THE SYNDROMIC NATURE OF SYMPTOMS IN ADHESIVE ARACHNOIDITIS
Adhesive arachnoiditis presents with diverse symptoms, which may relate to problems outside the CNS, and could therefore be described as a syndromic picture. However, bearing in mind that the treatments used for the neurological symptoms may cause a variety of side-effects, it is difficult to say exactly which symptoms can be directly and solely ascribed to arachnoiditis and which are more complex in origin.
The medical literature mostly describes symptoms in the lower back and or legs, with pain, weakness and sensory loss. Some authors also discuss bladder and sexual dysfunction. Jenik et al () described the symptoms as predominantly syringomyelic sensory deficits (see below).
A recent symptom survey amongst the support group COFWA (Circle of friends with Arachnoiditis) involving 66 members, has shown that there are a wide variety of symptoms. ()
One of the principal problems arachnoiditis sufferers experience is the dismissal of their symptoms as psychosomatic.
This section of the article will attempt to clarify the range of symptoms that may be experienced in arachnoiditis. It must, however, be stressed that many people with arachnoiditis will not have some of these symptoms, especially the uncommon ones.
The predominant and most distressing symptom of arachnoiditis is chronic, persistent pain which is primarily neurogenic (nerve generated) and thus difficult to treat.
This pain is transmitted from the dorsal root ganglia (DRG) in the spinal cord. In contrast with normal DRG, inflamed DRGs produce sustained pain impulse from any mild stimulus such as body movements or even breathing.
Pain tends to increase with activity. There is may be a delay after onset of activity, with a slow summation, to a point where the pain suddenly becomes unbearable and then persists once the activity has ceased. This can make it difficult for patients and physicians or physiotherapists to assess what is the tolerable level of exercise.
Pain may be due to other factors besides nerve damage. These include musculoskeletal secondary to disuse, overuse or compensatory use of muscle groups, due to alteration of spine dynamics. There may also be muscle tension due to being in pain, or increased muscle tone (spasticity) caused by nerve damage. Joint pain may be due to similar factors, or may be part of the autoimmune picture (see below).
Pain is generally described as burning, but often people are unable to describe it. This type of pain is termed dysesthesia (by definition indescribable, bizarre pain). It is not felt in normal people and is specifically a feature of incomplete nerve damage. It may sometimes be called deafferentation pain, or causalgia. Many patients suffer from burning feet, in particular.
The majority of patients also have transient shooting pains that may vary in intensity from an insect bite to an electric shock.
Some of the sensory problems may be generated from centres higher than the spinal cord. This is called central pain, and is due to hypersensitivity of the central nervous system. This type of pain may include feeling pain from normally painless stimuli especially from light touch such as clothing (this is termed allodynia). Changes in temperature commonly trigger this type of pain, so that sufferers have a very narrow window of comfort as regards temperature. (See also under autonomic effects).
Another problem may be an enhanced response to painful stimuli. This is called hyperpathia and may lead doctors to conclude that the patient has a low pain threshold. In fact, there is not a lowered threshold, rather a raised one, but once it is reached the response is magnified. This is called delay with overshoot. This is particularly noticeable in visceral hyperpathia in which normal bladder and bowel sensation is diminished, but once the signals of fullness are perceived, there is burning pain and urgency. This can lead to embarrassing accidents, especially if there is also nerve damage to bladder or bowel causing overactivity or sphincter dysfunction.
The areas commonly affected by pain are:
However, it is important to remember that one of the aspects of central pain is that pain may be experienced over large areas of the body, rather than just in the lower part. This may lead to fear that the disease has spread or may cause doctors to dismiss symptoms as psychological.
Therapeutically speaking, central (non-nociceptive) pain is generally acknowledged as being poorly responsive to opiate treatment. (See below). For this reason, it is important that evaluation of pain of central origin is undertaken.
Tingling and numbness are common features. Other sensory symptoms include loss of proprioception (sense of limb position up or down in relation to ground). This can result in tripping and falls. Temperature perception is sometimes diminished. There may also be bizarre sensations such as feeling as if you are walking on broken glass, water running down the legs, or insects crawling over the skin. These can be very distressing and many patients are reluctant to admit them to their doctor. A minority of patients may suffer from tinnitus and/or vertigo. Vertigo of cervical origin has been described in one paper (), with features of ataxia (unsteady gait).
Motor nerve damage may cause loss of muscle strength, especially in the lower back and legs, in some patients. In most cases with weakness, it is mild, but it may progress sufficiently in some patients to necessitate use of walking aids or even a wheelchair.
Also, many patients report that they fatigue quickly. There may be compensatory overuse of some muscle groups to allow the patient to walk, but this leads to the muscle fatiguing more rapidly than normal. This is similar to the picture seen in PostPolio Syndrome (PPS).
Increase in muscle tone is quite a common feature and makes the legs stiff, which may have an effect on mobility.
Muscle spasms and cramps may be violent and painful. Muscle twitches (fasciculations) are usually painless and transient.
A number of patients complain of symptoms suggestive of Restless Legs Syndrome, with nocturnal unpleasant sensations in the legs, accompanied by motor restlessness.
Less commonly there may be trouble swallowing, sometimes due to oesophageal muscle spasms. (See also under autonomic problems).
A common component of the arachnoiditis syndrome is the effect on the autonomic nervous system. (responsible for regulating involuntary processes such as blood pressure and temperature, bladder and bowel function etc.)
Disturbance of this system occurs because the nerves involved run along the spinal cord in the sympathetic and parasympathetic chains(thoraco-lumbar and cranio-sacral respectively).
Bowshers paper () on central pain describes how most patients with central pain develop autonomic instability, referring to increase of pain by physical and emotional stress, with cutaneous blood flow and sweating also being affected.
Ziegler et al () describe how systemic diseases such as diabetes can cause peripheral sympathetic neuropathy, giving rise to postural hypotension, heat intolerance etc. They
also maintain that patients with diseases of the sympathetic nervous system demonstrate marked abnormal stress responses to minor stresses such as change of posture or ambient temperature.
Principal symptoms of autonomic dysfunction include:
The following group of symptoms is reflective of the inflammatory nature of the condition and may point to an autoimmune component:
Miscellaneous problems such as osteoporosis (c.f. in RSD, or due to decreased mobility) low potassium (possibly due to medication), chest pain mimicking angina, recurrent sinusitis, dyspnoea (shortness of breath) are seen in a few patients.
Eye problems (see autoimmune symptoms) seem to be quite common, with patients who have undergone myelography complaining of photoaversion (intolerance of bright light). Some patients describe stabbing pains or tingling and seeing stars. There is an increased incidence of migrainous type headaches, often with auras. It should be noted that there is an association between photoaversion and anticonvulsant treatment, particularly phenytoin and carbamazepine. ()
Recurrent dental problems are quite common. Many patients undergo repeated root canal procedures but continue to suffer from facial pain and odontalgia (tooth pain) without attributable dental pathology. A number of patients also suffer from bleeding gums (periodontal disease) and a few have burning mouth syndrome. It is possible that some of these problems are related to medications that cause dry mouth, the lack of saliva contributing to reduced protection against infection and caries. The burning mouth symptoms could have a neuropathic component.
Dysphagia (difficulty swallowing) may affect some patients, especially those who have cervical pathology. In particular, this may occur if there is arachnoiditis accompanied by degenerative changes such as anterior osteophytes (bony outgrowths). However, it may also be experienced by those with only lumbar pathology, though the reasons are unclear.
Pharyngeal symptoms may include feeling as if a lump is stuck in the throat, and this may be dismissed by some clinicians as globus hystericus, a psychosomatic complaint.
Fatigue is a very common complaint, and can be due to a variety of factors.
Weight gain is a common problem. This is largely to do with decreased mobility and possibly to fluid retention secondary to medication (from drugs such as: Amitriptyline, Gabapentin, Ibuprofen, Morphine and other opiates, prednisolone/methylprednisolone).
Alternatively, some patients may suffer weight loss, due to general debility and often, poor appetite.
The cognitive effects of arachnoiditis are anxiety and reduced ability to think clearly, with some short-term memory impairment. These are usually in direct proportion to the pain level being experienced. ()
Sleep disturbance is common, and usually directly related to pain. It may contribute to depression, which is an understandable reaction to intractable pain, loss of function, loss of role and job, financial and relationship problems as seen in other chronic, debilitating conditions. Fear for the future (prognosis cannot be predicted) and uncertainty about the diagnosis substantially increase this problem.
Many sufferers are reluctant to admit to depression, as they fear that their more unusual symptoms may be more readily dismissed by doctors as a product of their mental state.
Side effects of medication. These occur, to some extent, in most arachnoiditis patients, largely because of the potent drugs involved, which are often in combinations. Opiates alone can cause a wide variety of side effects, but when taken in combination with adjuncts such as antidepressants, anticonvulsants or muscle relaxants, there may be a cumulative effect.
The most common side effects are dry mouth, constipation, drowsiness, nausea, dizziness, urinary retention and blurred vision. Some drugs, such as opiates, NSAIDS and certain antidepressants may cause fluid retention, and thus weight gain.
There are a few patients who develop liver and kidney problems, but it is difficult to distinguish adverse effects from medication (more probable) from effects of arachnoiditis on these organs, (which is unproven, but possible if it is an autoimmune syndrome).
IT MUST BE STRESSED THAT ANY PERSISTENT NEW SYMPTOM OR SUSTAINED INCREASE IN PAIN SHOULD BE CHECKED OUT BY A DOCTOR AND NOT ASSUMED TO BE PART OF THE ARACHNOIDITIS SYNDROME.