Seropositivity for antibodies that bind to or block ganglionic acetylcholine receptors identifies patients with various forms of autoimmune autonomic neuropathy and distinguishes these disorders from other types of dysautonomia. The positive correlation between high levels of ganglionic-receptor antibodies and the severity of autonomic dysfunction suggests that the antibodies have a pathogenic role in these types of neuropathy.

Foot drop is a common and distressing problem that can lead to falls and injury. Although the most frequent cause is a (common) peroneal neuropathy at the neck of the fibula, other causes include anterior horn cell disease, lumbar plexopathies, L5 radiculopathy and partial sciatic neuropathy. And even when the nerve lesion is clearly at the fibular neck there are a variety of causes that may not be immediately obvious; habitual leg crossing may well be the most frequent cause and most patients improve when they stop this habit. A meticulous neurological evaluation goes a long way to ascertain the site of the lesion. Nerve conduction and electromyographic studies are useful adjuncts in localising the site of injury, establishing the degree of damage and predicting the degree of recovery. Imaging is important in establishing the cause of foot drop be it at the level of the spine, along the course of the sciatic nerve or in the popliteal fossa; ultrasonography, CT and MR imaging are all useful. For patients with a severe foot drop of any cause, an ankle foot orthosis is a helpful device that enables them to walk better and more safely.

The purpose of this study was to evaluate sweating and cardiovascular autonomic function in patients with distal small fiber neuropathy (DSFN). Sweat testing by the quantitative sudomotor axon reflex test was abnormal in 32 of 40 (80%) patients. The thermoregulatory sweat test was abnormal in 18 of 25 (72%) patients; one or both tests were abnormal in 36 of 40 (90%). Minor heart rate abnormalities were present in 11 of 40 (28%) patients. We conclude that, in patients with DSFN: (a) the sympathetic sudomotor fibers are frequently affected, and that evaluation of sweating is a useful diagnostic test; (b) that the autonomic nerves controlling heart rate are less affected.