Pericarditis

Question 1

How much serous fluid is present normally within the pericardium?

Answer 1

50mL

Question 2

What is the mechanical function of the pericardium?

Answer 2

It restrains the volume of the heart. Parietal pericardium is stretchy initially but if the heart exceeds this reserve volume in the pericardial space, the pericardium serves to restrain the heart and pressure is transferred to the heart chambers.

Question 3

How is diagnosis of acute pericarditis made?

Answer 3

It is a clinical diagnosis is made with 2 from 4 clinical symptoms:

1. Chest pain - most common (85-90% of patients)
2. ECG changes - second most common (60% of patients)
3. Friction rub - reported to be in around 33% patients but a lot of times, pericarditis found is subacute and friction rub is only heard in the more severe forms of the condition.
4. Pericardial effusion (mild in 60%)

Question 4

Causes of pericarditis?

Infectious and non-infectious causes

Answer 4

80-90% idiopathic
Commonest cause is viral infection by coxsackie B virus for eg. in the developed world.

Secondary causes?

• primarily caused by viruses (coxsackie B virus, enteroviruses, herpes virus, adeno virus, parvovirus B19) in the developed world.
• Bacteria: mycobacterium TB (commonest cause worldwide and often accompanied by HIV so high mortality), lyme disease, pneumonia
• Fungal & parasitic - very rare (histoplasma & toxoplasma) - usually in immunocompromised

Causes of non-infectious pericarditis?

• Autoimmune (common) = Sjorgens syndrome, rheumatoid arthritis, SLE, IBD
• Neoplastic conditions - primary tumours are rare but secondary metastatic tumours are common (usually from lung, breast and lymphoma which leave deposits on pericardium)
• Metabolic - araemia, myxoedema (hypothyroidism), anorexia nervosa.
• Traumatic and iatrogenic (becoming more frequent due to surgeries and interventions) - can be due to direct injury, radiation injury, pacemaker insertions etc.
• Drug related (rare) - procainamide, penicillin, isoniazid, chemo.
• Other common causes - amyloidosis, aortic dissection, pulmonary arterial hypertension.

Question 5

What is the common clinical presentation of pericarditis?

Answer 5

Severe, sharp, pleuritic chest pain

• rapid onset of pain
• worse on inspiration = dyspnoea as a result
• relieved by sitting forward
• exacerbated by laying down
• cough
• hiccups may be present due to diaphragm stimulation
• fever may occur or viral infection present a few weeks prior to the chest pain

Question 6

Features of pericarditis on clinical exam?

Answer 6

• Pericardial rub (crunchin snow sound) heard at left sternal edge
• Sinus tachycardia
• Fever
• Signs of effusion (pulsus paradoxus)
• Becks Triad = distant heart sounds, distended jugular veins (elevated JVP), decreased arterial pressure (hypotension)

Question 7

Investigations for pericarditis?

Answer 7

ECG

• saddle shaped ST elevation
• PR depression
• No reciprocal ST depression (as you would see in STEMI) in lateral or inferior leads

Bloods

• FBC (increase in WCC, mild lymphocytosis),
• U+&, Troponin, LTFs (elevation suggests myopericarditis)
• ESR & CRP (high ESR may suggest aetiology)
• Troponin elevation suggests myopericarditis (higher mortality rate)

CXR

• often normal but looking for pneumonia which is common with bacterial pericardial effusion or underlying causes - need to exclude
• may show cardiomegaly which indicates pericardial effusion

Echocardiogram
- look for structural changes & help understand why they have pericarditis but also signs of pericardial effusion

Question 8

What are some differential diagnosis of pericardidis?

Answer 8

• MI (do not miss this)
• Pneumonia
• Pleuirsy
• Pulmonary embolism
• GORD
• Pneumothorax
• Pancreatitis
• Peritonitits
• Shingles

Question 9

What is cardiac tamponade?

What are the signs?

Answer 9

Pericardial effusion that raises intra-pericardial pressure, reducing ventricular filling and therefore, dropping cardiac output.
Can lead rapidly to cardiac arrest

Signs
- Reduced pulse 
- Pulsus paradoxus 
(fall in systolic BP >10mmHg in inspiration)
- Hypotension
- Increased JVP
- Kussmaul's sign
- Muffled S1 and S2

Question 10

How do big effusions occur?

Answer 10

Big effusions can occur when there is chronic and slow accumulation of fluid as the pericardium is able to adapt to the increase in fluid without transferring the pressure onto the heart chambers.
Slow accumulating effusions rarely cause. tamponade.

Question 11

What is a pericardial effusion?

Answer 11

Accumulation of fluid in a space. In pericardial effusion the fluid is accumulating in the pericardial sac.

Question 12

Management of pericarditis?

Answer 12

• NSAIDs (ibuprofen 600mg TDS PO 2/52) or Aspirin in USA (750-1000mg BD PO 2/52) with gastroprotection
• Colchicine (0.5mg BD PO 3/12) an anti-inflammatory & reduces occurrence of pericarditis and late complications but side effects often limit tolerability (nausea, diarrhoea)

Question 13

Prognosis of pericarditis? Risk of re-occurence?

Answer 13

• Most patients with acute pericarditis have a good long-term prognosis
• Cardiac tamponade rarely occurs in patients with acute idiopathic pericarditis
• Constrictive pericarditis may occur in 1% of patients with acute idiopathic pericarditis
• 15-30% of patients with acute pericarditis will develop recurrence - Colchine reduces recurrence rate by 50%

Question 14

What is the highest risk for developing constricting pericarditis?

Answer 14

Highest risk is if there is a bacterial aetiology - especially TB and purulent pericarditis.