**2. Etiology**

Similar to myocarditis, perimyocarditis is most commonly of viral aetiology and less likely due to bacterial infection. Viral etiologies are predominately due to the coxsackie B virus,

Perimyocarditis 107

Perimyocarditis has a wide spectrum of presentation with some cases being asymptomatic, some suffering from symptoms of the preceding viral illness and some presenting with acute heart failure and cardiogenic shock as in cases with fulminant myocarditis. 60% of the cases have constitutional symptoms including fever, arthralgia, malaise and chills. In 35% of the cases, there is chest pain which is usually mild, persistent, stitching, worsens with deep inspiration or coughing and radiates specifically to the trapezius ridge. Chest pain can sometimes be severe raising the suspicion of myocardial infarction which is always in the differential. Patients may also present with palpitations, syncope, Stokes-Adams attacks or sudden death due to arrhythmias including ventricular tachycardia and variable degrees of conduction abnormalities. Careful history taking is mandatory with specific reference to the patient's age, underlying medical problems including diabetes mellitus, hypertension, dyslipidemia, smoking history, positive family history of coronary artery disease and cocaine abuse that can place the patient at risk for myocardial ischemia. Clinical examination may be irrelevant with non-specific features as fever and tachycardia being the only positive clinical findings. Other clues in examination include a pericardial friction rub, however, only a minority of patients have pericardial rub on exam which tends to be transient and variable [26, 27]. A study of a cohort of patients with acute pericarditis confirmed poor sensitivity of a pericardial friction rub, which was found in only 35% of the cases [26]. Signs of decompensated heart failure (e.g. S3 gallop, elevated jugular venous pressure, lower limb edema and pulmonary congestion) can be detected in patients with

Laboratory investigations in perimyocarditis can reveal elevated white blood cell count (WBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and Brain natriuretic peptide (BNP) levels. Cardiac biomarkers are also elevated due to myocarditis. The incidence of elevated cardiac troponin I in patients with viral or idiopathic acute pericarditis has been reported to be 32.2%; of these patients 23.7% had a troponin I level at admission higher than those seen in myocardial infarction [28]. Elevated cardiac biomarkers in pericardial disease are not unusual and further complicate the diagnosis, raising suspicion for alternative diagnoses including myocardial infarction [29]. A study by Machdo et. al. concluded that perimyocarditis has a higher cardiac mortality than pericarditis [30]. This illustrates the importance of checking cardiac markers in all patients presenting with pericarditis. Studies also showed that elevated troponin is more common than elevated CKMB [31, 32]. The sole increase in troponin without other cardiac markers might represent

Because the pericardium is electrically inert, EKG changes found in patients with acute pericarditis are suggestive of an underlying myocardial involvement. The typical EKG evolution is seen in up to 60 % of cases of acute pericarditis [26]. EKG may reveal sinus tachycardia, diffuse ST segment elevation that is concave upwards involving any lead except aVR and V1. In pericarditis, T wave inversion occurs only after the elevated ST segment returns to baseline. ST-segment elevation associated with pericarditis should not

**3. Clinical picture** 

fulminant myocarditis.

a mild degree of myocardial injury.

**5. Electrocardiography** 

**4. Cardiac biomarkers and other laboratory tests** 

however, other viruses have been incriminated including cytomegalovirus [1], parvovirus B 19 [2], Epestein-Barr virus [3], Rubella [4], influenza A virus [5] and during hepatitis A virus infection [6]. The most famous bacterial pathogens associated with perimyocarditis are Borrelia burgderferi [7] and Campylobacter jejuni [8]. Others include Mycoplasma pneumonia [9], Chlamydia pneumonia, [10], Brucella [11], Rickettsia Helvetica [12], Yersinia enterocolitica [13], rickettsial Q fever [14], Shigella boydii [15], Shigella sonnei [16], tuberculosis [17], following Streptococcal tonsillitis [18] and Meningococcal septicemia[19]. The protozoan Toxoplasma gondii has also been described as a cause [20]. Immunizations have also been linked with perimyocarditis. The Smallpox vaccine has received great attention especially after its reinstitution for military personnel in 2002 and the report of 50 cases of perimyocarditis [21, 22]. There are several reported cases of perimyocarditis that developed hours after Diphtheria-Tetanus-acellular Pertussis (DTaP) vaccination [23, 24]. Perimyocarditis has also been linked to the administration of certain drugs including meselazine used in the treatment of inflammatory bowel disease [25]. Table 1 represents a compilation of reported etiologies of perimyocarditis.


Table 1. Causes of perimyocarditis.

however, other viruses have been incriminated including cytomegalovirus [1], parvovirus B 19 [2], Epestein-Barr virus [3], Rubella [4], influenza A virus [5] and during hepatitis A virus infection [6]. The most famous bacterial pathogens associated with perimyocarditis are Borrelia burgderferi [7] and Campylobacter jejuni [8]. Others include Mycoplasma pneumonia [9], Chlamydia pneumonia, [10], Brucella [11], Rickettsia Helvetica [12], Yersinia enterocolitica [13], rickettsial Q fever [14], Shigella boydii [15], Shigella sonnei [16], tuberculosis [17], following Streptococcal tonsillitis [18] and Meningococcal septicemia[19]. The protozoan Toxoplasma gondii has also been described as a cause [20]. Immunizations have also been linked with perimyocarditis. The Smallpox vaccine has received great attention especially after its reinstitution for military personnel in 2002 and the report of 50 cases of perimyocarditis [21, 22]. There are several reported cases of perimyocarditis that developed hours after Diphtheria-Tetanus-acellular Pertussis (DTaP) vaccination [23, 24]. Perimyocarditis has also been linked to the administration of certain drugs including meselazine used in the treatment of inflammatory bowel disease [25]. Table 1 represents a

**Etiology of perimyocarditis**

Rubella

Brucella

Cytomegalovirus Parvovirus B19 Epestein barr virus

Influenza A virus Hepatitis A virus

Borrelia burgderferi Campylobacter jejuni Mycoplasma pneumonia Chlamydia pneumonia

Rickettsia Helvetica Yersinia enterocolitica Rickettsial q fever shigella boydii Shigella sonnei Tuberculosis

Smallpox vaccine

tetanus vaccination alone

Systemic lupus erythematosus Acute rheumatic fever

Rheumatoid arthritis

vaccination

Methydolpa Sulphonamide Cocaine

Following streptococcal tonsiliitis Following meningococcal septicemia

Diphtheria-tetanus-acellular pertussis (DTaP)

compilation of reported etiologies of perimyocarditis.

Bacterial pathogens

Immunizations

Viral pathogens Coxsackie B virus

Protozoa Toxoplasma gondii

Immunologic/Connective tissue disease Sarcoidosis

Drug induced Meselazine

Table 1. Causes of perimyocarditis.
