Mononeuritis multiplex

Last reviewed: May 2019

Last updated: March 2018

Summary

Mononeuritis multiplex (MNM) consists of a heterogeneous group of peripheral nerve disorders.

Presents with sensory and motor deficits in the distribution of specific peripheral nerves, and may be acute, subacute, or, rarely, chronic.

MNM is most commonly caused by vasculitis, which may be either systemic or isolated to the nerves. Other causes include hypersensitivity reactions to drugs or infections, or direct viral or bacterial infection of nerves.

Diagnosis is based on clinical picture and characteristic changes seen on biopsy.

Therapy varies with underlying MNM etiology, with most vasculitic neuropathies treated with intravenous methylprednisolone, oral corticosteroids, and oral cyclophosphamide.

Plasma exchange and intravenous immune globulin may be useful in some forms of MNM.

Azathioprine and oral cyclophosphamide are used for chronic maintenance therapy.

Definition

Mononeuritis multiplex (MNM) is a term used to describe a distinctive clinical presentation of progressive motor and sensory deficits in the distribution of specific peripheral nerves. A heterogeneous group of diseases lead to MNM. Involvement of each nerve occurs either sequentially or simultaneously. Pain is a frequent symptom in MNM, often with both neuropathic pain within the area of sensory loss and a deep pain in the affected extremity.

History and exam

Key diagnostic factors

numbness
weakness
pain
sicca symptoms
parotid gland enlargement
rash, ulcerations, or pigment changes
wheeze, cough, other pulmonary signs
fever, weight loss, and malaise

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Other diagnostic factors

predisposing conditions causing vasculitis, inflammation, or other nerve damage

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Risk factors

age over 50 years
sarcoidosis
hepatitis C
cryoglobulinemia
hepatitis B
connective tissue disease
primary vasculitis
drug use
HIV infection
non-HIV, non-hepatitis infections
recreational intravenous drug use
genetic predisposition

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Diagnostic investigations

1st investigations to order

EMG
CBC with differential
ESR
CRP
serum creatinine
serum glucose
cryoglobulins
serum complement
hepatitis B surface antigen
hepatitis C antibodies or RNA
anti-HIV antigens or HIV RNA
Lyme disease antibodies
cytoplasmic and perinuclear antineutrophil cytoplasmic antibodies (c-ANCA and p-ANCA)
rheumatoid factor
ANA
anti-double-stranded (ds) DNA
anti-SSA or SSB antibodies
serum angiotensin-converting enzyme
protein electrophoresis and immunofixation
CXR
U/A
muscle and nerve biopsy

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Investigations to consider

anti-Sm antibodies
anti-topoisomerase I (anti-Scl 70) and anti-centromere (ACA) antibodies
skin biopsy
lip biopsy
anti-Hu antibodies
CSF analyses
CT of chest, abdomen/pelvis
PET scan of chest, abdomen, or pelvis
conventional angiography
MR angiography

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Treatment algorithm

ACUTE

Contributors

Authors VIEW ALL 

Kevin R. Scott, MD

Clinical Neurologist

Colorado Springs Neurological Associates

Colorado Springs

Disclosures

KRS declares that he has no competing interests.

Milind J. Kothari, DO

Professor of Neurology

Penn State College of Medicine

Hershey

Disclosures

MJK declares that he has no competing interests.

Acknowledgements

Dr Kevin Scott and Dr Milind Kothari would like to gratefully acknowledge Dr Jenice Robinson, the previous contributor to this monograph. JR declares that she has no competing interests.

Peer reviewers VIEW ALL 

John J. Kelly, MD

Professor and Chairman

Department of Neurology

The George Washington University Medical Center

Washington

Disclosures

JJK declares that he has no competing interests.

Cory Toth, BSc, MD, FRCP(C)

Assistant Professor of Neurosciences

Hotchkiss Brain Institute

University of Calgary

Alberta

Canada

Disclosures

CT declares that he has no competing interests.

Jeremy Bland, FRCP

Consultant Neurophysiologist

East Kent Hospitals NHS Trust

Canterbury

Kings College Hospital NHS Trust

London

Disclosures

JB declares that he has no competing interests.

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