8: Cell Accumulations

6 intracellular accumulations

lipid, glycogen, melanin, lipofuscin, ceroid, inclusions

lipidosis

abnormal accumulation of triglycerides in cells

where does lipidosis most commonly occur?

liver MOSTLY, heart/muscle/kidneys

causes of lipidosis

toxins, protein malnutrition, diabetes, anoxia

ways lipidosis could happen

anecrosis, abnormal metabolism of FFAs

anecrotic animal

increased mobilization of FFAs

liver with hepatic lipidosis

yellow, swollen, soft, friable (easy to crumble), will float in formalin/water

histology of hepatic lipidosis

sharply demarcated cells, have vacuoles inside that MOVE/CHANGE NUCLEUS

pathologic mechanisms of glycogen

hyperglycemia (diabetes), increased corticosteroids, enzyme deficiencies

histology of glycogen accumulation

poorly demarcated cells, vacuoles DO NOT cause nucleus to change/move

melanin

brown/black intracellular pigment

what makes melanin

melanocytes

melanosis

melanin deposits on less common tissues (brain/oral/esophageal mucosa)

hyperpigmentation

chronic inflammatory states/neoplasia (affects sheep/cows/chow chows)

albinism

absence of tyrosinase

leukotrichia

fading of coat color, wirey/lost hair

what causes leukotrichia (fading coat/hair loss)

copper deficiency

lipofuscin

lipoprotein that accumulates as residual bodies in cells

what is known as "wear and tear pigment" of aging animals?

lipofuscin

how does lipofuscin occur?

result of autophagocytosis with undegradable material

is lipofuscin bad for the cell?

NO

microscopic apperance of lipofuscin

membrane bound yellow-brown granular pigment in cytoplasm

can you see lipofuscin grossly?

NO

ceroid

looks like lipofuscin, but results from DISEASE/PATHOLOGY

causes of ceroid accumulation

cachexia, vitamin E deficinecy, lysosomal storage disease

ceroid macroscopically

generalized brown/tan discoloration

ceroid microscopically

membranous stacks of yellow/brown pigment

inclusions

protein accumulation

what causes protein accumulation (inclusion)

increased resorption/storage/production

what color do protein inclusions stair?

pink/orange/red

brick inclusions

crystalline protein inclusions, rhombus shaped

what cell types are affected by brick inclusions?

renal/hepatocyte epithelial cells

exclusively INTRANUCLEAR inclusions

herpes/adeno/parvo viruses

cytoplasmic inclusions

pox virus, rabies

both INTRANUCLEAR AND CYTOPLASMIC inclusion (THE ONLY ONE)

canine distemper

extracellular accumulations

amyloid, Ca/gout, cholesterol, carotenoids, fat, fibrosis, carbon, tetracycline, hyaline

true or false: amyloid accumulation is ALWAYS EXTRACELLULAR

TRUE

what causes amyloid accumulation

protein misfolding, can't be degraded, have beta-plated sheets

2 types of amyloidosis

primary and secondary

primary amyloidosis

light chain amyloid (AL)

secondary amyloidosis

serum amyloid (AA)

macroscopic appearance of amyloid

organ enlarged/pale/waxy with yellow/tan discoloration and rounded margins

what color does amyloid stain with Lugol's Iodine?

BROWN

microscopic appearance of amyloid

orange/red hue in normal light, candy apple green in polarized light

stain needed to see amyloid accumulation on histology

congo red

2 forms of calcium extracellular accumulation

metastatic and dystrophic

calcium extracellular accumulation

abnormal deposition of calcium salts in soft tissues

metastatic calcification targets what?

intima/tunica media of vessels

primary issues from metastatic calcification

renal failure, increase PTH secretion/bone resorption, hypercalcemia, vitamin D toxicosis

when does dystrophic calcification occur?

with injury/necrosis

what is dystrophic calcification?

destruction of tissues by calcium overload

gross apperance of calcification

chalky/white hard/gritty deposits on cut surface

histologic appereance of calcification

dark blue/purple (basophilic), fragmented/granular material, can be deposited along basement membranes

calcinosis

widespread excessive calcification

2 types of calcinosis

cutis and circumscripta

calcinosis cutis

involves cushing's disease

calcinosis circumscripta

unsure of cause, so if animal is without cushing's, just say its circumscripta

gout

deposition/accumulation of sodium urate crystals in tissue

what animals get gout?

birds, reptiles, primates

2 form of gout

articular and visceral

articular gout

in joints

visceral gout

on surface of serosa

2 main causes of gout in birds/reptiles are

renal failure, vitamin A deficiency

gross apperance of gout

white/firm crystalline deposits with a rough texture

gout on histology

granulomas present with star pattern (tophus/tophi)

tophus/tophi

radiating (star/firework like) crystalline material seen on gout histology

cholesterol extracellular accumulation

crystals of cholesterol cause granulomatous inflammation, dissolve and leave needle shaped clefts on histology

what are carotenoids

fat soluble pigments from plants

carotenoids is a precursor of this vitamin

vitamin A

where are extracellular accumulations of carotenoids seen?

in herbivores

important note of accumulation of carotenoids

NOT SEEN IN ORGANS! only in SQ tissue/fat

fibrosis

collagen deposits in interstitium of organs/tissues

true or false: fibrosis is a part of the healing process

TRUE (described like a band-aid)

what causes extracellular fat accumulation

obesity or cardiomyopathy

anthracosis

accumulation of carbon in tissues

what is tetracycline

antibiotic which bids to calcium phosphate in teth and bones

what does hyaline mean?

protein accumulation

6 hematogenous pigments

hemoglobin, hemosiderin, hematoidin, hematin, bilirubin, porphyrin

3 non-hematogenous pigments

melanin, lipofuscin, ceroid

hemoglobin

normal red pigment of RBCs

hemosiderin

formed from RBC breakdown (made of aggregates of ferritin)

color of hemosiderin

golden yellow/brown granular pigment

hemosiderin is common in these cells

macrophages

what can excess hemosiderin infer?

increased rate of RBC destruction or chronic vascular congestion

hematoidin

bright yellow/brown/orange/red crystalline pigment

where does hematoidin come from?

hemosiderin

does hemotoidin have iron?

NO

what forms bilirubin?

breakdown of heme in RBCs

icterus/jaundice

acculumation of bilirubin in serum/plasma

what forms hemain?

oxidized hemoglobin

2 types of hematin

acid and parasitic

acid hematin

pigment artifact from low pH areas and high RBCs in tissue

parasitic hematin

formed from parasites infecting/consuming RBCs (like liver flukes)

3 classifications of icterus

prehepatic, hepatic, posthepatic

prehepatic icterus

hemolysis - increased bilirubin production

hepatic icturus

hepatic injury - causes decreased uptake/secretion/conversion of bilirubin

posthepatic icterus

outflow of bile reduced/obstructed`

can you have hyperbilirubinemia WITHOUT icterus?

YES