Lupus is a very diverse disorder and this is one of the reasons it is sometimes difficult to diagnose, and why some patients wait for years for a proper diagnosis. It can affect many organ systems in a large number of ways. The lungs are frequently involved and can be the initial presenting complaint or occur late in the course of established disease. The seriousness of lung involvement varies from that which produces no symptoms and has no consequence to potentially very serious changes.
Microscopic examination of the patient's affected lung has shown a variety of changes including bleeding, inflammation and congestion. Thickening of the lung wall and damage to the blood vessels is also seen. It is thought that these problems are brought about by deposition of complexes which are formed when the body launches an immune attack against itself. Why these complexes should be deposited in the lungs (or anywhere else for that matter) is largely unknown, Types of lung involvement in lupus can be divided up as shown below. A brief description of each is included in brackets. Lupus commonly affects the lungs and has been reported in half of all patients with lupus. Its seriousness varies from the very worrying to the totally and wholly asymptomatic, not requiring any treatment at all. It is, in general, picked up by symptoms of lung involvement (chest pain), shortness of breath, coughing up blood, or by evidence of lung involvement on clinical examination and sometimes by special tests. Diagnosis may be simple or difficult depending on the type of underlying lung involvement.
1. Pleural Disease (Inflammation of the lung lining)
This is a disorder of the lining of the lung (pleura) and is the commonest manifestation of lung involvement in lupus. Inflammation gives rise to pleurisy, a type of chest pain characterised by sharpness, which is worsened by breathing in. The pain has a knife-like quality. this sort of problem has been recorded in about half of all patients with lupus. It may also occur without giving rise to any symptoms and has been seen in many patients who do not recall having had any chest pain at all. If the pleura does become inflamed then fluid may collect. this is normally small volumes and it is unusual to get large collections around the lungs.
The fluid that collects around the lungs in patients with lupus has certain characteristic abnormalities which may assist the doctor in diagnosing what the cause of the fluid is. In all patients other causes of fluid in the lungs needs to be excluded. the main lines of treatment are non-steroid anti-inflammatory drugs but small doses of oral steroid tablets (Prednisolone) are sometimes required to effectively relieve the pain. More aggressive treatments including surgical removing of the lining of the lung are, fortunately, rarely needed.
2. Acute Lupus Pneumonitis (lung inflammation)
This type of lung disease is fortunately rare and typically affects about 5% of all lupus sufferers. the patients present with shortness of breath, couch, rapid breathing and occasionally coughing up blood. What happens is that there is marked increase in the number of white cells within the lung which produces the clinical symptoms. The reason for this is unknown. Most patients who develop this complication have lupus involvement in other organ systems. An infectious cause for the symptoms must be rigorously excluded. High dose steroids are the mainstay of treatment.
3. Pulmonary/Alveolar haemorrhage (Bleeding into the lungs)
This is a very rare, dangerous manifestation of lupus. the presentation is similar to that of acute lupus pneumonitis but coughing up blood is a prominent symptom; this may be so bad that a patient loses so much blood that the blood pressure falls and they become shocked. in most patients this occurs in a background of pre-existing involvement of other organ systems. the blood count falls and the chest X-ray typically shows fluffy shadows. the diagnosis is made on the clinical presentation and by taking some lung to look at under the microscope. Aggressive treatment at a centre with experience is most likely to lead to a good outcome.
4. Diffuse Interstitial Lung Disease
This complication, which is seen commonly in rheumatoid arthritis, affects a small percentage of patients with lupus. the commonest presentation is a chronic cough, without sputum, and shortness of breath on mild exertion. the X-rays of such patients may be normal in the early stages but later show either small areas of thickened lung tissue, particularly at the bottom (bases) of the lungs. Breathing tests suggest that the lung is not as effective at exchanging gases as it ought to be. Lung scan (CT scan) gives a definitive diagnosis and will often show much of the changes are due to inflammation and how much due to the thickening and scarring. treatment is with (initially) high dose steroid and steroid sparing agents. there are also a number of experimental treatments which had not yet been validated by well designed controlled trials.
5. Pulmonary Embolism or clots on the lungs
This complication, whereby a clot which has formed in the calf veins, breaks off and travels through the venous system and ends up in the lungs causing death to a small a part of the lung. Although this may be seen in otherwise normal people, it is commoner in patients with lupus. It is much more common in those patients with lupus who have a circulating lupus anticoagulant or other anti-phospholipid antibodies. Treatment involves determining what the underlying cause is and thinning the blood down with initially Heparin, which is given by intravenous injection and later by Warfarin, tablet given by mouth. (See Hughes' Syndrome).
6. Pulmonary Hypertension (High blood pressure in the lungs)
Severe high blood pressure within the lungs is rare but mild cases are much more common. The most common complaints are shortness of breath on exertion and a chronic cough. Fatigue is another common but difficult to assess symptoms. It is thought that there is a strong genetic contribution to the development of this condition. there are a large number of treatments which can be tried, but none are terribly successful.
7. Shrinking Lung Syndrome
This was first described in a group of patients in 1965. The main symptom is shortness of breath with exertion but the patients are otherwise clinically well. the chest X-ray does not show any shadow, but the amount of lung available for gas exchange is markedly reduced. the diaphragm, which inflates the lung, also appears not to be working normally in such cases. This tends to be a chronic, low grade problem and treatment is with steroids but it is not always effective.
8. Airflow Limitation (narrowing of the airways)
This is seen in a small number of patients and is strongly associated with cigarette smoking, but it can occur in patients who have never smoked at all. It is thought that this condition is worsened by fatigue of the muscles of breathing which has been seen in 75% of lupus patients. Treatment is with sprays to open up the airways and perhaps tablets to assist this. the main symptoms are shortness of breath of exertion, sometimes accompanied by wheeziness.
9. Infection of the lungs (bronchitis and pneumonia)
This is commoner in patients with lupus than those without. this is partly due to the lupus itself and partly due to the use of steroid and other immunosuppressive drugs used to treat the underlying lupus. The presentation and clinical course of infection in lupus is often different to that of patients without lupus.