Diagnosis and Managing inflammatory diabetic neuropathies

1. Diagnosis and Managing
inflammatory diabetic neuropathies
Rahbar, M. MD

2. Case 1
• A 70 Y/O diabetic male with weakness and atrophy of right
upper since 6 months ago
• Acute onset and stable from the onset
• ↓reduced sensation and DTR: both sides, uppers>lowers,
right >Left
• MMT 1-2/5 in RU, 3-4/5 LU; lowers 5/5
• ROM; normal
• EMG and NCV studies of upper limbs
– Moderate neuropathy
– Severe C8-T1 (active denervation) and moderate, mainly, chronic
C5 to C7 radiculopathy
• Cervical MRI : moderate mid cervical spondylosis
• Lab Data, unremarkable except for BS

3. Nerve conduction Studies (NCS): Lowers

4. Nerve conduction Studies (NCS): Uppers

5. Case 2
• A 65 y/o female with sudden onset left lower weakness
since one weeks ago (WB)
• EMG report bilateral mild L5 and S1 root irritation?
• Lumbar MRI, mild spondylosis
• Brain, cervical and thoracic MRI, unremarkable
• Pelvic US, unremarkable
• No Hx DM but lab date, ↑FBS×2, (125-135 mg/dl)
• ↓Sensation in involved side
• MMT 1-3/5 in right and 4-5/5 in left; DTR ↓ or abolished in lowers

6. Case 2
• SNAPs, unobtainable
• Motor NVS, low amplitude with lower limit NCV, f-waves
and h-responses were unobtainable
• Femoral nerve CMAP; L, unobtainable and R, low
amplitude
• EMG, ↓recruitment with ↑firing rate; paraspinal, some
polyphasic MUPS with ↓recruitment

7. Synthesis of the examination findings
• Anatomical
– One lesion
– Multiple lesions
– A diffuse process?
• Syndromal or entity
– radiculopathy, neuropathy, plexopathy, MMN with CB, MND,
UML
• Aetiological (←anatomical or syndromal synthesis)
– discopathy/spondylosis, metabolic and toxic, vascular?

8. Anatomical Diabetic neuropathy classification
• Symmetrical length dependent
• Focal
– Median or ulnar neuropathy
• Multifocal
– Radiculoplexus neuropathies (affect roots, plexus and
individual nerves)

9. Etiology classification
• Metabolic complications
– Most diabetic neuropathies
• Diabetic polyneuropathy
• Compression/entrapment neuropathies
• Inflammatory
– Diabetic radiculoplexus neuropathy (microvasculitis)
• Diabetic lumbosacral radiculoplexus neuropathy
• Diabetic cervical radiculoplexus neuropathy
• Diabetic thoracic radiculopathy
• Painless diabetic motor neuropathy
– Non-diabetic radiculoplexus neuropathy
– Diabetic chronic inflammatory demyelinating polyradiculoneuropathy

10. →

11. Diabetic lumbosacral radiculoplexus neuropathy
• Well known of the inflammatory diabetic neuropathies
• Several different names in the literature
– Diabetic polyradiculopathy, diabetic amyotrophy, diabetic
mononeuritis multiplex and proximal diabetic neuropathy
• The differing names are reflective of historical controversy over the primary
site of nerve injury in these patients
• Common patterns
– Nerve damage at multiple levels
• Nerve roots, lumbar and/or sacral plexus, and peripheral nerve
(radiculoplexus neuropathy)
– Occurred In 1% of both insulin-dependent and noninsulin-dependent
diabetic patients

12. Common patterns
• Tends to occur in patients with shorter duration of diabetes
– Most patients with DLRPN do not have diabetic retinopathy or
nephropathy
• Presentation hallmarks
– Prominent pain component, marked asymmetric weakness, and
subacute presentation
• Classically begin focally with pain → weakness of a lower limb (lumbosacral)
• →bilateral with a median time to bilaterality of 3 months and involve the upper
limbs (cervical) or the trunk (thoracic)
• Occasionally painless

13. Nerve conduction
studies/electromyography
• Axonal-predominant neurogenic process in the lower extremities
– Asymmetric pattern
– Neurogenic findings more diffuse than the clinical presentation
• Outside the lumbosacral distribution
– Cervical radiculoplexus neuropathies
• Reduced sensory nerve action potentials
• Fibrillation potentials in lumbosacral paraspinal muscles
– Confirming the anatomical localization of root
• Cerebrospinal fluid protein
– Elevated with a normal cell count.
• Nerve pathology
– Microvasculitis, ischemic injury and axonal degeneration
– Secondary demyelinating changes due to underlying axonal atrophy

14. Diabetic cervical radiculoplexus neuropathy
• Upper extremity involvement in isolation, or is the
predominant neuropathic feature
– Unilateral or bilateral
• Usually pain followed by weakness
• More common in Type 2 diabetic patients
• Nerve conduction studies/EMG
– Axonal process
• ↑CSF proteins
• Nerve biopsies
– Ischemic injury, inflammation, and microvasculitis

15. CIDP
• Classical CIDP
– Symmetrical, motor predominant, proximal and distal weakness
neuropathy
• Diabetic CIDP as a controversial issue
– A coincidental occurrence
– Some diabetic radiculoplexus neuropathy misdiagnosed
“diabetic CIDP”
• Frequent coexistence of electrophysiological findings of axonal loss
and demyelination in diabetic polyneuropathy
– in some cases over interpreted as CIDP

16. Diabetic CIDP
• No pathophysiological association between the two conditions
– Some forms of radiculoplexus neuropathy such as the painless,
motor and lower limb predominant neuropathy
• CIDP in diabetic patients
– More axonal electrophysiological features than patients with CIDP
alone
• Partially secondary to coexisting diabetic polyneuropathy
– The first line treatments for CIDP
• Corticosteroids, intravenous immunoglobulins, and/or plasma exchange
– Immunotherapy responsive in most diabetic patients
• Less benefit than in idiopathic CIDP
• Greater axonal loss and/or an underlying diabetic polyneuropathy

17. Therapy
• Symptomatic therapy
– Pain control measures
– Physical therapy
– Gait assistive devices (when necessary)
• Immunotherapy
– Corticosteroids
– Improve pain
– Earlier treatment may result in a better and quicker response

18. Conclusion & future perspective
• Very important to recognize
– Their management and prognosis different from the more
common diabetic neuropathies
– Radiculoplexus neuropathies have inflammatory
pathophysiology due to microvasculitis from ischemic injury
– In most cases, appear to be monophasic
• Supportive therapies and pain control are important
• Immunotherapy