Pathology Flashcards
What causes congenital right to left shunts? 5 things
- Tetralogy of Fallot - MCC
- Transposition of great vessels
- Persistent Truncus arteriosus - failure of truncus arteriosus to divide into pulmonary trunk and aorta - most also have VSD
- Tricuspid atresia - characterized by absence of tricuspid valve and hypoplastic RV; requires both ASD and VSD for viability
- Total anomalous pulmonary venous return - pulmonary veins drain into right heart circulation (SVC, coronary sinus, etc); associated with ASD and sometimes PDA to allow for right-to-left shunting to maintain CO
What causes congenital left to right shunts? 3 things
VSD - most common congenital cardiac anomaly
ASD - loud S1; wide, fixed split S2
PDA - closed with indomethacin
Eisenmenger’s syndrome
Uncorrected VSD, ASD, or PDA causes compensatory pulmonary vascular hypertrophy, which results in progressive pulmonary hypertension.
As pulmonary resistance increases, the shunt reverses from left-to-right to right-to-left, which causes late cyanosis, clubbing, and polycythemia
Tetralogy of Fallot Cause: Presents with: How do you correct sx: Tx:
Caused by anterosuperior displacement of the infundibular septum. Pulmonary infundibular stenosis, RVH, Overriding aorta, VSD (PROVe).
Presents with early cyanosis caused by right to left shunt across the VSD bc pulmonary stenosis forces the right to left shunt and causes RVH (VSD alone is usually left to right).
Older patients learn to squat to relieve cyanotic sx (squatting reduced blood flow to the legs, increase peripheral vascular resistance, and decrease the cyanotic right to left shunt across the VSD).
Tx: primary surgical correction - early
D-transposition of great vessels
Cause:
Looks like:
Tx:
Caused by failure of the aorticopulmonary septum to spiral
Aorta leaves RV and pulmonary trunk leaves LV –> separation of systemic and pulmonary circulations –> not compatible with life unless a shunt is present to allow adequate mixing of blood (VSD, PDA, PFO)
Tx with surgical correction and without this most infants die within the first few months of life
Coarctation of the aorta results in:
Infantile type:
Adult type:
Aortic regurgitation
Infantile - aortic stenosis proximal to insertion of ductus arteriosus (Turner’s syndrome) –> check femoral pulses
Adult - stenosis is distal to ligamentum arteriosum. Associated with notching of the ribs (due to collateral circulation), hypertension in upper extremities, weak pulses in lower extremities –> bicuspid aortic valve.
Patent ductus arteriosus Shunting: Murmur: Cause: If uncorrected: Tx:
In fetal period - shunt is right to left then in neonatal –> lung resistance decreases and shunt becomes left to right with subsequent RVH and/or LVH and failure.
Murmur: continuous, “machine like” murmur
Cause: patency is maintained by PGE synthesis and ow O2 tension and if uncorrected can result in late cyanosis in the lower extremities
Tx: indomethacin
*Sometimes necessary to maintain life in conditions like transposition of great vessels
22q11 syndromes associated with
Truncus arteriosus, tetralogy of Fallot
Down syndrome associated with
ASD, VSD, AV septal defect (endocardial cushion defect)
Congenital rubella associated with
Septal defects, PDA, pulmonary artery stenosis
Turner syndrome associated with
Coarctation of aorta (preductal)
Marfan’s syndrome associated with
Aortic insufficiency and dissection (late complication)
Infant of diabetic mother associated with
Transposition of great vessels
Hypertension
RF
Features
Predisposition
- BP greater or equal to 140/90 mmHg
- Increase age, obesity, diabetes, smoking, genetics, black > white > asain
- 90% of HTN is primary and related to increase CO or TPR; other 10% is secondary to renal disease; malignant htn is severe (>180/120) and rapidly progressing
- atherosclerosis, LVH, stroke, CHF, renal failure, retinopathy, aortic dissection
Hyperlipidemia signs: Atheroma Xanthomas Tendinous xanthoma Corneal arcus
Atheromas: plaques in blood vessel walls
Xanthomas: plaques or nodules compsed of lipid-laden histiocytes in the skin, especially eyelids (xanthelasma)
Tendinous xanthoma: lipid deposit in tendon (Achilles)
Corneal arcus: lipid deposit in cornea, nonspecific (arcus senilis)
Atherosclerosis:
Monckeberg
Arterioloscerlosis
Atherosclerosis
Monckeberg: calcification in the media of the arteries, especially radial or ulnar (Usually benign, pipestem arteries) - do not obstruct blood flow and intima not involved
Arteriolosclerosis: hyaline (thickening of small arteries in essential htn or dm) and hyperplastic (onion skinning in malig htn)
Atherosclerosis: fibrous plaques and atheromas form in intima of arteries
Atherosclerosis: RF Progression Complications Location Sx
Dz of elastic arteries and large and medium sized muscular arteries
- RF: smoking, htn, hyperlipidemia, dm; age, gender, + fmhx
- Progression: inflammation important in pathogenesis; endothelial cell dysfxn –> MO and LDL accum –> foam cell formation –> fatty streaks –> smooth muscle cell migration (PDGF/FGF), proliferation, and ECM deposition –> fibrous plaques, complex atheromas
- Complications: aneurysms, ischemia, infarcts, peripheral vascular dz, thrombus, emobli
Location: Ab aorta > coronary artery > poplitearl artery > carotid artery
Sx: angina, claudication, asymptomatic
Aortic aneurysms
Pathologic dilation of blood vessel
Ab aortic aneurysms
Associated with:
Associated with atherosclerosis
More frequently with HTN males who smoke >50 yoa
Thoracic aortic aneurysms
Associated with:
Associated with htn, cystic medial necrosis (Marfan’s syndrome) and tertiary syphilis
Aortic dissection Associated with: Presents: CXR: Result in:
Longitudinal intraluminal tear forming a false lumen
Associated with htn, bicuspid aortic valve, cystic medial necrosis, inherited connective tissue disorders
Presents: tearing chest pain radiating to back
CXR: mediastinal widening, false lumen (limited to ascending aorta, propagate from ascending aorta, or propagate from descending aorta)
Results in: pericardial tamponade, aortic rupture, death
Angina
Types:
CAD narrowing >75%; no myocyte necrosis
Types:
- Stable: mostly secondary to atherosclerosis, ST depression on ECG (retrosternal chest pain with exertion)
- Prinzmetal’s variant: occurs at rest secondary to coronary artery spasm; ST elevation on ECG
- Unstable: thrombosis with incomplete coronary artery occlusion; ST depression on ECG (worsening chest pain at rest or with minimal exertion)
Coronary steal syndrome
Vasodilator may aggravate ischemia by shunting blood from area of critical stenosis to an area of high perfusion
Myocardial infarction
Most often acute thrombosis due to coronary artery atherosclerosis with complete occlusion of coronary artery and myoctye necrosis; ECG initially shows ST depression progressing to ST elevation with continued ischemia and transmural necrosis
Sudden cardiac death
Death from cardiac causes within 1 hour of onset of symptoms, most commonly due to a lethal arrhythmia (ventricular fibrillation)
Associated with CAD
Chronic ischemic heart disease
Progressive onset of CHF over many years due to chronic ischemic myocardial damage
Coronary artery occlusion: MC to LC
LAD > RCA > circumflex
MI symptoms
diaphoresis, nausea, vomiting, severe retrosternal pain, pain in left arm and/or jaw, shortness of breath, fatigue
0-4 hr of MI
No gross or microscopic signs
Risk: arrhythmia, CHF exacerbation, cardiogenic shock
4-12 hr of MI
Gross: Occluded artery, infarct, dark mottling, pale with tetrazolium stain
Microscopic: Early coagulative necrosis, edema, hemorrhage, wavy fibers
Risk: arrhythmia
12-24 hr of MI
Gross: Occluded artery, infarct, dark mottling, pale with tetrazolium stain
Microscopic: contraction bands from reperfusion injury, release of necrotic cell content into blood, beginning of PMN migration
Risk: arrhythmia
1-3 days of MI
Gross: hyperemia
Microscopic: extensive coagulative necrosis, tissue surrounding infarct shows acute inflammation, PMN migration
Risk: fibrinous pericarditis
3-14 days of MI
Gross: hyperemic border; central yellow-brown softening (maximally yellow and soft by 10 days)
Microscopic: macrophage infiltration followed by granulation tissue at the margins
Risk: free wall rupture leading to tamponade, papillary muscle rupture, ventricular aneurysm, interventricular septal rupture due to macrophages that have degraded important structural components
2 weeks of MI
Gross: recanalized artery, gray-white
Microscopic: contracted scar complete
Risk: Dressler’s syndrome
Diagnosis of MI in first 6 hours
ECG is the gold standard
Diagnosis of MI labs
Cardiac troponin I rises after 4 hours and is elevated for 7-10 days
CK-MB is predominantly found in myocardium but can also be released from skeletal muscle (useful in dx reinfarction following acute MI because levels return to normal after 48 hours)
Diagnosis of MI with ECG changes
ST elevation (transmural infarct), ST depression (subendocardial infarct), pathologic Q waves (transmural infarct)
Transmural infarct characteristics
Increased necrosis
Affects entire wall
ST elevation on ECG, Q waves
Subendocardial infarct characteristics
Due to ischemic necrosis of <50% of ventricle wall
Subendocardium especially vulnerable to ischemia
ST depression on ECG