What are the other Names for this Condition? (Also known as/Synonyms)

• Allergic Myocarditis
• Hypersensitivity Eosinophilic Myocarditis
• Myocarditis due to Drug Hypersensitivity

What is Hypersensitivity Myocarditis? (Definition/Background Information)

• Hypersensitivity Myocarditis is a heart condition that leads to an abnormal heart inflammation. It is caused by the body’s allergic reaction to a variety of medications, certain ingested compounds, or vaccines
• Individuals of any age (child or adult) may be affected by Hypersensitivity Myocarditis. The condition may cause chest pain, breathing issues, and congestive heart failure. It may result in complications that include arrhythmias or buildup of fluid around the heart (pericardial effusion)
• The diagnosis of Hypersensitivity Myocarditis may require a thorough physical checkup by the healthcare provider, blood tests, imaging studies of the heart, and an endomyocardial biopsy, if needed
• The treatment of Hypersensitivity Myocarditis includes steroid therapy, management of arrhythmias using anti-arrhythmic medication, and immunotherapy. However, the primary treatment is the discontinuation or stoppage of the offending medication/substance causing the condition
• With timely recognition of the condition and adequate treatment, the prognosis of Hypersensitivity Myocarditis is good. However, a delayed diagnosis and/or treatment may result in long-term damage to the heart

Who gets Hypersensitivity Myocarditis? (Age and Sex Distribution)

• Hypersensitivity Myocarditis is caused by certain ingested substances including medications (administered for other medical conditions); individuals of any age may be at risk
• Both males and females are affected
• There is no known racial, ethnic, or geographical preference

What are the Risk Factors for Hypersensitivity Myocarditis? (Predisposing Factors)

The risk factors for Hypersensitivity Myocarditis may include:

• The intake of certain substances or agents
• Use of certain medications such as antibiotics (amoxycillin)
• Vaccinations, in some cases

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Hypersensitivity Myocarditis? (Etiology)

• Hypersensitivity Myocarditis occurs as an adverse or allergic reaction to certain agents that may be taken for various conditions
• The offending substance/medication potentially causes an abnormal cell-mediated immune response in the body. This may take place after the first dose, in some cases; or, even after many dosages
• This hypersensitivity reaction affects the heart resulting in heart inflammation and a set of associated signs and symptoms

However, in some cases, the cause of the condition may be unknown (idiopathic Hypersensitivity Myocarditis).

What are the Sign and Symptoms of Hypersensitivity Myocarditis?

The signs and symptoms of Hypersensitivity Myocarditis vary from one individual to another; it may be mild in some and severe in others. In many cases, a sudden onset of the symptoms may be noted. Sometimes, the appearance of symptoms due to the drug may not be observed immediately.

Following are some of the common signs and symptoms noted:

• Chest pain and discomfort; acute chest pain can mimic heart attacks
• Fatigue
• Decreased ability to exercise, or decreased exercise tolerance
• Palpitations; abnormal heart beats
• Heart rhythm abnormalities (arrhythmias)
• If the individual has congestive heart failure, then it can result in shortness of breath, tiredness, and swelling of the extremities
• Difficulty in breathing may also occur while resting (in the absence of any physical activity)
• Skin rash, in some individuals, may be noted
• Liver function may be affected

There may be other symptoms related to the drug hypersensitivity.

How is Hypersensitivity Myocarditis Diagnosed?

A healthcare provider may use some of the following methods to diagnose Hypersensitivity Myocarditis:

• A complete physical examination and a thorough medical history, which includes the use of any drugs or other substances, is very important
• Examination of the heart
• Blood tests that include:
  • Calcium test and vitamin D blood level test
  • Angiotensin-converting enzyme blood test
  • Erythrocyte sedimentation rate (ESR) test
  • C-reactive protein levels in blood
  • Cardiac enzyme panel test; tests for cardiac enzymes
• Liver function test
• Imaging studies that include:
  • Chest X-ray
  • Doppler ultrasound: Sound waves are used to measure the speed and direction of blood flow
  • CT scan of the heart
  • Contrast-enhanced MRI scan of heart
  • Positron emission tomography (PET) scan
• Electrocardiogram (ECG): It is used to measure the electrical activity of the heart, in case of arrhythmias
• Endomyocardial biopsy: A tissue biopsy is performed and sent to a laboratory for a pathological examination. The pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

A differential diagnosis may be undertaken to eliminate the following heart conditions prior to arriving at a definitive diagnosis:

• Cardiac sarcoidosis
• Giant cell myocarditis
• Lymphocytic myocarditis

Note: A prominent eosinophilic inflammation may be observed on a myocardial biopsy.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Hypersensitivity Myocarditis?

Some potential complications of Hypersensitivity Myocarditis include:

• Abnormal heart rhythms and conduction disorders
• Inflammation of the sac surrounding the heart (called pericarditis) and collection of fluid around the heart (called pericardial effusion)
• Partial or complete heart block due to scarring of heart tissue

How is Hypersensitivity Myocarditis Treated?

Hypersensitivity Myocarditis may be treated through the following measures:

• Discontinuing use of the medication (or agent) responsible for the side effect or allergic reaction
• Steroid therapy; prescription of anti-inflammatory drugs, in severe cases
• For those with arrhythmias, anti-arrhythmic medication may be administered
• Immunosuppressive therapy
• Pacemaker and defibrillator implantation
• Pericardiocentesis (removal of fluid from pericardial sac) may be performed in case of pericardial effusion
• Observation and periodic checkups to monitor the condition is recommended

How can Hypersensitivity Myocarditis be Prevented?

Presently, there are no definitive preventative measures available for Hypersensitivity Myocarditis.

• Withdrawing or stopping the medication/agent causing the condition as early as possible is important. The healthcare provider may prescribe alternative medications to treat any existing, underlying condition
• Always notify the healthcare provider in case of any known allergy to a medication/vaccine

Periodic monitoring or follow-up of the condition with the healthcare provider is recommended.

What is the Prognosis of Hypersensitivity Myocarditis? (Outcomes/Resolutions)

• If diagnosed early and treated appropriately, the outcome of Hypersensitivity Myocarditis is usually good
• If the diagnosis is delayed, it can result in scarring of the heart muscles in the long-term, resulting in arrhythmias and other complications

Additional and Relevant Useful Information for Hypersensitivity Myocarditis:

The following article link will help you understand other heart conditions:

http://www.dovemed.com/healthy-living/heart-center/