Letter to the editor referring to "Peripheral nerve hypertrophy in chronic inflammatory demyelinating polyradiculoneuropathy detected by ultrasonography"

Ultrasound and neurophysiological correlation in common fibular nerve conduction block at fibular head

OBJECTIVE

Ultrasound (US) and neurophysiological examination are useful tools in the evaluation of common fibular mononeuropathy. There is only a report comparing US and electrophysiological parameters in patients with common fibular nerve (CFN) conduction block at fibular head. We investigated the correlation between US and neurophysiologic findings in this condition.

METHODS

We retrospectively reviewed patients with CFN assessed in our lab during last 2 years. Each patient underwent to clinical, neurophysiological and ultrasound evaluations. Cross sectional area (CSA) of CFN at fibular head was assessed.

RESULTS

Twenty-four patients were included. Motor nerve conduction study showed a reduction of distal compound muscle action potential (CMAP) amplitude in 10 patients (mean 1.3 mV). US showed an increased CSA in 10 patients. Statistical analysis revealed a strong correlation between the increased CSA and the CMAP reduction of CFN.

CONCLUSION

Our data suggest that usually US examination is normal in CFN conduction block at fibular head. However the association with axonal damage is frequently accompanied by an increase of CSA.

SIGNIFICANCE

Ultrasound evaluation may represent a powerful diagnostic/prognostic tool in cases with CPN conduction block at fibular head because it usually shows normal pattern in pure conduction block and increase of CSA in associated axonal damage.

Heterogeneity of root and nerve ultrasound pattern in CIDP patients

OBJECTIVE

The few published ultrasound (US) studies on chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) report diffusely increased cross-sectional area (CSA) of nerves. The data are, however, heterogeneous and correlations with clinical history or disease severity are lacking.

METHODS

Thirty-four patients with CIDP underwent US nerve evaluation by two neurologists blinded to clinical data. US nerve pattern for each patient was defined by a third neurologist blinded to clinical data. Three US classes were identified based on CSA and echogenicity: large nerves with hypoechoic nerves/fascicles (class 1); large nerves with heterogeneous hypo- and hyperechoic fascicles (class 2); normal size nerve but abnormal hyperechoic array (class 3).

RESULTS

In all patients, US nerve changes were observed: in most of the cases, enlarged nerves or nerve segments were observed. The three 'classes' of US nerve changes significantly correlated (R: 0.68, p<0.001) with disease duration, but not with age or Inflammatory Neuropathy Cause and Treatment (INCAT) disability score.

CONCLUSIONS

US may be of adjunctive diagnostic value in CIDP assessment. Nerve morphological changes may mirror the underlying pathophysiological mechanisms and seem to correlate with disease duration.

SIGNIFICANCE

These results offer the possibility of exploring the use of US to assess CIDP disease activity and treatment.

Multifocal enlargement and increased vascularization of peripheral nerves detected by sonography in CIDP: a pilot study

OBJECTIVE

Detection of nerve enlargement in polyneuropathies by sonography is a new research area. No systematic investigation has been done yet in chronic inflammatory demyelinating polyneuropathy (CIDP). Therefore we investigated this in CIDP.

METHODS

Eleven patients with CIDP fulfilling the international criteria on CIDP underwent ultrasonographic examination of the median, ulnar, fibular and posterior tibial nerves and sometimes the brachial plexus bilaterally, using a standardized protocol. We assessed presence of nerve thickening and increased nerve vascularization.

RESULTS

In 7 of the 11 patients multiple nerve enlargements were detected: ulnar nerve 7, fibular nerve 5, posterior tibial nerve 4 and median nerve in 4 patients. The number of enlarged nerves was related with the MRC sum-score (p=0.03) and the total protein in the cerebrospinal fluid (CSF) at diagnosis (p=0.02). Increased vascularization was seen in 6 of the 11 patients: 4 in one nerve and in 2 in multiple nerves. The number of nerves with increased vascularization was associated with the number of enlarged nerves (p=0.01) and total protein in the CSF (p=0.006).

CONCLUSION

Multiple nerve enlargements occur in CIDP showing a relation with a lower MRC sum-score, increased nerve vascularization and a higher total protein of the CSF.

SIGNIFICANCE

Our findings of nerve enlargement and increased nerve vascularization may be tools to monitor disease activity in CIDP, but further studies are needed.

Nerve ultrasound follow-up in a child with Guillain-Barré syndrome

INTRODUCTION

Nerve ultrasound has been used increasingly in neurophysiology laboratories, but data on Guillain-Barré syndrome (GBS) are still limited, and no follow-up studies are available.

CASE REPORT

An 8-year-old boy was admitted with severe demyelinating GBS. Serial neurophysiological evaluations were performed initially and in follow-up. Ultrasound studies showed diffuse and heterogeneous nerve swelling and focal enlargement of single fascicles inside the nerve. Together with clinical and electrophysiological improvement, progressive normalization of ultrasound changes was seen.

CONCLUSIONS

Ultrasound demonstrated structural nerve abnormalities in GBS. These changes normalized as the patient improved clinically and electrophysiologically. Further studies are needed to elucidate the diagnostic and prognostic value of ultrasound in GBS.