A therapy-relevant diagnosis can only be made myocardially (infectious or noninfectious myocarditis), taking into account the biopsy guidelines! All patients with etiologically unclear heart failure (cardiac insufficiency) must be clarified myocardially by myocardial biopsy.Laboratory parameters 1st order – obligatory laboratory tests.
- Small blood count [leukocyte count ↑ if applicable]
- Differential blood count
- Inflammatory parameters – CRP (C-reactive protein) or ESR (erythrocyte sedimentation rate) [if necessary ↑]* .
- High-sensitivity cardiac troponin T (hs-cTnT) or troponin I (hs-cTnI); NT-pro-BNP/NT-proBNP* [hs-cTnT: highly predictive of acute myocarditis when other causes of myocardial necrosis are excluded].
- Bacteriological/virological examination
- Electrolytes – sodium, potassium, calcium
- Renal parameters – urea, creatinine if necessary creatinine clearance.
Notice:
- * Normal values (leukocyte count, CRP, ESR) do not rule out acute or chronic myocarditis.
- Likewise, unremarkable troponin values do not rule out acute or chronic myocarditis.
Laboratory parameters 2nd order – depending on the results of the history, physical examination and obligatory laboratory parameters – for differential diagnostic clarification.
- Serology* * : AK against adenoviruses, borrelia, coxsackie viruses, CMV, Coxiella burneti, Candida sp., echinococci, echoviruses, influenza A u. B viruses, Mycoplasma pneumoniae, parainfluenza viruses, streptococci, Treponema pallidum (TPHA), Toxoplasma gondii.
- Bacteriology* * (cultural): blood culture or blood cultures (several at intervals of at least 60 min); streptococci (especially group A, viridans group); Mycoplasma pneumoniae; fungi and others, possibly mycobacteria.
- If autoimmune and rheumatic etiology is suspected: autoimmune serology: ASL, anti-DNAse, ANA, anti-cardiac muscle Ak (postinfarction), ANCA.
Further notes
- In the diagnosis of myocarditis, neither ECG changes nor an increase in cardiac enzymes by themselves have diagnostic value!
- * By means of N-terminal pro BNP (NT-proBNP), it can be clarified whether heart failure is present or not. NT-proBNP is synthesized by cardiac muscle cells mainly as a result of stretch stimuli and neurohumoral stimulation and released into the bloodstream.In patients with NT-proBNP levels below 125 pg/ml, left ventricular dysfunction (dysfunction of the left ventricle) can be ruled out despite the presence of suspected symptoms, such as dyspnea (shortness of breath)! Also, the NT-proBNP levels) increase significantly with increasing severity of heart failure (see below heart failure / laboratory diagnostics).
* * For an overview of all possible infectious causes, see “Causes.”
