Contrast-enhanced magnetic resonance imaging of the lumbosacral roots in the dysimmune inflammatory polyneuropathies

A comparative study of brachial plexus sonography and magnetic resonance imaging in chronic inflammatory demyelinating neuropathy and multifocal motor neuropathy

BACKGROUND AND PURPOSE

To compare the performance of neuroimaging techniques, i.e. high-resolution ultrasound (HRUS) and magnetic resonance imaging (MRI), when applied to the brachial plexus, as part of the diagnostic work-up of chronic inflammatory demyelinating neuropathy (CIDP) and multifocal motor neuropathy (MMN).

METHODS

Fifty-one incident, treatment-naive patients with CIDP (n = 23) or MMN (n = 28) underwent imaging of the brachial plexus using (i) a standardized MRI protocol to assess enlargement or T2 hyperintensity and (ii) bilateral HRUS to determine the extent of nerve (root) enlargement.

RESULTS

We found enlargement of the brachial plexus in 19/51 (37%) and T2 hyperintensity in 29/51 (57%) patients with MRI and enlargement in 37/51 (73%) patients with HRUS. Abnormal results were only found in 6/51 (12%) patients with MRI and 12/51 (24%) patients with HRUS. A combination of the two imaging techniques identified 42/51 (83%) patients. We found no association between age, disease duration or Medical Research Council sum-score and sonographic nerve size, MRI enlargement or presence of T2 hyperintensity.

CONCLUSIONS

Brachial plexus sonography could complement MRI in the diagnostic work-up of patients with suspected CIDP and MMN. Our results indicate that combined imaging studies may add value to the current diagnostic consensus criteria for chronic inflammatory neuropathies.

CIDP diagnostic pitfalls and perception of treatment benefit

OBJECTIVE

We aimed to explore the diagnosis and misdiagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) and to identify pitfalls that erroneously lead to a misdiagnosis.

METHODS

A retrospective study of 59 consecutive patients referred with a diagnosis of CIDP was performed. Patients were classified as having or not having CIDP according to European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) criteria. Diagnostic and treatment data were compared in the 2 groups.

RESULTS

Forty-seven percent of patients referred with a diagnosis of CIDP failed to meet minimal CIDP diagnostic requirements. All misdiagnosed patients who satisfied EFNS/PNS clinical criteria would be considered atypical as defined by the EFNS/PNS. CSF cytoalbuminologic dissociation was present in 50% of those without CIDP, although protein elevations were generally mild. Nerve conduction studies in patients without CIDP were heterogeneous, but generally showed demyelinating features better explained by a process other than CIDP. Patients frequently reported improvements after being treated with immunotherapy, even if the CIDP diagnosis was incorrect.

CONCLUSIONS

CIDP misdiagnosis is common. Over-reliance on subjective patient-reported perception of treatment benefit, liberal electrophysiologic interpretation of demyelination, and placing an overstated importance on mild or moderate cytoalbuminologic dissociation are common diagnostic errors. Utilization of clear and objective indicators of treatment efficacy might improve our ability to make informed treatment decisions.

Neuroimaging in diagnosis of atypical polyradiculoneuropathies: report of three cases and review of the literature

Neuroimaging is increasingly used in the study of peripheral nerve diseases, and sometimes may have a pivotal role in the diagnostic process. We report on three patients with atypical chronic inflammatory polyradiculoneuropathy (CIDP) in whom magnetic resonance imaging (MRI) and nerve Ultrasound (US) were crucial for a correct diagnostic work-out. A literature review on MRI and US in acquired demyelinating polyneuropathies is also provided. Awareness of the imaging features of CIDP will assist in confirmation of the diagnosis, institution of the appropriate therapy, and prevention of inadequate or delayed treatment in atypical CIDP.

MR Imaging of the Lumbosacral Plexus: A Review of Techniques and Pathologies

The lumbosacral plexus is a complex anatomic area that serves as the conduit of innervation and sensory information to and from the lower extremities. It is formed by the ventral rami of the lumbar and sacral spine which then combine into larger nerves serving the pelvis and lower extremities. It can be a source of severe disability and morbidity for patients when afflicted with pathology. Patients may experience motor weakness, sensory loss, and/or debilitating pain. Primary neurologic processes can affect the lumbosacral plexus in both genetic and acquired conditions and typically affect the plexus and nerves symmetrically. Additionally, its unique relationship to the pelvic musculature and viscera render it vulnerable to trauma, infection, and malignancy. Such conditions are typically proceeded by a known history of trauma or established pelvic malignancy or infection. Magnetic resonance imaging is an invaluable tool for evaluation of the lumbosacral plexus due to its anatomic detail and sensitivity to pathologic changes. It can identify the cause for disability, indicate prognosis for improvement, and be a tool for delivery of interventions. Knowledge of proper MR protocols and imaging features is key for appropriate and timely diagnosis. Here we discuss the relevant anatomy of the lumbosacral plexus, appropriate imaging techniques for its evaluation, and discuss the variety of pathologies that may afflict it.

Guillain-Barré syndrome

Guillain-Barré syndrome and its clinical variants are a group of rapidly progressing, potentially debilitating neurologic disorders that may have significant morbidity/mortality if left unrecognized or untreated. The most common symptoms include ascending limb weakness and paralysis, which may progress to respiratory failure. Diagnosis is made clinically with laboratory testing. Several treatment options exist, including plasma exchange and intravenous immunoglobulin administration. Most cases may resolve without sequelae, but those that do not may leave behind significant persistent debility.

Investigation of suspected Guillain-Barre syndrome in childhood: what is the role for gadolinium enhanced magnetic resonance imaging of the spine?

AIM

To review the role of gadolinium-enhanced magnetic resonance imaging of the spine in the diagnosis of paediatric Guillain-Barre syndrome and compare it with nerve conduction studies and cerebrospinal fluid analysis.

METHODS

A retrospective review of investigations undertaken in children admitted to our institution with acute Guillain-Barre syndrome over a 10-year period was performed.

RESULTS

Seven of eight children (88%) displayed post-gadolinium nerve root enhancement consistent with Guillain-Barre syndrome. This compared with supportive nerve conduction studies in 21/24 children (88%) and cerebrospinal fluid protein analysis consistent with the diagnosis in 16/20 children (80%).

CONCLUSION

Nerve conduction studies are the recognised 'gold standard' technique for confirming a clinical diagnosis of Guillain-Barre syndrome. In this study, a high positive rate was demonstrated. While more experience is necessary, this study and the literature support gadolinium enhanced magnetic resonance imaging of the spine as a valuable, although not necessarily superior, investigation in the diagnosis of Guillain-Barre syndrome. It may be of particular benefit when specialist neurophysiology expertise is unavailable.

Spinal leptomeningeal lymphoma presenting as pseudotumor syndrome

We describe 2 patients with inexorably progressive pseudotumor syndrome (intracranial hypertension without mass lesion or ventriculomegaly) both initially misdiagnosed as having idiopathic intracranial hypertension and who were eventually found to have spinal leptomeningeal lymphoma. Neither had, at any time, any clinical signs of a spinal cord or root lesion. We discuss the possible implications of these observations regarding the diagnosis and mechanism of the pseudotumor syndrome.

A male with progressive lower extremity weakness and monoclonal gammopathy

EDUCATIONAL OBJECTIVES

To discuss a case of progressive lower extremity paresis and paresthesias in a patient found to have monoclonal gammopathy.

KEY QUESTIONS

(1) What is the differential diagnosis of progressive lower extremity paresis and paresthesias? (2) How would one approach diagnostic testing for such a patient? (3) What is the differential diagnosis of neuropathy associated with gammopathy? and (4) What is the treatment for this patient?

Magnetic resonance imaging of childhood Guillain-Barre syndrome

OBJECTIVE

To describe the spinal magnetic resonance imaging (MRI) features in children with Guillain-Barre syndrome (GBS) and to investigate the correlation with the clinical/laboratory findings.

MATERIAL AND METHODS

Clinical/laboratory findings of 40 children (mean age 5.7 years; range, 3 months-15 years) who had a final diagnosis of GBS were retrospectively reviewed. Clinical severity was graded according to Hughes classification. Electromyogram and cerebrospinal fluid analysis of the patients were recorded. All patients had a contrast-enhanced spinal MRI. The contrast enhancement pattern was determined, and the diameters of anterior and posterior spinal nerve roots were measured. The clinical/laboratory findings were correlated with the MRI findings.

RESULTS

Twenty-eight patients had an electromyogram examination, and 25 of them revealed findings consistent with GBS. Cerebrospinal fluid analysis of 37 out of 40 patients showed albumino-cytologic dissociation. All but two patients had thickening and contrast enhancement of the nerve roots and cauda equina on spinal MRI. The most common MRI finding was enhancement of both the anterior and the posterior nerve roots of cauda equina which was prominent anteriorly. The mean anteroposterior diameter of the anterior nerve roots was 2.19 mm (range, 1.38-3.30 mm) and the posterior nerve root was 1.80 mm (range, 1.07-2.97 mm).

CONCLUSION

Spinal MRI is a reliable imaging method for the diagnosis of GBS as it was positive in 38 of 40 patients. The severity on MRI does not correlate with severity of the clinical condition. MRI can be used as a supplementary diagnostic modality to clinical and laboratory findings of GBS.

[Gadolinium enhancement of the cauda equina following ischemia of the lumbar cord]

Enhancement of the cauda equina is a well-recognized finding, in particular in patients with inflammatory diseases of the peripheral nervous system. However, we report an unusual case of a woman with an ischemic lesion in the lumbar intumescence who developed enhancement of the cauda equina 18 days after disease onset. Seventy-six days after the onset of illness, contrast uptake was no longer detectable. Severe injury to the motor neurons in the lumbar intumescence was evident clinically and electromyographically. We propose that the enhancement of the cauda equina was due to blood-nerve barrier disruption during Wallerian degeneration following ischemic injury to the motor neurons of the lumbar cord.

Detection of cervical nerve root hypertrophy by ultrasonography in chronic inflammatory demyelinating polyradiculoneuropathy

Several studies have demonstrated abnormal MRI findings in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), especially hypertrophy and abnormal enhancement of spinal nerve roots, but there have been few reports on ultrasonographic findings of spinal nerve roots in CIDP. To determine whether ultrasonography (US) enables detection of hypertrophy of the cervical nerve roots, how frequently hypertrophy occurs in CIDP, and whether US findings correlate with any clinical and laboratory features, US of cervical nerve roots was performed using a 7.5-MHz linear-array transducer in 13 CIDP patients and 35 control subjects. A coronal oblique plane with a transducer placed on the lateral side of the neck was used to visualize the cervical nerve roots just after their point of exit from the cervical foramina, and their diameters were measured. US demonstrated hypertrophy of the cervical nerve roots in 9 (69%) of the 13 CIDP patients as compared with findings in control subjects. The degree of hypertrophy was significantly associated with the level of CSF protein (chi2=5.8, p<0.05, logistic simple regression analysis) but not with other clinical features. US is considered to be a useful method for evaluating cervical nerve root hypertrophy, which is frequently seen in patients with CIDP, particularly in patients with elevated level of CSF protein.

Hypertrophic Neuropathy of the Cauda Equina: Case Report

OBJECTIVE AND IMPORTANCE

Hypertrophic neuropathy of the cauda equina (HNCE) is a rare form of peripheral neuropathy. The diagnosis is complicated by an insidious clinical presentation and complex radiographic images. We present a case of HNCE caused by chronic inflammatory demyelinating polyneuropathy with symptomatic improvement after decompressive lumbar laminectomy and dural expansion.

CLINICAL PRESENTATION

A 54-year-old woman with a history of back pain since she was in her 20s presented with low back and radicular pain that had increased during a period of 6 months, bilateral lower-extremity weakness, and sensory loss in the right thigh. Magnetic resonance imaging of the lumbosacral spine revealed multiple, poorly enhancing mass lesions and apparent intrathecal nerve root thickening from L1 to L5.

INTERVENTION

An L1-L5 decompressive laminectomy, performed with continuous somatosensory evoked potential and electromyographic monitoring, revealed multiple segmentally enlarged nerve roots. One nerve root that did not respond to high levels of stimulation was identified. This root was resected and submitted for pathological analysis. The dura was expanded with an 11-cm-long dural patch. The pathological examination revealed hypertrophic neuropathy, with extensive S-100-positive “onion bulb” formation. The patient's symptoms improved postoperatively.

CONCLUSION

HNCE is a rare disorder that can cause radicular pain and lower-extremity weakness, sensory loss, and hyporeflexia. One possible cause is demyelinating polyneuropathy. Although medical management is typically effective in the treatment of demyelinating polyneuropathy, it has little effect on compressive symptoms caused by intradural nerve root enlargement. As this case demonstrates, surgical management of symptomatic radiculopathy by lumbar laminectomy is a reasonable and effective approach to the treatment of HNCE.

Autoimmune neuropathies

Autoimmune neuropathies are common and treatable disorders of the peripheral nerves, which should be properly recognized. This article discusses their diagnosis, differential diagnosis and proper treatment.

MRI of the cauda equina in CIDP: clinical correlations

Isolated reports have documented enhancement and/or enlargement of spinal nerve roots on magnetic resonance imaging (MRI) in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). This work examines those findings in a consecutive series of 16 patients with CIDP, with blinded comparison to MRI in 13 disease controls, including five patients with Charcot-Marie-Tooth disease type 1A. MRI sequences consisted of T1 weighted sagittal and axial views, before and after administration of gadolinium. Blinded MRI interpretation was performed independently by two neuroradiologists. MRI results were correlated with data collected from chart review. Enhancement of the cauda equina was seen in 11 of 16 CIDP patients (69%), and in none of 13 control subjects. Nerve roots were enlarged, most significantly in the extraforaminal region, in three CIDP patients, and in one patient with Charcot-Marie-Tooth type 1A. MRI findings did not correlate with disease activity and severity, nor with any clinical or laboratory features in patients with CIDP.

Low back pain due to hypertrophic roots as presenting symptom of CIDP

Attention has recently been drawn to chronic inflammatory demyelinating polyneuropathy (CIDP) with symptomatic nerve root hypertrophy. A 31-year-old woman had fluctuating and worsening low back pain. Absent tendon jerks and a slight weakness of the hand interossei muscles suggested a diffuse neuropathy. The electrophysiological and histological findings were diagnostic for CIDP. Lumbar spine MRI showed marked nerve root enlargement with gadolinium enhancement. This case widens the range of the clinical presentations of CIDP. Further studies are warranted to ascertain whether cauda equina gadolinium enhancement may be a useful tool in the diagnosis of CIDP and a marker of disease activity for monitoring response to therapy.