The value of autonomic testing in postural tachycardia syndrome.

Postural tachycardia syndrome (POTS) is a fairly common condition that may or may not be associated with autonomic neuropathy. In a retrospective analysis, we compared two groups of patients based on clinical and autonomic criteria, those with POTS in isolation (POTS-Alone), and POTS with evidence of autonomic neuropathy (POTS-AN). Of 260 records reviewed, 57 patients met the criteria for POTS; 38 (67%) patients assigned to the POTS-Alone group and 19 (33%) patients assigned to the POTS-AN group. A decreased sweat output on the quantitative sudomotor axon reflex test is the most frequent abnormal finding in the POST-AN group suggesting sympathetic cholinergic neuropathy. Clinically, headache and gastrointestinal symptoms were more frequent among the POTS-AN group. Therefore, POTS may exist in isolation and may differ from those associated with AN.

New criteria for early electrodiagnosis of acute inflammatory demyelinating polyneuropathy.

A variety of electrodiagnostic methods are used to confirm the diagnosis of acute inflammatory demyelinating polyneuropathy (AIDP), but difficulties are frequent during the first few weeks of weakness. We compared the nerve conduction studies (NCS) of patients with AIDP to those with critical illness polyneuropathy (CIP), a subacute axonal polyneuropathy. New electrodiagnostic criteria with graded certainty (normal, nondiagnostic, suggestive, highly suggestive, and definite) were designed and applied in a blinded manner to both groups. Among the AIDP patients, 64% met the highly suggestive and definite criteria (specificity 95-100%, P < 0.01), whereas 80% of the CIP group fell in the nondiagnostic criteria (P < 0.001). The relative preservation of the sural sensory response in spite of at least two abnormal sensory NCS in the upper limb suggested acute demyelination (sensitivity 48%, specificity 96%, P < 0.001) and was even more conclusive when associated with absent or prolonged F waves. Motor and sensory response amplitudes were lower in the CIP group, with comparable mean motor and sensory distal latencies and motor conduction velocities. Motor conduction blocks were present in 10% of nerves in AIDP and were not encountered in CIP. The frequency of absent or delayed F waves and absent H reflex was similar in both groups. The correlation coefficient of the cerebrospinal fluid protein concentration with the designed criteria was higher in the AIDP group (r = 0.9). We conclude that a new criterion with graded certainty is of higher specificity in the majority of patients with early AIDP.

Multiple recurrences of diabetic muscle infarction: case report and literature review.

This is the report a case of diabetic muscle infarction (DMI) associated with multiple recurrences and a review of the literature on DMI from the first description in 1965 to the present. Specifically the review of the clinical, laboratory, and muscle histopathologic features of 86 reported cases of DMI.Patients with DMI usually present with acute or subacute focal lower extremity muscle pain or swelling. Elevations in the white blood cell count and erythrocyte sedimentation rate are common laboratory findings. Magnetic resonance imaging, a highly sensitive diagnostic test in DMI, shows increased T2-weighted signal and edema in affected muscles. Typical muscle histopathology includes muscle fiber necrosis and endomysial inflammation. Slow symptomatic improvement usually occurs over a period of 1 to 6 months. Conservative therapy and analgesics seem appropriate for most patients. Although self-limiting, DMI is often associated with recurrent muscle infarctions and multisystem diabetes-related complications. Diabetes-induced arteriosclerosis and microangiopathy are the suggested causes of DMI.It is concluded that DMI is an uncommon but probably underrecognized disorder causing focal muscle pain and swelling, usually of thigh or calf muscles, in patients with diabetes mellitus complicated by poorly controlled hyperglycemia and multiorgan complications.