Diabetic Lumbosacral Plexopathy

Diabetic Lumbosacral Plexopathy is a condition where proximal neuropathy occurs in nerves and often involves roots of lumbosacral plexus. It is also called lumbosacral radiculoplexus neuropathy.

It is said to involve about 0.1% of diabetic and is seen more commonly in type 2 diabetes.

Diabetic lumbosacral plexopathy results in pain, weakness of proximal muscles leading to difficulty in tasks like getting up from chair and climbing stairs etc.

It is seen commonly in patients greater than 50 years of age and is rare in children.

Anatomy of Lumbosacral Plexus

Read about the anatomy of lumbosacral plexus

Pathophysiology of Diabetic Lumbosacral Plexopathy

Exact mechanism of the condition is not known though the condition is most likely caused by inflammatory, immune-mediated vascular insult.

Clinical Presentation of Diabetic Lumbosacral Plexopathy

The patient may complain of pain in the hip and weakness of hip, thigh and knee muscles causing getting up from sitting position and ascent on stairs difficult.

There would be a history of poor control of blood sugar levels and concomitant history of sever weight loss may be present.

Patients may have underlying distal symmetrical polyneuropathy [typically bilateral].

A physical examination would reveal muscle weakness and wasting [[Glutei, hip adductors, iliopsoas and quadriceps are commonly involved.

The sensory deficit is minimal.

The knee reflex is usually absent but ankle reflex is often present [absent distal symmetrical polyneuropathy.]

Diagnosis

The diagnosis is mainly clinical and aided by neural studies.

Lab studies are used to ascertain diabetic status and include fasting blood glucose, hemoglobin A1C.

Additional laboratory studies to rule out other causes of neuropathy, as well as cancer and bleeding diathesis, are also important.

Lumbar spine and pelvic radiographs should be performed to evaluate for other causes of the plexopathy.  CT or MRI pelvis may be indicated to rule out mass lesions. 

Histological findings are rarely needed. These typically show an epineural and perivascular inflammation around the small vessels may be caused by infiltration by mononuclear cells, with or without polymorphonuclear cells.

Active axonal degeneration, microvasculitis, and ischemic injury are other findings

Electromyography

• Without distal symmetrical polyneuropathy
  • positive sharp waves and fibrillation potentials in the iliopsoas, hip adductors, and quadriceps.
• With an underlying distal symmetrical polyneuropathy, the following are seen in addition
  • Sural sensory nerve action potential is usually absent
  • Reduction in amplitudes of peroneal and tibial compound motor action potential

Differential Diagnosis

• Other causes of lumbosacral plexopathy
• Amyotrophic Lateral Sclerosis
• Lumbar Spondylolysis and Spondylolisthesis
• Mononeuritis Multiplex
• Limb-Girdle Muscular Dystrophy
• Meralgia Paresthetica
• Cauda Equina and Conus Medullaris Syndromes
• Guillain-Barre Syndrome
• Hypothyroid Myopathy

Treatment of Diabetic Lumbosacral Plexopathy

Most patients can be treated on outpatient basis. That means hospital admission and stay is usually not required.

Patients are managed with  medical treatment. Surgery is not required.

The patients are managed with control of blood sugar, physical therapy for functional mobility and rehabilitation.

It is followed by occupational therapy. The patient is educated about proper diet and exercise.

Apart from drugs used in the management of sugar levels, neuromodulator drugs for chronic neuropathic pain are used.

These drugs are gabapentin or pregabalin, and duloxetine.

Local counterirritant drugs may help too.

Intravenous human immunoglobulins are said to speed the recovery.

A good functional recovery is seen in 1-2 years in about two-thirds of patients.