Virulence is the ability to (1) invade the host, (2) cause disease, and (3) evade host defenses.
Virulence factors help bacteria to (1) invade the host, (2) cause disease, and (3) evade host defenses. The following are types of virulence factors:
Adherence Factors: Many pathogenic bacteria colonize mucosal sites by using pili (fimbriae) to adhere to cells.
Invasion Factors: Surface components that allow the bacterium to invade host cells can be encoded on plasmids, but more often are on the chromosome.
Capsules: Many bacteria are surrounded by capsules that protect them from opsonization and phagocytosis.
Endotoxins: The lipopolysaccharide endotoxins on Gram-negative bacteria cause fever, changes in blood pressure, inflammation, lethal shock, and many other toxic events.
Exotoxins: Exotoxins include several types of protein toxins and enzymes produced and/or secreted from pathogenic bacteria. Major categories include cytotoxins, neurotoxins, and enterotoxins.
Siderophores: Siderophores are iron-binding factors that allow some bacteria to compete with the host for iron, which is bound to hemoglobin, transferrin, and lactoferrin.
Lung reserve - the additional volume of air that the lungs can inhale and exhale when breathing to the limit of capacity in times of stress
The gastric mucosal barrier is the property of the stomach that allows it to safely contain the gastric acid
The barrier is broken by acetylsalicylic acid (ASA, aspirin) which diffuses back into the mucosa and causes damage to the stomach itself.
The barrier has three components. These provide the additional resistance for the mucosal surface of the stomach. They are :
A compact epithelial cell lining. Cells in the epithelium of the stomach are bound by tight junctions that repel harsh fluids that may injure the stomach lining.
A special mucus covering, derived from mucus secreted by surface epithelial cells and Foveolar cells. This insoluble mucus forms a protective gel-like coating over the entire surface of the gastric mucosa. The mucus protects the gastric mucosa from autodigestion by e.g. pepsin and from erosion by acids and other caustic materials that are ingested.
Bicarbonate ions, secreted by the surface epithelial cells. The bicarbonate ions act to neutralize harsh acids.
Factors that can damage the barrier:
-Bacterial Infection by Helicobacter pylori
Lipolysis /l?'p?l?s?s/ is the breakdown of lipids and involves hydrolysis of triglycerides into glycerol and free fatty acids. The following hormones induce lipolysis: glucagon, epinephrine, norepinephrine, ghrelin, growth hormone, testosterone, and cortisol.
Ammonia is a toxic product of nitrogen metabolism which should be removed from our body. The urea cycle or ornithine cycle converts excess ammonia into urea in the mitochondria of liver cells. The urea forms, then enters the blood stream, is filtered by the kidneys and is ultimately excreted in the urine.
Since 1992, local governance in India takes place in two very distinct forms. Urban localities, covered in the 74th amendment to the Constitution, have Nagar Palika but derive their powers from the individual state governments, while the powers of rural localities have been formalized under the panchayati raj system, under the 73rd amendment to the Constitution. The panchayati raj system is a three-tier system with elected bodies at the village, taluk and district levels
Tuberculosis of the skin
1. Lupus vulgaris
Persistent and progressive form of cutaneous TB
Small sharply defined reddish-brown lesions with a gelatinous consistency (called apple-jelly nodules)
Lesions persist for years, leading to disfigurement and sometimes skin cancer
Skin lesions result from direct extension of underlying TB infection of lymph nodes, bone or joints
Often associated with TB of the lungs
Firm, painless lesions that eventually ulcerate with a granular base
May heal even without treatment but this takes years and leaves unsightly scars
Coarctation of the aorta : a congenital condition where the aorta is narrow, usually where the ductus arteriosus (ligamentum arteriosum ) inserts. Coarctations are most common in the aortic arch. Other heart defects may also occur when coarctation is present, typically occurring on the left side of the heart. When a patient has a coarctation, the left ventricle has to work harder since the aorta is narrowed in order to force enough blood through the aorta. If the narrowing is severe enough, there is lack of blood to the lower half of the body.
Patent ductus arteriosus (PDA) is a condition where the ductus arteriosus fails to close after birth.
Early symptoms are uncommon, but in the first year of life include increased 'work of breathing' and poor weight gain. An uncorrected PDA may lead to congestive heart failure with increasing age.
Coarctation of aorta
Mycobacterium tuberculosis (or Koch's bacillus) is the causative agent for tuberculosis. Tuberculosis is making a come back due to the appearance of multi-resistant strains of the baterium. Pulmonary tuberculosis is the most widespread, but there are bone forms (Pott's disease (in the vertebra), knee, renal, intestinal, genital, meninginal and cutaneous forms (Lupus vulgaris and Scrofuloderma).
The genus Mycobacterium comprises a variety of species : Mycobacterium tuberculosis, M. bovis, M. bovis "bacillus Calmette Guerin", M. africanum, M. microti, M. pinnipedii. The cell wall structure corresponds to the gram-positive bacteria, but with an additional high lipid content with characteristic mycolic acids. The term "acid-proof/acid-fast" is based on the fact that the stained bacteria do not lose the color on washing with a mixture of acid and alcohol; that is they hold to the color fast (fast means strongly)
Usually it is an airborne infection pathogens reach beyond the upper airways in the lungs; the incubation period of six to eight weeks (positive tuberculin skin test = Mx = Mantoux test), but also longer. Approximately five to ten percent of those infected develop an infectious disease. The disease manifests itself in the majority of patients : pulmonary tuberculosis (primary complex), but it can also affect other organs (usually secondary), including the central nervous system. Due to the intake of dairy products contaminated with M.bovis, the intestine is affected. The onset of pulmonary tuberculosis is uncharacteristic, usually characterized by a chronic cough, rarely the sputum is tinged with blood, weight loss, fatigue, low-grade fever, evening rise of temperature, night sweats and other symptoms. Occasionally enlarged lymph nodes in the neck. In the context of immunosuppression (alcohol abuse, HIV, immunosuppressive therapy) may lead to a generalized resettlement of pathogens occurs in other organs including the central nervous system; In a progressive disease, lung nodules decompose and become cheesy: casseous necrosis. It causes caverns (cavities) with destruction of lung tissue particularly in immunocompromised patients, eg Alcoholics or patients of advanced age.
High-dose dexamethasone suppression test
Suppression is absent in patients with Cushing syndrome due to ectopic ACTH secretion or adrenal abnormalities. Suppression is present in patients with Cushing disease.
Cushing syndrome encompasses all causes of glucocorticoid excess, whereas Cushing disease is reserved only for pituitary-dependent Cushing syndrome.
Swan-Ganz catheterization is the passing of a thin tube (catheter) into the right side of the heart and the arteries leading to the lungs. It is done to monitor the heart's function and blood flow and pressures in and around the heart. This test is most often done in people who are very ill.
The pulmonary artery catheter is frequently referred to as a Swan-Ganz catheter, in honor of its inventors Jeremy Swan
Swan Ganz catheter (swahn ganz),
A balloon-tipped flexible catheter commonly used in the treatment of critically ill patients; introduced via a major peripheral vein, usually jugular or subclavian, and floated under pressure waveform guidance, with or without fluoroscopy, sequentially through the right atrium, right ventricle, and pulmonary artery, ultimately to wedge, when the balloon is inflated, in a small arterial branch where the tip measures pressure-transmitted retrograde from the left side of the heart, which is assumed to represent left ventricular end-diastolic pressure; side holes allow measurement of central venous pressure; with the balloon deflated, catheter measures pulmonary artery systolic, diastolic, and mean pressures; also allows infusion via catheter; some catheters are fitted with pacing electrodes.