morphologic diagnosis in inflammation Flashcards
what provides clues about the underlying cause
recognizing the gross and microscopic patterns
what is a morphological diagnosis
the way we describe and communicate about lesions
what are the important categories of words to include in your morphologic diagnosis
severity, time course, type of exudate, extent of the lesion, designation of the organ
mild
less than 30% of the organ is affected
moderate
30-60% of the organ is affected
severe
more than 60%
review time course designation
in previous lectures
serous inflammation is characterized by
outpouring of a translucent, thin fluid that may accumulate on a mucosal surface, skin, or in the peritoneal, pleural, and pericardial cavities
serous inflammation usually indicats
the insult is mild
what does serous exudate look like
clear to yellowish fluid that accujulates in a blister or a runny nose in hay fever
serous exudates are usually the result of
mild, transient irritation
serous exudate consists mostly of
serum (or plasma) but protein is high enough to make it an exudate
what is the significance of a serous exudate
may ust be the early phase of a more intense edudate and harbinger of a more serous problem
what is the outcome of a serous exudate
if it doesnt progress to something worse, the fluid is reabsorbed as the inflammation resolves; can progress to fibrinous or hemorrhagic exudate
when does fibrinous exudation occur
in more severe conditins that allow the escape of larger fibrinogen molecules from the vascular system
when fibrinogen reaches the tissue it is converted to
fibrin
prime locations inlude
entire respiratory tract, digestive tract, pleura, periotneum, and pericardium
surface with fibrinous exudate appearance
slightly roughened appearance; dull; granular; yellowish strands present that can be peeled off as fibrin increases
pseudomembrane
thick layering of fibrin that can be peeled away
diphtheric membrane
extensive necrosis of underlying areas so that the fibrin is tightly adhered to the tissue and cant be peeled away
fibrin cast
so much fibrin that it gushes out and forms a large accumulation mimicking the shape of a tubular organ
fibrin casts occur in
every single ntestinal infection (parvovirus, salmonelosis)
what does fibrin look like microscopically
appears as an eosinophilic meshwork of fine strands or as an amorphous dull slightly granular eosinophilic coagulum
whatis the significance of fibrinous inflammation
- prevents excessive blood loss by hemostasis
- protects the underlying tissues from further irritation
- form a framework to allow leukocytes to migrate in and help and later to allow repair to occur
what is the outcome of fibrinous inflammation if not too severe
may resolve without any sequelae; or fibroblasts eventually migrate in and begin organizing the exudate through the generation of fibrous connective tissue
how can this be harmful?
fibrin-covered serosal surfaces may stick to each other (impede gut motility); impede heart or lungs movements
as fibrinous inflammation begins it is refferred to as
organizing
once fibrinous inflammation is fully organized it is referred to as
firbrous tissue
ibrosis or fibrous tissue
is NOT a type of inflammation, it is growth on tnew cells and laying down collagen leading to rpeair
fibrinous means
fibrin is present
fibrous means
laying down of connective tissue (scarring)
fibrin
(fibrinous) acute
fibrous
(fibrosis) chronic
catharrhal exudate
excessive mucus production; used in inflammation in organs where mucus is already being produced
most often associated with mucosal surfaces of
intestinal, reproductive, upper respiratory tracts (places with goblet cells)
catarrhal inflammation appearance
a thin gray-yellow blanket of excess mucus
what does catharral inflammation look like microscopically
thicker than normal coat of mucus on the luminal surface; goblet cells may be more numerous
purulent exudate
an accumulation of dead neutrophils
neutrophils have enzymes that help ______ so the result is a homogenous mass f creamy pus
liquefy the surrounding tissue
another term for purulent inflammation is
suppurative
what does pyogenic bacteria mean
bacteria that produce pus
pyogenic bacteria are strongly chemotactic for
neutrophils
what bacterias are pyogenic bacteria
streptococcus, staphylococcus, truperella pyogenes
if pus is present for a while and the inciting agent is removed, the pus becomes
dry or “inspissated”
almost all cases of pus formation are due to
bacteria
abscess
purulent inflammation is well circumscribed and surrounded by a fibrous wall or capsule
how does purulent exudate appear microscopically
beaucoup neutrophils
what is the significance of purulent inflammation
a prompt and violent reaction against irritants and pathogens; bacteria will be there or HAD been there in 99% of cases
what are the outcomes of purulent inflammation
localized, purulent inflammation can break loose and spread to other areas. (septicemia is spread to blood)
resorption of pus if not spread: fever, and general signs of illness
formation of a fistulous tract to dishcarge to the outside
fibroblasts move in to organize this type of inflammation so there is eventually a scar
abscess are usually formed in response to
a focal bacterial infection
fibrous wall prevents
delivery of antibiotics to the site
hemorrhagic exudate
holes in the blood vessels are large enough that everything comes out so that the appearance of the exudate is very much like clotted blood
hemorrhagic exudate are usually mixed with
serum, fibrin, and leukocytes
what is the significance of hemorrhagic inflammation
usually caused by highly virulent microorganisms or by acute poisoning by certain chemicals; arises quickly and is often fatal; massive damage to endothelium
what is the outcome of hemorrhagic inflammation
often gaurded
mixed exudates
more common
granulomatous exudates
majority of cells are macrophages; done usually ooze so are more termed granulomatous inflammation;
