ABSTRACT
Ultrasonography is a new imaging method for visualizing peripheral nerves. In vasculitic neuropathy, pain or axonopathy often can prevent the lesion from being localized during electrophysiological examinations, but the ability of ultrasonography to evaluate it morphologically is unknown. Our aim was to determine whether ultrasonography could be used to detect abnormalities in tibial vasculitic neuropathy at the medial ankle. We evaluated 11 tibial nerves in 8 patients with tibial vasculitic neuropathy, and 35 tibial nerves in 35 control subjects. In the controls, the tibial nerve was successfully visualized as a hyperechoic nodule with multiple round hypoechoic areas transversely; in the patients, the tibial nerve appeared enlarged and hypoechoic. The affected nerve area was significantly larger (13.5 +/- 3.7 mm(2)) than in controls (7.2 +/- 1.5 mm(2)). Our results suggest that ultrasonography is a useful neuroimaging method for evaluation of tibial vasculitic neuropathy, especially when nerve conduction study findings are inconclusive.
Subject(s)
Peripheral Nervous System Diseases/diagnostic imaging , Tibial Nerve/diagnostic imaging , Tibial Nerve/pathology , Tibial Neuropathy/diagnostic imaging , Ultrasonography/methods , Vasculitis/diagnostic imaging , Adult , Aged , Aged, 80 and over , Diagnosis, Differential , Female , Foot/innervation , Humans , Male , Middle Aged , Muscle, Skeletal/innervation , Muscle, Skeletal/physiopathology , Neural Conduction/physiology , Peripheral Nervous System Diseases/etiology , Peripheral Nervous System Diseases/physiopathology , Predictive Value of Tests , Prospective Studies , Tibial Nerve/physiopathology , Tibial Neuropathy/etiology , Tibial Neuropathy/physiopathology , Vasculitis/complications , Vasculitis/physiopathologyABSTRACT
Patients with juvenile muscular atrophy of distal upper extremity (Hirayama's disease) often show marked weakness of the fingers occurring with exposure to cold. We term this phenomenon cold paresis. We conducted an original test to induce cold paresis (Cold Paresis Inducement Test) in 11 patients of this disease and 10 normal controls. Cold paresis was induced in 9 of 11 patients, but was not induced in the 2 patients who had the disease longer than 20 years and in all normal controls. We examined the electromyogram of abductor digiti minimi during 5 Hz and 20 Hz rate of ulnar nerve stimulation at cooling. The patients in whom cold paresis was induced exhibited a waning of amplitude of compound muscle action potential (M wave) during 20 Hz stimulation. This waning was aggravated by intravenous administration of anticholinesterase (edrohponium). We found a remarkable conduction delay of M waveform at the waning by means of waveform analysis. These results suggest that cold paresis may be caused by a conduction block of the muscle fiber membrane in re-innervating muscles after active denervation.
