Diabetic Amyotrophy

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

About

• Once called Bruns Garland syndrome
• Diabetic amyotrophy is a neurological condition affecting diabetic patients
• Seen most commonly in Type 2 DM
• Management is improving diabetic control

Epidemiology

• Rare neurological complication of diabetes
• Type-2 diabetes (1.1%) and Type-1 diabetes (0.3%)

Aetiology

• A combination of autoimmunity , metabolic derangements, microvascular insufficiency, oxidative and nitrosative stress, and deficiencies in neurohormonal growth factors.
• Impaired blood flow and endoneurial micro vasculopathy play critical roles in its pathogenesis.
• Metabolic disturbances in the presence of an underlying genetic predisposition cause reduced nerve perfusion.
• Damage to nerves from a multifocal immune mediated microvasculitis.

Clinical

• Diabetic amyotrophy occurs with a gradual or acute onset, most commonly in patients aged 50 years or older.
• Acute or subacute, progressive, asymmetrical weakness and pain in the muscles of the proximal lower limbs
• Distal onset and slow proximal progression affecting both legs. May begin unilaterally and can spread bilaterally.
• Symptoms may include pain in the hip, buttock or thigh. It may be asymmetrically progressing to symmetrical
• Usually a monophasic course that can be protracted (up to 3 years) and often causes significant disability.
• Recovery of function occurs without medical treatment but maybe slow and incomplete.
• May also be weight loss. Proximal muscle weakness and wasting in quadriceps, hip adductors and iliopsoas muscles are characteristic. A mild sensory loss is observed due to coexistence with chronic DPN.
• The knee-jerk reflex is absent, with ankle jerks commonly preserved; however, ankle jerks also may be absent with underlying distal symmetrical polyneuropathy.
• In older patients who have diabetes, peripheral neuropathies have detrimental effects on stability, sensorimotor function, gait a

Differential

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

Investigations

• All patients with a suspected peripheral neuropathy should have a random blood glucose test
• Baseline haematinic studies to rule out vitamin B12/folate deficiency
• Lumbar puncture if AIDP/CIDP is suspected
• Electromyography/nerve conduction studies reveal axonal damage in the classic form of proximal motor neuropathy. If it shows demyelination, a diagnosis of CIDP should be considered
• MRI lumbosacral spine to rule out structural disorders
• CSF may show elevated protein

Management

• It is important to recognise that the condition can be the presenting feature of diabetes mellitus.
• Classify into the axonal or demyelinating type as the latter responds dramatically to certain treatments
• Treatment includes strict glycaemic control and aggressive physiotherapy
• Early recognition, strict glycaemic control (with insulin at least initially) and aggressive physiotherapy are the mainstays of treatment.
• Neuropathic pain may co-exist and treatment maybe difficult. Tricyclic antidepressants, antiepileptic drugs and analgesics are often used as first-line drugs in the treatment plan.
• It is important to divide proximal syndromes, such as diabetic amyotrophy, into either an axonal or a demyelinating type (e.g., chronic immune demyelinating polyneuropathy because the latter response dramatically to IVIG, plasmapheresis, steroids and immunosuppressive agents.
• An opinion from a neurologist to clarify the above dilemma could help

References

• DIABETIC AMYOTROPHY: FROM THE BASICS TO THE BEDSIDE