myocarditis and pericardial disease

Question 1

what is myocarditis

Answer 1

inflammation of the myocardium

Question 2

what are the 2 main types of triggers for myocarditis

Answer 2

external - infections (usually viral e.g. Coxsackie B, COVID), drugs;
internal (immune mediated) - hypersensitivity reaction to vaccines, autoimmune disease

Question 3

what is the pericardium and what are the components

Answer 3

two-layered sac that encircles the heart - tough outer fibrous layer (parietal pericardium); inner serosal layer (visceral pericardium - same as outer layer of the heart); there is a small fluid filled space between the layers to allow for reduced friction during beating

Question 4

3 main roles of the pericardium

Answer 4

1. anatomical - anchors the heart in the thorax, fixes the heart through its ligamentous function;
2. barrier - acts as a barrier to infection and reduced external friction;
3. mechanical - limits sudden dilation of the heart, maintains ventricular complicance, aids atrial filling

Question 5

3 diseases of he pericardium and how to treat them

Answer 5

1. effusion (fluid) - drain/diuretics;
2. pericarditis (inflammation) - anti-inflammatory;
3. constriction (fibrosis, thickened, scarred) - surgery

Question 6

what is the usual cause of acute pericarditis

Answer 6

vrial/idiopathic

Question 7

what is the treatment for acute pericarditis

Answer 7

NSAIDs and colchicine; usually self limiting; corticosteroids as 2nd line

Question 8

ECG changes in acute pericarditis

Answer 8

widespread saddle shaped ST elevation

Question 9

what is cardiac tamponade and what can cause it (4)

Answer 9

a medical emergency where effusion compresses the cardiac chambers and limits the filling of the heart; common causes - neoplastic, postviral, uraemic, traumatic

Question 10

what is beck’s tirade

Answer 10

1. low blood pressure (weak pulse or narrow pulse pressure)
2. muffled heart sounds
3. raised jugular venous pressure

Question 11

what determines whether pericardial effusion will result in fatal effects (tamponade) or not

Answer 11

the rate at which fluid accumulates - if it accumulates slowly then the pericardium has time to adapt and can become stretchy and so it takes more fluid to constrict the heart, if it rises rapidly then it only takes a small amount to compress the heart

Question 12

pericardial effusion QRS

Answer 12

QRS compleses may be short and vary in height form beat to beat (electrical activity insulated)

Question 13

what is the tamponade quadrad

Answer 13

1. hypotension - pericardial effusion interferes w filling of the heart -> decr preload -> decr SV -> hypotension;
2. tachycardia - compensatory mechanism to hypotension, heart cannot tolerate normal venous return in tamponade due to increased pressure on the chambers;
3. raised JVP - venous circulation pressure rises due to decr ability of heart chambers to accomodate;
4. pulses paradox - a decr of BP by >10 during inspiration (occurs with a smaller change in healthy individuals)

Question 14

normal pulses paradox mechanism

Answer 14

when breathing in, venous return incr to right heart causing the RV to bulge out and => the septum to bulge into LV, reducing its volume => filling decr -> decr SV -> systolic BP decr

Question 15

why is pulses paradox exaggerated in tamponade

Answer 15

RV can’t bulge out so septum bulges even more => LV filling is even more impaired

Question 16

how is tamponade treated

Answer 16

pericardiocentesis - aspirate with pericardial fluid

Question 17

what is constrictive pericarditis

Answer 17

thickened scarred paricardium forms a rigid shell around the heart -> inhibits normal filling of chambers

Question 18

what causes clinical features on constrictive pericarditis

Answer 18

1. incr systemic venous pressure (incr JVP, distended neck veins, peripheral oedema etc.)
2. low CO (fatigue, low BO)

Question 18

what is kussmaul’s sign

Answer 18

incr JVP on inspiration (opposite to normal); KEY differential for tamponade

Question 19

what is pericardial knock

Answer 19

an early diastolic sound due to ventricles filling v rapidly and stopping rapidly bc expanded to max

Question 20

treatment for constrictive pericarditis

Answer 20

surgical removal of pericardium

Question 21

what is dressler’s syndrome

Answer 21

an autoimmune form of pericarditis that occurs 2-3 weeks following MI (reaction to MI antigens)

Question 22

what is perimyocarditis

Answer 22

inflammation extending to the myocardium, can be fibrous or effusive w purulent, serous or haemorrhagic exudate

Question 23

what are the main causes of pericardial disease (9)

Answer 23

infectious: bacterial, TB, viral;
non-infectious: autoimmune, cancer, metabolic, trauma, radiation, drugs

Question 24

what are the 4 types of myocarditis

Answer 24

Giant cell myocarditis A: severe myocardial necrosis and fibrotic
replacement of the cardiomyocytes with granulation tissue and fibrosis in
anterolateral left ventricular wall
B: a sharp demarcating border between vital and necrotic myocardium,
confirmed by additional immunohistochemical staining for myoglobin
C: inflammatory border, cells consisting of prominent multi-nucleated
giant cells, macrophages, lymphocytes, and eosinophilic granulocytes
seen in close proximity to vital myocardium;
D: immunohistochemical staining for complement 4d is positive in all
vessels: complement cascade activation