Myocarditis

MYOCARDITIS

Description 







 

When the heart is involved in an inflammatory process, often caused by an infectious agent, myocarditis is said to be present Inflammation may involve the myocytes, interstitium, vascular elements &/or pericardium Characterized by isolated pockets of inflamed & necrotic myocardial cells Myocardial involvement may be local or diffuse, but the myocardial lesions are generally randomly distributed in the heart & thus the clinical consequences are dependent on the size & number of lesions and the location of the lesions; a small single lesion residing in the conductive tissue may result in a fatal arrhythmia May be chronic or acute Usually of sudden onset

Risk Factors/ Etiology Age  Gender  Region 

A. Infectious etiology/agents 

:i) viral [measles, mumps, influenza]



ii) bacterial [diphtheria] iii) fungal [aspergillosis] iv) protozoan [toxoplasmosis, trypanosoma] v) roundworm [trichinosis] vi) rheumatic fever vii) serum sickness viii) chemical agent [lead] ix) collagen disease x) radiation xi) metabolic [uremia]

        

B. Toxic Etiology/ Agents 





 

Drugs that cause hypersensitivity reactions (clozapine, penicillin, ampicillin, hydrochlorothiazide, methyldopa, and sulfonamide drugs) Medications (eg, lithium, doxorubicin, cocaine, numerous catecholamines, acetaminophen) that may exert a direct cytotoxic effect on the heart. Environmental toxins include lead, arsenic, and carbon monoxide. Wasp, scorpion, and spider stings Radiation therapy may cause a myocarditis with the development of a dilated cardiomyopathy.

C. Immunologic Etiology/ Agents 

Connective tissue disorders such as systemic lupus erythematosus (SLE), rheumatoid arthritis, scleroderma, and dermatomyositis that can often result in a dismal prognosis



Idiopathic inflammatory and infiltrative disorders such as Kawasaki disease, sarcoidosis, and giant cell arteritis

Myocarditis also sometimes occurs when a person is exposed to: 





Certain chemical. These may include substance such as arsenic and hydrocarbons. Medication that may cause allergic or toxic reaction. These include antibiotics such as penicillin and sulfonamide drugs, as well as some illegal substances, such as cocaine Sytemic disease. The include lupus, other connective tissue disorder, inflammation of blood vessels(vasculitis), and rare inflammatory conditions such as Wegener’s granulomatosis.

Pathophysiology invasion of myocardium production of myocardial toxin immunologically mediated myocardial damage Inflammation of the myocardium

Assessment Findings Myocarditis vary from person-to-person depending on the cause and the severity. Symptoms may appear slowly or come on suddenly. 



      

If you have any of these symptoms you should contact your doctor right away. Flu-like complaints, including fever, fatigue, muscle pain, vomiting, diarrhea , and weakness Rapid heart rate Chest pain Shortness of breath and respiratory distress Loss of consciousness Sudden, unexpected death Sudden, intense myocarditis can lead to congestive heart failure . Some people have no symptoms (asymptomatic).

Diagnostic test  

laboratory Studies Cardiac enzyme levels  







These levels are only elevated in a minority of patients. Normally, a characteristic pattern of slow elevation and fall over a period of days occurs; however, a more abrupt rise is observed in patients with acute myocardial infarction.

Cardiac troponin I may be more sensitive because it is present for longer periods after myocardial damage from any cause.2 Erythrocyte sedimentation rate (ESR) is elevated in 60% of patients with acute myocarditis. Leukocytosis is present in 25% of cases.

 





Imaging Studies Chest radiography  A chest radiograph often reveals a normal cardiac silhouette, but pericarditis or overt clinical CHF is associated with cardiomegaly.  Vascular redistribution  Interstitial and alveolar edema  Pleural effusion Echocardiography  Impairment of left ventricular systolic and diastolic function  Segmental wall motion abnormalities  Impaired ejection fraction  A pericardial effusion may be present, although findings of tamponade are rare.  Ventricular thrombus has been identified in 15% of patients studied with echocardiography. MRI is capable of showing abnormal signal intensity in the affected myocardium.  Cardiac MRI is an emerging field in general, and contrast-enhanced T1- weighted MRI has been shown to have sensitivities and specificities approaching 100% for diagnosis.3  MRI can demonstrate nodular and patchy areas of inflammation, often seen first in the lateral and inferior wall and can be used to guide later biopsy.  MRI is also one of the modalities used in the evaluation of young patients with apparently idiopathic dysrhythmias, and this imaging study can differentiate focal and diffuse inflammation from the rare electrically significant myocardial tumor.

 

 



Other Tests Electrocardiography  Sinus tachycardia is the most frequent finding.  ST-segment elevation without reciprocal depression, particularly when diffuse, is helpful in differentiating myocarditis from acute myocardial infarction.  Decreased QRS amplitude and transitory Q-wave development is very suggestive of myocarditis.  As many as 20% of patients will have a conduction delay, including Mobitz I, Mobitz II, or complete heart block.  Left or right bundle-branch block is observed in approximately 20% of abnormal ECG findings and may persist for months. Viral isolation from other body sites may be supportive of the diagnosis. Polymerase chain reaction (PCR) identification of a viral infection from myocardial tissue, pericardial fluid, or other body fluid sites can be helpful. Persistent viral genome, as detected by PCR, has been identified as one marker of increased incidence of dilated cardiomyopathy and mortality. If a systemic disorder (eg, SLE) is suspected, antinuclear antibody (ANA) and other collagen vascular disorder laboratory investigations may be useful.

NCP PROBLEM: fatigue NURSING DIAGNOSIS: Activity intolerance related to muscle weakness NURSING INTERVENTION  Facilitate development of appropriate activity/ rest schedule.  Instruct patient in energy conserving techniques, e.g. carrying out activities at a slower pace  Encourage progressive activity/self care when tolerated and provide assistance as needed.

Problem: Shortness of Breathing Nursing Diagnosis: Ineffective Breathing Pattern related to depressed ventilation NURSING INTERVENTIONS  Monitor respiratory rate, depth, and ease of respiration.  Note pattern of respiration  Ausculatate breath sounds noting decreased or absence sounds, crackles or wheezes.  Observe color of tongue, oral mucosa and skin color.  monitor presence of pain and provide pain medication as for needed

Problem: Risk for infection Nursing Diagnosis: Risk for infection related to inadequate secondary defenses NURSING INTERVENTIONS  Perform/promote meticulous handwashing by caregivers and patient.  Maintain strict aseptic techniques with procedures/wound care.  Stress need to monitor/limit visitors.Provide protective isolation if appropriate. Restrict live plants/cut flowers..  Encourage frequent position changes/ ambulation, coughing, and deep-breathing exercises.  Monitor temperature. Note presence of chills and tachycardia with/without fever.

Dietary Management salt restriction and medications to control heart rhythm may be necessary  Avoid alcoholic beverages, cigarettes and vigorous exercises. Taking these steps can reduce the workload on your heart. 

Medical Intervention 



Management of myocarditis involves treating the underlying cause, such as the particular infection that may have set the stage for your heart inflammation. There’s no specific theraphy for cosackievirus B –the most common type of virus that causes myocarditis- other than treatment to relieve pain and other symptoms

Treating mild cases 



 

In mild cases of inflammation, your doctor may advise rest and prescription medication to give your body a chance to fight off the underlying infection while your heart recovers. If bacteria are causing your infection, your doctor will prescribe antibiotics. If it is viral, antiviral agents will be prescribed. Immunosuppressive therapy may be used if myocarditis is due to an autoimmune disorder such as lupus or scleroderma.

Drugs to help your heart Beta-adrenergic blockers  Beta-blockers should be avoided in the acutely decompensated phase of CHF and fulminant case of myocarditis but show long-term improvements in mortality. Loop diuretics  These agents are used for management of fluid overload. Calcium channel blockers  Although they have limited use in ischemic causes of CHF, calcium channel blockers may prove to be useful in myocarditis-related myopathies. Amlodipine, in particular, perhaps due to its effect on nitric oxide, showed benefit in animal models and in a placebo controlled trial. Angiotensin converting enzyme inhibitors  These agents are beneficial in the management of blood pressure and LV function in heart failure. Captopril, in particular, has been shown to be beneficial in the treatment of significant LV dysfunction. Other ACE inhibitors have not shown the same effect in animal trials, indicating captopril's oxygen radical scavenging properties in the morbidity effect.

Treating severe cases 





In many cases, the myocardial inflammation subsides, leading to a complete recovery. In people without symptoms, their heart get better spontaneously. Even people with very severe congestive heart failure may improve dramatically, often in just few day.

Surgical Management Place of a pump in the aorta (intra-aortic ballon pump)  Use of temporay artificial heart (assist device)  Consideration of urgent heart transplantation 

Client teaching 



Teach to monitor pulse rate and rhythm, encourage taking CPR traing. Advice to continue self monitoring and to schedule clinical follow up appointment

Myocarditis is hard to prevent. To help reduce your chances of getting myocarditis, reduce your exposure to identified causes. Some examples include:  Practice good hygiene to avoid the spread of infection. For example, wash your hands regularly.  Always use latex condoms during sexual activity.  Have sex with only one partner, who has sex only with you.  Do not use illegal drugs.