LECTURES notes Pathology Exam I

Hoorcolleges Pathology deeltentamen I

Hoorcollege – Introduction

Pathology: The definition
- Pathology is the study of the causes and effects of disease or injury.
- The word pathology also refers to the study of disease in general, incorporating a wide range
of biology research fields and medical practices. However, when used in the context of
modern medical treatment, the term is often referred to the diagnose of diseases, mostly
through analysis of orangs, tissues, cells, and body fluids.

Disease: The definition
- Any abnormality that causes loss of health  Ill health.
- Characterized by a specific set of features (signs, symptoms, functional and morphological
manifestations) that are not normal.
- Everything that is not normal.

Normal: The definition
- Normal  Most frequent state in a population defined by age distribution, gender, etc.

Pathology is part of disease’s systematic description.
- Epidemiology.
o How manifest the disease in general population  Incidence, prevalence.
- Cause of the disease  Etiology.
- Pathogenesis  Disease mechanisms.
o How does the disease progress?
- Clinical signs and symptoms.
- Morphologic (tissue, cellular, genetic) manifestations.
o The changes you can see in tissue, cells and/or genetics that are caused by the
disease.
- Complications and sequelae.
- Prognosis.
- Mortality.
- Pathology provides information to the doctors of all the above.

Terminology
- Prefixes  Word you put before another word.
o Hyper-  Increased.
o Meta-  Similar.
o Hypo-  Decreased.
o Etc.
- Suffixes  Word you put at the end of a word.
o -itis  Inflammation.
o -oma.
o -oid  Tumors that resemble from another carcinoma.
- Eponyms  When disease is given the name of the person who discovered and described
the disease.

,The department of Pathology.
- From the operation room to the diagnosis.
o A peace of tissue is gathered at the operation  This is processed in order to make it
possible to look at the tissue under the microscope for diagnosis.
- In total 40,00 diagnoses a year:
o Histology (25.000 a year):
 Biopsies.
 Resections.
 Frozen sections.
o Cytology (15,000 a year):
 Fine needle aspirations (lymph node).
 Brushes (biliary tract).
 Fluids (ascites, pleural fluid).
 Smears (uterine cervix).
 Urine.
 Cerebrospinal fluids.
o Additional  Obtain as much information as possible from cells and tissues 
Molecular diagnostics.

Autoptic pathology
- Making a diagnosis on a whole body.
- Pathology implies also figuring out the disease mechanisms.
- Pathology also do research about the effect of treatments on the diseases.

In the daily practice:
- First step  Registration of the material that arrives.
- Specimen grossing  The cutting room.
o Tumor is fixed in formalin and than cut in slices to see where the tumor in the tissue
actually is.
o They also save some tissue of the tumor to investigate the DNA of the tumor.
- Specimen selection and embedding in cassettes.
o The tissue is embedded in paraffin  Fatty substance (wax) that makes the tissue
hard so it can be cut in very thin slices  3-5 mm thick tissue sections.
o Tissue has to be very small and thin so the light of the microscope can shine through.
- Tissue processing:
o Fixation  Formalin.
o Dehydration.
o Embedding.
o Paraffin blocks.
o Cutting.
o Slides.
o H&E stain  Basic staining that shows nuclei, proteins and cytoplasm of the cell.
- Evaluation by residents and pathology specialists.
- Pathologic diagnosis: Source of relevant information.
o Diagnosis:
 Benign versus malignant?
 Type of tumor?

, o Prognosis:
 TNM classification?
 Radicality.
o Prediction:
 Response to treatment?

Who ends up as a pathologist?  Someone who:
- Enjoys anatomy and physiology.
- Prefers working in a lab behind a microscope.
- Is drawn to the scientific, analytical, technical aspect of medicine.
- Enjoys solving mysteries or finding answers to the unknown.

, Hoorcollege – Chapter 2: Cell- and tissue adaptation, & damage

What is disease?
- Dysfunction of an organ or tissue, because of damage of the cells.
- The damage can be of many causes  Chemical, thermal, radiation, DNA damage, micro
bacterial, etc.
- The damaging agent is the etiology, the influence on and the changes in cellular processes
reflect the pathogenesis.

Etiology i.e. radiation
- Radiation causes damage on your DNA
 Example a missense mutation
because of replacement of a single
nucleotide.
o This leads to an incorrect amino
acid, which may produce a
malfunctioning protein.
o Example  Sickle cell anemia:
 Very common in people
who live in places where
malaria is prevalent.
 The mutation protects people from getting malaria.
 Here the mutation gives the people an advantage.
 When malaria is rare, the disadvantages of the mutation occurs.
 Places where oxygen levels are lower, your blood will start to
crystalize and block blood vessels.
- The pathogenesis here is often a sequence.

Etiology of cholera versus pathogenesis of diarrhea of cholera.
- Etiology  V. cholerae.
- The bacteria can produce a toxin and the toxin is
the pathogenesis of what happens when you get
cholera.
o Toxin interferes with your fluid balance
and causes massive diarrhea  You
loose a lot of fluids.

The first picture from basis pathology.
- A lot of damage occurs in the cell when
something goes wrong in the nucleus.
- In the nucleus you find our genetic material 
Highly complex structure.