41 - Inflammation Flashcards
Do u know
review
general knowledge of inflammation
- “To set on fire”
- Cardinal signs - Rubor, calor, tumor, dolor (Celsus) - Functio laesa (Virchow)
- “-itis” = inflammation of
- Component parts:
- Blood vessels - Leukocytes - Chemical mediators
- Acute versus chronic
What are the features of acute inflammation in the vascular system?
- Vascular events:
- Vasodilation (hyperemia)
- Increased capillary permeability (edema)
- Increased viscosity
- Decreased venous drainage (congestion)
- Increased lymphatic flow (lymphangitis)
- Mediated by histamine, nitric oxide
What are the features of acute inflammation in leukocytes?
- Primarily neutrophils
- Neutrophil events:
- Peripheralization
- Attachment to endothelial cells (margination)
- Emigration across vessel wall
- Chemotaxis
- Phagocytosis (opsonization)
- Cell killing
How are microbes engulfed by phagocytes?
What role does inflammation have in tissue injury? (vascular, leukocytes, bacterial killing)
What are the morphological features of acute inflammation?
- Infiltrate of neutrophils (first 24 hours)
- Bacterial infections, ischemic cell injury
- After first 24-48 hours, macrophages become the
more dominant cell - Eosinophils
- Allergic reactions, parasites, asthma, neoplasia,
collagen-vascular diseases
What are the types of inflammatory edema (exudates)?
- Serous
- Fibrinous
- Purulent
- Hemorrhagic
What does serous edema/exudate look like?
Serous edema, also known as serous effusion, refers to the accumulation of a clear, pale-yellow fluid called serous fluid in body cavities or tissues. This condition occurs when there is an imbalance between the production and drainage of serous fluid, leading to its accumulation. Serous fluid is a component of the body’s extracellular fluid and is typically found in the pleural, pericardial, and peritoneal cavities, where it serves to lubricate and reduce friction between tissue layers.
What does fibrinous edema look like?
Fibrinous edema, also known as fibrinous exudate, is a type of edema characterized by the accumulation of fibrin-rich fluid in tissues or body cavities. Edema, in general, refers to the abnormal accumulation of fluid in interstitial spaces or body compartments. Fibrinous edema is unique because it contains a significant amount of fibrin, a fibrous protein involved in blood clotting and wound healing. Fibrin forms a mesh-like structure that traps cells and fluid, contributing to the thick, gelatinous appearance of fibrinous exudate.
What does hemorraghic edema look like?
Hemorrhagic edema, also known as hemorrhagic exudate or hemorrhagic effusion, is a type of edema characterized by the accumulation of blood within tissues or body cavities. Edema is the abnormal buildup of fluid in interstitial spaces or body compartments, and when this fluid is mixed with blood, it leads to hemorrhagic edema.
What does purulent edema look like?
Purulent exudate, also known as purulent discharge or simply pus, is a type of fluid that is typically produced as a result of an infection or inflammation in the body. It is characterized by its thick, yellowish or greenish appearance and consists of dead white blood cells, bacteria, tissue debris, and other inflammatory substances.
What is an ulcer?
- Sloughing of necrotic tissue and inflammatory debris
along the surface of a tissue/organ - May become chronic and associated with fibrosis
What are the outcomes of acute inflammation?
What are the causes of chronic inflammation?
What are the morphological characteristsics of chronic inflammation?
What is granulomatous inflammation?
- Pattern of chronic inflammation
- Inciting stimulus that is difficult to eradicate
- Tuberculosis, fungi, sarcoidosis, foreign bodies
- Morphology
- Localized collections of macrophages (giant cells) +/- central caseous necrosis
- Peripheral rim of lymphocytes and plasma cells
- Rule out infectious etiology
What are the systemic effects of inflammation?
- Fever
- Acute phase reaction
- Leukocytosis
- Other clinical symptoms : rouleaux
Additional common manifestations of the acute inflammation include tachycardia, elevated blood
pressure, decreased sweating (shunting of blood from cutaneous to deep vascular beds), shivering,
chills, decreased appetite, fatigue, and malaise.
What is needed for a fever to occur during inflammation?
Fever develops secondary to stimulation of cells of the hypothalamus by pyrogens, which
may be of bacterial (exogenous) or leukocyte (endogenous) origin. Specifically, hypothalamic cells
upregulate prostaglandin synthesis (PGE2), which stimulates production of cAMP and leads to resetting
of body temperature at a higher level. In view of this mechanism, it is understandable why aspirin and
other non-steroidal anti-inflammatory drugs (that block cyclo-oxygenase activity) have an anti-pyretic
effect. Examples of endogenous pyrogens include interleukin-1 (IL-1) and tumor necrosis factor. In
addition to fever, IL-1 also causes hyperalgesia (increased pain sensitivity), vasodilation and
hypotension.
viral induction of inflammation looks like
Viral infections are generally associated with some degree of suppression of the neutrophil count with a
corresponding increase in the number of lymphocytes. In viral infections (e.g. Epstein-Barr virus), the
lymphocytes often demonstrate “atypical” reactive morphology with increased size and basophilia of
their cytoplasm. The figure below shows two “atypical” viral lymphocytes in a case of infectious
mononucleosis.
leukocytosis induced by inflammation
Leukocytosis or elevation of the white blood cell count (usually neutrophils) typically accompanies acute
inflammation. When this elevation is extreme (>40,000 cells/μL), it is referred to as a leukemoid
reaction, because clinically it may be confused with leukemia. Leukocytosis results initially from
increased release of mature myeloid cells from a storage pool in the bone marrow and then later from
increased production of myeloid cells by the bone marrow. With inflammatory states, myeloid cells are
released at an earlier stage than normal, resulting in increased circulating immature myeloid cells
(bands, metamyelocytes, etc.). This phenomenon is referred to as a left shift. The circulating myeloid
cells often also demonstrate “toxic” features, including prominent granulation, vacuolization, and
formation of basophilic cytoplasmic inclusions called Döhle bodies.
What are acquired neutrophil disorders?
- Neutropenia
- By far the most common cause of an altered inflammatory response
The importance of neutrophils in the acute inflammatory response can be further demonstrated by reviewing several rare, inherited disorders, the pathophysiology of which involves derangements in neutrophil function.
