Final Exam Degeneration & Necrosis Deck 1 Flashcards
What are the 6 pathological processes in a tissue?
Degeneration/Necrosis
Inflammation and Repair
Circulatory Disorders
Disturbances of growth (hypoplasia, neoplasms, congenital)
Deposits and Pigmentations (cellular accumulations)
Biochemical dysfunction
What are the 7 categories of etiologies of pathogenic processes?
Genetic/inherited
Infectious
Metabolic
Toxicologic
Autoimmune
Idiopathic
Iatrogenic
T/F:
You know an animal DOES NOT have a circulatory disorder when you see the presence of PAPULES and NODULES
True
A palpable elevation with clear fluid that is LESS than 1 cm
Vesicle
A palpable elevation with clear fluid that is MORE than 1 cm
Bulla
What are 4 things that can cause the formation of a
Vesicle or Bulla?
Autoimmune Dermatoses
Viral Infections
Chemical Irritants
Burns
Another word for “intercellular edema”
Spongiosis
What is “acantholysis”?
Disruption of intercellular junctions
What is another word for “INTRAcellular edema”?
Hydropic degeneration
The condition of fluid accumulation between cells.
If this becomes severe enough, all cells come apart and vesicles form
Spongiosis
T/F
VESICLES are very prone to secondary infections
TRUE
What type of exudate would be seen with
Acantholysis
or
“disruption of intercellular junctions”?
PUS
An immune mediated process, this will progress to a pustule
In a _______ vesicle, the stratum corneum forms the roof of the vesicle, as in *Impetigo *or Pemphigus Foliaceous
subcorneal vesicle
In a ______ vesicle, a portion of the epidermis (stratum spinosum) forms the roof, as in Pemphigus vulgaris
suprabasal vesicle
In a ______ vesicle, the entire epidermis separates from the dermis and forms the roof, as in Bullous pemphigoid
subepidermal vesicle
A **pustule **is always indicative of this type of reaction
INFLAMMATORY
What is the cause of pustules?
Leukocyte infiltration
Dried exudate, serum, blood, and scale that is adhered to the skin surface is called
CRUST
A palpable solid elevated mass LESS than 1 cm in diameter
like vesicles but with a solid center
Papules
What can cause a papule?
Infiltration by inflammatory or neoplastic cells
Epidermal hyperplasia
Deposit of mineral like calcium
A palpable solid elevated mass GREATER than 1 cm in diameter is called a
Nodule
Deeper than a papule
When papules coalesce, it is called a
PLAQUE
A loss of epidermis with exposure of dermis that is secondary to
- epidermal necrosis*
- inflammation*
- infarction*
- neoplasia*
Ulcers
Which is more severe, an ulcer or an erosion?
An ULCER is more severe
Ulcers start out as erosions (partial defect in dermis)
An accumulation of loose keratinized cells
caused by
- Disorders of keratinization*
- Chronic dermatitis*
SCALE
______ is an example of scale, from extra skin from the stratum corneum
dandruff
What is an epidermal collarette?
A circular rim of scale that occurs secondary
to rupture of a vesicle or papule
Thickening and hardening of the skin caused by
- chronic inflammation*
- chronic irritation*
Lichenification
T/F
Pigmentation can be a side effect of Lichenification
TRUE
What is the difference between a papule and a pustule?
A pustule oozes fluid
T/F:
When collecting a skin biopsy you should surgically prep the site, grasp with forceps, and biopsy the center of the lesion
FALSE!! DON’T DO ANY OF THIS!
Degenerative/Necrotic lesions tend to _______
and become inflammation/repair over time
ULCERATE
Primary _____ disorders often lead to degeneration/necrosis
circulatory
A flock of 300 merino ewes and lambs have swelling and erythema of the skin, and have **crust **in poorly wooled areas. Some of the crust has broken off and left ulcers.
The pathological process is likely
epidermal ____________ or
_____________
The pathological process is likely epidermal
Degeneration/Necrosis
or
Inflammatory (infectious)
A flock of 300 merino ewes and lambs have swelling and erythema of the skin, and have crust in poorly wooled areas. Some of the crust has broken off and left ulcers.
What are your differential diagnoses?
Photosensitization
Dermatophilus
Viral Infection: *Blue Tongue, Pox (Orf), *or
Vesicular Disease (FMD, VS)
A flock of 300 merino ewes and lambs have swelling and erythema of the skin, and have crust in poorly wooled areas. Some of the crust has broken off and left ulcers.
What can be done to determine the cause?
Culture
Cytology
Biopsy
Describe the pathogenesis of photosensitization
UV light absorbed by photodynamic chemicals in skin →
Free radical damage →
Epidermal necrosis of lightly pigmented or sparsely haired areas
**Primary photosensitization (Type 1 Exogenous) **in sheep is caused by
Plants containing photosensitive chemicals
like
St. Johns Wort
Lucerne
Perennial Ryegrass
Primary Photosensitization (Type II Intrinsic)
in sheep is caused by
Porphyria
an inherited deficiency of porphyrinogen III cosynthetase
which leads to a defect in heme synthesis and then a
build-up of porphyrins
Secondary Photosensitization (Type III Hepatogenous)
in sheep is caused by
poor hepatic clearance of Phylloerythrin
which is a
product of a ruminal chlorophyll transformation
In Secondary Photosensitization (Type III Hepatogenous)
which toxins can cause biliary obstruction?
Lantadenes (Red Lantan)
Steroidal Saponins (Tribulus, Pancium)
Sporodesmin (Facial Eczema):
Lolium perenne + Pithomyces chartarum → Sporodesmin toxicosis
Pyrolizidine alkaloids
Aflatoxin
Phomopsin
What is cholestasis?
Any condition in which the flow of bile from the liver stops or slows
Ingestion of toxic alkaloids produced by the fungus
Claviceps purpurea
Ergot Poisoning
A flock of 300 merino ewes and lambs have swelling and erythema of the skin, and have crust in poorly wooled areas. Some of the crust has broken off and left ulcers.
How was Type III Photosensitization ruled out?
By doing a serum test and analyzing the levels,
also using clinical signs
Wound contraction is a feature of healing by _____ intention
second intention
Fibrous union is a feature of healing by _____ intention
first intention
If skin is trying to heal by first intention, in 24 hours, it will have formed a ____
scab
Chronic (years) of UV light exposure leads to
Solar/Actinic Keratosis
T/F
You will never see crusts in Solar Injury
FALSE
You WILL see crusts in solar injury
Acute UV light exposure leads to _______
sunburn
What is the pathogenesis of a sunburn?
Acute UV light exposure → Erythema → Blistering/Vesicles
→ Sloughing of necrotic skin
T/F
Cytokine production has a role in the pathogenesis of sunburns
TRUE
Epidermal hyperplasia
and
Dermal fibrosis and elastosis
caused by UV light exposure is called
Solar/Actinic Keratosis
In chronic UV light exposure (Solar/Actinic Keratosis)
there is an increased risk for _______
due to direct DNA injury and subsequent mutations
Neoplasia
In solar dermatitis, when a comedone ruptures and releases its follicular contents causing a foreign body inflammatory response and secondary bacterial infection,
it is called
Furunculosis
Cutaneous Horns
are indicative of this epidermal pathogenesis
Solar/Actinic Keratosis
What is a cutaneous horn?
Keratoses formed from multiple layers of compacted stratum corneum
Solar dermatitis related
infundibular keratinzing acanthoma
is known as
Adnexa
In solar dermatitis, skin is thickened by this process
Acanthosis
Injury to the epidermis,
reddened or darkened necrotic epidermis
and
complete healing
are characteristic of ____ degree thermal burns
1st degree
Damage to the epidermis and dermis
vesicle formation
and
some adnexa being preserved allowing epidermal regeneration with some scarring
is indicative of a ____ degree thermal burn
2nd degree
When damage to the full thickness of the epidermis and dermis, plus or minus the subcutis, sloughing of necrotic tissue followed by granulation tissue, and scar or life-threatening fluid or protein loss (a portal for sepsis) occurs,
it is indicative of a ____ degree thermal burn
3rd degree thermal burn
_____ form with thermal 3rd degree burns
vesicles
What is the main differential when you suspect a chemical burn?
Contact hypersensitivity dermatitis
A ______ is simply a discolored spot on the skin
macule
The pathogenesis of
Erythema Multiforme
and
Toxic Epidermal Necrolysis
is thought to involve Type ____ Hypersensitivity
Type 4 Hypersensitivity
Erythema Multiforme & Toxic Epidermal Necrolysis
are induced via ______ ______
and feature widespread coalescing erythematous macules
which eventually turn into vesicles and ulcers
antigenic mimicry
What is the difference between Erythema Multiforme
and Toxic Epidermal Necrolysis?
- Erythema Multiforme* is Milder with single cell apoptosis
- Toxic Epidermal Necrolysis* is Severe with sheets of apoptotic/necrotic cells
What are 4 other names for Superficial Necrolytic Dermatitis?
- Diabetic dermatopathy*
- Hepatocutaneous Syndrome*
- Necrolytic Migratory Erythema*
- Metabolic Epidermal Necrosis*
T/F
Superficial Necrolytic Dermatitis is a common disorder in older dogs with Diabetes Mellitus
FALSE
it is RARE, but is reported primarily in older dogs with Diabetes mellitus or hepatic dysfunction
Long-term anticonvulsant therapy
and
rare ingestion of mycotoxins
precede this rare disease
Superficial Necrolytic Dermatitis
T/F
Superficial Necrolytic Dermatitis is more common in cats than dogs
FALSE
it is more common in older dogs and RARE in cats
An older dog with Diabetes Mellitus comes in and is exhibiting scales and crusts with ulceration on its mucocutaneous junctions, genitals, ear pinnae, elbows and hock, ventral thorax, and even on its pawpads. Because of these painful ulcers on his pawpads, he is having difficulty walking.
What is your diagnosis?
Superficial Necrolytic Dermatitis
What is the predominant cell type in the epidermis?
Keratinocytes
Dendritic cells (antigen presenting immune cells) of the skin and mucosa are called
Langerhaan’s Cells
These cells contain birbeck granules
Langerhaan’s Cells
Oval receptor cells found in the skin of vertebrates that have synaptic contacts with somatosensory afferents are called
Merkel’s Cells
