| Back Pain - Neuropathic Pain
History
This 41 year old woman was initially injured in 2003. She lifted a box from a bench and intended to turn around and place it onto a trolley. She thought the box was light. It was much heavier than she thought (the weight turned out to be 20 kg). She lifted it and collapsed to floor with it as she twisted. .
She developed back pain that day, and was worse the following day, by which time she developed right leg pain. This was a diffuse type of pain and less severe than the back pain. The back pain remained the worse problem thereafter.
She underwent various conservative therapies over the following few months; the pain settled to some extent. Her job was not re-offered and there were various interactions with the legal system concerning liability and treatment. She became increasingly stressed. This situation was aggravated by an assault. Subsequent to that she started to have panic attacks.
She presented with both back and neck pain. The pain was relatively stable. The neck pain spread from the neck across the shoulders. The back pain was generally across the back and into the right buttock and thigh. The thigh pain was diffuse both in the front and the back of the thigh. It was also milder than the back pain. Both the back and neck pain had a burning quality, in addition to general aching. The pain tended to get worse as the day progressed. Her sleep was prominently disturbed by this burning pain. The pain was worse also with static activity such as sitting and standing.
She was taking medications for sleep, anxiety and pain. She had tried tramaldone and codeine phosphate. She obtained virtually no relief from any of the pain killers. In addition, the combination of medication made her drowsy during the day. She had also been tried on various anti-depressants but they had been ineffective Discussion about stronger pills (opioids) had ensued but she had been told (reasonably) that these would probably not help the pain to a great extent and would make her more dopey.
She had been advised on exercise, tried it without much intensity, and had given it up. She was not drinking, smoking or taking other drugs. She had seen a psychologist regarding he stress and panic attacks. She had found the advice to be of some help.
Examination:
She was overweight. Her weight had increased by 6 kg in the previous year. Back and neck movements were reasonably good with lumbar flexion 70 degrees, extension 30 degrees and soreness in right side bending at 20 degrees. Tenderness was present in the muscular system generally. The hips moved normally. Straight leg raise was normal.
Investigations:
Tests including MRI had not shown any specific abnormality.
Diagnosis:
1. The pain: the burning quality of pain was also associated with spontaneous spasms of pain in the low back. This suggested neuropathic pain, in addition to possible nociceptive causes (such as from injury to the internal part of a disc). It was considered that the pain was too general to initiate tests, such as facet joint nerve supply blocks or discogram) designed to specifically isolate the source of pain.
2. Anxiety: this had been addressed ineffectively by some cognitive-behavioural therapy and medication.
3. Weight gain: this had been addressed ineffectively by the psychologist and a dietician. She was not exercising.
Management:
1. Pain management: She had not undergone a pain management course. It was deemed relevant to introduce such a management plan in an attempt to combine information dissemination with exercise and further cognitive therapy aimed at the pain, anxiety and weight gain.
2. Medication: The medication had proved to be unsuccessful. She had not tried medication specific for neuropathic pain. The issues when selecting medication for pain relief included the possibility of addressing sleep disturbance and anxiety. It was decided to commence her on pregabalin, which has proven efficacy for the management of neuropathic pain in other pain states (such as central pain following spinal cord injury) with the added possible benefit of improvement in the levels of anxiety.
It was decided to start with 75 mg twice a day. She was warned that she might get some initial drowsiness and dizziness (these occur respectively in 40% and 20% of patients, but tolerance tends to develop and about 5% of patients stop the medication because of these side-effects). She was told that the sleep disturbance, the anxiety and the burning stabbing general pain might be helped by these anti-neuropathic drugs. Another alternative was to trial low dose tricyclic anti-depressants at night: but, because of the combined effects of pregabalin and the level of day-time pain this medication was not considered to be the next to trial.
Continuing history:
She was reviewed regularly over the following two months. At day four she reported that the pregabalin had made a difference from the first night. The burning pain had diminished 50% and she was able to sleep better. She was tolerating the medication well. At day 10 the improvement had been maintained. As she still had some burning pain the dose was increased to 150 mg. Further review revealed further benefit, with pain levels down from 7-8/10 to 3/10. Anxiety levels had also improved.
An increased dose to 225 mg twice a day did not help any further and so the dose was reduced to 150 mg twice a day again.
By the time she was ready to commence the pain management program the overall problem was significantly improved. She was then in a position to be able to work on other issues including the weight problem and lack of exercise.
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