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Cardio Dz & Bugs - Exam 3

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darodri6's version from 2016-09-19 02:33

Cardio Dz Presentation & associated Bugs

ConditionPresentationCommon EtiologyOther
MyocarditisCardiac symptoms = systolic or diastolic LV dysfunction, tachy-or brady-arrhythmias --> dyspnea, fatigue, decreases exercise tolerance, palpitations, chest discomfort, DCM (late stage)

Other symptoms = fever, malaise, fatigue, arthralgias, myalgias, and skin rash

On PE (signs similar to CHF) = Tachycardia, HYPOtension, Fever
*tachycardia disproportionate to degree of fever, Murmurs of mitral or tricuspid regurgitation are common, S3/S4 gallops possible,
-JVD, pulmonary crackles (rales, wheezes, peripheral edema all possible
Mainly VIRAL causation =
Coxsachievirus B (50%), ECHO, influenza, CMV. 50% HIV pts also have this at autopsy.

Bacterial = Corynebacterium diptheria, Neisseria meningitidis, B. burgdorferi

Protozoan = Trypanosoma cruzi (esp in S. America)

Fungal = Candida
Triphasic disease process:
Viral Infection & Replication (myocyte injury related to virus) --> Autoimmunity & injury (myocyte related to immune response) --> Dilated Cardiomyopathy (from elevated cytokine levels)

EMB + Dallas criteria (looks for injured myocytes + inflammatory infiltrate into myocardium) used for diagnostic purposes
Lab studies may show:
Leukocytosis and/or eosinophilia, elevated ESR or CRP, elevated cardiac enzymes (troponin I or T) and/or creatine kinase

Imaging studies may show:
Echo may show diffuse hypokinesis (slow movement) & diastolic dysfunction, wall motion abnormalities, wall thickening, pericardial effusion
-EKG may show sinus tach, nonspecific ST or T-wave changes, heart block & arrhythmias (most common in Chagas dz = RBBB w or w/o bifasicular block in 50% & vent arrhythmia in 40%)
EndocarditisAlmost ALWAYS FEVER & MURMUR, ANEMIA, abnormal heartbeat, symptoms similar to an MI, possible abdominal/side pain, petechiae over upper half of body & under fingernails, Oslers nodules, splinter hemorrhages

Subacute may show enlarged spleen

Cardiac symptoms = Mitral valve prolapse, aortic sclerosis, bicuspid aortic valvular dz
most common organisms = Oral Streptococcus & Enterococcus, Staph aureus, Candida (fungal), Coagulase - Staph, G- rods ((HACEK): H. aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae)

#1 in Native & Prosthetic valves (late) = Oral Streptococcus (Enterococcus)

#1 in Prosthetic valves (early) = Coagulase negative Staph

#1 in IV drug users = Staph aureus
aka 'infection of the heart valves'

Diagnosis via the Duke criteria (one major + 3 minor, or 2 major, or 5 minor)
SepticemiaFever (prominent symptoms) + HYPOtension, HYPOvolemia, often exhibits Tachypnea & Resp alkalosis, pt may appear ill w/altered mental state, shaking chills & GI symptomsmany different bacteria (mainly G- organisms...think HACEK) and a few fungiTreatment = broad spectrum antibiotic until indentification is processed.
memorize

Viral & other Causes of Myocarditis

PathogenPresentationDisease(s) causedOther
Coxsackievirus B (genus of Picornaviridae)Peri-/Myo-carditis symptoms mimic an MI = fever, precordial pain, arrhythmias and signs of HF

Neonatal myocarditis = fever, poor feeding, irritability, respiratory distress & RAPIDLY progressing cardiac failure (acquired from mom during birth)

Pleurodynia = abrupt onset fever & INTENSE abdominal/chest pain
Pericarditis & myocarditis

Neonatal myocarditis

Pleurodynia
human is only reservoir --> enters mouth --> replicates in oropharynx & intestine --> spreads to target organs (e.g. the heart) --> enters cardiomyocytes & macrophages --> replication & destruction of infected cells --> priduction of viral proteases that cleave host proteins (e.g. dystrophin) --> contractility problems & fibrosis --> activated immune response leads to autoimmune injury (molecular mimicry)Treatment of myocarditis possible via analgesics --> limits damage to heart tissue by immune response. Also limit activity & salt intake
Trypanooma cruziDILATION of HEART, Megacolon, Megaesophagus

Arrhythmias are COMMON (RBBB with or w/o bifasicular block in 50% & ventricular arrhythmias in 40%)
Chagas Disease (prevalent in S. America & Central America) that can lead to severe myocarditistransmitted to humans via feces of the TRIATOMID BUG (Reduviid big/kissing bug) --> multiplication of Amastigotes in the heart --> inflammatory response triggers autoimmune-related damage to endocardium/blood vessels/striated muscle --> HEART DILATES TREMENDOUSLY!Parasite prefers to infect cardiac, smooth & skeletal muscle & DOES NOT undergo antigenic variation (= no cyclic fevers)
Pts with HIVnormally clinically silent

when symptoms are present = fever dyspnea, CHEST PAIN, fatigue, cough, orthopnea

PE = HEPATOMEGALLY & JVD, crackles (rales), systolic murmurs, and presence of S3 gallop
Myocarditis (>90%) and Endocarditis (5%), and PericarditisMost commonly observed in AIDS pts

Exact mechanism unknown
Infectious causes of Cardiac Dz in HIV-infected pts:

Bacterial = Mycobacterium tuberculosis, Mycobacterium avium-intracellulare, Nocardia asteroides, Actinomyces

Fungi = Cryptococcus neoformans, etc.

Viruses = CMV, HSV, HIV

Protozoa = Toxoplasma gondii, Pneumocystis jirovecii
Diagnosis via:
cardiomegaly on X-ray, Echo may show ventricular enlargement, pericardial effusion & ventricular hypokinesis

Treatment = diuretic therapy (for CHF) and/or ACEI/ARBs/BBs to reduce preload and afterload & correct arrhythmias
memorize