Representation of the thoracic outlet syndrome as a problem in chronic pain and psychiatric management

The diagnosis of thoracic outlet syndrome depends upon subjective complaints and sometimes rather limited physical findings. There is a tendency to favour other non-specific diagnoses, like ‘soft tissue damage’ or to suspect neurosis, particularly in patients who have had motor vehicle or other injuries for which they claim compensation. We report here 3 patients in whom the diagnosis of thoracic outlet syndrome was overlooked and who responded to surgical treatment with good or excellent results.     

The experience of headache — An assessment of the qualities of tension headache pain

The subjective component of headache pain has been neglected in headache research. In this study of 65 chronic headache sufferers, assessment of the subjective component was amplified using the McGill Pain Questionnaire (MPQ) as well as headache diaries. The overall level of pain experienced was as high as that previously reported for cancer and phantom-limb patients. Assessment of sensory pain qualities (MPQ) revealed differences between tension and migraine headache types; tension headaches were felt to be “tight”, while migraines were experienced as “sharp”, “blinding”, “nauseating” and “sickening”. The results thus support a dichotomous rather than a continuum model of headache.The relationship between the subjective experience of headache and mood (Wakefield Depression Scale) and personality (EPQ) was examined. Pain intensity and affective reactions to pain were associated with general mood state; however, no subjective measures correlated with personality indices.It was argued that the MPQ provided valuable additional information to be used with headache diaries, particularly in the assessment of sensory qualities and affective reactions to pain.     

Acute pain in an emergency clinic: Latency of onset and descriptor patterns related to different injuries

Features of acute pain were examined in patients at an emergency clinic. Patients who had severe, life-threatening injuries or who were agitated, drunk, or ‘in shock’ were excluded from the study. Of 138 patients who were alert, rational and coherent, 51 (37%) stated that they did not feel pain at the time of injury. The majority of these patients reported onset of pain within an hour of injury, although the delays were as long as 9 h or more in some patients. The predominant emotions of the patients were embarrassment at appearing careless or worry about loss of wages. None expressed any pleasure or indicated any prospect of gain as a result of the injury.The occurrence of delays in pain onset was related to the nature of the injury. Of 46 patients whose injuries were limited to skin (lacerations, cuts, abrasions, burns), 53% had a pain-free period. Of 86 patients with deep-tissue injuries (fractures, sprains, bruises, amputation of a finger, stabs and crushes), only 28% had a pain-free period. The McGill Pain Questionnaire was administered to patients who felt pain immediately after injury or after a delay, and revealed a normal distribution of sensory scores but very low affective scores compared to patients with chronic pain. The results indicate that the relationship between injury and pain is highly variable and complex.     

Vibratory stimulation for the relief of pain of dental origin

The present paper describes the effect of vibratory stimulation on pain of dental origin in 36 patients. The patients were from a clinic for dental surgery and all had suffered pain from pulpal inflammation, apical periodontitis or postoperative pain following extraction of an impacted wisdom tooth for more than 2 days. Vibration at 100 Hz was applied to various points in the facial region or the skull. All the patients except three experienced an effective reduction of the intensity of the pain. In the patients who experienced pain reduction there was usually a best point at which vibration had a greater pain alleviating effect than at other points. At some points the stimulation added to the pain. In 16 patients the stimulation caused a reduction in pain intensity of 75–100%; out of these 12 patients reported a complete relief of pain.     

Memory for pain.

Memory for head pain was assessed by means of the McGill Pain Questionnaire (MPQ). Sixteen neurosurgical patients were divided into two groups in order to examine the decay of memory over time; one group recalled pain after 5 days and the other recalled pain after one day and then again, after 5 days. Contrary to expectations, the recall of pain was surprisingly accurate. The memory for pain showed littled decay over time. The small subgroup of patients who made specific errors when recalling their pain comprised women who had high levels of pain and affect at the initial assessment. Overall, the findings provide some welcome reassurance about the accuracy and reliability of pain reports from memory.     

Reduction of arthritis and pain behaviour following chronic administration of amitriptyline or imipramine in rats with adjuvant-induced arthritis

Tricyclic antidepressants (TCAs) are used extensively to treat chronic pain in man without an adequate explanation for their activity. The purpose of the present study was to investigate this problem by testing the effect of chronic TCAs in an animal pain model: the arthritic rat. Sprague-Dawley rats with adjuvant-induced arthritis were injected daily for 4 weeks with amitriptyline (10 mg/kg) or imipramine (10 mg/kg) or saline, beginning 21 days after the induction of arthritis. Baseline evaluations were made prior to the injection series and at 4 weeks, 24 h after the last injection. Both TCAs significantly reduced 'scratching' and increased 'exploring' behaviour, without changing the response to graded foot pressure. In addition clinical signs of arthritis (ankle circumference, swelling, conjunctivitis, balanitis ...) were significantly reduced, while mobility was increased. This study shows that both amitriptyline and imipramine decrease pain behaviour and arthritis in this chronic pain model. Possible 'antiinflammatory' effects of TCAs and their eventual 'analgesic' effect will be discussed.     

The use of antibiotics in the initial management of recent dog-bite wounds

The use of antibiotics in the initial management of dog-bite wounds presented within eight hours of injury was studied. Of 211 wounds occurring in 150 patients seen during the study period, 66 wounds occurring in 33 patients comprised the study sample. All wounds were managed according to a strict protocol that included cleaning, debridement, and pressure irrigation. The wounds studied were randomly assigned to either an antibiotics (penicillinase-resistant penicillin or erythromycin) or placebo group. Two of the 35 antibiotic-treated wounds became infected, and three of the 31 placebo-treated wounds became infected. There was no significant difference in outcome between antibiotic and placebo groups. Hand wounds became infected significantly more often than other wounds. The administration of a penicillinase-resistant antibiotic is not indicated in the initial management of dog-bite wounds presented within eight hours of injury.     

How do children describe pain? A tentative assessment

In a study to determine how children describe the experience of pain, we queried a convenience sample of 100 children in hospitals and 114 children in church and private schools who were between 9 and 12 years old. The questions were designed to seek correlations by age among boys and girls and between hospitalized and non-hospitalized children that would aid health professionals in strategies that will identify and assist the child who is in pain. The preliminary results show that children clearly describe pain, that there are no appreciable differences by age groups, but that children who are hospitalized describe pain differently from children who are not.     

The systemic administration of local anaesthetics produces a selective depression of C-afferent fibre evoked activity in the spinal cord

An electrophysiological analysis of the antinociceptive effects of systemic lidocaine and its longer acting primary amine congener, tocainide, has been performed in the decerebrate-spinal unanaesthetised rat. Neither of these local anaesthetic drugs when administered systemically in doses of up to 10 mg/kg (lidocaine) or 100 mg/kg (tocainide), produced any evidence of a block in the conduction of action potentials in A beta, A delta or C primary afferents. The local anaesthetics also failed to reduce mustard oil induced neurogenic extravasation, a test of cutaneous C-fibre terminal function. Lidocaine produced a transient (1-2 min) depression in monosynaptic reflexes at doses of greater than or equal to 1 mg/kg while tocainide had no effect on this reflex at any dose up to a 100 mg/kg. Both drugs, however, significantly suppressed the C-fibre evoked polysynaptic reflex generated by stimulating the sural nerve. The tocainide effect was longer lasting with less action on the short latency A beta-evoked reflex than lidocaine. The reflex activity in hamstring flexor alpha-motoneurones evoked by pinching the toes of the ipsilateral hind paw was reduced by both drugs but not abolished. Thermal and noxious chemical evoked reflexes were, however, completely suppressed by the local anaesthetic drugs, again with a longer action from tocainide. These results demonstrate that the systemic administration of drugs which increase the inactivation of sodium channels can produce a selective central block of certain types of afferent evoked activity in the spinal cord. There are resemblances between the selective C-fibre suppressing actions of systemically administered local anaesthetic and the pharmacological actions of narcotic opiates which may represent a similar mechanism for the analgesic action of these quite different classes of drugs.     

The formalin test: a tonic pain model in the primate

The formalin test has been used in monkeys for assessing pain. After formalin injection in the palmar surface of the hand just proximal to the base of the fingers, the monkey's responses are rated for 1 h according to objective behavioral criteria. The present 'tonic' pain model has a fair degree of objectivity, validity, reproducibility and quantifiability. The analgesic effects of morphine and pethidine have been evaluated.     

Possible involvement of opioid peptides of caudate nucleus in acupuncture analgesia

Rabbits chronically implanted with permanent cannulae were used in brain perfusion and microinjection experiments. Potassium iontophoresis applied to the rabbits' ear skin served as a noxious stimulus and the electric current used to elicit the defense response was taken as the pain threshold. The brain perfusate was analysed by radioreceptor assay and the level of endogenous opioid peptides (EOP) was expressed as competition rate. Electroacupuncture (EA) elicited an increase in pain threshold and a rise in EOP level in the perfusate from the anterior part of the head of the caudate nucleus (n = 10, P less than 0.002) but not from the posterior part. The pain threshold raising effect of EA could readily be reversed by microinjection of naloxone into the anterodorsal part of the head of the caudate (n = 12, P less than 0.01). With the techniques of multimicropipettes and microiontophoresis, caudate neuronal activity was recorded and examined in acute animals anesthetized with chloralose and urethane. It was found that microiontophoresed etorphine produced a strong, naloxone reversible inhibition of the spontaneous activity of the caudate neurons (61/162). Most etorphine sensitive neurons were identified in the dorsal part of the head of the caudate (P less than 0.01). EA produced inhibition of some etorphine sensitive neurons (16/35) and the inhibition could also be reversed by microiontophoresis of naloxone (4/8). The results indicate the participation of intracaudate opioid peptides in acupuncture analgesia.     

A stable uterine binding protein preparation for the assay of plasma oestriol in pregnancy

A competitive protein-binding assay for the measurement of plasma oestriol in pregnancy is described, using a binding protein prepared from lamb uterus. The method involves an acid hydrolysis with subsequent extraction and partition of the oestriol followed by competition with labelled oestriol for binding sites on the uterine cytosol preparation. The binding protein was prepared in bulk and freeze-dried to avoid the problems involved in dealing with small, variable batches. The protein was found to be specific for oestrogens and extremely stable and showing no deterioration after storage for seven months at ambient temperature.     

Chronic pain: Which patients may a pain-management program help?

To ascertain whether chronic-pain patients who are likely to benefit from a pain-management program can be identified before treatment, we studied for differences discernible at the beginning of treatment a group who succeeded and did well at 1-year follow-up (n = 34) and a group who failed (n = 35). The two groups differed significantly (P less than 0.01) in regard to duration of pain, work time lost, number of operations, subjective pain level, and drug dependency. Deviations on the MMPI were greater in failures than in successes; but the differences were not statistically significant. A 7-item rating scale based on these data differentiated a favorable group (including 71% of the successes) from an unfavorable group (including 86% of the failures). This scale should be helpful in selection of candidates for a pain-management program, even though it needs further validation.     

In vitro assessment of the intra luminal phase of gliadin digestion in coeliac disease: γ-glutamyl transpeptidase-like activity in saliva

γ-Glutamyl transpeptidase (GGTP) is an enzyme of potential relevance to the digestion of dietary gliadin, and hence of possible importance in the development of coeliac disease (CD). We have confirmed that human saliva has GGTP-like activity. Comparison of this activity between treated CD patients in long-term remission, age- and sex-matched normal control subjects, and unaffected relatives of CD patients did not show statistically significant differences. Although our results have not demonstrated a primary abnormality of this particular enzyme activity in CD, the intraluminal phase of gliadin processing is potentially important in the aetiology and pathogenesis of CD and thus deserves further study.     

Tertiary gain and chronic pain

The authors present a brief review of the role of primary and secondary gain in chronic pain patients. The concept of tertiary gain is discussed. Case presentations are offered to illustrate the various types of gain and the roles they play in chronic pain problems. The discussion involves the conceptualization of gain and its part in the evaluation of chronic pain patients.     

Abnormal and collateral innervations of sympathetic and peripheral sensory fields associated with a case of causalgia

A 41-year-old female developed spontaneous burning pain (causalgia) and stimulus-induced dysesthesia (allodynia) of the dorso-lateral part of her right foot following trauma. An L3 and L4 sympathectomy eliminated the spontaneous burning pain for only 1 year, but did not affect the stimulus-induced dysesthesia. We evaluated her two years post-sympathectomy with grouped sequential anesthetic blocks and sensory testing. Sympathetic blocks at L1 and L2 eliminated the burning pain and normalized heat perception from baseline hyperalgesia, indicating that the causalgia had been reactivated via more rostral sympathetic ganglia. Anesthetic block of the sural nerve eliminated both the burning pain and the stimulus-induced dysesthesia. During the sural nerve block, perception of touch and pin, but not heat, was preserved in the sural distribution. All perception was lost following subsequent block of the peroneal branches. When the peroneals were blocked first, perception of touch, pin and heat remained in the sural distribution. With peroneal block the burning pain was eliminated, but the stimulus-induced dysesthesia remained, even in the anesthetic peroneal territory. When sural block was added to the peroneal block the stimulus-induced dysesthesia was eliminated, and sensation in the sural distribution was lost. We conclude that the sural distribution received overalapping innervation for touch and pin-prick perception, but that heat perception, burning pain and the stimulus-induced dysesthesia were sural nerve dependent. Further, we were able to dissociate causalgia pain from allodynia in this patient.     

Intrathecal somatostatin in terminally ill patients. A report of two cases

Intrathecal morphine has been shown to be reliable in producing analgesia in patients with intractable cancer pain. Recently, we have demonstrated that intrathecal somatostatin is as effective in the treatment of cancer pain as intrathecal morphine. This report presents 2 cases in whom analgesia could be maintained for 60 and 25 days, respectively, under continuous intrathecal infusion of somatostatin by means of infusion devices.     

Skin histidase activity and urine formiminoglutamic acid (FIGLU) in patients with histidinemia found by screening newborn infants

Skin histidase activities and urine formiminoglutamic acid (FIGLU) levels were measured in 20 patients with histidinemia, identified by Guthrie's screening method, and their family members as well as control subjects. There was a significant positive correlation between skin histidase activities and the amounts of urine FIGLU.Although the difference of skin histidase activity and the amount of urinary FIGLU was significant between any two of the three groups (i.e. controls, parents and patients; p < 0.005, these levels ranged widely and a considerable number of the cases overlapped among groups. When a discriminant function was computed to obtain the minimum probability of misclassification between the groups using the above two parameters, a better segregation was observed. However, even though the number of misclassifications decreased, the overlapping cases were still present, especially between the parent and patient groups. It is concluded that either skin histidase activity, urine FIGLU, or both, can be used as genetic markers of the disease to a large but still limited extent.     

Epidural narcotics in volunteers: Sensitivity to pain and to carbon dioxide

Tolerance to pain and sensitivity to rising concentrations fo inhaled carbon dioxide were measured before and after administration of metadone, 5 mg, or hydromorphone, 0.5 mg, by the intravenous route and by epidural injection in the lumbar or upper thoracic region in 5 subjects. Tolerance to periosteal pressure, cutaneous electrical stimulation and the cold pressor response to ice-water immersion were measured in both upper and lower limbs. Tolerance to all three pain modalities was greater in the epidural “blocked” limbs than in the “unblocked” limbs or after intravenous administration, and this difference was sustained after a second injection of narcotic. Sensitivity to carbon dioxide was less depressed by epidural narcotic than by intravenous administration; however, after a second dose of narcotic, depression of CO₂ sensitivity by epidural injection was comparable to that produced by intravenous injection.These observations support the hypothesis that epidural narcotics have a segmental action as well as a systematic effect, and that both actions are dose-dependent.