Chronic inflammatory demyelinating polyneuropathy mimicking an acute painful diabetic neuropathy.

Abstract

Acute diabetic painful neuropathy associated with weight loss, also known as ‘‘diabetic neuropathic cachexia’’, presents with severe burning pain, particularly in the feet and the onset is associated with weight loss. Clinical features are the presence of allodynia and hyperalgesia, as well as depression and erectile dysfunction. There are commonly no motor signs and nerve conduction studies are also usually normal or mildly abnormal [1]. Moreover, relapses are not typically observed [2]. Herein, we report a patient with chronic inflammatory demyelinating polyneuropathy (CIDP) presenting with a clinical picture resembling that of acute diabetic painful neuropathy. The patient, a 56-year-old man affected by type 2 diabetes mellitus and on hypoglycemic drug, referred to our Institute with a 3-month history of acute-onset painful neuropathy at lower limbs associated with unintentional weight loss (10 kg). He complained of intense burning and stabbing pain worsened by clothing and bedding, and associated with sensations of needles involving the thighs. Additionally, he complained of distal paresthesia, fatigue and autonomic disturbances as impotence and paroxysmal episodes of profuse sweating. Pharmacological management of pain provided only minimal relief. The patient appeared pale and to be chronically ill (BMI = 17.3, nv = 18.5–24.9). His mood was also depressed. Neurological examination showed the absence of ankle reflexes, decreased sensitivity to light touch and pinprick in the feet, and allodynia and hyperalgesia at the thighs. Muscular strength and vibration sense were preserved. Electrodiagnostic testing revealed a primary demyelinating sensory-motor polyneuropathy and a diagnosis of CIDP was assessed (Table 1) [3]. Cerebrospinal fluid examination showed an increased protein level (1.1 g/L, normal range 0.15–0.45 g/L). An extensive laboratory workup to rule out other acquired causes of neuropathy was negative. Serum glucose and glycosylated hemoglobin levels were also within the normal range. The patient received intravenous immunoglobulin (IVIG) treatment (400 mg/kg/day for 5 days) and in the following weeks, fatigue and sensory complaints significantly improved and autonomic dysfunctions resolved. At neurological examination allodynia and hyperalgesia were not observed whereas nerve conduction study was unchanged. The improvement lasted 3 months after which the patient needed IVIG treatment again for pain reappearance. At 6-month follow-up after the second IVIG treatment the patient still complained of fatigue and dysesthesias at lower limbs. In this patient, the clinical picture at onset resembled that of acute diabetic painful neuropathy but electrophysiological study showed demyelinating features consistent with CIDP. Increased protein level in cerebrospinal fluid (CSF) corroborated this diagnosis as well. CIDP encompasses typical clinical picture and several different atypical variants, including sensory-predominant CIDP [3]. The sensory-predominant form of CIDP is characterized clinically by sensory symptoms and signs including pain that can also represent the major presenting symptom of CIDP. Despite the lack of weakness, the nerve conduction studies demonstrated significant motor A. Topa R. Dubbioso R. Iodice L. Santoro F. Manganelli (&) Department of Neurosciences, Reproductive Sciences and Odontostomatology, University Federico II of Naples, Via Sergio Pansini, 5, 80131 Naples, Italy e-mail: fiore.manganelli@unina.it