Lecture 1: Microbiology of the Cardiovascular System Flashcards
What are 6 differential diagnoses for Myocarditis?
- Acute MI
- Acute and/or chronic HF
- Atypical chest pain
- Pericarditis
- Cardiomyopathies
- Valvular disease
During PE/ausculation of patient with myocarditis what are 3 possible findings?
- Soft S3/S4 (impaired ventricular function)
- New murmur (2’ to valvular insufficiency - variable)
- Pericardial friction rub (if extension into pericardium)
With myocarditis the signs and sx’s will be similar to CHF of which part of h cardiac cycle?
What signs/sx’s?
- Systolic CHF (decreased contractility)
- Orthopnea, dyspnea on exertions, crackles, paroxysmal noctural dyspnea
Upon extra-workup for myocarditis utilizing an EKG what are you assessing for and what are the most common findings?
Which rhythm is most common?
- A assess for arrhythmia (sinus TACHY most common)
- Transient ST-T wave
What are 5 workups that should be considered to aid in your diangosis of myocarditis?
- EKG
- CXR
- Echocardiogram
- PCR - detection of viral genome
- Labs
What would an echocardiogram help you assess in a patients with suspected myocarditis?
- Ventricular function and structure
- Evaluation of ejection fraction, LV size, and wall abnormalities
Which 5 lab values would be helpful in the diagnosis of myocarditis?
- CBC (possible leukocytosis)
- Cardiac enzymes (likely ↑ 2’ to myocyte damage)
- BNP (signs/sx’s of HF)
- CPK (assesing muscle damage)
- ESR and CRP
Which invasive diagnostic study may aid in the definitive diagnosis of Myocarditis?
Endomyocardial biopsy
What are 3 possible complications of myocarditis?
- Dilated cardiomyopathy
- Myopericarditis
- Sudden cardiac death (20%)
Which 3 drug classes are feasible options for treating myocarditis?
- Beta blockers
- ACE-I
- Diuretics
What are 3 things that need to be avoided or reduced in a patient with myocarditis?
- NSAIDs and Alcohol
- Exercise (restricted)
What are the 3 most common infectious etiologies of Myocarditis?
- Coxsackie B
- Trypanosoma cruzi
- Trichinella spiralis
Which viral family does Coxsackie B virus belong to and what is it’s morphology?
- Picornaviridae, Enterovirus
- (+) ssRNA virus, small, naked, icosahedral
When is the peak incidence of Coxsackie B virus and it’s mode of transmission?
- Summer and fall
- Fecal-oral transmission
What are 4 clinical manifestations caused by Coxsackie B virus?
- URI
- Pleurodynia (Devil’s grip - severe intercostal pain and fever)
- Myocarditis (most common infectious etiology)
- Aseptic meningitis
Which parasitic cause of Myocarditis is described as a hemoflagellate (intracellular protozoa)?
Trypansoma cruzi
What are 2 diagnostic methods for Chagas disease (Trypanosoma cruzi)?
- Peripheral smear for trypomastigotes
- Xenodiagnosis
Signs/sx’s of acute phase Chagas Disease?
- Chagoma, Romana sign
- Fever, malaise, LAD
- CV: myocarditis
- CNS: severe meningoencephalitis (young pt’s)
What are the sign/sx’s of chronic Chagas Disease, both CV and GI?
- CV: dilated cardiomyopathy, arrhythmias
- Megalcolon and achalasia
What type of helminth is Trichinella spiralis**?
Invasive nematode
How is Trichinella spiralis transmitted?
Ingestions of cysts from raw pork (boars OR even horses)
Explain the life cyle of Trichinella spiralis upon ingestion of cysts, where do larvae mature and disseminate?
- Develop in gut –> mate –> larvae disseminate hematogenously
- Penetrate muscle tissue: skeletal, heart, and brain
What are the signs/sx’s Trichinella spiralis based on location in the body?
- Abdominal pain, diarrhea, fever (small intestines)
- Muscle aches (muscle invasion)
Periorbital edema, myositis, and eosinophilia should make you consider the diagnosis of which organism?
Trichinella spiralis
What are diagnostic techniques utilized for Trichinella Spiralis?
- Serologic (ELISA, etc.)
- Latex agglutination
- CPK levels
- Muscle biopsy
Extension of myocarditis into the pericardium is termed what?
Myopericarditis
What are the common presenting signs/sx’s of Pericarditis?
- Chest pain that is sharp, often positional and pleuritic in nature
- Often relieved by leaning forwards
- Fever
- Palpitations
What are the common PE findings associated with Pericarditis?
- Friction rub upon auscultation
- Rapid or irregular pulse
What is the hallmark EKG findings and in what leads for Pericarditis?
DIFFUSE ST elevations w/ RECIPROCAL dpressions in leads aVR and V1 w/ PR depression
Majority of CXRs with pericarditis show minimal abnormalities, what is the exception?
What characteristic findings?
- Pericardial effusion >250 mL –> symmetrically enlarged cardiac silhoutte
- “Water bottle sign”
Which imaging modality should be used in pericarditis to assess for pericardial effusion and/or tamponade, as it is more sensitive than CXR.
Transthoracic Echocardiogram
What would be a PE finding in pt with suspected Pericarditis that would warrant blood cultures?
Temp >38°C
What labs would be useful for diagnosing Pericarditis?
- Cardiac enzymes (serial)
- CBC w/ diff
- ESR
- CRP
- Blood cultures if temp >38°C
What is a possible complication of Pericarditis and how is it treated?
- Cardiac Tamponade
- Tx w/ pericardiocentesis
*Counsel about activity restrictions*
Which drugs should be utilized in Pericarditis due to viral etiology?
What is contraindicated?
- High dose ASPIRIN x3/day (ibuprofen, Indomethacin are options too)
AND
- Colchicine
- ANTICOAGULANTS ARE CONTRAINDICATED!!!!
Which infectious agent most often causes serous pericarditis and which most often causes causeous pericarditis?
- Coxsackie B = serous pericarditis
- Mycobacterium tuberculosis = caseous pericarditis
What is distinct morphology of Mycobacterium Tuberculosis?
Oxygen dependency and facultative intracellular in what?
- Acid fast bacillus (weakly G +)
- Obligate aerobes
- Facultative intracellular in Macrophages
Due to the mycolic acid cell wall composition Mycobacterium tuberculosis is highly resistant to what?
Desiccation (drying out) including NaOH
The virulence of Mycobacterium Tuberculosis is related to what factors?
- Facultative intracellular
- Sulafatides
- Cord factor
- Surface protein can cause delayed hypersensitivity and cell mediated immune rxn
- Wax D
Which 2 stains can be used for Mycobacterium Tuberculosis and the appearance of the organism with each?
- Acid Fast (Ziehl-Neelsen, Kinyon) = “red rods“
- Auramin-rhodamine stain = fluorescent apple green color