MYOCARDITIS

• Myocarditis is an inflammatory process involving the myocardium, can cause heart dilation, thrombi on the heart wall, infiltration of circulating blood cells around the coronary vessels and between the muscle fibers, and degeneration of the muscle fibers themselves.

Etiology

• Infectious Etiology/ Agents
  • Viral - (most common cause)
  • Most common cause - coxsackie virus A and B,
  • Other - HIV, influenza A, cytomegalovirus, adenovirus, parvovirus, herpes simplex and hepatitis C
  • Bacterial –
  • Most common bacterial cause is diphtheria,
  • Other - streptococcus pyogenes, staphylococcus aureus, salmonella, leptospira, borellia burgdorferi, mycoplasma pneumoniae, chlamydia, rickettsia
  • Protozoal - most common, Chagas disease in South America,
  • parasitic, - Trypanosoma cruzii, Toxoplasma
  • Fungi: Aspergillus (common), Candida
• 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.
• 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

Pathophysiology

Clinical Manifestation

• The symptoms of acute myocarditis depend on the type of infection, the degree of myocardial damage, and the capacity of the myocardium to recover.
• Patients may be asymptomatic, with an infection that resolves on its own.
• They may develop mild to moderate symptoms and seek medical attention, often reporting fatigue and dyspnea, palpitations, and occasional discomfort in the chest and upper abdomen.
• The most common symptoms are flulike including fever, fatigue, muscle pain, weakness etc.
• Patients may also sustain sudden cardiac death or quickly develop severe congestive heart failure.

Diagnostic test

• Laboratory Studies
  • Cardiac enzyme levels
  • These levels are only elevated in a minority of patients.
  • Cardiac troponin I may be more sensitive because it is present for longer periods after myocardial damage from any cause.
  • Erythrocyte sedimentation rate (ESR) is elevated in 60% of patients with acute myocarditis.
  • Leukocytosis is present in 25% of cases.
• Imaging Studies
  • Chest radiography
  • Echocardiography
  • MRI is capable of showing abnormal signal intensity in the affected myocardium.
• Electrocardiography 
  • Sinus tachycardia is the most frequent finding.
  • ST-segment changes

Management

• Patients are given specific treatment for the underlying cause and are placed on bed rest to decrease cardiac workload.
• Bed rest also helps decrease myocardial damage and the complications of myocarditis.
• In young patients with myocarditis, activities should be limited for a 6-month period or at least until heart size and function have returned to normal.
• Physical activity is increased slowly
• Management
• If heart failure or dysrhythmia develops, management is essentially the same as for all causes of heart failure and dysrhythmias, except that beta-blockers are avoided because they decrease the strength of ventricular contraction (have a negative inotropic effect).
• 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

Nursing management

Nursing Diagnosis

• Activity intolerance related to muscle weakness
• Ineffective Breathing Pattern related to depressed ventilation
• Risk for infection related to inadequate secondary defenses

Nursing Interventions

Promoting activity intolerance

• Facilitate development of appropriate activity/ rest schedule.
• Instruct patient in energy conserving techniques, eg. Carrying out activities at a slower pace
• Encourage progressive activity/self care when tolerated and provide assistance as needed.

Maintain airway and Breathing

• 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

Infection prevention

• 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.

Health Education

• Dilatory modification
  • 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.
• 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.
• Advice to continue self-monitoring and to schedule clinical follow up appointment