Makindo Medical Notes

Related Subjects: |Autosomal Dominant |Autosomal Recessive |X Linked Recessive

🦶 Foot Drop is the inability to dorsiflex the foot due to weakness of the tibialis anterior. It usually arises from lesions of the common peroneal nerve or L5 nerve root, but many neurological and systemic conditions can cause it. Patients often present with a high-steppage gait to avoid tripping.

🚨 Causes of Foot Drop

• 🧠 CNS: Stroke, Multiple Sclerosis, Motor Neuron Disease (ALS).
• 🦵 Nerve Root: L5 radiculopathy (commonly due to lumbar disc herniation).
• 🩻 Peripheral Nerve: Peroneal nerve compression (leg crossing, fibular head trauma, casts).
• 🧬 Genetic/Neuromuscular: Charcot-Marie-Tooth disease (progressive neuropathy, high arches).
• 🍬 Metabolic: Diabetic neuropathy (chronic sensory-motor polyneuropathy).
• 🩺 Trauma/Surgery: Hip or knee surgery, fractures causing direct nerve injury.

🩺 Clinical Features

• 👣 Gait: High-steppage gait (lifting the knee higher than normal).
• ⚡ Weakness: Inability to dorsiflex ankle or extend toes.
• 🔎 Sensation: Numbness over dorsum of foot (peroneal nerve) or posterolateral leg (L5).
• 🧩 Other signs: Fasciculations (MND), spasticity (MS/stroke), high arches (CMT).

🔬 Assessment

• 📖 History: Recent trauma, back pain, systemic illness, family history.
• 🩺 Exam: Test dorsiflexion, inversion/eversion, sensation, reflexes.
• 📊 Investigations:
  • EMG & Nerve Conduction Studies – localise lesion.
  • MRI Lumbar Spine – L5 radiculopathy.
  • MRI/CT Brain – stroke, MS.
  • Limb Imaging – trauma, compression.
  • Bloods – HbA1c, ferritin, autoimmune screen if relevant.

📋 Differential Diagnosis & Management

💡 Clinical Tip

Always look for **“high-steppage gait”** in suspected foot drop. It’s the classic OSCE clue — patients exaggerate hip/knee flexion to clear the toes.