RHEUMATIC HEART DISEASE

Worldwide, rheumatic heart disease remains a major health problem. Chronic rheumatic heart disease is estimated to occur in 5-30 million children and young adults; 90,000 individuals die from this disease each year. The mortality rate from this disease remains 1-10%. A comprehensive resource provided by the World Health Organization (WHO) addresses the diagnosis and treatment

Definition

Rheumatic heart disease is a condition in which permanent damage to heart valves is caused by a disease process that generally begins with a strep throat caused by bacteria called Streptococcus, and may eventually cause rheumatic fever. In the pediatric age group, the sequelae of rheumatic fever consist of mitral, aortic, tricuspid valve stenosis.

orRheumatic heart disease is the most dreaded complication of rheumatic fever. The term "rheumatic heart disease" refers to the chronic heart valve damage that can occur after a person has had an episode of acute rheumatic fever. This valve damage can eventually lead to heart failure.

Epidemiology

Mortality/morbidity

Rheumatic heart disease is the major cause of morbidity from rheumatic fever and the major cause of mitral insufficiency and stenosis in the United States and the world. Variables that correlate with severity of valve disease include the number of previous attacks of rheumatic fever, the length of time between the onset of disease and start of therapy, and sex. (The disease is more severe in females than in males.) Insufficiency from acute rheumatic valve disease resolves in 60-80% of patients who adhere to antibiotic prophylaxis.

Race

Native Hawaiian and Maori (both of Polynesian descent) have a higher incidence of rheumatic fever (13.4 per 100,000 hospitalized children per year), even with antibiotic prophylaxis of streptococcal pharyngitis. Otherwise, race (when controlled for socioeconomic variables) has not been documented to influence disease incidence.

Sex

Rheumatic fever occurs in equal numbers in males and females, but the prognosis is worse for females than for males.

Age

Rheumatic fever is principally a disease of childhood, with a median age of 10 years, although it also occurs in adults (20% of cases).

PATHOPHYSIOLOGY

It is believed that certain proteins produced by the group A Streptococci are structually similar to those found in the heart. The immune system reacts to the presence of bacteria by producing specific substances, called antibodies, to attack them and stop their spread inside the body. But as these antibodies attack the bacteria, some of them also attack or cross-react with the tissues in the heart, and this often results in the manifestation of many RHD symptoms.

Classification

RHD

Mitral valve aortic valve tricuspid valve

Regurgitation Regurgitation Regurgitation

stenosis

A. MITRAL REGURGITATION: 

A condition which is characterized by a regurgitation of blood from the left ventricle into the atrium due to a problem with the mitral valve.

or

Backflow of blood from the left ventricle into the left atrium, owing to imperfect functioning of the mitral valve.

Hemodynamics

Chronic compensated stage

In this stage, the LV compensates by allowing greater diastolic filling and developing LV enlargement to augment forward stroke volume. More importantly, the left atrium dilates in response to the increased volume. Compensation for the increased volume can occur without resulting in increased pressure in the pulmonary circulation and the right heart. Left atrial compliance decreases the afterload on the LV, whereas LV dilation and hypertrophy increases contractility. These important changes keep the overall afterload on the left heart normal or unchanged. Although the regurgitant fraction may be high, the larger stroke volume compensates, maintaining a nearly normal forward cardiac output (see the image below).

Acute mitral regurgitation stage

Acute mitral regurgitation causes sudden volume overload of the left atrium and LV. Initially, the undilated left atrium restricts the regurgitant volume at the expense of increase in both left atrial and LV end-diastolic pressures.

Although total ventricular stroke volume increases compared to normal, total forward stroke volume usually decreases, thereby lowering cardiac output. In the acute situation, rapidly increasing left atrial pressure results in elevated pulmonary venous pressure causing pulmonary congestion and, eventually, pulmonary edema (see the image below).

Symptoms:

Children with mild to moderate regurgitation usually do not develop any symptoms and lead a normal life. Children with more severe leakage may experience symptoms such as:

 

 Shortness of breath

 Difficulty breathing, especially during exertion

Fatigue

 Rapid breathing

tachypnoea

 Poor feeding

 Delayed growth and failure to thrive

 Excessive sweating

 Fast heart rate

 Palpitations

 congestive Heart failure

Heart sounds: Upon auscultation, the first heart sound is usually slightly diminished, whereas the second heart sound is usually split. With more severe mitral regurgitation, a third heart sound and a mid diastolic low frequency murmur may be present, caused by increased ventricular filling.

Murmur: Patients with mild mitral regurgitation may reveal no signs other than a characteristic apical systolic murmur. The sound of the typical mitral regurgitation murmur is characterized as blowing and high pitched, and it is loudest over the apex with radiation to the left axilla. The murmur is often pansystolic, beginning immediately after the first heart sound, and may continue beyond the aortic component of the second heart sound, thus obscuring the murmur.

B. MITRAL STENOSIS

Definition

Mitral valve stenosis results from a pathologic process that narrows the effective mitral valve orifice.

Hemodynamics

Mitral stenosis obstruction to blood flow from LA to LV increase LA pressure hypertrophy of LA increase pulmonary venous pressure pulmonary congestion dyspnoea

Clinical manifestation

Patients with mitral stenosis may present with exertional dyspnea, fatigue, atrial arrhythmias, embolic events, angina-like chest pain, hemoptysis, or even right-sided heart failure. Previously asymptomatic or stable patients may decompensate acutely during exercise, emotional stress

The characteristic findings of MS on auscultation are an accentuated first heart sound, an opening snap, and a mid-diastolic rumble.

C. AORTIC REGURGITATION

Definition : A condition which is characterized by a backward leak from aorta into the left ventricle during diastole.

Classification

Mild :difference between systolic pressure in brachial artery and femoral artery is less than 20 mm of hg

Moderate: pressure difference is 20-40 mm of hg Severe: pressure difference is 40-60 mm of hg

HEMODYNAMICS

 Blood volume in LV increase increase size of LV impaired forward flow of blood

Wide pulse pressure diastolic pressure goes up on prolong time LV pressure increase pulmonary congestion

aortic valve insufficiency results in volume overload on the LV because the LV is forced to pump the entire diastolic volume received from the left atrium and the regurgitant volume from the aorta through an incompetent aortic valve. Over time, such volume overload (ie, increased preload) causes eccentric hypertrophy of the LV. If on prolong time LV myocardial functioning is failing diastolic pressure goes up and leads to increase LA pressure leading to pulmonary congestion

CLINICAL MANIFESTION

Palpitation, wide pulse pressure, decrease diastolic BP, prominent carotid pulsation ( corrigan’s sign), visible arterial pulsation, nodding of head may be present with each systole due to sudden filling of carotid vessel, arteriolar pulsation may be seen over the nail beds, uvula, lips, ear lobes.

Difference in systolic pressure between brachial and femoral artery. Cardiac examination reveals enlarge heart with apex displaced downward and outward,

D. TRICUSPID REGURGITATION

Definition: Refers to the failure of the heart's tricuspid valve to close properly during systole. As a result, with each heart beat some blood passes from the right ventricle to the right atrium, the opposite of the normal direction. 

Hemodynamics

Systolic leak volume load of RV, RA increase Increase size of RA, RV RA, RV diaplace downward and outward

Clinical features

Systolic and diastolic murmur loud during inspiration, pain right hypochondrium, fatigue, dyspnoea, pulmonary arterial hypertension, enlarged RA and RV displaced downward, prominent V waves in the jugular venous pulse, systolic pulsation of liver, systolic murmur in lower left sternal border increasing intensity with inspiraton

DIAGNOSIS Of RHD

History Physical examination

Vital signsCardiac examination

Laboratory Studies

Throat culture 

Throat culture findings for group A beta hemolytic Streptococcus are usually negative by the time symptoms of rheumatic fever or rheumatic heart disease appear. Attempts should be made to isolate the organism before the initiation of antibiotic therapy to help confirm a diagnosis of streptococcal pharyngitis and to allow typing of the organism if it is isolated successfully.

Rapid antigen detection test 

This test allows rapid detection of group A streptococcal antigen and allows the diagnosis of streptococcal pharyngitis and the initiation of antibiotic therapy. Because the rapid antigen detection test has a specificity of greater than 95% but a sensitivity of only 60-90%, a throat culture should be obtained in conjunction with this test.

Antistreptococcal antibodies 

The clinical features of rheumatic fever begin at the time antistreptococcal antibody levels are at their peak. Thus, antistreptococcal antibody testing is useful for confirming previous group A streptococcal infection. Sensitivity for recent infections can be improved by testing for several antibodies. Antibody titers should be checked at 2-week intervals in order to detect a rising titer.

Imaging Studies

Chest roentgenography 

Cardiomegaly, pulmonary congestion, and other findings consistent with heart failure may be seen on chest radiography. When the patient has fever and respiratory distress, chest radiography helps differentiate heart failure from rheumatic pneumonia.

Doppler-echocardiogram 

In acute rheumatic heart disease, Doppler-echocardiography identifies and quantitates valve insufficiency and ventricular dysfunction.

Other Tests

On ECG, sinus tachycardia most frequently accompanies acute rheumatic heart disease.

Histologic Findings

Pathologic examination of the insufficient valves may reveal verrucous lesions at the line of closure.

Procedures used for diagnosis

Exercise stress testing

o Exercise stress testing can usually be performed in children aged 6 years or older and is helpful in eliciting symptoms that may not be evident from routine history. Doppler studies can be helpful in determining whether exercise restrictions are necessary by measuring the change in aortic valve gradient from rest to immediately after maximal exercise.

o Exercise stress testing may also provide some risk stratification if intervention is delayed or contemplated. Factors such as heart rate, blood pressure response to exercise (blunted), exercise duration (reduced), provocable arrhythmias (ventricular ectopy of left ventricular origin) or ECG ischemic changes, and measured oxygen consumption provide useful data on which to base decisions regarding timing of intervention.

Cardiac catheterization

o Cardiac catheterization is usually performed in infants, children, and older adolescents in anticipation of balloon aortic valvuloplasty.

o Other indications for catheterization may include the need for accurate hemodynamic assessment in patients with multiple levels of obstruction, such as mitral stenosis or subaortic stenosis in combination with aortic valve stenosis.

MEDICAL MANAGEMENT

Medications: Medications do not rectify the valves but treat the complications and reduce the consequences. Medications cannot make up the mechanical problems due to narrowing of valves especially in stenotic cases which essentially require surgery. Medications are generally effective in valvular regurgitation cases.

Prophylactic penicillin for prevention of recurrence of rheumatic fever. Penicillin is an antibiotic that prevents the bacteria from forming a stable cell wall. Without this cell wall the bacteria are unable to reproduce and the patient's immune system can destroy the infection.Penicillin G and penicillin V. erythromycin in case of penicillin sensitive patient. An injection of 0.6-1.2 million units of benzathine penicillin G intramuscularly every 4 weeks.penicillin V 250mg BD or TDS. Benzyl penicillin G 600000 units IM single dose for wt <27 kg and 1.2 million for wt >27 kg.

1. Angiotensin Converting Enzyme (ACE) Inhibitors: These are used to widen blood vessels, lower blood pressure and decrease the workload on heart (in valvular regurgitation). Eg ramipril, 1.5mg/day

2. Antiarrhythmics: These maintain a regular heartbeat and reduce the rapid heart rhythms. Thus, the heart beats less frequently but pumps blood more throughout the body . Inj atropine

Age (years) Approximate (kg)

Dosage in ml (Four Times Daily)

2 11-14 1.5-3.03 12-16 2.0-3.04 14-20 2.0-4.05 16-23 2.5-4.5

6-8 17-32 2.5-5.09-12 23-55 3.5-5.0

3. Anticoagulants: Valvular problems can lead to blood clots. Anticoagulants help prevent clot formation inside the heart chambers or on a damaged heart valve. Eg aspirin 3-5 mg/kg/day

4. Antibiotics: Antibiotics are given to the patients suffering from valvular heart disease before any dental procedure, surgery and IV drug to prevent bacteria from sticking to abnormal heart valves. Amoxicillin 50 mg/kg orally 1 h before procedure. Ampicillin 50 mg/kg I.M./I.V. within 30 min before procedure

5. Beta-blockers: Beta-blockers slow the heart rate so the work of heart is made easier. Eg propanolol 2-4 mg/kg/day in two devided doses orally.

9. Digitalis: Digitalis is prescribed for treatment of arrhythmias, particularly atrial fibrillation. This drug increases the force of the heart muscle’s contraction and is helpful if a person has suffered congestive heart failure. Eg: digoxin 20–30 μg/kg IV; give 1/2 the initial dose, then 1/3 of dose at 8–12 h.

10. Diuretics: These drugs help the body rid of excess fluid and salt. Diuretics also reduce swelling and ease the workload on heart. Eg thiazide 2mg/kg/day BD and Infants under 6 months of age may require up to 3 mg/kg per day, in 2 divided doses. 

Surgical management

Valve repair: This is an open heart surgery in which the surgeon cuts in to repair the damaged valve. One such surgery is commissurotomy used to rectify mitral stenosis. In this procedure the narrowed valve leaflets are widened by opening the fused leaflets or commissures with a scalpel.

Prosthetic valve replacement Commissurotomy or vulvotomy Percutaneous Balloon Valvuloplasty: This is a nonsurgical catheter based procedure to treat

valvular stenosis. In this procedure, a catheter is threaded up to the heart through an artery in the groin and guided through the narrowed valve. At the point of narrowed valve, the balloon is gently inflated to stretch the valve. Once the valve is widened, the balloon is deflated and removed.

Diet

The diet should be nutritious and without restrictions except in the patient with congestive heart failure. In these patients, fluid and sodium intake should be restricted. Potassium supplementation may be necessary if steroids or diuretics are used.

Activity

Initially, patients should be placed on bed rest followed by a period of indoor activity before being permitted to return to school. Full activity should not be allowed until the acute phase reactants have returned to normal levels.

Nursing management

A. Assessment

The objective assessment is to collect data on :

Cardiac function

Tolerance to client activity and attitudes toward restrictions on activities

Nutritional Status

Discomfort level

Sleep disruption

Client's ability to overcome problems

The things that can help clients

Knowledge of parents and patients (according to the patient's age) of patient understanding.

Assessment :

Hospital chart

Monitor cardiac complications

Cardiac auscultation, heart sounds with the rhythm of marching weakened diastole

Vital signs

The presence of pain

The existence of joint inflammation

The presence of skin lesions

Nursing Diagnosis :

1. Reduced cardiac output associated with valve stenosis

goal :

Clients shows a decrease dyspnea

Participating in activities and demonstrate increased tolerance

Intervention :

Monitor blood pressure, pulse apical and peripheral pulse

Monitor cardiac rhythm and the frequency

Sleeping position 450 semifowler

Instruct the client to do stress management techniques (quiet environment, meditation)

Aids client activity as indicated when the client is able

Collaboration and providing oxygenation therapy

2. Activity intolerance related to decreased cardiac output, oxygenation supply and demand imbalance

goal :

Verbal Response fatigue is reduced

Carrying out activities within the limits of his ability (pulse activity can not be greater than 90 X / minute, no chest pain)

Intervention :

Energy saving clients during the acute

Maintain a sleep until the results of laboratory and clinical status improved

In line with the better situation, monitor the gradual increase in the level of activity

Create a schedule of activity and rest

Teach to participate in activities.

Teach the children / parents who do not realize that the movement is connected with the Korean and temporary.

In case of chorea, protect from accidents, bedrest and provide appropriate sedation program.