Pericarditis (Pediatrics)

Pericarditis is an inflammatory disease of:
 * Pericardium
 * Pericardial space
 * Adjacent tissues of the heart and large vessels

Acute viral pericarditis (causative include coxsackie viruses, adenoviruses, influenza virus, herpes viruses, ECHO viruses, and EB virus) represents one of the most common diseases in childhood, while purulent pericarditis secondary to bacterial sepsis is believed to be rare. Pericarditis can also be an accompanying symptom in diseases such as rheumatic fever, autoimmune diseases, malignancies, renal failure, tuberculosis, or fungal infections.

Sudden onset of high fever is typically present. A characteristic pericardial friction murmur is audible in systole and diastole during physical examination, intensifying when the stethoscope is pressed harder against the chest. As pericardial effusion increases, the pericardial murmur disappears and the heart sounds become noticeably quiet. The effusion can result in cardiac tamponade and sudden circulatory collapse.

Common symptoms of cardiac tamponade include severe shortness of breath, tachycardia, hepatomegaly, a weakly palpable peripheral pulse, paradoxical pulse, and hypotension with a small systolic-diastolic difference (low pulse pressure). As a result of pericarditis, pericardial adhesions may occur, and may also lead to constrictive pericarditis. Fortunately, this condition is very rare in children.

Etiology
Fibrinous (dry) pericarditis is characterized by large deposits of fibrin on the pericardium. Of the viral causative agents, the most common culprits are coxsackieviruses, adenoviruses, influenza, herpes, and echoviruses.
 * It usually manifests in the early stage of exudative inflammation, in which effusions accumulate between the layers of the pericardium.
 * The accumulating fluid in the pericardium can be transudate, exudate, blood,or pus.
 * As a result of pericarditis, adhesions of both layers can form in the pericardium, which can sometimes result in constrictive pericarditis.


 * Viral pericarditis is usually preceded by an upper respiratory tract infection or other viroses.
 * The prognosis is usually good, but recurrences are common (up to 30% of patients); however, their course is usually shorter and milder.

Purulent pericarditis is a rare, but life-threatening disease.
 * Usually, it occurs as a result of hematogenous spread secondary to bacterial sepsis resulting from bacterial infections of distant sites (pneumonia, meningitis, or septic arthritis).
 * The most common causative agents are Staphylococcus aureus and Haemophilus influenzae type b (Hib).
 * Constrictive pericarditis may develop later on.

Pathogenesis
The pericardium is a thin envelope of the heart and proximal parts of large blood vessels. There is a space between the visceral and parietal pericardium, which usually contains about 30 ml of lymph fluid in adults (facilitates the movement of the heart in the pericardial sac). The effect of pericarditis on hemodynamics results into excessive fluid accumulation in the pericardial space or anatomical changes of the pericardium (it turns into a rigid envelope - constrictive pericarditis). Accumulation of fluid in the pericardial space can cause increased intrapericardial pressure, which reduces diastolic filling of the heart => decrease in heart rate and CO / CI along with decrease in coronary perfusion. Rapid accumulation of pericardial fluid can cause cardiac tamponade and cause life-threatening situation, even with a slow accumulation of large volume of fluid, this may not lead to serious circulatory disorders.

In the pericardial tamponade, several compensatory mechanisms are involved, the most effective being an increase in heart rate (tachycardia compensates for a decrease in diastolic heart filling). Pulsus paradoxus is a common symptom of acute tamponade. It is defined as a fall of systolic blood pressure of >10 mmHg during the inspiratory phase. At the same time the finding can indicate a weakly filled pulse in periphery, which weakens in inspiration and disappears. During inspiration, the venous return to the right atrium and ventricle increases, but at the same time more blood accumulates in the lungs => paradoxical decrease in left ventricular output. Pulsus paradoxus is also found in constrictive pericarditis and asthmatic status.

Clinical picture

 * The onset of pericarditis is usually sudden with a high temperature.
 * Cough and respiratory pain indicate a current pleural impairment.
 * Fibrous pericarditis causes pain behind the sternum, which radiates up to the shoulder and neck.
 * Dyspnoea is accompanied by a tickly, dry cough.
 * It is auscultated by the pericardial friction murmur audible in systole and diastole . The murmur is formed by the displacement and friction of the inflammatory altered leaves of the pericardium during heart movements, the loudest being when standing forward. Reminiscent of crunching frozen snow under a shoe. It amplifies when the stethoscope is pressed harder against the chest and disappears with increasing fluid in the pericardium.
 * Exudative pericarditis is manifested by increasing dyspnoea. The heart sounds are noticeably quiet and the friction murmur disappears.
 * The liver is enlarged and we often find swelling.
 * Cardiomegaly can compress the left lung lobe, resulting in weakening and altered respiratory phenomena (Ewart's symptom).

Cardiac tamponade

 * A rapidly developing effusion in the pericardium can cause a cardiac tamponade.
 * The hemodynamic disorder is limited by filling of the heart in diastole and increased central venous pressure.
 * In advanced cases, cardiac output decreases and blood circulation collapses rapidly.
 * The main subjective symptom is severe dyspnoea.
 * During the physical examination, we often find dilatation of the jugular veins (the visibility is always limited in children), tachycardia, hepatomegaly.
 * Pulse paradoxus and a decrease in systemic arterial pressure with a small systolic-diastolic difference are advanced symptoms of cardiac tamponade, which can result in sudden cardiac arrest.

ECG and X-ray examination
ECG changes depend on the stage of the disease. In the initial stage we can find the elevation of the ST segments and the positive T wave, later the T wave becomes isoelectric and in the next course it inverts symmetrically. The voltage of QRS complexes is low. During the recovery period, the described changes gradually normalize.

On X-ray, we can notice that the heart shadow is enlarged in both directions during the pericardial effusion with a balanced left contour and a shortened and wide heart apex. If there is no large pericardial effusion, the heart can have a normal shape and size.

Echocardiography
We demonstrate the accumulation of fluid in the pericardium during echocardiographic examination. Invasion (inherniation) of the wall of the right atrium or even the right ventricle during massive pericardial effusion is a warning indirect sign of cardiac tamponade. In case of an exudate with a high protein content, there are often clear dense bands in the fluid corresponding to the fibrinoid fibers.

Laboratory examination
In pericarditis of unclear etiology, laboratory tests are focused mainly on the detection of viral or bacterial etiology. In addition to standard examinations, we collect blood cultures and serum for virological examinations (PCR, serology). At the same time, we have to use autoimmune markers to rule out the autoimmune origin of pericarditis. Fluid accumulation in the pericardium may also occur secondarily in malignant mediastinal disorders. In this case, we proceed with CT of mediastinum.

Therapy

 * Treatment of viral pericarditis is symptomatic. Bed rest and NSAIDs are highly recommended (e.g. ibuprofen 10 mg/kg, 3 times a day). Corticoids are added only if treatment fails after 48 hours. Pericardiocentesis is indicated for more significant effusion.
 * Treatment of purulent pericarditis usually requires surgical drainage of the pericardium and intravenous antibiotic treatment . Most often we choose potentiated aminopenicillins or Third-generation cephalosporins up to 3 or 4 weeks.
 * Pericardiocentesis is indicated in urgent cases with clear signs of cardiac tamponade and severe circulatory alterations. It is usually ineffective in terms of total elimination of effusion, due to its high viscosity and its high protein content.

Pericardiocentesis
In the case of a large pericardial effusion, especially if there is a risk of cardiac tamponade, therapeutic drainage of the pericardial cavity is indicated. Pericardiocentesis in children is performed under general anesthesia with echocardiographic control and continuous ECG monitoring. In the elevated position, a pig tail catheter is inserted from the subxiphoidal puncture approach. The second option is to introduce a chest drain from a subxiphoidal incision. After the initial evacuation of the fluid to release the cardiac tamponade, the rest of the effusion is discharged slowly while replenishing the blood volume. This approach allows severe hypotension from relative hypovolemia to be prevented by redistributing the circulating blood volume after tamponade release. The obtained puncture is sent for microbiological, virological examination and for biochemical analysis. We determine the total protein and perform lipoprotein electrophoresis to detect the presence of chylomicrons when chylous pericardium (chylopericardium) is suspected.

Constrictive pericarditis
Constrictive pericarditis is very rare in children, mostly associated with TB infection. Clinically, it manifests as exertional dyspnoea, weakness, fatigue, edema, chest pain and sometimes also with syncope (passing out). The determining factors in diagnosing constrictive pericarditis are discrepancy between the severe circulatory failure, the poor physical findings on the heart and the small heart on the chest X-ray. The ECG may show P-wave changes, reduced voltage of QRS complexes, T-wave changes that are flattened to inverted. On echocardiography we can sometimes see thickening of the pericardium. The indirect signs are atypical septal movement in diastole, dilatation of the inferior vena cava and enlarged atrium. Pericardiectomy is recommended.

Postpericardiotomy Syndrome
Postpericardiotomic syndrome is a non-specific reaction of the pericardium, epicardium and pleura, manifested by general inflammatory manifestations and increased production of pericardial and pleural effusions. It can occur days, even weeks after heart surgery. Clinical manifestations include subfebrile illness, chest pain, abdominal pain and rarely vomiting. Laboratory findings can show elevation of FW (erythrocyte sedimentation) and CRP. The pharmacological treatment consist of taking NSAIDs with corticosteroids. Overall prognosis is good.

Related articles

 * Pericarditis (internal)
 * Heart inflammation: Infectious endocarditis (pediatrics) • Myocarditis (pediatrics)

Source

 * HAVRÁNEK, Jiří: Srdeční záněty. (upraveno)