CONFIRMING DIAGNOSIS Endomyocardial biopsy is rarely performed to diagnose myocarditis; the procedure is invasive and costly. A negative biopsy doesn’t exclude the diagnosis, and a repeat biopsy may be needed.
ECG typically shows diffuse ST-segment and T-wave abnormalities as in pericarditis, conduction defects (prolonged PR interval), and other supraventricular arrhythmias. Echocardiography demonstrates some degree of left ventricular dysfunction, and radionuclide scanning may identify inflammatory and necrotic changes characteristic of myocarditis.
Stool and throat cultures may identify bacteria.
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Diseases (Eighth Edition), 2005
Pericarditis:
Diagnosis
(Professional Guide to Diseases (Eighth Edition))
Because pericarditis commonly coexists with other conditions, diagnosis of acute pericarditis depends on typical clinical features and elimination of other possible causes. The pericardial friction rub, a classic symptom, is a grating sound heard as the heart moves. It can usually be auscultated best during forced expiration, while the patient leans forward or is on his hands and knees in bed. It may have up to three components, corresponding to the timing of atrial systole, ventricular systole, and the rapid-filling phase of ventricular diastole. Occasionally, this friction rub is heard only briefly or not at all. Nevertheless, its presence, together with other characteristic features, is diagnostic of acute pericarditis. In addition, if acute pericarditis has caused very large pericardial effusions, physical examination reveals increased cardiac dullness and diminished or absent apical impulse and distant heart sounds.
Chest X-ray, echocardiogram, chest magnetic resonance imaging (MRI), heart MRI, heart computed tomography scan, and radionuclide scanning can detect fluid that has accumulated in the pericardial sac. They may also show enlargement of the heart and signs of inflammation or scarring, depending on the cause of pericarditis.
In patients with chronic pericarditis, acute inflammation or effusions don’t occur — only restricted cardiac filling.
Laboratory results reflect inflammation and may identify its cause:
❑ normal or elevated white blood cell count, especially in infectious pericarditis
❑ elevated erythrocyte sedimentation rate
❑ slightly elevated cardiac enzyme levels with associated myocarditis
❑ culture of pericardial fluid obtained by open surgical drainage or cardiocentesis (sometimes identifies a causative organism in bacterial or fungal pericarditis)
❑ electrocardiography showing the following changes in acute pericarditis: elevation of ST segments in the standard limb leads and most precordial leads without significant changes in QRS morphology that occur with MI, atrial ectopic rhythms such as atrial fibrillation and, in pericardial effusion, diminished QRS voltage.
Other pertinent laboratory data include blood urea nitrogen levels to check for uremia, antistreptolysin-O titers to detect rheumatic fever, and a purified protein derivative skin test to check for tuberculosis. In pericardial effusion, echocardiography is diagnostic when it shows an echo-free space between the ventricular wall and the pericardium.
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Diseases (Eighth Edition), 2005
Myocarditis:
Diagnosis
(Handbook of Diseases)
The patient history commonly reveals recent febrile upper respiratory tract infection, viral pharyngitis, or tonsillitis. A physical examination shows supraventricular and ventricular arrhythmias, third and fourth heart sounds, a faint first heart sound, possibly a murmur of mitral insufficiency (from papillary muscle dysfunction) and, if pericarditis is present, a pericardial friction rub.
ECG typically shows diffuse STsegment and T-wave abnormalities (as in pericarditis), conduction defects (prolonged PR interval), and other supraventricular arrhythmias.
Echocardiography may show a weak heart muscle, an enlarged heart, or fluid surrounding the heart.
Stool and throat cultures may identify the causative bacteria. An endomyocardial biopsy can confirm the diagnosis, but it’s rarely performed.
Laboratory tests can’t unequivocally confirm myocarditis, but the following findings support this diagnosis:
❑ Cardiac enzyme levels (creatine kinase [CK], the CK-MB isoenzyme, aspartate aminotransferase, and lactate dehydrogenase) are elevated.
❑ White blood cell count and erythrocyte sedimentation rate are increased.
❑ Antibody titers (such as antistreptolysin O titer in rheumatic fever) are
elevated.
❑ Blood cultures may indicate infection.
» READ BOOK EXCERPT ONLINE »
Source: Handbook of Diseases, 2003
Pericarditis:
Diagnosis
(Handbook of Diseases)
Because pericarditis often coexists with other conditions, diagnosis of acute pericarditis depends on typical clinical features and elimination of other possible causes. It may be detected with X-ray, echocardiogram, magnetic resonance imaging, computed tomography, and coronary angiography. These tests may show scarring, contracture of the pericardium, or enlargement of the heart.
CLINICAL TIP: A classic symptom, the pericardial friction rub, is a grating sound heard as the heart moves. It can usually be auscultated best during forced expiration, with the patient leaning forward or resting on his hands and knees in the bed.
Pericardial friction rub may have up to three components, corresponding to the timing of atrial systole, ventricular systole, and the rapid-filling phase of ventricular diastole, Occasionally, it’s heard only briefly or not at all. Nevertheless, its presence, together with other characteristic features, is diagnostic of acute pericarditis.
In addition, if acute pericarditis has caused large pericardial effusions, the physical examination reveals increased cardiac dullness and diminished or absent apical impulse and distant heart sounds. Acute inflammation or effusions don’t occur in patients with chronic pericarditis — only those with restricted cardiac filling.
Laboratory results reflect inflammation and may identify its cause:
❑ normal or elevated white blood cell count, especially in infectious pericarditis
❑ slightly elevated cardiac enzyme levels with associated myocarditis
❑ culture of pericardial fluid obtained by open surgical drainage or cardiocentesis (sometimes identifies a causative organism in bacterial or fungal pericarditis).
Electrocardiography shows the following changes in acute pericarditis: elevation of ST segments in the standard limb leads and most precordial leads without the significant changes in QRS-complex morphology that occur with an MI, atrial ectopic rhythms such as atrial fibrillation, and diminished QRS complex in pericardial effusion.
Other pertinent laboratory studies include blood urea nitrogen level to check for uremia, antistreptolysin O titers to detect rheumatic fever, and a purified protein derivative skin test to check for tuberculosis. In pericardial effusion, echocardiography is diagnostic when it shows an echo-free space between the ventricular wall and the pericardium.
» READ BOOK EXCERPT ONLINE »
Source: Handbook of Diseases, 2003
Endocarditis:
Diagnosis
(Handbook of Diseases)
Three or more blood cultures in a 24- to 48-hour period identify the causative organism in up to 90% of patients. The remaining 10% may have negative blood cultures, possibly suggesting fungal infection or infections that are difficult to diagnose such as Haemophilus parainfluenzae. Other abnormal but nonspecific laboratory test results include:
❑ normal or elevated white blood cell count
❑ abnormal histiocytes (macrophages)
❑ elevated erythrocyte sedimentation rate
❑ normocytic, normochromic anemia (in 70% to 90% of endocarditis cases)
❑ positive serum rheumatoid factor (in about one-half of all patients with endocarditis after the disease is present for 3 to 6 weeks).
Echocardiography may identify valvular damage. Transesophageal echocardiography allows visualization of cardiac structures. Electrocardiography may show atrial fibrillation and other arrhythmias that accompany valvular disease.
» READ BOOK EXCERPT ONLINE »
Source: Handbook of Diseases, 2003
Learn what factors may dictate whether you need treatment to prevent an infection in your heart.
Heart trouble may sound like a click away if you have mitral valve prolapse (MVP). But this common misfiring in the heart is seldom serious. Learn...
Health insurance is important to everyone, especially people with chronic conditions like Crohn's disease and ulcerative colitis. Tune in to...
Sleep is necessary to feel refreshed, but now we know sleep actually impacts the way the body functions. Sleeping poorly can affect how often you get...
See full list of 4 related videos
» Next page: Signs of Endocarditis
Rate This Website
What do you think about the features of this website?
Take our user survey and have your say:
Website User Survey
Medical Tools & Articles:
Next articles:
Tools & Services:
Medical Articles:
Forums & Message Boards
- Ask or answer a question at the Boards:
