Charcot Marie Tooth Disease

Physical Examination

Inspection:

• High-arched feet or pes cavus

• Hammer toes

• Muscle wasting, predominantly in the lower legs ('inverted champagne bottle' appearance)

Motor Examination:

• Tone: Normal or slightly reduced

• Power: Weakness, most noticeable in foot dorsiflexion and intrinsic foot muscles

• Reflexes: Reduced or absent ankle reflexes

Cerebellar Examination:

• No expected cerebellar signs in Charcot-Marie-Tooth disease

Sensory Examination:

• Soft Touch: Normal or slightly reduced sensation

• Pin Prick: Normal or slightly reduced sensation

• Vibration: Likely reduced, particularly at the ankles

• Proprioception: Generally preserved but may be reduced in advanced cases

Additional Examination:

• Steppage gait or foot drop due to weakness of foot dorsiflexion

• Upper limb examination may reveal similar findings to lower limbs but usually less severe

• Check for scoliosis, common in Charcot-Marie-Tooth disease

Causes of Motor Predominant Peripheral Neuropathy

• Charcot-Marie-Tooth Disease

• Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)

• Guillain-Barre Syndrome (especially the acute motor axonal neuropathy subtype)

• Multifocal Motor Neuropathy

• Lead Poisoning

• Diphtheria

• Porphyria

• Certain drugs and toxins (e.g., vincristine, cisplatin)

Investigations

Laboratory Tests:

• Complete Blood Count: To rule out systemic illnesses or anaemia.

• Biochemical profile: Assessing kidney, liver, and thyroid function.

• Fasting glucose, HbA1c: Assessing for diabetes.

• Serum protein electrophoresis: To look for monoclonal gammopathy.

• Genetic testing: Indicated if hereditary neuropathies like Charcot-Marie-Tooth disease are suspected.

Imaging:

• CT of chest/abdomen/pelvis: To look for malignancies if paraneoplastic syndrome is suspected.

Invasive:

• Nerve conduction studies and electromyography: To confirm diagnosis and classify the neuropathy.

• Lumbar puncture: If Guillain-Barre Syndrome or an inflammatory cause is suspected.

• Nerve/Muscle biopsy: Rarely performed but can help confirm specific diagnoses.

Management

General Management:

• Patient education: Explaining the nature and course of the disease.

• Physical therapy: To maintain mobility and muscle strength.

• Occupational therapy: To aid with daily tasks and provide assistive devices if needed.

• Regular monitoring: For disease progression and to manage complications.

Medical Management:

• Pain relief: Neuropathic pain agents (amitriptyline, gabapentin, or pregabalin) if needed.

• Treatment of underlying condition: Control of diabetes, autoimmune conditions etc.

Surgical Management:

• Orthopaedic surgery: Correction of skeletal deformities like pes cavus or hammer toes.

• Tendon transfers: For significant foot drop or hand weakness.

Other Management:

• Genetic counselling: If the condition is inherited, like in Charcot-Marie-Tooth disease.

• Psychosocial support: Managing the psychological impact of a chronic disease.

• Nutritional advice: For those with difficulty in swallowing or weight loss.

Causes of Pes Cavas

• Charcot-Marie-Tooth disease

• Polyneuritis

• Syringomyelia

• Friedreich’s ataxia

• Cerebral palsy

• Spinal cord tumors

• Poliomyelitis (Unilateral)

• Malunion of calcaneal or talar fractures (Unilateral)

• Burns

• Sequelae resulting from compartment syndrome