Clinical and electrophysiological parameters distinguishing acute‐onset chronic inflammatory demyelinating polyneuropathy from acute inflammatory demyelinating polyneuropathy

Up to 16% of chronic inflammatory demyelinating polyneuropathy (CIDP) patients may present acutely. We performed a retrospective chart review on 30 acute inflammatory demyelinating polyneuropathy (AIDP) and 15 acute‐onset CIDP (A‐CIDP) patients looking for any clinical or electrophysiological parameters that might differentiate AIDP from acutely presenting CIDP. A‐CIDP patients were significantly more likely to have prominent sensory signs. They were significantly less likely to have autonomic nervous system involvement, facial weakness, a preceding infectious illness, or need for mechanical ventilation. With regard to electrophysiological features, neither sural‐sparing pattern, sensory ratio >1, nor the presence of A‐waves was different between the two groups. This study suggests that patients presenting acutely with a demyelinating polyneuropathy and the aforementioned clinical features should be closely monitored as they may be more likely to have CIDP at follow‐up. Muscle Nerve, 2010     

Myasthenia gravis and chronic inflammatory demyelinating polyneuropathy

We describe a patient with the previously unreported association of chronic inflammatory demyelinating polyneuropathy (CIDP) and myasthenia gravis (MG). Immunosuppressive treatment with azathioprine and prednisone achieved clinical and electrophysiological remission of MG and improvement of CIDP. As ophthalmoplegia occurs infrequently in CIDP, the possibility of MG should be considered when this sign is present in a patient with CIDP. Since current therapy with corticosteroids, plasma exchange and other immunomodulating agents is effective against both diseases, their association may be undereported.     

Electrophysiological sensory demyelination in typical chronic inflammatory demyelinating polyneuropathy

Background: The presence of electrophysiological demyelination of sensory nerves is not routinely assessed in the evaluation of suspected chronic inflammatory demyelinating polyneuropathy (CIDP). Whether this can be useful is unknown. Methods: We compared, using surface recording techniques, in 19 patients with typical CIDP and 26 controls with distal large fibre sensory axonal neuropathy, the forearm median sensory conductions, sensory nerve action potential (SNAP) amplitudes and durations and sensory nerve conduction velocities (SNCVs) of median, radial and sural nerves. Results: Median nerve sensory conduction block (SCB) across the forearm was greater in CIDP patients than in controls (P = 0.005). SNAP durations were longer in CIDP patients for median (P = 0.001) and sural nerves (P = 0.004). Receiver operating characteristic (ROC) curves provided sensitive (>40%) and specific (>95%) cut‐offs for median nerve SCB as well as median and sural SNAP durations. SNCVs were significantly slower for median and sural nerves in CIDP patients, but ROC curves did not demonstrate cut‐offs with useful sensitivities/specificities. Median SCB or prolonged median SNAP duration or prolonged sural SNAP duration offered a sensitivity of 73.7% for CIDP and specificity of 96.2%. Used as additional parameters, they improved diagnostic sensitivity of the American Academy of Neurology (AAN) criteria for CIDP of 1991, from 42.1% to 78.9% in this population, with preserved specificity of 100%. Discussion: Sensory electrophysiological demyelination is present and may be diagnostically useful in typical CIDP. SCB detection and SNAP duration prolongation appear to represent more useful markers of demyelination than SNCV reduction.     

慢性炎性脱髓鞘性多发性神经病的治疗进展

慢性炎性脱髓鞘性多发性神经病（chronic inflammatory demyelinating polyradiculopathy,CIDP）是一种获得性的免疫介导的周围神经病.临床特征包括进展性或复发性的肢体无力、感觉缺失和腱反射消失等.     

Differences between acute‐onset chronic inflammatory demyelinating polyneuropathy and acute inflammatory demyelinating polyneuropathy in adult patients

Acute inflammatory demyelinating polyneuropathy (AIDP) and acute‐onset chronic inflammatory demyelinating polyneuropathy (A‐CIDP) are conditions presenting overlapping clinical features during early stages (first 4 weeks), although the latter may progress after 8 weeks. The aim of this study was to identify predictive factors contributing to their differential diagnosis. Clinical records of adult patients with AIDP or A‐CIDP diagnosed at our institution between January 2006 and July 2017 were retrospectively reviewed. Demographic characteristics, clinical manifestations, cerebrospinal‐fluid (CSF) findings, treatment and clinical evolution were analyzed. Nerve conduction studies were performed in all patients with at least 12 months follow‐up. A total of 91 patients were included (AIDP, n = 77; A‐CIDP, n = 14). The median age was 55.5 years in patients with A‐CIDP vs 43 years in AIDP (P = .07). The history of diabetes mellitus was more frequent in A‐CIDP (29% vs 8%, P = .04). No significant differences between groups were observed with respect to: human immunodeficiency virus (HIV) status, presence of auto‐immune disorder or oncologic disease. Cranial, motor and autonomic nerve involvement rates were similar in both groups. Patients in the A‐CIDP group showed higher frequency of proprioceptive disturbances (83% vs 28%; P < .001), sensory ataxia (46% vs 16%; P = .01), and the use of combined immunotherapy with corticoids (29% vs 3%; P = .005). There were no significant differences in CSF findings, intensive care unit (ICU) admission, or mortality rates. During the first 8 weeks both entities are practically indistinguishable. Alterations in proprioception could suggest A‐CIDP. Searching for markers that allow early differentiation could favor the onset of corticotherapy without delay.     

Nerve ultrasound score in distinguishing chronic from acute inflammatory demyelinating polyneuropathy

ObjectiveAim of this study was to develop and evaluate the applicability of an ultrasound score (Bochum ultrasound score – BUS) in distinguishing chronic (CIDP) from acute inflammatory demyelinating polyneuropathy (AIDP).Methods

• •Step 1: For the development of BUS 75 healthy-controls, 20 CIDP, 20 AIDP patients underwent US 4.55 ± 3.5 and 3.4 ± 2.91 years, respectively after onset. After comparing the distribution pattern and frequency of pathological US changes between the two study groups, we developed BUS, summarizing the cross sectional area (CSA) of: (1) the ulnar nerve in Guyons’ canal, (2) the ulnar nerve in upper-arm, (3) the radial nerve in spiral groove, (4) the sural nerve between the gastrocnemius muscle.
• •Step 2: The BUS underwent blinded evaluation in further 10 CIDP, 21 AIDP patients 3.8 ± 2.7 and 2.3 ± 1.5 years, respectively after onset.
• •Step 3: The BUS underwent blinded, prospective evaluation in 8 patients with acute/subacute polyradiculoneuropathy (5 CIDP, 3 AIDP) 2.6 ± 1.8 weeks after onset.

ResultsThe BUS showed a sensitivity of 90% and specificity of 90.4% (positive predictive value, PPV = 81.8%; negative predictive value, NPV = 95%) in distinguishing CIDP from AIDP, when they showed no differences in disease duration (p = 0.0551).In addition, the BUS distinguished subacute-CIDP from AIDP with a sensitivity of 80%, specificity of 100% (PPV = 100%, NPV = 75%).ConclusionThe BUS seems to allow a reliable distinction of CIDP from AIDP.SignificanceThe BUS may be helpful in distinguishing subacute-CIDP from AIDP.     

Mixed nerve action potentials in acquired demyelinating polyneuropathy

Uncertainty about motor and sensory contributions in abnormal nerves has limited the use of mixed nerve action potentials (MNAPs). We recorded MNAPs in 21 patients with an acquired demyelinating neuropathy, 18 age-matched control subjects, and 10 patients with an axonal polyneuropathy. Bipolar and unipolar recordings from median and ulnar nerves were made above the elbow after electrical stimulation of the nerves at the wrist. Antidromic digital sensory action potentials and motor conduction velocity were also recorded for both nerves. In 19 median and 12 ulnar nerves from demyelinating polyneuropathy patients, compared with control subjects, MNAP amplitudes were significantly reduced (mean, 6 μV vs. 31 μV), MNAP velocities were mildly reduced (mean, 50 m/s vs. 62 m/s), motor conduction velocities were significantly reduced (mean, 33 m/s vs. 57 m/s), and MNAPs were significantly dispersed, with markedly prolonged rise times (mean, 2.0 ms vs. 1.0 ms). Compared with the axonal polyneuropathy group, MNAP amplitudes from the median nerve were similarly reduced (mean, 8 μV vs. 9 μV), MNAP velocities were only slightly slower (mean, 52 m/s vs. 58 m/s), but the rise times were significantly prolonged (mean, 2.0 ms vs. 1.2 ms). We conclude that, in acquired demyelinating neuropathies, the onset and, in some cases, the whole MNAP is from afferent fibers, which can be abnormally dispersed, and that, over the same segment, MNAP velocity is less affected than motor conduction velocity. 1995.© 1995 John Wiley &Sons, Inc.     

Onset and course of chronic inflammatory demyelinating polyneuropathy

Chronic inflammatory demyelinating polyneuropathy (CIDP) is clinically heterogeneous. Our purpose was to determine whether initial progression time, clinical features, and distribution of nerve conduction slowing at presentation correlate with clinical course and prognosis. We examined how findings at presentation related to clinical course during an average follow-up time of 4.0 (range 1.0-9.0) years in 44 patients with CIDP. We calculated terminal latency index (TLI), a measure of differential slowing in distal relative to more proximal nerve segments. Patients with acute or subacute onset (progression over less than 8 weeks) had a higher remission rate (P = 0.012) than patients with chronic onset (progression over more than 8 weeks). Patients with proximal weakness had a higher remission rate than patients with the distal phenotype (P < 0.001). All 5 patients with a relapsing course had subacute onset. They had lower TLIs, suggesting a more distal pattern of demyelination, than patients with a monophasic or chronic course. In conclusion, subacute onset and presence of proximal weakness are good prognostic signs that correlate with a high rate of recovery to normal in CIDP. Distal accentuation of conduction slowing at presentation correlates with subacute onset and a relapsing course.     

The dropped head syndrome with chronic inflammatory demyelinating polyneuropathy

The dropped head syndrome occurs in a variety of neuromuscular disorders. We present a woman with chronic inflammatory demyelinating polyneuropathy who developed this syndrome, likely reflecting severe demyelination of nerves to cervical paraspinal muscles. © 1994 John Wiley & Sons, Inc.     

Mandibular nerve involvement in diabetic polyneuropathy and chronic inflammatory demyelinating polyneuropathy

Sensory complaints in the area of the mandible and mouth often escape notice or remain undiagnosed. Using electromyographic recording of the trigeminal reflexes and motor responses, we sought trigeminal dysfunction in 50 patients with peripheral neuropathy, and tried to gain pathophysiological information on the mechanisms provoking trigeminal damage. Trigeminal reflex recordings (early and late blink reflex after supraorbital stimulation, early and late masseter inhibitory reflex after mental stimulation, and jaw jerk) disclosed abnormalities caused by sensory trigeminal neuropathy in 8 out of 15 patients with chronic inflammatory demyelinating polyneuropathy (CIDP), 13 out of 23 patients with severe diabetic polyneuropathy, and in none of 12 patients with mild diabetic polyneuropathy. Six patients had abnormal motor responses in facial or masseter muscles. The response affected most frequently was the masseter early inhibitory reflex (also called first silent period, SP1) after mental nerve stimulation, its latency being strongly delayed. We found these long delays not only in patients with CIDP, but also in diabetic patients with severe polyneuropathy. We conclude that peripheral polyneuropathies often cause subclinical damage to the trigeminal nerve, especially to its mandibular branch. We believe that the nerve fibers running along the alveolar–mandibular pathway are more exposed to damage because of their cramped anatomical route in the mandibular canal and below the internal pterygoid muscle and fascia. © 1998 John Wiley & Sons, Inc. Muscle Nerve 21: 1673–1679, 1998     

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.     

Subclinical electrophysiological alterations of phrenic nerve in chronic inflammatory demyelinating polyneuropathy

Alterations of the phrenic nerve (PN) and pulmonary function tests (PFTs) have been described in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). This study was aimed at assessing the relationship between PN and respiratory function in CIDP patients without clinical signs of respiratory failure. Bilateral PN and right median nerve conduction studies were carried out along with blood gas analysis and PFTs: maximal inspiratory pressure; maximal expiratory pressure; forced vital capacity. The amplitude of the compound muscle action potential of the PN was seen to be altered in 19/24 (79%) patients and latency in 22 (92%). Eighteen patients (75%) showed at least one abnormal PFTs or CO₂ partial pressure value. Electrophysiological alterations of the PN were observed in a high percentage of the CIDP patients studied. No statistically significant correlation was observed between PN and PFTs alterations.     

Sensory sparing patterns and the sensory ratio in acute inflammatory demyelinating polyneuropathy

The relative preservation (sparing) of sural sensory nerve action potentials (SNAPs) is a useful diagnostic finding in patients with acute inflammatory demyelinating polyneuropathy (AIDP). However, recording of sural SNAPs is not always technically feasible, especially in obese, edematous, or elderly individuals. Hence, we systematically evaluated the predictive values of the commonly employed SNAPs in the diagnosis of AIDP within 2 weeks from onset of symptoms. Sensory sparing patterns and sensory ratios of the sural, radial, median, and ulnar SNAPs of AIDP patients were included in a retrospective and blinded analysis, and compared to patients with diabetic polyneuropathy (DPN) and controls. Logistic regression models for the sural plus radial SNAPs/median plus ulnar SNAPs (sensory ratio) were constructed. A sural sparing pattern was present only in the AIDP group (34.4%, P < 0.001). A radial sparing pattern did not discriminate the AIDP from the DPN groups. The sural/radial sensory ratio was useful to ascertain DPN, but did not discriminate AIDP from controls. The sensory ratio was higher in AIDP compared to DPN and controls and was an independent predictor for AIDP. This study implies that the sensory ratio is a useful predictor for the diagnosis of AIDP and may substitute for sural sparing in technically difficult situations.     

Chronic inflammatory demyelinating polyneuropathy with tongue fasciculation: A case report

Chronic inflammatory demyelinating polyneuropathy is one of the immune-mediated polyneuropathies responsive to immunotherapy. Its usual clinical presentation is a chronic course of symmetric sensorimotor affectation of both proximal and distal extremities with signs of demyelination on electrophysiologic studies. Cranial nerve signs in this condition is not commonly encountered, particularly involvement of the hypoglossal nerve. To date, there are only three published cases of hypoglossal involvement in this condition. This case report presents a patient with tongue fasciculation, which is an uncommon finding in chronic inflammatory demyelinating polyneuropathy. This paper highlights the importance of considering chronic inflammatory demyelinating polyneuropathy in the differential diagnoses of a patient with tongue fasciculation as it has been found to be responsive to immunotherapy in comparison to other lower motor neuron syndromes.