LUPUS: A GP Guide to Diagnosis
At some stage in the disease more than half of lupus patients will develop a heart abnormality. It is therefore one of the important clinical manifestations of lupus to detect although, of course, it need not necessarily be serious.
Lupus involvement of the heart may affect all its layers: the pericardium, myocardium, endocardium as well as the coronary arteries. Involvement may be primary or secondary to lupus damage to other organs, such as the lungs. In addition, symptoms may be confused with other clinical conditions such as reflux oesophagitis, pleurisy and costochondritis.
Working step-wise through the layers of the heart this chapter will describe how they may be involved in lupus and what the clinical manifestations are.
This is the most common heart abnormality in lupus and reports estimate that 6-45% of lupus patients will have some form of pericardial abnormality (it may, however, go undiagnosed).
Inflammation of the pericardium can cause symptoms due to the inflammatory mediators that accumulate and stimulate pain receptors. In some instances a pericardial effusion will occur and sometimes the effects of pericardial inflammation cause the pericardium to constrict, which may cause additional symptoms. An uncommon complication that may occur is for the pericardium to become infected by organisms (usually bacterial) that are carried to it in the blood.
The symptoms that may occur are as follows:
If a diagnosis is suspected, it can be confirmed by listening to the heart when a friction rub may be heard on auscultation. In addition, characteristic electrocardiographic changes may be present (tall T waves and elevated ST segments). An echocardiogram is useful for visualising pericardial effusions.
This is not a common problem and estimates suggest that up to only10% of patients will develop this cardiac abnormality.
Similar inflammation may also be found in skeletal muscles and myocarditis may be part of a generalised myositis. Some reports suggest that anti-RNP antibodies may be more prevalent in these patients. Interestingly, anti-myocardial antibodies have been detected in some patients with lupus, but they do not correlate with heart involvement.
Immune complex deposition within the myocardium is also thought to form part of the pathological process by activating the complement cascade.
Clinical symptoms of myocarditis:
Signs of congestive heart failure may also be present, with a gallop rhythm and other heart murmurs that may be heard on auscultation.
Investigations may demonstrate heart enlargement on x-ray and arrhythmias when the ECG is taken.
In lupus this can be called Libman-Sachs endocarditis. Inflammation of this heart structure results in small nodules (vegetations) being formed. These range from about 1-4mm in diameter and may be singular or conglomerate and have been described as "mulberry-like clusters". They are usually found near the edge of valves but can also occur between the atrial and ventricular chambers. Some reports suggest that antiphospholipid antibodies are associated with valvular heart disease, particularly affecting the mitral valve.
Clinical symptoms of endocarditis are:
Echocardiography can be used to visualise the vegetations and on auscultation murmurs can be heard as the blood becomes turbulent as it passes the vegetations.
Complications of endocarditis may be heart failure which could be due to the valves working inefficiently as a result of them not being able to close properly or due to valve stenosis, where the valves do not open fully. In addition, vegetations may break off from the valves and cause damage in a number of other locations such as the brain where a stroke may occur, the lungs where pulmonary embolism may result and peripheral vessels which may become blocked. Libman-Sachs endocarditis may be complicated by infection as the endocardium will be predisposed to attack by blood borne organisms. There may also be anaemia as a result of the inflammatory process.
Coronary thrombosis will cause myocardial infarction and, unfortunately, its incidence appears to be increasing. This may be because atherosclerosis is accelerated by long-term corticosteroid use and by lupus associated inflammation. Rarely is there inflammation of the coronary arteries (vasculitis) which results in occlusion of the vessel.
Coronary angiography may help differentiate atherosclerosis from arteritis.
It is estimated that an abnormal ECG is found in between 34-74% of patients. These abnormal tracings may reflect a primary abnormality of the heart itself, such as pericarditis or myocarditis or isolated conduction defects may occur such as complete heart block and atrial premature contraction. Sometimes the abnormal tracings may be secondary to other abnormalities in the body, such as an imbalance in the blood electrolytes e.g. a raised potassium level, which could be associated with kidney disease, or the use of drugs such as corticosteroids and diuretics.
NLS is a rare complication of lupus pregnancy and congenital complete heart block is one of its features. The presence of maternal IgG anti-Ro (SSA) and anti-La (SSB) antibodies are thought to be associated with damage to the heart's conduction pathways in the fetus. Whether or not these antibodies are involved in conduction defects that may occur in adult patients has yet to be established.
About a quarter of lupus patients will have blood pressure readings over 140/90 at some stage in their clinical course. This may of course be unrelated to lupus as it is a common condition but lupus associated causes are kidney disease and corticosteroid treatment.
Sometimes no treatment is required, for example, in small asymptomatic pericardial effusions. If the cause of the heart abnormality is thought to be associated with lupus, treatment should be aimed at reducing inflammation with NSAIDs, anti-malarial agents (e.g. hydroxychloroquine), corticosteroids and sometimes cytotoxic drugs such as azathioprine or cyclophosphamide.
Other drugs may also be necessary to counteract heart arrhythmias (e.g. beta-blockers) or heart failure (e.g. diuretics). If any part of the heart becomes infected then antibiotics, usually given intravenously, will be necessary. High blood pressure can be treated effectively by such drugs as nifedipine and ACE inhibitors. Drugs such as hydralazine, methyldopa and beta-blockers which may cause lupus-like syndrome can also be safely used without exacerbating the disease.
It is recommended that all lupus patients should receive antibiotic prophylaxis prior to and during surgery, including dental procedures.
Table 1 - Chest Pain in Lupus
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Dr. John Axford
Reader & Consultant Physician
Academic Unit for Musculoskeletal Disease
St George's Hospital Medical School
Cranmer Terrace
London, SW17 0RE