Non-Ischemic Myocardial Disease Flashcards
1
Q
the most common cause of myocarditis in the US is _____ which is caused mainly by ______
A
the most common cause of myocarditis in the US is viral myocarditis which is caused mainly by Coxsackie A & B
2
Q
describe the pathogenesis of viral myocarditis
A
- direct viral cytotoxicity
- cell-mediated immune rxns against infected myocytes
- cytokines release can aggravate myocardial dysfunction
3
Q
A
4
Q
describe clinical features of viral myocarditis
A
- clinical features:
- varies from asymptomatic to sudden acute heart failure or arrhythmias
- usually nonspecific symptoms
- flu-like
- fatigue, dyspnea, palpitations, chest pain, fever
- may mimic acute MI
5
Q
describe investigations of viral myocarditis
A
- investigations:
- PCR for viral nucleic acids
- serologic studies
6
Q
describe complications of viral myocarditis
A
- acute heart failure
- viral myocarditis may lead to dilated cardiomyopathy → chronic CHF
- arrhythmias: ventricular arrhythmias are the most dangerous → SCD
7
Q
describe myocarditis caused by Trichinella spiralis (Trichinosis)
A
- most common helminth associated with myocarditis
- histologically: eosinophils predominance
8
Q
describe myocarditis caused by Trypanosoma cruzi (Chaga’s disease)
A
- endemic in South America
- myocardium is involved in majority of cases
- parasitization of scattered myofibers by trypanosomes accompanied by a mixed inflammatory infiltrate
9
Q
describe myocarditis caused by Toxoplasmosis (Toxoplasma gondii)
A
- household cats are the most common vector
- causes myocarditis in immunocompromised
10
Q
A
11
Q
fungal myocarditis occurs in ____ individuals
describe the cells seen
A
fungal myocarditis occurs in immunocompromised individuals
- morphology is characterized by the presence of mixed inflammatory infiltrate composed of neutrophils, lymphocytes and plasma cells
12
Q
describe immunologically mediated myocarditis
A
- immunologically mediated
- SLE, polymyositis
- drug hypersensitivity:
- methyldopa, sulfonamides
- mild, self-limiting
- composed of lymphocytes, macrophages and a high proportion of eosinophils
13
Q
describe giant cell myocarditis
A
- idiopathic
- associated with SLE, thyrotoxicosis
- fatal disease of adults in their 3rd or 5th decades
- cause of death = CHF or arrhythmias
- histologically:
- granulomatous inflammation with many giant cells, lymphocytes, eosinophils and plasma cells
- focal to extensive necrosis
14
Q
A
15
Q
describe dilated cardiomyopathy (DCM)
A
- also called congestive cardiomyopathy
- characterized by:
- progressive cardiac dilation
- eccentric hypertrophy
- contractile (systolic) dysfunction
- leading to progressive heart failure
16
Q
name the etiopathogenesis of DCM
A
- idiopathic: majority of cases
- genetic mutations = 25-35% of cases
- most common: AD inheritance of mutations affecting cytoskeletal proteins
- less common: X-linked DCM due to mutations in the dystrophin gene
- uncommon: mutation of mt proteins involved in oxidative phosphorylation
17
Q
____ deficiency and chronic ____ can lead to cardiomyopathy
A
thiamine deficiency and chronic anemia can lead to cardiomyopathy
18
Q
____, a chemotherapy drug, can cause cardiomyopathy
A
doxorubicin, a chemotherapy drug, can cause cardiomyopathy
19
Q
describe peripartum cardiomyopathy
A
- occurs in the later period of gestation to first few weeks after delivery
- due to pregnancy-associated
- volume overload
- HTN
- nutritional disturbances
- 50% recover spontaneously
20
Q
A
21
Q
A
22
Q
describe clinical features of DCM
A
- affects mostly individuals between 25-50 years
- fundamental defect is ineffective contraction
- ejection fraction is <25% (normal = 50-65%)
- progressive CHF refractory to therapy, usually end-stage by the time of clinical discovery
- treatment = cardiac transplantation
23
Q
describe arrhythmogenic right ventricular cardiomyopathy (ARVC)
A
- AD disorder
- characterized by thin RV due to myocyte replacement by fatty infiltration → right-sided HF and arrhythmia → SCD
- defect in desmosomal adhesion proteins
- associated with Naxos Syndrome
24
Q
in ARVC, there is a defect in _____ and is associated with _____
A
in ARVC, there is a defect in desmosomal adhesion proteins and is associated with Naxos Syndrome
25
26
describe hypertrophic cardiomyopathy (HCM)
* characterized by:
* myocardial hypertrophy
* abnormal diastolic filling
* in 30% of cases there is intermittent left ventricular outflow obstruction (caused by anterior leaflet of MV)
* **primarily a problem with impaired diastolic filling rather than systolic dysfunction**
* overall size of LV chamber is small
* presents as exertional dyspnea or sudden death in young adults
27
describe the etiology of HCM
* familial AD with variable expression in most cases
* occurs due to missense point mutation in any of the following genes coding for sarcomeric proteins:
* B-myosin heavy chain = most common
* myosin-binding protein C
* cardiac troponin T
28
describe the pathogenesis of HCM
* pathogenesis of HCM
* gain of function mutation of the sarcomeric proteins → myocyte hypercontractility → increase energy use → intense compensatory hypertrophy (myofiber disarray) and fibroblast proliferation
29
describe the image
**hypertrophic cardiomyopathy**
30
describe the gross morphology of HCM
* gross:
* massive myocardial hypertrophy (thick walled) without ventricular dilation
* asymmetric septal hypertrophy: most prominent in the subaortic region
* on longitudinal section: banana-like configuration of ventricular cavity
* endocardial plaque/sclerosis in left outflow tract
31
**HCM: disarray, extreme hypertrophy and characteristic branching of myocytes, as well as interstitial fibrosis**
32
describe the clinical features and treatment of HCM
* clinical features
* exertional dyspnea
* angina or MI
* harsh ejection systolic murmur
* sudden death due to arrhythmias
* CHF
* treatment: therapy to relax the ventricles, partial septal muscle excision to reduce the outflow obstruction
33
describe restrictive cardiomyopathy
* least common type of cardiomyopathy
* characterized by stiff walls → loss of ventricular compliance → impaired ventricular filling during diastole (like constrictive pericarditis, HCM) → **diastolic dysfunction**
* systole is not forceful → **systolic dysfunction**
34
\_\_\_\_ is the most common cause of RCM
list other causes of RCM
**endomyocardial fibrosis** is the most common cause of RCM
* Loffler's syndrome
* radiation fibrosis
* amyloidosis
* hemochromatosis (can cause DCM)
* metastatic tumors
35
list clinical features and complications of RCM
* clinical features of RCM
* exertional dyspnea
* fatigue
* chest pain
* complications:
* arrhythmias
* CHF
36
describe the morphology and diagnosis of RCM
* _morphology of RCM_
* ventricles normal in size or slightly enlarged
* cavities are not dilated
* myocardium is firm
* both atria dilated
* patchy variable interstitial fibrosis
* _diagnosis_:
* endomyocardial biopsy
37
\_\_\_\_ is the most common cause of RCM
describe this condition
**endomyocardial fibrosis (EMF)** is the most common cause of RCM
* type of RCM
* children and young adults
* Africa and the tropics
* dense fibrosis of endocardium and subendocardium from apex to AV valves
* reduced volume and compliance of affected chambers
38
\_\_\_\_ is another form of RCM that leads to peripheral hypereosinophilia
explain this condition
**Loefflers endomyocarditis** is another form of RCM that leads to peripheral hypereosinophilia
* clinically a RCM
* endocardial fibrosis with large mural thrombi
* peripheral hypereosinophilia
* **abnormal degranulated eosinophils**
* **MBP from the granules damage the endocardium leading to necrosis and fibrosis**
