Shigetaka Hakusui

A radiological analysis of heart sympathetic functions with meta-[123I] iodobenzylguanidine in neurological patients with autonomic failure

Cardiac scintigraphy with meta-[123I]iodobenzylguanidine (MIBG) is used to assess cardiac sympathetic function. We performed [123I]MIBG scintigraphy in 7 patients with neurological diseases presenting orthostatic hypotension and other autonomic failures (AF), 22 neurological patients without AF, and 9 healthy subjects. Thallium scintigraphy and echocardiography were also performed in all subjects. In this series, patients with any evidence of cardiac dysfunction were excluded. No [123I]MIBG accumulation was observed in all patients with AF, and cardiac defects were noted in 7 patients (5 with Parkinsons disease [PD], 2 with spinocerebellar degenerations [SCD]), and in some patients without AF. In contrast, the distribution of [123I]MIBG was normal in all the healthy subjects. No decrease in [123I]MIBG accumulation was resulted from drug therapy (droxidopa, amezinium and thyrotropin-releasing hormone). In conclusion, reduced accumulation on [123I]MIBG scintigraphy may be due to myocardial beta-adrenoceptor dysfunction or reduced central sympathetic activity of the heart, or both.

Altered response in cutaneous sympathetic outflow to mental and thermal stimuli in primary palmoplantar hyperhidrosis

Skin sympathetic nerve activities (SSNAs) were recorded simultaneously from the tibial and peroneal nerves by microneurography at an ambient temperature of 25 degrees C in five subjects with primary palmoplantar hyperhidrosis. The resting of the tibial SSNA innervating the sole (glabrous skin) increased moderately (36.5 +/- 1.5 bursts/min), while mental arithmetic provoked marked responses (1,003.3 +/- 457.4% compared with the resting level) in the hyperhidrosis group compared with the control normohidrosis group (n = 5, 25.3 +/ 4.2 bursts/min and 142.2 +/- 58.4%, respectively). Differentiation of the tibial SSNA into sudomotor (innervating sweat glands) and vasoconstrictor (innervating presphincter of skin vessels) revealed that this SSNA enhancement was attributable to not only sudomotor but also vasoconstrictor components during mental arithmetic. In contrast, the responses in the peroneal SSNA (innervating the dorsum pedis, hairy skin) of the hyperhidrosis group were only slightly changed, exhibiting no significant difference from those in the normohidrosis group. Reflex bursts elicited by sound and electric stimulation were normal in amplitude and latency. When the ambient temperature was elevated to 30 degrees C, the tibial SSNAs became more enhanced than did the peroneal SSNAs. The tibial SSNA was markedly enhanced in the hyperhidrosis group (290.0 +/- 78.5%) compared with the normohidrosis group (78.3 +/- 25.4%). We conclude that the excessive responses in SSNA to the plantar glabrous skin to both mental and thermal stimuli may be responsible for the profuse sweating in subjects with primary palmoplantar hyperhidrosis.

A scintigraphical qualitative analysis of peripheral vascular sympathetic function with meta-[123I]iodobenzylguanidine in neurological patients with autonomic failure.

In order to assess qualitatively the sympathetic functions of the peripheral vessels, we performed a scintigraphical study of the entire body with meta-[123I]iodobenzylguanidine (MIBG) in 13 patients with autonomic failure and 11 healthy subjects as control. The patients comprised seven with multiple system atrophy (MSA), two with pure autonomic failure (PAF), three with Parkinsons disease with autonomic failure (PD with AF) and one with familial amyloid polyneuropathy (FAP). No clinical evidence of vascular disease was noted in any of the patients and the control subjects. We investigated their autonomic functions using the head up tilt test as well as norepinephrine and isoproterenol infusion tests. We found that: (i) All of the control subjects showed satisfactory MIBG uptake; (ii) all of the patients with PAF and FAP, most of whom had postganglionic sympathetic lesions, showed supersensitivity and low MIBG uptake; (iii) almost all the patients with MSA, who were considered to have mainly preganglionic sympathetic lesions, showed supersensitivity and diminished MIBG uptake, although the patients with olivopontocerebellar atrophy showed supersensitivity but not diminished MIBG uptake. In conclusion, these results suggest that peripheral vascular scintigraphy using MIBG is useful in detecting peripheral adrenergic dysfunction.

Motor conduction studies in Miller Fisher syndrome with severe tetraparesis.

Some patients with Miller Fisher syndrome (MFS) have a severe tetraparesis such as that observed in Guillain–Barré syndrome (GBS). To determine whether pathophysiologic differences exist between the tetraparesis in MFS and that in GBS, we compared clinical and motor conduction findings in 4 MFS patients who developed severe tetraparesis with those in 5 MFS patients without tetraparesis, and 14 GBS patients. MFS patients with or without tetraplegia had normal motor conduction velocities, distal motor latencies, compound muscle action potential (CMAP) amplitudes, and F‐wave latencies. CMAP amplitude tended to be lower in tetraparetic MFS patients than in MFS patients without tetraparesis, but not significantly. F‐wave occurrence was slightly reduced in 1 MFS patient with tetraparesis and 1 MFS patient without tetraparesis. Motor conduction parameters were abnormal in 13 of 14 patients with GBS, and showed demyelinating features in 10. Our results suggest that the pathophysiology of tetraparesis in MFS differs from that in GBS.

Treatment of postprandial hypotension with selective α1 and β1 adrenergic agonists

Abstract In order to treat postprandial hypotension (PPH), we orally administered a combination of denopamine (10 mg, a selective β1-adrenergic agonist) and midodrine-HCl (4 mg, a selective α1-adrenergic agonist) to eight patients with autonomic failure (AF) prior to and after eating. When the patients were given 75 g glucose with 225 ml water without drugs, blood pressure fell subsequently, cardiac output (CO) was unchanged, and vascular resistance of the lower legs (LVR) decreased. However, concomitant administration of denopamine and midodrine-HCl prevented PPH and increased CO and LVR. The portal blood flow was not indifferent to the drugs. A marked increase in heart rate after drug administration was seen in some patients with AF, which reflects the supersensitivity to denopamine. Combined oral administration of denopamine and midodrine-HCl is a safe and useful therapy for PPH in patients with AF.

Postprandial hypotension: hemodynamic differences between multiple system atrophy and peripheral autonomic neuropathy

To clarify the mechanism of postprandial hypotension (PPH), we performed hemodynamic investigation after oral glucose ingestion in ten patients with multiple system atrophy (MSA), three patients with peripheral autonomic neuropathy (PN) and 16 normal controls. Blood pressure (BP) and heart rate (HR) were measured with an automatic sphygmomanometer; cardiac out (CO) and lower leg blood flow (LBF) with impedance plethysmography; and portal blood flow (PBF) using a B-mode pulse Doppler. In normal subjects, BP, LBF and vascular resistance of the lower leg (LVR) were not changed, but HR slightly increased, and PBF and CO significantly increased after oral ingestion of 75 g glucose. In the patients with MSA, BP fell significantly 15 min after glucose ingestion, and HR and CO did not increase. PBF and LBF increased and LVR fell significantly. In PN patients, BP decreased at 15 min after glucose ingestion, but soon recovered. Increase of PBF and decrease of LVR in them were almost similar to those in the MSA group, and increase of CO was greater than that in the controls. These results suggest that both systemic vasodilatation (presumably due to gastrointestinal vasodilatatory peptides) and lack of compensatory increase of CO and LVR play important roles in PPH.