Chapter 6 Clinical Case Studies & Critical Thinking Questions – Flashcards

Ans: The older person may be at higher risk for poor wound healing, although there is no concrete evidence that impaired would healing is a function of aging. Older adults frequently have chronic conditions that impede would healing; they often take medications that affect would healing; they have a diminished immune system that may interfere with healing; and they have age-related physiologic changes in the skin that include decreased capillary perfusion that may effect wound healing.

Ans: The major role of macrophages in wound healing is to keep the wound free of extraneous debris. For healing to progress, the fibrin clot over the wound must be dissolved and replaced with normal tissue or scar tissue. As the clot is dissolved, macrophages invade the area and clear away debris. Macrophages are the primary phagocyte of debridement. They secrete collagenase, which promotes repair of injured collagen fibers in the wound. They also secrete the following substances that aid in wound healing: fibroblast-activating factor (which stimulates fibroblasts to enter a lesion and synthesize and secrete the collagen precursor procollage); angiogenesis factor (which stimulates vascular endothelial cells to form capillary buds that grow into the lesion); and an unidentified factor that stimulates epithelial cells to grow over and seal the wound surface. As new capillaries grow into the wound, erythrocytes leak into the wound bed. Macrophages engulf and phagocytize them as the scar matures and repair becomes complete

Ans: Neonates have depressed immune function. Their neutrophils and macrophages are not capable of efficient chemotaxis. They are partially deficient in complement, and they have inability to isolate an infection. If the problem is a simple urinary tract infection (UTI), the bacteria can disseminate into the bloodstream, causing septicemia. The bacteria could also cause inflammation of the blood-brain barrier, resulting in a severe case of bacterial meningitis.

Ans: The skin is the body's first line of defense against invasion by pathogens. It serves as an anatomic and biochemical barrier. Destruction of this barrier predisposes an individual to invasion of the underlying tissues by pathogens. Invasion by pathogens initiates an inflammatory response. In massive burn injury, the sites for invasion are immense. The body's defenses are unable to respond to such a massive injury, thereby increasing the risk of invasion.

Ans: The physician can explain how normal flora protect us from microorganisms. Prolonged used of antibiotic medications can increase the production of other microorganism such as candida albicans (yeast0 and Clostridium difficile (bacteria). Prolonged antibiotic treatment can also decrease the production of Lactobacillus, which would put a person at risk for urologic or vaginal infections.

Ans: Once the injury has taken place, heat and redness occurs because of more blood flow to the injured site. When the exudate accumulates, the area begins to swell. When pressure builds up in the area due to the exudates and prostaglandins, and bradykinin appear at the site, pain results.

Ans: During acute inflammation, heat, swelling, redness, and pain normally appear and follow a trajectory of healing in less than 2 weeks. However, if the wound has not resolved within 2 weeks, it is classified as chronic inflammation. This includes and drainage of pus from the wound.

Ans: Prevent infection of the injured tissue Exp: If the epithelial barrier is damaged, a highly efficient local and systemic response (inflammation) is mobilized to limit the extent of damage, protect against infection, and initiate repair of the damaged tissue.

Ans: Clostridium difficile Exp: The normal intestinal flora can be altered by prolonged antibiotic treatment, decreasing its protective activity, and leading to overgrowth of other microorganisms, such as the yeast C. albicans or the bacerium C. difficile.

Ans: Increased capillary permeability Exp: The increased flow and capillary permeability result in leakage from the vessels, causing swelling (edema) in the surrounding tissue.

Ans: Vasodilation Exp: The increased blood flow and increasing concentration of red cells at the site of inflammation cause locally increased warmth and redness.

Ans: Coagulation Exp: The clotting (coagulation) system is a group of plasma proteins that form a fibrinous meshwork at an injured or inflamed site. This (1) prevents the spread of infection to adjacent tissues, (2) traps microorganisms and foreign bodies at the site of inflammation for removal by infiltrating cells (e.g. neutrophils and macrophages), (3) forms a clot that stops bleeding, and (4) provides a framework for future repair and healing.

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Ans: It directs leukocytes to the inflamed area. Exp: Two chemotactic factors, neutrophil chemotactic factor and ECF-A, are also released during mast cell degranulation. Neutrophil chemotatic factor attracts neutrophils, and ECF-A attracts eosinophils to the site of inflammation.

Ans: inhibited Exp: Binding of histamine to the H1 receptor is essentially proinflammatory, that is, it promotes inflammation. On the other hand, binding to the H2 receptor is generally anti-inflammatory because it results in suppression of leukocytes function.

Ans: Antagonistic Exp: Both types of receptors are distributed among many different cells and are often present on the same cells and may act in an antagonistic fashion. For instance, neutrophils express both types of receptors, with stimulation of H1 receptors resulting in the augmentation of neutrophil chemotaxis, and H2 stimulation resulting in its inhibition.

Ans: Prostaglandins and bradykinin Exp: The primary kinin produced from the kinin system is bradykinin, which causes dilation of blood vessels, acts with prostaglandins to stimulate nerve endings and induce pain, causes smooth muscle cell contraction, increases vascular permeability, and may increase leukocyte chemotaxis.

Ans: Platelet-activating factor (PAF) Exp: The biologic activity of PAF is virtually identical to that of leukotrienes, namely causing endothelial cell retraction to increase vascular permeability, leukocyte adhesion to endothelial cells, and platelet activation.

Ans: It decreases mast cell function and decreases platelet aggregation. Exp: Effects of NO on inflammation include vasodilation by inducing relaxation of vascular smooth muscle, a response that is local and short-lived, and suppression of mast cell function as well as platelet adhesion and aggregation.

Ans: Recognition, engulfment, fusion, destruction Exp: Once the phagocytic cell enters the inflammatory site, the process of phagocytosis involves the following steps: (1) opsonization, recognition of the target and adherence of the phagocyte to it, (2) engulfment (ingestion or endocytosis) and formation of phagosome, (3) fusion with lysosomal granules within the phagocyte (phagolysosome), and (4) destruction of the target.

Ans: Neutrophils Exp: Neutrophils are the predominant phagocytes in the early inflammatory site, arriving within 6 to 12 hours after the initial injury, where they ingest (phagocytose) bacteria, dead cells, and cellular debris.

Ans: Monocytes Exp: The next phagocytes on the scene are monocytes and macrophages, which perform many of the same functions as neutrophils but for longer time and in a later stage of the inflammatory response.

Ans: Eosinophils release histaminase that limits the effects of histamine during acute inflammation Exp: Eosinophil lysosomes contain several enzymes that degrade vasoactive molecules, thereby controlling the vascular effects of inflammation. These enzymes include histaminase, which mediates the degradation of histamine, and arylsulfatase B, which mediates the degradation of some of the lipid-derived mediators produced by mast cells.

Ans: Eliminate malignant cells Exp: The main function of NK cells is recognition and elimination of cells infected with viruses, although they are also somewhat effective at elimination of other abnormal host cells, specifically cancer cells.

Ans: Fever and leukocytosis Exp: The three primary systemic changes associated with the acute infammatory response are fever, leukocytosis (a transient increase in circulating leukocytes), and increased levels in circulating plasma proteins.

Ans: Endogenous pyrogens acting Exp: These fever-causing cytokines are known as endogenous pyrogens to differentiate them from pathogen-produced exogenous pyrogens. Pyrogens act directly on the hypothalamus, the port of the brain that controls the body's thermostat.

Ans: Normal Saline Exp: Normal saline is the most innocuous solution that can be used to cleanse or irrigate a wound that is healing primarily by epithelialization.

Ans: Underlying chronic illness(es) Exp: In some cases, impaired healing is not directly associated with aging in general but can instead be linked to a chronic illness such as a cardiovascular disease or diabetes mellitus