Brain and Nerves involvement in rheumatic diseases
Rheumatic diseases include different types of arthritides, connective tissues diseases, vasculitides, myositis etc. All of these are basically autoimmune diseases where one’s own immune system attacks their own body due to defects in differentiation between self vs foreign. Principal tissues to be affected are usually joints; however many other organs are also commonly affected including the nervous system. The nervous system can be divided into central nervous system (brain and spine) and peripheral nervous system (nerves, neuromuscular junctions and muscles). Each rheumatic disease can affect nervous system in a different way, at a different time in the disease duration. We will see about the common rheumatic diseases and neurological involvement in them.
Rheumatoid arthritis (RA) is a chronic, progressive, systemic inflammatory disorder where joints are the primary target. Extra-articular (other than joints) manifestations usually appear late in disease and usually seen in patients who have aggressive joint disease which is untreated/inadequately treated for long durations. These manifestations are also more common in whom antibodies for RA (rheumatoid factor and anti-CCP antibodies) are positive than in whom they are negative (I.e. Seropositive vs seronegative RA). RA can affect both central as well as peripheral nervous system.
Cervical spine involvement:
It is a late and severe manifestation of RA, usually seen in untreated RA patients. The incidence is reducing day by day with better availabilities of treatment facilities and better treatments as compared to past. Atlanto-axial subluxation (joint between first 2 vertebrae in the neck)is the commonest complication which can cause cervical spinal cord compression.The symptoms usually are neck pain along with tingling or numbness in hands and later can also develop motor weakness in hands. The diagnosis can be made by simple x-ray, but sometimes MRI may be needed. Some patients have ongoing inflammation (pannus) in these joints and may benefit from steroids and disease modifying anti rheumatic drugs (DMARDs), while others may need surgical intervention to stabilise the cervical spine. This manifestation needs to be identified at the earliest because if goes undetected this can lead to quadriplegia (weakness in all four limbs) and even to death.
Peripheral Nerve Involvement:
Entrapment neuropathies occur commonly with RA and can occur early in the disease. The commonest is carpal tunnel syndrome where median nerve (nerve that supplies a part of hand) is compressed at the level of wrist. Symptoms include tingling and numbness in the fingers of the hands usually sparing the little finger. It may also progress to motor weakness in these fingers. Majority of the patients improve with the treatment of RA with DMARDs. A small proportion of patients may need local steroid injection and an even smaller proportion may need surgical procedure to release the median nerve from the compression.
Long standing Seropositive, erosive RA can sometimes cause vasculitis (inflammation in blood vessels) which can sometimes affect multiple peripheral nerves at the same time (mononeuritis multiplex). This condition needs immediate treatment with aggressive immunosuppression to prevent permanent damage to nerves.
Ankylosing spondylitis is an inflammatory arthropathy that affects predominantly axial skeleton (spine). It begins in lower spinal joints called sacro-ileic (SI) joints and then ascends to involve the remaining spine. In late form of the disease, it can lead to spinal cord impingement at multiple levels and may need surgical intervention. Early diagnosis and effective treatment can prevent this manifestation.
Systemic Lupus Erythematosus (SLE):
SLE is a mutisystem inflammatory disease where organs other than joints are commonly affected from the initial presentation. Neurological manifestations are common. Common neurological conditions seen in SLE are psychiatric symptoms, headache, seizures. It may also cause stroke, transeverse myelitis (acute involvement of spinal cord leading to weakness in limbs as well as bowel/bladder incontinence); involvement of cranial nerves, peripheral nerve involvement (mononeuritis multiplex). Nervous system involvement in SLE is considered as a serious manifestation and almost all the patients usually have involvement of other major organs like kidneys, lungs, heart etc. It needs immediate hospitalisation and aggressive treatment with immunosuppression in most of the cases.
It is usually a mild connective tissue disease affecting mainly the tear secreting lacrimal glands and saliva producing salivary glands leading to dryness of mouth and eyes. Rarely, it can involve nervous system ranging from involvement of brain and/or spine with demyelinating disease to peripheral nerve involvement. Nerve involvement again can be mild with only sensory symptoms to mononeuritis multiplex which needs aggressive treatment with immunosuppression.
Vasculitis means inflammation of blood vessels. Inflamed vessel walls reduce the diameter of the blood vessel impairing the blood supply to the organ to which it supplies. Vasculitis can affect any organ in the body and is usually is serious systemic autoimmune disease. It can broadly be divided into three main groups: large vessel vasculitis (Takayasu arteritis, Temporal arteritis/Giant cell arteritis), Medium Vessel vasculitis (Polyarteritis Nodosa, Kawasaki disease) and small vessel vasculitis (ANCA associated vasculitis). Like other organs, nervous system is also commonly affected in these diseases.
Large vessel vasculitis can cause light headedness, dizziness, headache and visual disturbances. They can also lead to strokes. Medium vessel vasculitis can cause peripheral nerve involvement including mononeuritis multiplex. Small vessel vasculitis like ANCA (antineutrophil cytoplasmic antibodies is a blood test) associated vasculitis (previously called Wegener’s granulomatosis, Churg Strauss syndrome) can involve peripheral nerves in the form of polyneuropathies or mononeuritis multiplex as well as can involve brain in the form of mass, stroke etc. These all vasculitis warrant immediate consultation with a rheumatologist and aggressive treatment with immunosuppression. If left untreated, they can lead to permanent organ damage and even to death within few days to weeks.
Apart from above mentioned diseases, there are many other rheumatic diseases which can affect brain, spine or nerves in different ways and at a different time duration in the disease process. Myositis are the group of diseases which affect muscles and cause weakness in limbs. If untreated, they can lead to permanent muscle damage and disability. Respiratory muscle involvement can be fatal if not treated immediately.
Thankfully, almost all of these diseases and their nervous system involvement can be treated effectively. Early diagnosis, prompt and timely intervention can prevent permanent neurologic sequele as well as loss of precious life.