Abnormal spinal interactions from hand afferents to forearm muscles in writer's cramp.

OBJECTIVE: Spinal reflexes from hand to wrist muscles were investigated in writer's cramp. METHODS: Stimulus-triggered rectified EMG averages after ulnar nerve and cutaneous stimulation, in wrist flexors and extensors during tonic contraction, were compared in 18 controls and 19 patients. RESULTS: On the patient dystonic side, ulnar-induced EMG suppression was decreased in wrist extensors, and facilitation in wrist flexors modified dependent on the dystonic wrist posture during writing. No change was found on the patient non-dystonic side. Cutaneous stimulation increased wrist flexor EMG on both sides of the patients with normal wrist posture during writing, but had no effect in controls and patients with abnormal wrist posture. CONCLUSIONS: Comparison between cutaneous and mixed nerve stimuli suggests that spindle afferents from intrinsic hand muscles may mediate patients' ulnar-induced EMG modulations. Abnormal proprioceptive control was only observed on dystonic side, while bilateral unusual cutaneous control was found in patients. Changes in spinal transmission were partly related to the dystonic wrist posture, suggesting that systems involved in sensory processing can be differentially altered in writer's cramp. SIGNIFICANCE: Changes in spinal transmission, probably related to peripheral and/or cortical inputs, might either take part in primary or adaptive mechanisms underlying writer's cramp.     

Measurement of alveolar derecruitment in patients with acute lung injury: computerized tomography versus pressure–volume curve

Introduction  

Positive end-expiratory pressure (PEEP)-induced lung derecruitment can be assessed by a pressure–volume (P–V) curve method or by lung computed tomography (CT). However, only the first method can be used at the bedside. The aim of the study was to compare both methods for assessing alveolar derecruitment after the removal of PEEP in patients with acute lung injury or acute respiratory distress syndrome.     

Les onze propositions issues des 3es États généraux des malades du cancer et de leurs proches de la Ligue contre le cancer

Sans résumé     

Répercussions biologiques de l'hypothyroïdie fruste

Subclinical hypothyroidism, defined by an isolated increased TSH level, is a frequently encountered condition the clinical outcomes of which are difficult to assess. It's therapeutic management is being discussed. It is essential that biological changes resulting from subclinical hypothyroidism should be known, because they contribute to the prognosis of this condition. Conversion to overt hypothyroidism is not systematic. It is however more likely to occur when the TSH concentration exceeds 10 mUI/l and in patients with thyroid autoimmunity. The impact of subclinical hypothyroidism, as a cardiovascular risk factor seems to be related to lipid abnormalities. An increase in total cholesterol and LDL-cholesterol, reversible with thyroxine treatment, is significant only when the TSH concentration exceeds 10 mUI/l. New biological risk factors — Lp(a), CRP, plasmatic homocysteine — are neither disturbed nor influenced by thyroxine treatment. Other biological abnormalities are less significant and do not contribute to the diagnosis or prognosis of subclinical hypothyroidism.     

Exploration simplifiée des atteintes plexiques par réduction aux atteintes nerveuses et radiculaires connues

The anatomic complexity of the brachial plexus makes its electrophysiological exploration difficult. Electrodiagnosis nevertheless plays a crucial role in assessing brachial plexopathies, particularly in the perspective of post-traumatic surgical reconstructions. The evaluation aims to locate as precisely as possible injuries within the plexus, as well as to determine their severity and capacity for recovery. This requires various sensory nerve conduction studies and needle EMG recordings of “marker” muscles. Plexopathies differ from radiculopathies by altered sensory nerve responses and unaltered functional innervation of paracervical muscles. We propose to simplify the exploration of brachial plexopathies by following some practical rules derived from a reanalysis of the brachial plexus anatomic sketch. Two main simplification rules can be deduced from an analysis of the anatomic sketch. First it would be judicious to associate the plexopathies involving a single element of the brachial plexus with distinct etiological and symptomatic patterns according to the altered element, as one does for peripheral nerve and root pathologies. The second proposal relies on the observation that each supraclavicular “truncal” element (upper, middle, or lower) of the brachial plexus results from reunion of cervical root nerves and behaves like a “super-root” for the upper limb, while each infraclavicular “cord” element (posterior, lateral, or medial) is the sum of two or more peripheral nerves and behaves like a “super-nerve”. Accordingly, the motor and sensory abnormalities associated with the lesion of a single plexus branch may occupy a clinical and electrophysiological territory that recovers those of its constituants. Except the unaltered paracervical muscles, it is useful to reduce the topographical semiology of truncal lesions to well-known cervical radiculopathies (upper trunk neuropathy to C5 and C6 associated radiculopathies, middle trunk neuropathy to C7 radiculopathy, lower trunk neuropathy to C8 and T1 associated radiculopathies); and that of cord lesions to well-known mononeuropathies of the upper limb (for example, a posterior cord neuropathy may be considered as a full radial mononeuropathy associated with an axillary one). This method of simplification allows to demystify the brachial plexopathies and to facilitate their comprehension and exploration.