Respiratory/Cardio Flashcards
Chinese adult presents with cervical lymphadenopathy gets biopsy and shows pleomorphic keratin-positive epithelial cells in a background of lymphocytes. What disease comes to mind and what is it commonly associated with?
Nasopharyngeal carcinoma (squamous cell carcinoma) - malignant tumor of NP; associated with EBV
Most common bug that causes rhinitis (common cold)?
RSV according to uWorld
most common cause of acute epiglottis in immunized and non-immunized children?
H. influenza b
Laryngotracheobronchitis
Croup; inflammation of upper airway; parainfluenza (paramyxovirus) most common cause; presents with hoarse ‘barking’ cough and inspiratory stridor
two major mediators behind pleuritic chest pain from pneumonia?
bradykinin and prostaglandin E2, inflammation of lung parenchyma, every time lung stretches with breathing it irritates the pleura and results in pleuritic chest pain
What are the two most common causes of lobar pneumonia?
Streptococcus pneumoniae (95%) and Klebsiella pneumoniae
lobar pneumonia; commonly caused community acquired pneumonia by streptococcus pneumonia
interstitial (atypical) pneumonia
interstitial (atypical) pneumonia on biopsy
What is the most common cause of interstitial (atypical) pneumonia?
Mycoplasma pneumoniae; typically affects young adults (military recruits/students living in a dormitory); complications include autoimmune hemolytic anemia (IgM) which causes cold hemolytic anemia and erythema multiform; not visible on gram stains due to lack of cell wall
Bug that causes an atypical pneumonia that is seen in veterinarians and farmers and causes a HIGH fever (Q fever)?
Coxiella burnetii
Primary TB
inhalation of aerosolized Mycobacterium tuberculosis; focal caseating necrosis of lower lobe of lung and hilar lymph nodes; foci undergo fibrosis and calcifications and forms ghon complexes; often asymptomatic but has a positive PPD
Primary TB
inhalation of aerosolized Mycobacterium tuberculosis; focal caseating necrosis of lower lobe of lung and hilar lymph nodes; foci undergo fibrosis and calcifications and forms ghon complexes; often asymptomatic but has a positive PPD
Secondary TB commonly arises due to what 2 things?
AIDS and aging; primary TB is usually asymptomatic with a positive PPD; but secondary is symptomatic
primary TB v. secondary TB with area of lung affected?
1 - lower lobes with Ghon complexes
2- apex of the lung (oxygen tension is highest at the apex)
lung biopsy of pt with secondary TB?
caseating granulomas and AFB stain with red acid-fast bacilli
AFB stain with red acid-fast bacilli as seen in secondary TB
What is the most common organ affected by TB in systemic spread?
kidneys; results in sterile pyuria
pulmonary TB; stimulation of CD4 T lymphocytes releasing interferon gamma; form multinucleated Langerhans giant cells; center of the granuloma will be caseating “cheese-like”
pulmonary TB; stimulation of CD4 T lymphocytes releasing interferon gamma; form multinucleated Langerhans giant cells; center of the granuloma will be caseating “cheese-like”
pink PAS+ globules; built up A1AT in hepatic cells in a pt with A1AT deficiency; results in panacinar emphysema; warn pt against smoking
What is the only pneumoconiosis with increased risk for TB?
Silicosis
lung biopsy showing asbestosis bodies; long rod-shaped particles with round brown deposits (iron); seen in asbestosis pneumoconiosis
air sacs of the lung lined by hyaline membrane as seen in ARDS due to alveolar-capillary damage (leaking)
grainy/hazzy appearance of the lung that is characteristic in a neonate with RDS; “diffuse granularity” or “diffuse atelectasis”; decrease type II pneumocystis that produce surfactant
adenocarcinoma of the lung; located at the periphery (contrast to central with small and squamous); increased mucus and glands; seen in females nonsmokers
normal lung on R; left shows a collapsed lung and thorax full of air as seen in a spontaneous pneumothorax; note that trachea deviates to the side of the collapse
thickening of the pleura that encompasses the lung as seen in mesothelioma; malignancy of the pleura; asbestos exposure is a high risk factor; histology: spindle cells; immunohisto: cytokeratins that are calretinin positive and EM will show abundant tonofilaments
Which pathology of the premature newborn is consistent with a continuous murmur and bounding peripheral pulses?
Patent ductus arteriosus; left to right shunting increases blood return to the left atrium; decreases systemic vascular resistance; increase in stroke volume and cardiac output causes increased pulse pressure (large differences between diastolic and systolic pressure) leading to bounding pulses
What immune cells are the key players in the formation of lung abscess?
neutrophils; they release cytotoxic granules
Which vein has the most de-oxygenated blood?
the coronary sinus
NO increases which secondary messenger to promote vasodilation?
cGMP
Effects of cocaine on the heart?
causes coronary artery vasoconstriction (alpha adrenergic receptors) which leads to decreased coronary O2 supply by also increasing the O2 demand of the heart via tachycardia and increased contractility leading to an acute MI
Changes in ATP level during an acute MI?
depleted ATP in cardiac myocytes IMMEDIATELY (w/I seconds); immediately w/I seconds, ischemic MI switch from aerobic to aerobic glycolysis leading to depleted ATP; you can see myofibril relaxation leading to the ventricle not wanting to move (constrict) and a drop in cardiac output
Reversible cell injury (early pathological changes in an MI)
cellular and mitochondrial swelling, glycogen depletion and clumping of chromatin (under 20-30 mins)
Irreversible damage
mitochondrial vacuolization or membrane rupture (more than 20-30 mins); cells will release their contents - troponin I and CK-MB
Stunned myocardium
delay in time before the myocytes become back to normal after reversible injury; viable myocytes do not immediately return to full activity) lasts a few hours to days after reversible myocardia injury (reperfusion)
Reperfusion injury
restoring blood flow to ischemic areas can damage it even more; adds more calcium and induces hypercontracture - cells become stuck in a contracted state; also free radicals can build up and induce further damage to surrounding myocytes (more inflammatory cells - destroying other myocytes)
ischemic cardiomyopathy
chronic ischemic heart disease leads to progressive heart failure; longterm subclinical ischemia; usually a hx of MI, evidence of “patchy fibrosis” leading to systolic heart failure (contraction phase)
CAD
coronary artery disease; atherosclerotic plaque in one or more coronary arteries leading to decreased coronary blood flow and ischemic injury of myocytes
Risk factors for CAD?
obesity, smoking, hyperlipidemia
Stable angina
FIXED coronary plaques causing >70% stenosis (anything under is asymptomatic) will present with chest pain during exertion or when emotionally stressed; radiates to left arm or jaw; improved with rest and nitroglycerin; lasts under 30 mins; reversible injury
Which zone gets injured first during stenosis of coronary arteries?
subendocardial zones (furthest away)
Nitroglycerin
increases vasodilation (mostly veins) and decreases venous return to the heart and decreases the preload/workload
recurrent episodes of chest pain that occur at random intervals unrelated to exertion or stress. “Hey doc I get these random chest pains, I’m not really doing anything when it happens, sometimes even at 2am.”
vasospastic angina also called prinzmetal angina; smooth muscle hyperactivity in the coronary wall; risk factor of smoking; encourage pt to quit
ACS
acute coronary syndrome - umbrella term for three conditions - unstable angina, NSTEMI and STEMI
unstable angina
chest pain at rest, needs an immediate work up; high risk for MI
NSTEMI
non-ST elevation MI; you can see ST depression (subendocardial injury)
STEMI
ST elevation on EKG; very bad occlusion causes a transmural injury (epi, myo and endo) fully occlusive thrombus leading to a full thickness infarct; EKG would show hyperacute T waves with “tombstone” shaped ST segments; negative Q waves and then T waves becomes inverted; watch for a later onset of left bundle branch block LBBB due to non-functioning ventricle (LAD is commonly affected artery)
What are the two types of MI?
Non-ST elevation MI = NSTEMI
ST elevation MI = STEMI
What is the most sensitive and specific cardiac enzyme in irreversible cell injury?
Tropinin - more sensitive
(stays high for 7-10 days so CK-MB is more specific for 2nd in 3 days or 72 hrs)
Tropinin I - more specific
Tropinin T - more sensitive (has a T)
LAD occlusion MI
ischemia of the LV and anterior 2/3rds of the inter ventricular septum and apex; can knock out LV function
s4 heart sound
abnormal regardless of patient age; occurs in late diastole “atrial kick” best heard at the apex in a lateral decubitus/recumbent position; associated with LV non compliance (a stiff ventricle); LAD occlusion causing depleted ATP of LV (relaxation); can lead to cardiogenic shock - sudden death!!
RCA occlusion
affects the SA and AV nodes (pacemakers of the heart) can lead to bradycardia, heart block and sick sinus syndrome; also supplies the RV, posterior 1/3rd of the interventricular septum and posterior LV; leads II, III and aVF
pt with crushing chest pain, ST elevation on ECG and some lung findings what should you think of?
Left sided infarction (commonly LAD is involved)
pt with sudden chest pressure, nausea, bradycardia or heart block what should you think of?
Right sided infarction (RCA - gives rise to the posterior descending artery); may also mention JVD; inferior leads of the ECG (II, III and aVF**)
0-4 hours following a MI
NORMAL microscopic or gross changes
4-12 hours post MI
wavy fibers on histology; dead and non-contractile muscle fibers, edema and punctate hemorrhaging and can start seeing coagulative necrosis
12-24 hours post MI
dead cells without nuclei, contraction band necrosis; Ca2+ entering dead cells causing contraction
1-3 days post MI
first responders neutrophils are in abundance (infiltrating blue cells); whitish tan; watch for early onset fibrinous pericarditis (only in transmural MI)
your pt is 3 days post MI and onset of chest pain, but the pain is sharp and not dull like how they came in. Pain increases every time the pt swallows or takes a deep breath. Pain is better when the pt leans forward.
pleuritic chest pain that is worse on inspiration and better when leaning forward; caused by early onset pericarditis; a couple days post MI due to neutrophils going into the necrotic tissue; usually short lived and relieved with asprin
3-14 days post MI
macrophages are predominate; granulation tissue - precursor to scar tissue; watch for ruptures:
- papillary muscle rupture = mitral regurg happens; holosystolic blowing murmur that radiates to the left axilla; solely supplied by the posterior descending artery
- septum rupture; supplied by the LAD; immediate R to L shunting (holosystolic murmur)
- LV free wall rupture; LCA occlusion; can lead to cardiac tamponade - blood collecting in the pericardiac sac; muffled heart sounds, JVD and systemic hypotension
holosystolic blowing murmur that radiates to the left axilla is indicative of what kind of murmur?
mitral valve regurgitation (mitral insufficiency); can occur with papillary muscle rupture 3-14 days post MI
the papillary muscle of the LV is solely supplied by which artery?
posterior descending artery a branch off the RCA; posterior medially papillary muscles
blood collecting in the pericardiac sac; muffled heart sounds, JVD and systemic hypotension
LV free wall rupture 3- 14 days post MI due to a LCA occlusion; cardiac tamponade
after 14 days post MI
scar formation; can cause fatal ventricular arrhythmias leading to sudden cardiac death
weeks to month post MI
myocardial scar formation can lead to an aneurysm (ballon-like dilation) floppy failing heart balloon
Dressler’s syndrome
late onset pericarditis (6 weeks later) pt has pleuritic chest pain; delayed response due to antibodies (IgG) exposed in the pericardium
histology of the lung showing hemosiderin-laden macrophages AKA heart failure cells; typically seen with LHF, pul edema causes increased blood to be in the pulmonary circuit and rupture blood vessels causing increased blood into the alveoli and macrophages phagocytosing the RBC and having a buildup of iron.
How can systolic heart failure be assessed?
Ejection fraction measures the heart ability to pump (SV/EDV); will be lowered with systolic heart failure (ex dilated cardiomyopathy - all 4 chambers are dilated and pumping ability is decreased)
Ejection fraction measurement?
stroke volume divided by the end-diastolic volume (SV/EDV); how effective it the heart is at pumping blood out during systole; normal is 55-80%; pathological under 40%
systolic heart failure
heart is unable to contract and pump out blood effectively; emptying problem (ex. dilated cardiomyopathy)
diastolic heart failure
the heart is unable to fill appropriately; filling problem (ex. restrictive cardiomyopathy) - reduced ventricular compliance; can pump out blood just fine; heart failure with preserved ejection fraction (55-80%)
Hypertrophic obstructive cardiomyopathy (HOCM)
ventricular septum hypertrophy causes diastolic heart failure; the inability to appropriately fill the heart because a big bulky septum in the way
Constrictive pericarditis
the pericardium becomes somewhat fibrosis and restricts the heart from filling due to a non-compliant ventricle; can cause diastolic heart failure
eccentric hypertophy
caused by VOLUME overload (increased preload) causes a dilated cavity
concentric hypertophy
caused by PRESSURE overload (increased afterload) causes a more restricted cavity due to wall thickness
ANP
atrial natriuretic peptide (ANP) released by stretched cardiomyocytes in the atria (increased preload); MOA is the decreased afterload by promoting vasodilation (decreases SVR) and decreases preload by promoting salt excretion (natriuresis/diuresis) by decreasing aldosterone and decreased renin
BNP
brain natriuretic peptide (BNP) released by stretched cardiomyocytes in the ventricles (increased preload); MOA is the decreased afterload by promoting vasodilation (decreases SVR) and decreases preload by promoting salt excretion (natriuresis/diuresis) by decreasing aldosterone and decreased renin
How does the body try to compensate for low CO?
release of EPI to get the sympathetic going (increase HR and increased SVR via vasoconstriction) and activation of RAAS to increase aldosterone release to increase salt and water retention and increased ADH release to retain free water
Orthopnea
SOB when laying flat; “hey doc everytime I lay down it feels like I’m drowning” can be due to left heart failure that has backed up into the pulmonary circuit causes pulmonary congestion/edema
paroxysmal noctural dyspnea
waking in the middle of the night due to SOB “gasping awake”; can be due to laying flat with left heart failure
bibasilar inspiratory crackles
sign of pulmonary edema/congestion caused by left heart failure, blood backflows into the pulmonary circuit and goes into the base of the lungs (crackles - fluid into the interstitium)
chest x-ray findings for left heart failure?
diffuse vascular congestion “cephalization” of the pulmonary vessels (pulm vessels more defined compared to normal); fluffy b/l “batwing shaped” opacities and Kerley B lines indicating fluid accumulation between lobes; air bronchograms (dark airways); and an enlarged cardiac silhouette indicating cardiomegaly (takes up more than half of the thorax)
heart sounds in a pt with left heart failure?
S3 (S2/S3 gallop) - more common in systolic heart failure (comes right after s2) as blood comes back down from not being able to be ejected from the ventricles
S4 - more common in diastolic heart failure (comes right before S1) as blood is pushed against a stiff wall; occurs during the “atrial kick”
mitral regurg - systolic murmur; due to dilation of the mitral annulus
cor pulmonale
right heart failure caused by pulmonary HTN
heart sounds in a pt with right heart failure
tricuspid regurg due to dilation of tricuspid annulus; systolic murmur
Kussmaul sign - JVD increases during inspiration seen in RHF
Kussmaul sign
JVD increases during inspiration seen in RHF
Which zone of the liver is affected the most in right heart failure?
centrilobular zone (zone 3) necrosis due to hepatic venous congestion in RHF; “nutmeg liver”
cardiomyopathies
myocardial diseases resulting in cardiac dysfunction; dilated cardiomyopathy is the most common form
dilated cardiomyopathy, dilatation of all 4 chambers of the heart; results in a systolic dysfunction (not able to pump/contract appropriately)
lymphocytic infiltrated with cardiomyocytes as seen in myocarditis most commonly caused by coxsackie b virus; late complication of dilated cardiomyopathy
What is the most common cause of sudden death in young athletes?
ventricular arrhythmias due to hypertrophic cardiomyopathy; diastolic heart failure, inability to fill the lungs results in a decreased CO; genetic mutation in sarcomere proteins (AD inheritance)