Pathoma High Yield Principles Flashcards
How is the cytoskeleton and organelles broken down during atrophy?
Cytoskeleton - tagged via ubiquination -> proteasome pathway
Organelles - via autophagy
Why is BPH a notable exception to pathologic hyperplasia?
It is one type of pathologic hyperplasia which does NOT increase risk for cancer
(i.e. vs endometrial hyperplasia)
What is keratomalacia? What causes it?
Disorder of the conjunctiva of the eye which causes it to thicken
-> due to loss of Vitamin A, which is required for differentiation of specialized epithelial surfaces
What cellular phenomena are streak ovary and unilateral renal agenesis examples of?
Streak ovary - hypoplasia (decreased cell production during embryogenesis)
Renal agenesis - aplasia - failure of cell production during embryogenesis
What is the definition of hypoxemia?
PaO2 < 60 mmHg, SaO2 <90% (hemoglobin saturation %)
How are PAO2 and PACO2 related?
As PACO2 goes up (i.e. hypoventilation, COPD), PAO2 must fall (crowding out O2 in the alveoli) -> results in hypoxemia and ultimately decreased SaO2
How does carbon monoxide affect PaO2 and SaO2?
PaO2 - normal
SaO2 - decreased (less oxygen bound since it is tightly binding CO)
What is the earliest symptom of carbon monoxide poisoning?
Headache
What are the causes of methemoglobinemia?
- Oxidant stress - i.e. nitrates, drugs like benzocaine (anesthetic)
- Newborns -> decreased ability to reduce iron back to Fe+2
What is the classic physical exam findings with methemoglobinemia and what is the treatment?
Cyanosis with chocolate-colored blood
Treatment - IV METhylene blue, Vitamin C
What happens to microvilli during reversible hypoxic injury?
Microvilli are lost -> like inflating a nitrile glove so you can’t differentiate between the fingers
-> due to cellular swelling
What happens to protein synthesis in reversible cellular injury and why?
It decreases, since ribosomes pop off of the ER which is swelling
In what type of tissue can red infarction occur?
- If blood can re-enter the tissue
2. The tissue must be loosely organized so blood, i.e. testicle or lung
Why does liquefactive necrosis occur in the brain?
Microglial cells liquefy the brain by release of hydrolytic enzymes
What type of necrosis happens in the parenchyma of the pancreas in acute pancreatitis?
Liquefactive necrosis -> digestive via proteolytic enzymes
Fat necrosis occurs in the surrounding fat. - peripancreatic fat
What is the most damaging free radical species and how is it generally produced?
Hydroxyl free radical -> because it can only be broken down by glutathione peroxidase
Generally produced via ionizing radiation
What is the underlying pathophys of damage in Wilson’s dz or Hemochromatosis?
Generation of free radicals -> cirrhosis
What causes Familial Mediterranean fever? What is the hallmark of the condition
Autosomal recessive mutation in pyrin, a regulator of pro-inflammatory cytokines. Leads to recurring fever, joint pains, and serositis with overproduction of IL-1 -> systemic accumulation of AA amyloid (SAA)
-> this is a neutrophil dysfunction disorder
What is the most commonly involved organ in amyloidosis? Other classical findings?
Kidney -> leads to nephrotic syndrome
Restrictive cardiomyopathy
Tongue enlargement
Hepatosplenomegaly, malabsorption
What amyloidopathies do normal vs mutated transthyretin cause?
Normal - Commonly an asymptomatic senile cardiac amyloidosis (common in elderly) - ATTR
Mutated - Familial amyloid polyneuropathy / cardiomyopathy - deposition of ATTR in peripheral nerves and in heart.
What are the three major factors which stimulate degranulation of mast cells (to release histamine)?
- Tissue trauma
- Complement proteins C3a / C5a
- IgE cross-linking
What is the immediate response to histamine? Late response?
Arteriolar vasodilation, postcapillary venule increased capillary permeability
Late response: Leukotriene synthesis and release (vasoconstriction, bronchospasm, increased vascular permeability)
What is the classical pathway? What pathway is most similar to it?
GM makes classic cars. Complement protein binds IgM or IgG
Other pathway most similar to it is Mannose-binding lectin (MBL) -> a lectin is a sugar-binding protein which binds mannose residues on microorganisms
The MBL acts as an antibody which triggers the cascade
What is the alternative pathway?
Microbial products directly activate complement
C3b directly binds to the pathogen and is stabilized by factor B and properdin to C3 convertase for further opsonization