A 56-year-old male, known hypertensive on Tab. Amlodipine 5 mg OD, presented to our emergency department with history of cough with expectoration – mucoid whitish sputum for 2 days, bilateral leg swelling, scrotal swelling and abdominal distension for 2-3 days, decreased urine output for 2-3 days, shortness of breath (NYHA Grade 2 to 3) with orthopnea for 2-3 days. He had history of high grade intermittent fever for 3 days, 1 week back for which he took supportive medications (afebrile for 1 week). He had no history of chest pain, palpitation, syncope, sweating, giddiness, abdominal pain, vomiting, diarrhea, rhinitis, sore throat, myalgia, arthralgia, rashes at presentation or the preceding month. His pulse rate was 90/min, blood pressure- 130/90 mmHg, respiratory rate – 22/ min, SpO2- 99% in room air, temperature- 98F, capillary blood glucose – 122 mg/dl. On examination, he was conscious, oriented to time, place and person, afebrile. He had bilateral pitting pedal edema, elevated jugular venous pressure, scrotal swelling without pain, tenderness, erythema. Systemic examination of respiratory system and central nervous system were normal. Per abdominal examination revealed a soft, uniformly distended abdomen with normal bowel sounds. ECG showed poor R wave progression and low voltage complex. ECHO revealed global hypokinesia, LVEF- 40% with no dilatation of cardiac chambers. Basic blood investigations done showed elevated Trop I(2.24), elevated NT pro BNP( 1865 pg/ml), elevated d dimer(10770 ng/ml), dilutional hyponatremia( 124.5 mmol/L), mildly elevated SGOT, SGPT and GGT. Complete blood count, renal function test were within normal limits (normal eosinophil count). In view of volume overload, patient was given Inj. Furosemide iv bolus and started on Inj. Furosemide iv infusion. Patient was started on dual anti-platelets, statin, beta blocker, ARNI, mineralocorticoid receptor antagonist and other supportive medications. Cardiologist opinion was sought and coronary angiogram was planned after stabilization of dyspnoea. CAG revealed normal coronaries. A provisional diagnosis of myocarditis/ inflammatory cardiomyopathy was made. Dengue IgM, Scrub IgM, HIV, Anti HCV, HbsAg, MPQBC, HHV-6 RTPCR, Parvovirus IgG were all negative. Blood culture done to rule out post bacterial myocarditis showed no growth. With the above measures, patient’s volume overload status improved. So, further work up for etiology was not pursued (including work up for Giant cell arteritis, Sarcoidosis). Cardiac MRI and endomyocardial biopsy were not done because of improvement with current treatment. Patient improved symptomatically and clinically. Patient was discharged after 4 days of hospital stay with oral medications (diuretic, antiplatelets, statin, beta blocker). Repeat ECHO done after 1 month showed an LVEF of 50%.
Case Discussion:
First description of myocarditis was made in 1749 by Jean Baptiste Senac in Versailles, France in his book ‘Treatise on disease of heart’ well before the description of coronary artery disease as a cause for angina pectoris was given by Nikolay Anichkov in 1950s. His book was based on autopsy studies and he described Myocarditis as an inflammation of the heart. Despite crossing two centuries since its first description and having Cardiac MRI in our armament, myocarditis remains under diagnosed in several circumstances. 10- 30% of all dilated cardiomyopathy is due to myocarditis but an attempt to diagnose it is not always made. Myocarditis is defined as the inflammatory disease of the myocardium diagnosed by established histological, immunological and immunohistochemical criteria. Myocarditis with LV dysfunction is inflammatory cardiomyopathy which could be acute or chronic. A definitive diagnosis of myocarditis cannot be made unless a tissue sample is obtained by endomyocardial biopsy (EMB). In general practice, EMB is not done in most centres for diagnosis of myocarditis. It is done only in life threatening conditions (cardiogenic shock, mobitz type 2 or higher heart block, sustained pleomorphic VT due to sarcoidosis, GC myocarditis or TB myocarditis). It is the only investigation which can help identify the etiology. Dallas criteria(histological): 14 or more lymphocytes/mm3 including 4 or more monocytes/mm3, 7 or more CD3 + T lymphocytes/mm3, necrosis and degeneration of adjacent myocytes in a pattern not consistent with ischemia. All myocarditis satisfy Dallas criteria except rheumatic myocarditis. A three tiered clinical classification for diagnosis of myocarditis by level of diagnostic certainty includes: 1) Possible subclinical acute myocarditis where the patient has no cardiovascular symptoms but biomarkers of cardiac injury are elevated, ECG shows findings suggestive of cardiac injury and ECHO/Cardiac MRI shows LV dysfunction. 2) Probable acute myocarditis where all the above feature are present with cardiovascular symptoms. 3) Definite myocarditis by EMB.
ECG changes include sinus tachycardia out of proportion to LV dysfunction, changes of pericarditis (due to myopericarditis), ST elevation or depression, wide QRS complex, pleomorphic VT(granulomatous myocarditis), heart block. ECHO shows global hypokinesia (RWMA can also be present), LV dysfunction, DCM, pericardial effusion (myopericarditis) ECHO is normal in subclinical myocarditis. CAG is normal.
Lake Louise criteria for cardiovascular magnetic resonance (CMR): Late Gadolinium Enhancement (LGE) patterns for ischemia are subendocardial infarct and transmural infarct. LGE patterns for myocarditis are midwall and epicardial patterns. 18 FDG PET scan is done only for sarcoidosis.
Myocarditis has the following presentations: Fulminant, asymptomatic, ACS-like, sudden cardiac death and chronic. Patients with fulminant myocarditis have two outcomes: death or resolution. Patients with asymptomatic myocarditis can have resolution but they can also develop DCM. Asymptomatic patients present with DCM without any antecedent infection history. Chronic myocarditis usually causes DCM.
Etiology of myocarditis is very vast. It can be due to infection with viruses, bacteria (Typhoid, TB, cholera, tetanus, etc),protozoa( Malaria, leishmania, chagas). Toxins like ethanol, cocaine, anthracycline drugs and systemic disorders like hypereosinophilia, sarcoidosis, Kawasaki disease, and granulomatosis with polyangitis are also causes. Most common cause of myocarditis is idiopathic. Most common identifiable cause is viral infection. HHV-6 and parvovirus-B 19 are the most common causes of viral myocarditis worldwide. Coxsackie and enterovirus used to be the most common cause earlier. HIV, Hepatitis C , CMV, EBV, mumps, rubella can also cause myocarditis. Even drugs like Dobutamine and clozapine can cause myocarditis.
Pathogenesis of viral infection: Viral infection can cause direct myocardial injury which has two outcomes. Either, there is complete resolution in course of time or the patient develops dilated cardiomyopathy due to severe myocardial injury. Viral infection can trigger immune response which causes viral clearance. If the immune response is inadequate, there is persistence of virus which can lead to DCM. Cross reactivity with self antigens due to molecular mimicry causes autoimmune myocarditis which can also cause DCM.
Treatment:
1) Acute fulminant myocarditis: supportive treatment with diuretics, ISDN. If the patient is in shock, inotropes can be used. IABP, ECMO, VAD can be used. Cardiac transplant is the final resort. If the patient survives, he/she will have near normal ECHO after recovery. Patient should avoid exercise for 6 months.
2) Subclinical myocarditis is usually not treated.
3) DCM is treated as HFrEF with diuretics, ACEI, beta blockers, MRA.
4) Prednisolone/Azathioprine/ Cyclosporine are used in Giant cell myocarditis, Sarcoidosis, eosinophilic myocarditis and CTD associated myocarditis after EMB.
Dr. M. Azharuddin
DNB 2nd Year Resident (General Medicine)
Kauvery Hospital Chennai