Respiratory weakness in neuralgic amyotrophy: report of two cases with phrenic nerve involvement.

An isolated affection of the phrenic nerve is a rare feature in patients with neuralgic amyotrophy. We report 1 case each of bilateral and unilateral phrenic neuropathy. The first patient presented a sudden onset of severe respiratory failure without pain. The second patient developed intense pain in the neck and in the right shoulder followed by dyspnea on mild effort and orthopnea. Chest X-rays showed elevation of the diaphragm. Needle electromyography revealed denervation restricted to the diaphragm. The phrenic nerve conduction was within the normal range. The diagnosis of neuralgic amyotrophy may be particularly difficult when the palsy of the phrenic nerve appears without brachial plexus involvement or the typical shoulder pain of acute onset. In our patients, electrophysiological evaluation combined with radiographic studies, ventilatory parameters and biochemical analyses were helpful in establishing the diagnosis.

beta-CIT SPECT demonstrates blockade of 5HT-uptake sites by citalopram in the human brain in vivo.

The cocaine analogue 2-beta-carbomethoxy-3-beta-(4-iodophenyl)-tropane (beta-CIT) is a potent ligand for both dopamine- and serotonin uptake sites which in its 123I labeled form can be used for single photon emission computerized tomography (SPECT). It was demonstrated previously by SPECT-studies in non-human primates that 123I-beta-CIT binds to dopamine transporters in the striatum and to serotonin transporters in hypothalamus and midbrain. The aim of the present study was to compare 123I-beta-CIT binding in the brain stem of normal controls and a group of subjects under treatment with the selective serotonin reuptake inhibitor (SSRI) citalopram. 123I-beta-CIT-SPECT was performed in 12 depressed patients under 20 mg (n = 5), 40 mg (n = 6) and 60 mg (n = 1) citalopram daily, in one untreated depressed patient and in 11 controls at regular time intervals up till 24 hours p.inj. A highly significant reduction of beta-CIT binding was found in an area including mesial thalamus, hypothalamus, midbrain and pons in patients under citalopram compared to controls (44.1 +/- 14.4 vs. 82.3 +/- 18.6cpm's/mCi x kg body weight; specific binding 4 hrs p.inj.; p = 0.0001). No differences were seen between the high and low dose group and no changes were found in the striatum. 123I-beta-CIT binding in the brain stem and striatum in one untreated depressed patient fell within the range of control values. To our knowledge this is the first report directly demonstrating the effect of a selective serotonin uptake inhibitor in the brain in humans in vivo. SPECT measurements of serotonin uptake sites in patients with depression and other psychiatric disorders might provide better insights into the pathophysiology of these disorders and into mechanisms of drug action.