fourth most common form of cancer in the United States and the third leading cause of cancer-related death in the Western world.^[1][2] Colorectal cancers arise from adenomatous polyps in the colon. These mushroom-shaped growths are usually benign, but some develop into cancer over time. Localized colon cancer is usually diagnosed through colonoscopy.

Invasive cancers that are confined within the wall of the colon (TNM stages I and II) are curable with surgery. If untreated, they spread to regional lymph nodes (stage III), where up to 73% are curable by surgery and chemotherapy. Cancer that metastasizes to distant sites (stage IV) is usually not curable, although chemotherapy can extend survival, and in rare cases, surgery and chemotherapy together have seen patients through to a cure.^[3] Radiation is used with rectal cancer.

On the cellular and molecular level, colorectal cancer starts with a mutation to the Wnt signaling pathway. When Wnt binds to a receptor on the cell, that sets in motion a chain of molecular events that ends with β-catenin moving into the nucleus and activating a gene on DNA. In colorectal cancer, genes along this chain are damaged. Usually, a gene called APC, which is a “brake” on the Wnt pathway, is damaged. Without a working APC brake, the Wnt pathway is stuck in the “on” position.^[3]

 

Signs and symptoms

The symptoms of colorectal cancer depend on the location of tumor in the bowel, and whether it has spread elsewhere in the body (metastasis). Most of the symptoms may occur in other diseases as well, and hence none of the symptoms mentioned here is diagnostic of colorectal cancer. Symptoms and signs are divided into local, constitutional (affecting the whole body) and metastatic (caused by spread to other organs).

Local

Local symptoms are more likely if the tumor is located closer to the anus. There may be a change in bowel habit (new-onset constipation or diarrhea in the absence of another cause), and a feeling of incomplete defecation (rectal tenesmus) and reduction in diameter of stool; tenesmus and change in stool shape are both characteristic of rectal cancer. Lower gastrointestinal bleeding, including the passage of bright red blood in the stool, may indicate colorectal cancer, as may the increased presence of mucus. Melena, black stool with a tarry appearance, normally occurs in upper gastrointestinal bleeding (such as from a duodenal ulcer), but is sometimes encountered in colorectal cancer when the disease is located in the beginning of the large bowel.

A tumor that is large enough to fill the entire lumen of the bowel may cause bowel obstruction. This situation is characterized by constipation, abdominal pain, abdominal distension and vomiting. This occasionally leads to the obstructed and distended bowel perforating and causing peritonitis. A large left colonic tumour may compress the left ureter and cause hydronephrosis.

Certain local effects of colorectal cancer occur when the disease has become more advanced. A large tumor is more likely to be noticed on feeling the abdomen, and it may be noticed by a doctor on physical examination. The disease may invade other organs, and may cause blood or air in the urine (invasion of the bladder) or vaginal discharge (invasion of the female reproductive tract).

Constitutional

If a tumor has caused chronic occult bleeding, iron deficiency anemia may occur; this may be experienced as fatigue, palpitations and noticed as pallor (pale appearance of the skin). Colorectal cancer may also lead to weight loss, generally due to a decreased appetite.

More unusual constitutional symptoms are an unexplained fever and one of several paraneoplastic syndromes. The most common paraneoplastic syndrome is thrombosis, usually deep vein thrombosis.

 

 

See also

• Hereditary nonpolyposis colorectal cancer
• Diet and cancer
• Bowel & Cancer Research
• Mouse models of colorectal and intestinal cancer

References

1. ^ “Cancer”. World Health Organization. February 2006. http://www.who.int/mediacentre/factsheets/fs297/en/. Retrieved 24 May 2007.
2. ^ “Cancer”. National Cancer Institute. 2009. http://www.cancer.gov/cancertopics/commoncancers.
3. ^ ^{a b c d e f} Markowitz SD, Bertagnolli MM (December 2009). “Molecular basis of colorectal cancer”. N. Engl. J. Med. 361 (25): 2449–60. doi:10.1056/NEJMra0804588. PMID 20018966.
4. ^ Levin KE, Dozois RR (1991). “Epidemiology of large bowel cancer”. World J Surg 15 (5): 562–7. doi:10.1007/BF01789199. PMID 1949852.
5. ^ Penn State University health and disease information
6. ^ Strate LL, Syngal S (April 2005). “Hereditary colorectal cancer syndromes”. Cancer Causes Control 16 (3): 201–13. doi:10.1007/s10552-004-3488-4. PMID 15947872.
7. ^ American Cancer Society Smoking Linked to Increased Colorectal Cancer Risk – New Study Links Smoking to Increased Colorectal Cancer Risk 6 December 2000
8. ^ ‘Smoking Ups Colon Cancer Risk’ at Medline Plus
9. ^ Chao A, Thun MJ, Connell CJ, et al. (January 2005). “Meat consumption

 

 

 

Hepatitis

Hepatitis:

Hepatitis (plural hepatitides) is an inflammation of the liver characterized by the presence of inflammatory cells in the tissue of the organ. The name is from the Greek hepar (ἧπαρ), the root being hepat- (ἡπατ-), meaning liver, and suffix -itis, meaning “inflammation” (c. 1727).^[1] The condition can be self-limiting (healing on its own) or can progress to fibrosis (scarring) and cirrhosis.

Hepatitis may occur with limited or no symptoms, but often leads to jaundice, anorexia (poor appetite) and malaise. Hepatitis is acute when it lasts less than six months and chronic when it persists longer. A group of viruses known as the hepatitis viruses cause most cases of hepatitis worldwide, but it can also be due to toxins (notably alcohol, certain medications and plants), other infections and autoimmune diseases.

 

 

Signs and symptoms

[edit] Acute

Initial features are of nonspecific flu-like symptoms, common to almost all acute viral infections and may include malaise, muscle and joint aches, fever, nausea or vomiting, diarrhea, and headache. More specific symptoms, which can be present in acute hepatitis from any cause, are: profound loss of appetite, aversion to smoking among smokers, dark urine, yellowing of the eyes and skin (i.e., jaundice) and abdominal discomfort. Physical findings are usually minimal, apart from jaundice in a third and tender hepatomegaly (swelling of the liver) in about 10%. Some exhibit lymphadenopathy (enlarged lymph nodes, in 5%) or splenomegaly (enlargement of the spleen, in 5%).^[2]

Acute viral hepatitis is more likely to be asymptomatic in younger people. Symptomatic individuals may present after convalescent stage of 7 to 10 days, with the total illness lasting 2 to 6 weeks.^[3]

A small proportion of people with acute hepatitis progress to acute liver failure, in which the liver is unable to clear harmful substances from the circulation (leading to confusion and coma due to hepatic encephalopathy) and produce blood proteins (leading to peripheral edema and bleeding). This may become life-threatening and occasionally requires a liver transplant.

[edit] Chronic

Chronic hepatitis often leads nonspecific symptoms such as malaise, tiredness and weakness, and often leads to no symptoms at all. It is commonly identified on blood tests performed either for screening or to evaluate nonspecific symptoms. The occurrence of jaundice indicates advanced liver damage. On physical examination there may be enlargement of the liver.^[4]

Extensive damage and scarring of liver (i.e. cirrhosis) leads to weight loss, easy bruising and bleeding tendencies, peripheral edema (swelling of the legs) and accumulation of ascites (fluid in the abdominal cavity). Eventually, cirrhosis may lead to various complications: esophageal varices (enlarged veins in the wall of the esophagus that can cause life-threatening bleeding) hepatic encephalopathy (confusion and coma) and hepatorenal syndrome (kidney dysfunction).

Acne, abnormal menstruation, lung scarring, inflammation of the thyroid gland and kidneys may be present in women with autoimmune hepatitis.^[4]

 

 

Alcoholic hepatitis

Main article: Alcoholic hepatitis

Ethanol, mostly in alcoholic beverages, is a significant cause of hepatitis. Usually alcoholic hepatitis comes after a period of increased alcohol consumption. Alcoholic hepatitis is characterized by a variable constellation of symptoms, which may include feeling unwell, enlargement of the liver, development of fluid in the abdomen ascites, and modest elevation of liver blood tests. Alcoholic hepatitis can vary from mild with only liver test elevation to severe liver inflammation with development of jaundice, prolonged prothrombin time, and liver failure. Severe cases are characterized by either obtundation (dulled consciousness) or the combination of elevated bilirubin levels and prolonged prothrombin time; the mortality rate in both categories is 50% within 30 days of onset.

Alcoholic hepatitis is distinct from cirrhosis caused by long term alcohol consumption. Alcoholic hepatitis can occur in patients with chronic alcoholic liver disease and alcoholic cirrhosis. Alcoholic hepatitis by itself does not lead to cirrhosis, but cirrhosis is more common in patients with long term alcohol consumption. Patients who drink alcohol to excess are also more often than others found to have hepatitis C.^{[citation needed]} The combination of hepatitis C and alcohol consumption accelerates the development of cirrhosis.

 

Non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the occurrence of fatty liver in people who have no history of alcohol use. It is most commonly associated with obesity (80% of all obese people have fatty liver). It is more common in women. Severe NAFLD leads to inflammation, a state referred to as non-alcoholic steatohepatitis (NASH), which on biopsy of the liver resembles alcoholic hepatitis (with fat droplets and inflammatory cells, but usually no Mallory bodies).

The diagnosis depends on medical history, physical exam, blood tests, radiological imaging and sometimes a liver biopsy. The initial evaluation to identify the presence of fatty infiltration of the liver is medical imaging, including such ultrasound, computed tomography (CT), or magnetic resonance (MRI). However, imaging cannot readily identify inflammation in the liver. Therefore, the differentiation between steatosis and NASH often requires a liver biopsy. It can also be difficult to distinguish NASH from alcoholic hepatitis when the patient has a history of alcohol consumption. Sometimes in such cases a trial of abstinence from alcohol along with follow-up blood tests and a repeated liver biopsy are required.

NASH is becoming recognized as the most important cause of liver disease second only to hepatitis C in numbers of patients going on to cirrhosis.^{[citation needed]}

Ischemic hepatitis

Main article: Ischemic hepatitis

Ischemic hepatitis is caused by decreased circulation to the liver cells. Usually this is due to decreased blood pressure (or shock), leading to the equivalent term “shock liver”. Patients with ischemic hepatitis are usually very ill due to the underlying cause of shock. Rarely, ischemic hepatitis can be caused by local problems with the blood vessels that supply oxygen to the liver (such as thrombosis, or clotting of the hepatic artery which partially supplies blood to liver cells). Blood testing of a person with ischemic hepatitis will show very high levels of transaminase enzymes (AST and ALT), which may exceed 1000 U/L. The elevation in these blood tests is usually transient (lasting 7 to 10 days). It is rare that liver function will be affected by ischemic hepatitis.

See also

• World Hepatitis Day
• Hepatocellular carcinoma

References

1. ^ Online Etymology Dictionary
2. ^ Ryder S, Beckingham I (2001). “ABC of diseases of liver, pancreas, and biliary system: Acute hepatitis”. BMJ 322 (7279): 151–153. doi:10.1136/bmj.322.7279.151. PMID 11159575.
3. ^ ^{a b} V.G. Bain and M. Ma, Acute Viral Hepatitis, Chapter 14, First principle of gastroenterology (an online text book)
4. ^ ^{a b} Chronic hepatitis at Merck Manual of Diagnosis and Therapy Home Edition
5. ^ Figure 7.12 (Some causes of acute parenchymal damage), Parveen, M.D.

 

 

 

 

 

Pneumonia

PNEUMONIA:

Pneumonia is an inflammatory condition of the lung.^[1] It is often characterized as including inflammation of the parenchyma of the lung (that is, the alveoli) and abnormal alveolar filling with fluid (consolidation and exudation).^[2]

The alveoli are microscopic air filled sacs in the lungs responsible for gas exchange. Pneumonia can result from a variety of causes, including infection with bacteria, viruses, fungi, or parasites, and chemical or physical injury to the lungs. Its cause may also be officially described as unknown when infectious causes have been excluded.

Typical symptoms associated with pneumonia include cough, chest pain, fever, and difficulty in breathing. Diagnostic tools include x-rays and examination of the sputum. Treatment depends on the cause of pneumonia; bacterial pneumonia is treated with antibiotics.

Pneumonia is common, occurring in all age groups, and is a leading cause of death among the young, the old, and the chronically ill.^[3] Vaccines to prevent certain types of pneumonia are available. The prognosis depends on the type of pneumonia, the treatment, any complications, and the person’s underlying health.

 

 

Pneumonia can be caused by microorganisms, irritants and unknown causes. When pneumonias are grouped this way, infectious causes are the most common type. The symptoms of infectious pneumonia are caused by the invasion of the lungs by microorganisms and by the immune system‘s response to the infection. Although more than one hundred strains of microorganism can cause pneumonia, only a few are responsible for most cases. The most common causes of pneumonia are viruses and bacteria. Less common causes of infectious pneumonia are fungi and parasites.

Signs and symptoms

 

Pneumonia fills the lung’s alveoli with fluid, keeping oxygen from reaching the bloodstream. The alveolus on the left is normal, while the alveolus on the right is full of fluid from pneumonia.

 

 

Main symptoms of infectious pneumonia, click play to hear the sounds of an actual Pneumonia Patient.

	Crackles Crackles heard in the lungs of a person with pneumonia using a stethoscope.
Problems listening to this file? See media help.

 

 

People with infectious pneumonia often have a cough producing greenish or yellow sputum, or phlegm and a high fever that may be accompanied by shaking chills. Shortness of breath is also common, as is pleuritic chest pain, a sharp or stabbing pain, either experienced during deep breaths or coughs or worsened by them. People with pneumonia may cough up blood, experience headaches, or develop sweaty and clammy skin. Other possible symptoms are loss of appetite, fatigue, blueness of the skin, nausea, vomiting, mood swings, and joint pains or muscle aches. Less common forms of pneumonia can cause other symptoms; for instance, pneumonia caused by Legionella may cause abdominal pain and diarrhea, while pneumonia caused by tuberculosis or Pneumocystis may cause only weight loss and night sweats. In elderly people, manifestations of pneumonia are seldom typical. They may develop a new or worsening confusion (delirium) or may experience unsteadiness, leading to falls. Infants with pneumonia may have many of the symptoms above, but in many cases they are simply sleepy or have a decreased appetite.^[9]

 

 

See also

• List of pneumonia victims

References

1. ^ pneumonia at eMedicine Dictionary
2. ^ pneumonia at Dorland’s Medical Dictionary
3. ^ “Causes of death in neonates and children under five in the world (2004)”. World Health Organization.. 2008. http://www.who.int/entity/child_adolescent_health/media/causes_death_u5_neonates_2004.pdf.
4. ^ ^{a b c d} Table 13-7 in: Mitchell, Richard Sheppard; Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson (2007). Robbins Basic Pathology (8th ed.). Philadelphia: Saunders. ISBN 1-4160-2973-7.
5. ^ “UpToDate Inc.”. http://www.uptodate.com/online/content/topic.do?topicKey=pedi_id/18313&selectedTitle=1~1&source=search_result.
6. ^ Krause DC, Balish MF (February 2004). “Cellular engineering in a minimal microbe: structure and assembly of the terminal organelle of Mycoplasma pneumoniae”. Mol. Microbiol. 51 (4): 917–24. doi:10.1046/j.1365-2958.2003.03899.x. PMID 14763969.
7. ^ Girard TD, Bernard GR (March 2007). “Mechanical ventilation in ARDS: a state-of-the-art review”. Chest 131 (3): 921–9. doi:10.1378/chest.06-1515. PMID 17356115.