Treatment of neuropathic pain in a patient with diabetic neuropathy using transcutaneous electrical nerve stimulation applied to the skin of the lumbar region.

BACKGROUND AND PURPOSE: Diabetic neuropathy can produce severe pain. The purpose of this case report is to describe the alteration of pain in a patient with severe, painful diabetic neuropathy following application of transcutaneous electrical nerve stimulation (TENS) to the low back. CASE DESCRIPTION: The patient was a 73-year-old woman with pain in the left lower extremity over the lateral aspect of the hip and the entire leg below the knee. The pain prevented sound sleep. The intensity of pain was assessed with a visual analog scale. INTERVENTION: The TENS (80 Hz) was delivered 1 to 2 hours a day and during the entire night through electrodes placed on the lumbar area of the back. OUTCOMES: Following 20 minutes of TENS on the first day of treatment, the patient reported a 38% reduction in intensity of pain. After 17 days, the patient reported no pain following 20 minutes of TENS and that she could sleep through the night. Application of TENS to the skin of the lumbar area may be an effective treatment for the pain of diabetic neuropathy.

High-frequency transcutaneous electrical nerve stimulation alters thermal but not mechanical allodynia following chronic constriction injury of the rat sciatic nerve.

OBJECTIVE: To determine if daily transcutaneous electrical nerve stimulation (TENS) can alter the thermal and mechanical allodynia that develops after chronic constriction injury (CCI) to the right sciatic nerve of rats. DESIGN: A completely randomized experimental design was used. Four groups of rats underwent CCI surgery to the right sciatic nerve and either were not treated with TENS or received TENS starting at different times after the CCI surgery. INTERVENTIONS: TENS was delivered daily for 1 hour to CCI rats through self-adhesive electrodes applied to skin innervated by the right dorsal rami of lumbar spinal nerves L1-6. Rats of different groups received daily TENS starting immediately, 20 to 30 hours, or 3 days after the CCI surgery. MAIN OUTCOME MEASURE: Thermal and mechanical pain thresholds of hind paws were assessed bilaterally in all rats twice before the CCI surgery (baseline) and then 2, 7, 12, and 14 days after surgery. Thermal and mechanical allodynia were expressed as difference scores between the pain thresholds of right and left hind paws. These values were normalized to differences that existed between the two paws at baseline. RESULTS: Daily TENS beginning immediately after CCI surgery prevented the development of thermal allodynia at all assessment times (p < .05). Daily TENS starting 1 day after surgery reduced thermal allodynia, but only on days 2 and 14 (p < .05). Daily TENS beginning 3 days after surgery had no effect on the development of thermal allodynia. Regardless of when it was started, daily TENS did not consistently alter mechanical allodynia in CCI rats. CONCLUSION: It appears that daily TENS can prevent thermal but not mechanical allodynia in this model. However, early intervention with the treatment is critical if it is to be effective at all.

Captopril renal scintigraphy in renovascular hypertension.

Renovascular disease is a common cause of secondary hypertension. Renal artery stenosis is present in up to one third of patients with clinical markers suggestive of renovascular hypertension, such as hypertension refractory to medical management, severe hypertension in a young patient and worsening of renal function after the use of an angiotensin-converting enzyme inhibitor. Early discovery of renal artery stenosis may allow amelioration or cure of the hypertension and halt progressive loss of renal function. Although renal arteriography remains the gold-standard aid to diagnosis and to planning surgical intervention, it is an invasive procedure that may cause deterioration of renal function. In the presence of renal artery stenosis, glomerular filtration is maintained by angiotensin. Administration of captopril in renal scintigraphy removes this compensatory mechanism and causes a temporary impairment of renal function in the affected kidney. Nuclear tracers can visualize this impairment, thus allowing assessment of the physiologic significance of a renal artery stenosis. The test can be done as a outpatient procedure.

The influence of experience on the reliability of goniometric and visual measurement of forefoot position.

Goniometric measurement of forefoot position relative to the rearfoot is a routine procedure used by rehabilitation specialists. This measurement is also frequently made by visual estimation. The influence of tester experience on the reliability of these two techniques at the forefoot is unknown. The purpose of this investigation was to directly examine the reliability of goniometric and visual estimation of forefoot position measurements when experienced and inexperienced testers perform the evaluation. Two clinicians (> or = 10 years experience) and two physical therapy students were recruited as testers. Ten subjects (20-31 years old), free from pathology, were measured. Each foot was evaluated twice with the goniometer and twice with visual estimation by each tester. Intraclass correlation coefficient (ICC) and coefficients of variation method error were used as estimates of reliability. There was no dramatic difference in the intratester or intertester reliability between experienced and inexperienced testers, regardless of the evaluation used. Estimates of intratester reliability (ICC 2,1), when using the goniometer, ranged from 0.08 to 0.78 for the experienced examiners and from 0.16 to 0.65 for the inexperienced examiners. When using visual estimation, ICC (2,1) values ranged from 0.51 to 0.76 for the experienced examiners and 0.53 to 0.57 for the inexperienced examiners. The estimate of intertester reliability [ICC (2,2)] for the goniometer was 0.38 for the experienced examiners and 0.42 for the inexperienced examiners. When using visual estimation, ICC (2,2) values were 0.81 for the experienced examiners and 0.72 for the inexperienced examiners. Although experience does not appear to influence forefoot position measurements, of the two evaluation techniques, visual estimation may be the more reliable.

White clot syndrome associated with renal failure.

In a minority of patients, heparin administration is associated with thrombocytopenia and this thrombocytopenia may be associated with thromboembolic events. Heparin-associated thromboembolism is described as heparin-associated thrombocytopenia and thrombosis or white clot syndrome. White clot syndrome is caused by antibodies to a heparin-platelet membrane complex. The diagnosis carries a high mortality and morbidity from limb thromboembolism. Treatment includes discontinuation of heparin, use of alternate anticoagulants, and aggressive treatment of thromboses. A case in which acute renal failure occurred in the setting of heparin treatment and thrombocytopenia is described, and evidence that renal failure was a result of white clot syndrome is provided.

N-methyl-D-aspartate receptor antagonism alters substance P and met5-enkephalin biosynthesis in neurons of the rat striatum.

A reduction of striatal excitatory amino acids or of corticostriatal axons alters substance P (SP) and met5-enkephalin (ME) biosynthesis in striatal neurons of the rat. To determine the role of the N-methyl-D-aspartate (NMDA) receptor in this effect, adult rats were treated acutely with a single i.c.v. injection or chronically by 7 days of continuous infusion of an NMDA antagonist. The striatal content of preprotachykinin (PPT) and preproenkephalin (PPE) mRNA was assessed by in situ hybridization histochemistry while the content of SP and ME in, respectively, the substantia nigra and globus pallidus was measured by quantitative radioimmunocytochemistry. Eight hours after a single injection, striatal PPT and PPE mRNA levels were significantly reduced. At 24 hr, the level of PPE had returned to control level whereas that of PPT mRNA remained depressed. Nigral SP and pallidal ME levels were not acutely changed. Chronically, the effect of NMDA antagonist at low doses was to increase the striatal content of PPE mRNA. However, at higher concentrations, the effect was to reduce in a dose-dependent manner the striatal content of PPT and PPE mRNA and the level of pallidal ME. The nigral level of SP did not change significantly at any dose. The results suggest that excitatory amino acid transmission mediated by the NMDA receptor serves as a tonic signal to stimulate neuroactive peptide biosynthesis.

Striatal preprotachykinin and preproenkephalin mRNA levels and the levels of nigral substance P and pallidal Met5-enkephalin depend on corticostriatal axons that use the excitatory amino acid neurotransmitters aspartate and glutamate: quantitative radioimmunocytochemical and in situ hybridization evidence.

Because excitatory amino acid (EAA) neurotransmission has been implicated in long-term postsynaptic events, we conducted an initial study to determine whether or not the EAA-utilizing corticostriatal projection might influence peptide biosynthesis in neurons of the rat's basal ganglia. The content of EAAs in the caudatoputamen was reduced by frontal cortical ablation or by chronic intracerebroventricular infusion of methionine sulfoximine (MS). At 7 days following cortical ablation striatal Asp and Glu were reduced by 15% and 24%, respectively, while MS infusion (24 micrograms/day) for 7 days reduced synaptosomal levels of Asp by 61% and Glu by 48%. With either treatment, quantitative radioimmunocytochemistry revealed that substance P (SP) in the substantia nigra was increased by approximately 38%, while Met5-enkephalin (ME) in the globus pallidus was not changed. In situ hybridization with oligonucleotide probes revealed changes in the rostral striatum of preprotachykinin (PPT) and preproenkephalin (PPE) mRNA levels: cortical ablation reduced PPT mRNA by 17% and PPE mRNA by 20% dorsally, while it increased PPE mRNA (but not PPT mRNA) by 23% ventrally. Likewise, the infusion of MS decreased PPT (32%) and PPE mRNA (28%) dorsally, and increased PPE mRNA (50%) ventrally. In addition to the 7 day time point, the same measurements of EAAs, peptides and mRNAs were made at 14, 21 and 28 days after cortical excisions. At 14 days, the level of striatal Asp had returned to control value, but Glu remained depressed by 21%; nigral SP remained increased by 24%, and pallidal ME decreased by 15%. PPT and PPE mRNA remained depressed dorsally by 15% and 25%, respectively, while the increase in PPE mRNA noted ventrally at 7 days had returned to control values by 14 days. With the exception of Glu, which remained depressed by 18% at 21 and 28 days, all other values had returned to control levels by 21 days. The results indicate that a large reduction in EAA neurotransmission can influence differentially the steady-state levels of neuropeptides in striatal neurons and this change is brought about, at least in part, by an alteration in gene transcription.

Chronic methionine sulfoximine administration reduces synaptosomal aspartate and glutamate in rat striatum.

Methionine sulfoxime (MS) is an inhibitor of glutamine synthetase, an astroglial enzyme believed to be involved in the maintenance of glutamine, a major precursor for neurotransmitter pools of the excitatory amino acids aspartate and glutamate in striatal afferent axon terminals. MS was infused for 7 days (24 micrograms/day) into the lateral cerebral ventricle of rats. On the side of MS infusion, there was a decrease of striatal synaptosomal aspartate (61%), glutamine (63%), and glutamate (48%), while taurine and gamma-aminobutyrate were unaltered when compared to vehicle-treated rats. The results indicate that chronic MS infusion is an effective means by which neurotransmitter aspartate and glutamate levels can be selectively reduced in the striatum.