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Neurological
Aspects of Arachnoiditis by Dr. Sarah Smith IMPORTANT
NOTE: Part
Three: TYPES OF PAIN: In arachnoiditis, the predominant pain tends to be neuropathic (neurogenic), i.e. arising from nerve damage. However, one must also bear in mind that there may be musculoskeletal pain both from the original underlying spinal problem and also as a secondary feature due to muscle tension in response to unalleviated pain. So there may be a variety of different types of pain experienced. The commonest ones appear to be:
PINS AND NEEDLES The term paraesthesiae encompasses a wide variety of abnormal sensory experiences, which tend to be described as:
These sensations can arise from central nervous system abnormalities or peripheral nerve damage (peripheral neuropathy is a common cause). They
are most commonly experienced in the feet, hands, arms and legs, but can
occur anywhere on the body. SUMMARY: There are 3 important points to remember:
SWEATING: Excessive
sweating (hyperhidrosis or diaphoresis)
occurs when the sympathetic nervous system (part of the autonomic
nervous system which regulates involuntary body functions) is running on
overdrive. This seems to be a common problem in arachnoiditis, and is
probably in part due to direct effects on the sympathetic chain, which
runs alongside the spine, and also partly due to the chronic stress of
unremitting pain. A further reason might be that arachnoiditis patients
can experience intermittent low grade fevers and the sweating
(especially at night) might be related to this. Note that sweating can
occur regardless of environmental temperature (even in the cold) or
emotional state, cold sweats are
often quite profuse. The best bet is to implement some general measures: Firstly, avoid overheating your home or going to places which are likely to be overheated. If you can, avoid dealing with large temperature fluctuations. Reduce your caffeine intake. For
menopausal symptoms, HRT can be successful. · Bathe frequently, but avoid very hot baths/showers as this may well trigger a burst of sympathetic activity and thus profuse sweating.
AUTONOMIC DYSFUNCTION Symptoms:
Peripheral circulation abnormalities: Raynaud type syndrome: vasoconstriction of blood vessels in hands and feet: poor circulation. Changes in temperature cause a 3-phase colour sequence: white>blue>red. Can also affect nose, ears and tongue. Repetitive movements such as typing may worsen the symptoms. Overheating the affected part may also make matters worse Treatment: (a) Postural dizziness: elastic stockings, fludrocortisone 0.1-0.3mg daily, ephedrine, midodrine. (b) Reflux/delayed gastric emptying: metoclopramide 10mg before meals (c) Nocturnal diarrhoea: metoclopramide 10mg 8 hourly (d) Post-gustatory sweating: propantheline hydrobromide before meals (e) Bladder dysfunction/urinary retention: specialist assessment and treatment (see appropriate article*) (f) Impotence: specialist assessment and treatment (see appropriate article*) (g)
Raynaud’s: Avoidance of caffeine and nicotine can be helpful as
they both act as vasoconstrictors. Medication: nifedipine, prazosin.
topically-applied nitric oxide gel, (a study in 1999 showed it tripled
the blood flow to patients’ fingers, to the extent that it approached
that found in untreated healthy volunteers) fish oil, Evening primrose
oil (EPO), Gingko biloba(but note: increased risk of bleeding
abnormalities, especially if taken with anti-inflammatory medication
including aspirin). Invasive treatments such as a sympathectomy (usually
a toxic chemical such as phenol is injected into a sympathetic ganglion
to destroy the nerve), are not advised by the Arachnoiditis Trust. TINNITUS: This term refers to noises heard ‘in the ears’ or ‘in the head’ which don’t come from an external source.
There
may also be heightened sensitivity to external sounds : hyperacusis The Jastreboff model is as yet unfamiliar with many medical practitioners. The basic tenet of this model is that tinnitus is not an ear problem, but a brain one, and that retraining this part of the brain is feasible: this is known as Tinnitus Retraining Therapy. The goal of this therapy is to habituate the patient to the tinnitus. The
first vital step is to understand that the subconscious parts of the
brain which act as ‘filters’ and which focus on weak electrical
signals from the inner ear need to be retrained. This is NOT to suggest
that tinnitus is a psychological problem. However, it must be noted that
psychological distress (anxiety, agitation, anger) often accompany
tinnitus: these emotional responses are targeted in the retraining
strategy. What
retraining involves:
habituation of reaction: the initial stage of retraining habituation of perception: tinnitus becomes quieter and eventually disappears or becomes part of the natural background ‘sound of silence’. Retraining therapy takes time, about 2 years. *
hearing loss will cause a tendency to strain to hear, thereby increasing
the amplification of sound signals, increasing the sensitivity of the
brain and thus the ease with which tinnitus is picked up. GAIT ABNORMALITIES:
These problems cause:
FOOT DROPIn some arachnoiditis patients with leg weakness, this can progress to the point where the muscles in the top part of the ankle are too weak to hold the foot at the 90 degree angle, this causing difficulties in walking. The toes tend to catch on the floor, which leads to trips and falls. Foot drop occurs most commonly if there is arachnoiditis at levels L4/5 and L5/S1 because this is the spinal level from which the innervation of the common peroneal nerve arises. This nerve supplies both sensory and motor innervation to the top of the foot (dorsum) and toes. Whilst people may be aware of spinal problems at the relevant levels (arachnoiditis, epidural fibrosis, disc herniation etc.), there must be a thorough investigation to rule out other sites of nerve compression and causes such as diabetes, hyperthyroidism (pretibial myxoedema) and Polyarteritis nodosa. Physiotherapy and/or splints may be of assistance in this condition. WEAKNESSWeakness is a broad term which can have a variety of meanings. It may be used to refer to generalised fatigue or malaise; or it may be more specifically muscle weakness. People with arachnoiditis often suffer from fatigue (76% in the 1999 survey). They
also frequently have muscle weakness, which can be mild, moderate or
severe. 82% of the 1999 Survey respondents reported weakness as a
symptom. In arachnoiditis, there may well be nerve root damage, at one or several spinal levels. Weakness will tend to occur in the same areas as pain sensation. The commonest areas are in the foot and calf. Also buttock muscles may be affected, with muscle wasting. If there is cervical (neck) pathology, then spasticity may be evident. Other causes: Disuse atrophy Muscle
wasting may be due to disuse/immobility. Potassium
abnormality: Either high(hyperkalaemia) or low (hypokalaemia) potassium can cause muscle weakness. Hyperkalaemia is most commonly caused by excessive use of salt substitutes. Hypokalaemia: low blood potassium seems to occur in a number of people with arachnoiditis, but it is not specific to this condition as it also occurs in other people with chronic illness. Causes include:
*note
that in chronic pain conditions, the stress involved may lead to a
sustained increase in stress hormones, of which cortisol ( a
glucocorticoid) is one. MISCELLANEOUS
CONDITIONS: Plantar neuroma (also known as Morton’s neuroma) is a relatively common peripheral neuropathy. Also known as plantar digital neuritis(intermetatarsal/interdigital neuritis IDN), a term which describes the condition more accurately as it involves interdigital (between the toes) nerve on the sole of the foot. It tends to be on one foot, usually between the 3rd and 4th. toes. The symptoms are: agonising pain in the sole after walking/standing in closed shoes for a variable period of time; relief can only be obtained by stopping, sitting down, removing the footwear and resting and/or massaging the foot. The pain tends to be well localised: more diffuse pain is likely to be from a different condition. Typical descriptions are: “like walking on a hot pebble”; “having a hot poker thrust between the toes.” Mild
forms present with burning pain and occasional numbness or tingling. By contrast, PLANTAR FASCIITIS is a form of heel pain. It involves inflammation of the thick band of tissue in the sole of the foot, called the plantar fascia. This strong tissue connects the heel to the base of the toes, maintaining the arch of the foot. This inflammation tends to occur either after prolonged standing or from repetitive stress such as walking/running/athletic activity. (none of which are particularly likely in someone with arachnoiditis!) Heel
pain can also be caused by nerve entrapment, stress fracture, heel spur
(calcaneal spurs: bony outgrowth) or as a part of inflammatory
conditions such as rheumatoid arthritis or gout. Bearing in mind the
probable link between arachnoiditis and autoimmune disorders, it may be
that plantar fasciitis is a feature of arachnoiditis. Foot care: If you have numbness, you are less likely to notice injuries or sores, which could become infected or ulcerated if left untended. The following are useful tips:
If
you get a sore, seek medical attention to ensure necessary treatment is
implemented. Sarah
Smith MB BS |
