Makindo Medical Notes

Related Subjects: Type 1 DM |Type 2 DM |Diabetes in Pregnancy |HbA1c |Diabetic Ketoacidosis (DKA) Adults |Hyperglycaemic Hyperosmolar State (HHS) |Diabetic Nephropathy |Diabetic Retinopathy |Diabetic Neuropathy |Diabetic Amyotrophy |Maturity Onset Diabetes of the Young (MODY)

Cardinal symptoms include the abrupt onset of severe proximal leg pain involving the thigh, hip, or back, followed by progressive weakness and atrophy within weeks.

About

• Also called Bruns Garland syndrome.
• Diabetic amyotrophy is a rare neurological complication of diabetes, affecting mainly type 2 diabetic patients.
• The primary management involves improving glycemic control.

Epidemiology

• Affects approximately 1.1% of Type 2 diabetes and 0.3% of Type 1 diabetes patients.

Aetiology

• A multifactorial condition involving autoimmunity, metabolic derangements, microvascular insufficiency, oxidative stress, and deficiencies in neurohormonal growth factors.
• Impaired blood flow and endoneurial microvasculopathy play critical roles in its pathogenesis.
• Reduced nerve perfusion due to metabolic disturbances in genetically predisposed individuals causes damage to nerves via an immune-mediated microvasculitis.

Clinical Features

• Occurs with a gradual or acute onset, most commonly in patients aged 50 or older.
• Characterized by asymmetrical weakness and pain in the muscles of the proximal lower limbs.
• Symptoms typically involve pain in the hip, buttock, or thigh, which may start unilaterally and progress bilaterally.
• Proximal muscle weakness, especially in the quadriceps, hip adductors, and iliopsoas, along with muscle wasting.
• Symptoms may be accompanied by mild sensory loss due to coexisting diabetic peripheral neuropathy (DPN).
• Knee-jerk reflexes may be absent, while ankle jerks may be preserved unless distal symmetrical polyneuropathy is present.
• Recovery is often slow and incomplete, with a protracted course lasting up to 3 years.

Differential Diagnosis

• Cauda equina syndrome
• Guillain-Barre syndrome
• Spinal canal stenosis
• Neoplastic lumbosacral plexopathy
• Chronic demyelinating neuropathy

Investigations

• Random blood glucose test for suspected peripheral neuropathy.
• Haematinic studies to rule out vitamin B12/folate deficiency.
• Lumbar puncture if AIDP/CIDP is suspected.
• Electromyography (EMG) and nerve conduction studies to assess axonal damage.
• MRI of the lumbosacral spine to rule out structural disorders.
• Cerebrospinal fluid (CSF) analysis may show elevated protein levels.

Management

• Recognize that diabetic amyotrophy can be the presenting feature of diabetes mellitus.
• Classify into axonal or demyelinating types. The demyelinating type (e.g., CIDP) may respond dramatically to IVIG, plasmapheresis, steroids, and immunosuppressive agents.
• Strict glycemic control, initially with insulin, and aggressive physiotherapy are the mainstays of treatment.
• Treat associated neuropathic pain with tricyclic antidepressants, antiepileptic drugs, and analgesics.
• Neurologist consultation may be required to clarify the diagnosis and management.

References

• DIABETIC AMYOTROPHY: FROM THE BASICS TO THE BEDSIDE