LAB - Infectious Disease A, B, C, and D Flashcards
Acute appendicitis: what changes are seen? (4) what layers are found in the normal appendix? (5)
Changes:
- -Infiltration of neutrophils: can extend from mucosa all the way down to serosa
- -Ulceration of mucosa
- -Subserosal edema (white space between muscularis and serosa) with infiltration of neutrophils (and sometimes eosinophils)
- -Edema/infiltrate pulling apart muscularis layer, infiltrating in between muscle layers
Layers: Mucosa (normally has some lymphocytes) Submucosa Submucosal fat Muscularis Serosa: thin layer of flattened/low cuboidal cells
Acute pyelonephritis: what can cause this? what changes are seen? (7)
Causes: ascension of a bacterial infection from the bladder
Changes:
- -Hypercellular, blue stripes/bands seen at low power
- -Leukocytes in interstitium (between tubules, glomeruli, vascular elements)
- -Tissue elements in stripes harder to recognize because of necrosis
- -See lakes of NEUTROPHILS, MOs, necrotic debris
- -Tubules filled with neutrophils, killed off
- -Bacteria seen as basophilic haze
- -Creation of pus-filled abscess over time
Acute pleuritis with empyema: what can cause this? what changes are seen in the lung (2), pleura (1), and outside of the pleura (5)?
Causes: initial insult = aspiration of mixed population of bacteria from mouth/respiratory tract (breathing in large amounts of spit/vomit)
–Initial inflammatory process + actions of bacteria -> destruction of tissue -> bacterial abscess -> pleuritis/empyema
Changes:
- -Lung edematous
- -Some alveolar spaces empty, others full of infiltrate and neutrophils (looks like very thick walls, but isn’t)
- -Pleura -> granulation tissue to wall off abscess (thin walled capillaries, highly activated fibroblasts, active endothelial cells)
- —[Normal pleura = thin layer of cuboidal epithelium]
–Outside of pleura = PUS (neutrophils, inflammatory debris, bacteria, fibrin deposition [pinkish material])
- -Outside of pus = hypocellular area
- —Bacteria! (basophilic clumps)
- —Few neutrophils/inflammatory cells
- —Lots of inflammatory debris
- —Polymerized fibrin (pink, lacy) from fibrin that leaked from blood vessels
Acute bacterial pneumonia in neonate: what can cause this? what changes are seen? (3)
Causes: bacterial infection in neonate
Changes:
- -Fibrin accumulations (pink stringy/clumpy stuff)
- -Sparse inflammatory infiltrate: few neutrophils/MOs
- -Lots of hemorrhage (seen in lungs of neonates with inflammation)
Acute bacterial endocarditis: what can cause this? what changes are seen? (6)
Cause: Staphylococcus aureus
Changes:
- -Tons of fibrin, bacteria (purple) and inflammatory cells
- -Normal valve tissue = pink (lots of collagen)
- —Mostly dissolved by inflammatory process
- -May have vegetations hanging off the side or detached
- -Granulation tissue forming between the valve and the myocardium
- -Vegetation: LOTS of FIBRIN, degenerating leukocytes, bacteria
Acute mycotic aneurysm: what can cause this? what changes are seen?
Cause: primary site of Aspargillis fungal infection in lung -> pieces break off, go through LV -> circulation -> brain (in this example)
- -Aspargillis loves to grow through vessel wall -> thrombosis
- -Mycotic aneurysms can be of fungal, yeast, OR bacterial nature
Changes: (in immunosuppressed patient)
- -Thrombus in vessel
- -Neutrophils at inner surface of vessel where thrombus meets wall
- -Blood vessel wall ballooned out, quite massive, purple
- —Layered fibrin accumulates in ballooned out portion
- -Vessel wall (smooth muscle) being infiltrated by densely packed hyphae of fungus
- -Vessel wall dead
- -Neutrophils attacking hyphae
Bacterial pneumonia: what can cause this? what changes are seen? (8ish)
Cause: Pneumococcus
Changes: hyperemia, then HEPATIZATION (lung firm, looks like liver)
Red hepatization stage: (first)
- -Hyperemia with hemorrhage as capillaries lose integrity
- -Edema - alveolar spaces full of eosinophilic fluid
- -Tons of RBCs, fibrin
- -Congested capillaries
Gray hepatization stage: (second)
- -Lung firm, looks like liver
- -Massive leukocyte (neutrophil) infiltration after RBCs break down
- -Alveolar spaces filled with neutrophils and fibrin, NOT many RBCs or bacteria
- -Very congested capillaries
Septic emboli of kidney: what can cause this? what changes are seen? (6)
Cause: fragments of vegetation from endocarditis vegetations can break off lodge in blood vessels
Changes:
- -Changes seen in GLOMERULI
- -Most glomeruli look deep blue
- -Some glomeruli totally broken down, replaced with tons of neutrophils and bacteria as well as fibrin
- -Some glomeruli have large blue dots = colonies of bacteria
- -Bowman’s capsules filled with neutrophils, which then dissolve glomeruli
- -MICROABSCESSES can form: highly eosinophilic necrosis surrounded by neutrophils and bacteria
Opportunistic fungal infection of the lung: what can cause this? what changes are seen? (3)
Cause: severe immunosuppression
–Aspargillis: INFARCTION -> DEAD TISSUE -> FUNGUS FOOD in multiple organs
Changes:
- -Extremely extensive necrosis, no normal parenchyma of lung
- -45 degree branching hyphae of Aspargillis: kills lung tissue via infarction, then uses it as its culture medium
- -Very little/no immune response
Opportunistic fungal infection of the placenta: what can cause this? what changes are seen? (4)
Cause: immunosuppression
Changes:
- -Necrosis -> ghosts of vili
- -Outside of placenta (inside embryonic sac), see tons of fungal forms
- —Large and thick walled = Aspargillis
- —Small and thin walled (pseudohyphae) = Candida
Candida infection of the esophagus: what can cause this? what changes are seen? (4)
Cause: severe immunosuppression
Changes:
- -Along non-keratinized squamous epithelium, see thin or absent parts (ulcers) with Candida
- -Very little inflammatory response (few MOs)
- -Candida infiltrating into tissue, extending pseudohyphae
- -Greenish-blue dots are the yeast form, or hyphae cut in cross section
Typhoid fever in ileum and liver: what can cause this? what changes are seen? (2)
Cause: S. typhi
Changes:
–Erythroid phagocytosis: phagocytes eating RBCs
Liver:
–Small, indistinct typhoid nodules: little areas where the hepatocytes have been replaced by phagocytes, which contain S. typhi
Cytomegalovirus infection of kidney: what can cause this? what changes are seen? (3)
Cause: CMV in immunosuppressed patient
Changes:
- -Cells that are HUGE with large INTRAnuclear inclusions
- -Massively dilated tubules with huge cells in them
- -Intranuclear inclusions: dark pink blobs in nucleus, often have clear halo around them
Measles pneumonia in lung: what can cause this? what changes are seen? (7)
Cause: measles in a child that -> pneumonia
Changes:
- -Large GIANT CELLS scattered throughout lung parenchyma (look for purple dots)
- —Giant cells (and some parenchymal cells) have INTRAnuclear eosinophilic inclusions
- -Large areas of consolidation with no visible parenchyma
- -Thickening/neutrophilic infiltration of alveolar walls (interstitium)
- -Bronchioles filled with neutrophils, possibly destroyed
- -Proliferating pneumocytes, fibroblasts, and macrophages
- -Lots of fibrin debris, hemorrhage
HSV hepatitis in liver: what changes are seen? (3)
Changes:
- -Mottled appearance -> focal areas of necrosis with congested sinusoids full of RBCs
- -In areas with living cells, see amphiphilic (blue and pink) nuclear inclusion bodies
- —Chromatin in ring around nucleus, then clear zone around pink viral inclusion body
