David Bowsher

The effects of pre-emptive treatment of postherpetic neuralgia with amitriptyline: a randomized, double-blind, placebo-controlled trial.

Seventy-two patients older than 60 years of age who received a diagnosis of herpes zoster (HZ) were entered into a randomized, double-blind, placebo-controlled trial of daily amitriptyline 25 mg. Treatment with either amitriptyline or placebo continued for 90 days after diagnosis. Pain prevalence at 6 months was the primary outcome. Results showed that early treatment with low-dose amitriptyline reduced pain prevalence by more than one-half (p < 0.05; odds ratio, 2.9:1) This finding makes a strong case for the pre-emptive administration of amitriptyline, in combination with an antiviral drug, to elderly patients with acute herpes zoster.

Ascending projections of the medial cerebellar (fastigial) nucleus: An experimental study in the cat

Summary (1) Small stereotaxic lesions were placed unilaterally in the medial cerebellar (fastigial) nucleus of cats; the course and termination of ascending degeneration was subsequently traced by the method of Nauta. (2) Ascending efferents arise almost entirely from the caudal half of the nucleus. All fibres decussate in the cerebellum, and pass out in the contralateral superior peduncle. (3) In the midbrain, fastigial afferents pass dorsal to the brachium conjunctivum; some terminals are distributed to the deep layers of the superior colliculus of both sides. (4) In the thalamus, symmetrical bilateral degeneration is found in the n. ventralis medialis and the adjacent medial part of the n. ventralis lateralis; degeneration is much more dense in the side of the thalamus contralateral to the cerebellar lesion. (5) There is no significant degeneration in the midbrain reticular formation, centrum medianum, n. ventralis anterior or zona incerta. (6) Differential origins, the organization, and functional implications are discussed.

Pain and protopathic sensibility. A review with particular reference to the teeth

“When all that is speculative and abstract is removed from Head’s contribution to this subject, there remains a most impressive body of observations that must have a permanent value and will serve as the material for a more realist interpretation.” So wrote Walshe [loll at the end of his famous review on cutaneous sensation, in which by an intellectu~ tour de force as impressive as that of Head himself, he had succeeded in reducing the notions of ‘protopathic” and ‘epicritic’ to a laughing stock, Despite Walshe’s anathema, the terms ~p~ti~ul~ly protopathic) have been creeping back into the literature, and the time seems ripe for another review in the light of more recent clinical and physiological findings. The writers

Terminal distribution of primary afferent trigeminal fibers in the rat

Abstract The pattern of preterminal and terminal degeneration was studied in adult albino rats by the methods of Nauta and Glees following intracranial section of the trigeminal nerve proximal to the semilunar ganglion. Terminal degeneration was found in all the sensory trigeminal nuclei, including a small amount passing to the contralateral nuclei, and in the rostral part of the solitary nucleus. Degeneration was also seen in the motor trigeminal and facial nuclei, and in the ventral horn of the spinal gray matter in the C3 segment. In the region of the principal sensory trigeminal nucleus, the degeneration did not extend into the reticular formation, but it did so adjacent to the descending trigeminal nucleus. Between the levels of the facial motor and gracile nuclei, the degeneration extended medially into the gigantocellular reticular nucleus. The findings are discussed with particular reference to the problem of trigeminal pain.

The prediction of diabetic neuropathic plantar foot ulceration by liquid-crystal contact thermography

OBJECTIVE To assess whether the development of plantar foot ulceration could be predicted from the mean plantar foot temperature (MFT), as assessed by liquid-crystal contact thermography (LCT), in patients with peripheral neuropathy. RESEARCH DESIGN AND METHODS Fifty patients with painful diabetic sensorimotor neuropathy were studied prospectively. Initially, 30 patients had no significant peripheral vascular disease (PVD) (ankle:brachial systolic blood pressure ratio >1.0). LCT was used to assess the MFT from eight standard plantar sites. RESULTS Initial MFT was higher in the patients without PVD (28.2 ± 2.9°C, mean ± SD) than in patients with PVD (25.6 ± 1.9°C, P < 0.001) and in nondiabetic control subjects (25.7 ± 2.1°C, P < 0.001). At review, on average 3.6 (range 3.0–4.1) years later, 11 patients had died (6 of whom had PVD), and one was lost to follow-up. Six patients (seven feet) from the group without PVD had developed neuropathic plantar foot ulcers. The initial MFT was significantly higher in these seven feet (30.5 ± 2.6°C) than in the 38 feet of the 19 survivors in this group (27.8 ± 2.3°C, P < 0.01). Only one patient with PVD developed a plantar ulcer, although four required foot surgery for ischemie feet. CONCLUSIONS LCT is a simple, inexpensive, and noninvasive method of identifying the neuropathic foot at increased risk of ulceration. Patients with high plantar foot temperatures are at increased risk of neuropathic foot ulceration. A normal or low MFT in the neuropathic foot is a marker of PVD, which confers an increased risk of ischemie foot disease.

Diencephalic projections from the midbrain reticular formation

(1) Physiologically guided stereotaxic coagulation was placed so as to avoid major through pathways in the midbrain reticular formation of 7 cats. Diencephalic degeneration resulting from this was traced by the Nauta method. (2) Preterminal degeneration was found in: the intralaminar nuclei and the posterior group (PO); the ventral group of thalamic nuclei; the ventral thalamus, including the zona incerta, subthalamus and fields of Forel; and the lateral hypothalamus. (3) The results are discussed in relation to somatomotor reactions, reticular influences on the electroencephalogram and telencephalic representation of pain.

Trigeminal neuralgia: an anatomically oriented review.

Trigeminal neuralgia (TGN) is a peculiarly painful paroxysmic disorder with an annual incidence of 4.3 per 100,000, which undergoes spontaneous remissions and recurrences. The pain, which is subserved by large, not small, fibers, can in some cases be triggered from outside the trigeminal territory and by other than mechanical stimuli. There are strong autonomic influences on the pain, and there is cutaneous vasoconstriction in the trigeminal territory in which it occurs. There are also sensory perception deficits for temperature in the affected region and for touch in the whole trigeminal territory. There is now increasing evidence that the majority of cases are caused by vascular compression of the fifth nerve at its point of entry into the pons, for the pain can be relieved (with restoration of the sensory deficit) by surgical decompression. No anatomical abnormalities of the (peripheral) trigeminal nerve have ever been satisfactorily demonstrated. Arguments are examined for the hypothesis that TGN is essentially a disorder of central processing, the term being taken to include the oligodendroglial‐sheathed proximal segment of the nerve. Clin. Anat. 10:409–415, 1997.

TREATMENT OF INTRACTABLE PAIN BY ACUPUNCTURE

Abstract A series of eighteen well-documented cases of intractable pain, resistant to orthodox procedures, were treated by acupuncture. Most were relieved for varying periods, and six are described in detail.

Postherpetic neuralgia and its treatment: A retrospective survey of 191 patients

One hundred and ninety-one patients with postherpetic neuralgia (PHN) in whom treatment was begun 3 or more months after acute herpes zoster (HZ) were retrospectively considered. Relieved (> or = 75% fall in visual analogue score for worst pain within last 24 hr) and unrelieved groups were subdivided into those who had and those who had not received antiviral treatment for their acute shingles. More than 90% of all patients experienced allodynia with a clinically evident sensory deficit for temperature and/or pinprick sensation. The probability of relief is worst in patients with PHN of the isolated ophthalmic nerve and of the brachial plexus, and best when involving the jaw, neck, and trunk. The presence (90%) or absence of allodynia has no predictive significance; but the small number of patients without allodynia or sensory deficit (all of whom had had antiviral treatment for their acute shingles) all improved. The probability of pain relief was found to correlate very strongly with the brevity of the interval between rash onset and commencement of treatment with an adrenergically active antidepressant. Further, time to relief in patients treated with an antidepressant starting at the same interval after HZ is significantly shorter in patients who received acyclovir for their original HZ. With the possible exception of dextroamphetamine added to the antidepressant, other treatments (particularly analgesics, anticonvulsants, and sympathetic blockade) were found to be without value in most cases. Thirty percent of patients who recover from PHN and have had their original shingles treated with acyclovir subsequently suffer from severe itching. It is recommended that elderly patients be given low-dose antidepressant on diagnosis of shingles, and asked to report back in 6 weeks. If they are pain-free at this interval, low-dose antidepressant should be continued for another month or so and then stopped. If, however, pain is present at 6 weeks, the dose of antidepressant should be increased and the patient reviewed every 2 months.

Contralateral mirror-image pain following anterolateral cordotomy.

A hypothesis is put forward to explain the occurrence of mirror-image pain following pain relief by anterolateral cordotomy. This depends upon the fact that some nociceptive neurones in the deep spinal grey matter have bilaterally symmetrical receptive fields, one-half of which is normally subject to tonic descending inhibitory control. It is suggested that some cordotomy lesions may damage this descending inhibitory pathway. Experience following naloxone injection in our own cases further suggests that this inhibitory mechanism may normally involve enkephalinergic interneurones.