tips for laboratory practical exampeople.upei.ca/hanna/gen-path-mock exam/tips for lab practical...
TRANSCRIPT
TIPS FOR LABORATORY PRACTICAL EXAM
Winter 2013
LABORATORY PRACTICAL EXAM
GENERAL PATHOLOGY - VPM 152
Friday April 19, 2013
YOU NEED TO BRING: Clip Board (To Write On), Pen / Pencil
WHAT TO WEAR: Lab Coat
Gloves (optional - since specimens can only be touched under supervision)
REMINDERS: Read the history carefully and answer the questions that are asked!
There will be 25 stations with 80 minutes to complete the exam - so organize your
time accordingly (~ 3 minutes per station)
With 30 students and 25 stations there will be times when there are 2 people at one
station (but no more than 2 people at any one station at a time)
Do not touch the specimens without supervision - if you need to manipulate a
specimen to see a different angle or texture, please put your hand up so an instructor
can assist you.
Be warned that any observation of cheating will result in a grade of zero for this exam - -
- - do not let your eyes wander
SCHEDULE: Group A 9:30 to 10:50 - Acheson to Glaude
Group B 11:00 to 12:20 - Gordon to Woodside
IS IT INFLAMMATION
OR OTHER?
If Inflammation
Mostly you decide
its inflammation
when you see
exudate.
What does the
exudate tell you
about etiology?
Fibrinous • esp Bacteria - ACUTE
Suppurative
• esp Bacteria
Granulomatous
• specific bacteria, many fungi
Hemorrhagic
• Toxin (bacterial or otherwise)
• Ischemia
Eosinophilic
• esp parasites & allergies
FIBRINONECROTIC EXUDATE
• typically occurs when there is necrosis
of well-vascularized epithelial surface
= necrosis + fibrin exudation
• examples - above is an acute
fibrinonecrotic tracheitis due to viral
infection and to the right an acute
fibrinonecrotic enteritis due to bacterial
infection
Organ Exudate (type of inflammation)
Distribution Duration Extent
Nephritis Suppurative Focal Peracute Minimal
Fibrinous Multifocal Acute Mild
Pneumonia Necrotizing Locally extensive
(segmental) Subacute Moderate
Enteritis Granulomatous Diffuse Chronic Marked
Hepatitis Catarrhal Chronic-active (severe)
Etc. Etc. Etc.
Use the following formula for a morphologic diagnosis of an inflammatory response
& you already have 2 parts (organ-itis + exudate)
Distribution
FIBRIN NEUTROPHILS
(pus) ACUTE
FIBROSIS NEUTROPHILS
and/or FIBRIN
CHRONIC-ACTIVE
GRANULOMATOUS INFLAMMATION
FIBROSIS CHRONIC
OR
OR
&
&
Duration
Above - Acute fibrinous pericarditis
Right – Chronic (chronic-active) fibrinous pericarditis
Above - Acute fibrinous or fibrinopurulent arthritis
Right – Chronic (chronic-active) fibrinous arthritis
Abscesses are a type of
suppurative inflammation that is
chronic (chronic-active); ie pus
surrounded by a fibrous capsule!
M.Dx = Hepatitis, suppurative,
multifocal, chronic (chronic-active),
severe = Hepatic abscess
Caseous exudate in most
mammals means
granulomatous
(& implies mycobacteria,
fungal, foreign body, etc).
Be aware of caseous
lymphadenitis in sheep, in
which the caseous
exudate is dried
(inspisated) pus (ie
suppurative, not
granulomatous exudate)
& birds which don’t have
neutrophils, caseous
exudate can represent
heterophilic or
granulomatous
inflammation
Extent / Severity
Mild
Moderate
Marked (severe)
How much tissue damage?
How much exudate?
If its not inflammation – is it:
Necrosis / degeneration
Pigmentary change
Circulatory disturbance
Adaptation / Growth disturbance
Neoplasia
Necrosis / degeneration
M.Dx. = Myocardial necrosis & mineralization,
locally-extensive, marked
Name of Dz = Nutritional myopathy
or White muscle disease
Etiology = deficiency of Vit E &/or Sel
Pathogenesis = free radical damage due to
reduced antioxidant protection
Gross - enlarged yellow liver with rounded
edges, that is greasy when cut and floats
when placed in water.
Histo - hepatocytes are swollen with clear
well delineated vacuoles (which would stain
positive with oil red O = lipid) which often
displace the nucleus to the periphery
M.Dx. = Hepatic lipidosis, diffuse, marked
Necrosis / degeneration
Gross - enlarged yellow liver with rounded
edges, that is not greasy when cut & does not
float when placed in water
Histo - hepatocytes are swollen with clear poorly
delineated vacuoles (which would stain positive
with PAS = glycogen) and nucleus not displaced
to periphery.
M.Dx. = Glycogen hepatopathy, diffuse, marked
H&E PAS
Necrosis / degeneration
Necrosis / degeneration
Pigmentary change or tissue deposits
Pigmentary change or tissue deposits
Circulatory disturbance – eg edema, congestion, hemorrhage,
infarct, thrombosis, embolism, etc
Circulatory disturbance – eg edema, congestion, hemorrhage,
infarct, thrombosis, embolism, etc
Circulatory disturbance – eg edema, congestion, hemorrhage,
infarct, thrombosis, embolism, etc
note thrombus or thromboemolus
in pulmonary artery (above) and
at bifurcation of distal abdominal
aorta (right)
Adaptation
Atrophy vs hypertrophy
normal
normal
Growth disturbance - hypoplasia / aplasia, hyperplasia, etc
Atrophy vs Hypoplasia?
normal
Epidermal hyperplasia
Nodular hyperplasia – common change in older animals
Growth disturbance - hypoplasia / aplasia, hyperplasia, etc
Neoplasia Benign Neoplasia – note well delineated and well differentiated
Neoplasia
Malignant Neoplasia
- note local invasion
Neoplasia
Malignant Neoplasia
- note local invasion & metastasis
Malignant Neoplasia
- local invasion with blocked lymphatics (note pitting edema bottom left), tumor
embolus in vessel (top right) and metastasis to lymph node (bottom right).