Lupus and the brain

Karel De Ceulaer, Contributor

Systemic lupus erythematosus, commonly called lupus, is an auto-immune disease which can affect any organ at any time. The organ can be impaired by two mechanisms: a direct attack of antibodies or decreased blood circulation.

Under normal circumstances, the brain is protected from attacks by viruses and bacteria by a membrane, blocking the exchange of organisms and large proteins. Under these conditions, antibodies find it hard to cross this barrier. In principle, autoantibodies would hardly cause any disease. However, if inflammation damages the barrier, the antibodies can reach the brain cells and the brain will then malfunction.

Autoantibodies are thought to cause general malfunction of the brain, as is seen in psychosis, cognitive disorders and mood disorders (severe depression). Patients can develop bizarre behaviour. They can have difficulty with social interactions, or be unable to carry out daily, life activities. They can develop hallucinations and delusions. All of this is very alarming to the patient's family and circle of friends.

However, treatment with corticosteroids and cytotoxic drugs (for example, cyclophospha-mide) can decrease the antibody load, reduce the inflammation, and the patient will return to normal. It is important, however, that the patient's relatives and friends understand that this episode is a temporary expression of the disease, rather than a permanent sign of some brain disease. Many lupus patients have lost many good friends due to misinterpretation of their behaviour.

When lupus interferes with blood circulation, the blood vessels may narrow, become completely occluded or the blood flow slows down to a minimum. This creates, at best, a shortage of vital oxygen in parts of the brain, and many patients will get small or large infarcts. Depending on the size and the location of the infarcts, there are many resulting clinical features.

Stroke and epileptic fits are the classic examples. The eye is often involved, leading to decreased or loss of vision. Some antibodies, called anti-phospholipid antibodies, are notorious for causing thrombosis and infarcts. Indeed, any lupus patient who has experienced a deep venous thrombosis, stroke or myocardial infarct should be checked for it. If these antibodies are present in high concentration, thinning of the blood with Warfarin may be life-saving.

Lupus may affect the spinal cord and the peripheral nerves. The commonest symptom would be a numbness in the feet. But some patients experience muscle weakness. In a few, the muscle weakness my ascend from the feet to the legs, then the abdomen and involve the muscles of the chest. Obviously, this is a dangerous situation. Other patients lose the temporary use of the legs because of poor blood supply to the spinal cord.

The lupus symposium will be held October 31, at the preclinical Lecture Theatre, University of the West Indies, at noon.

Dr Karel De Ceulaer, consultant rheumatologist, University Hospital of the West Indies, and president, Lupus Foundation of Jamaica; email: yourhealth@gleanerjm.com.