Makindo Medical Notes

🧠 About

• Hereditary Spastic Paraparesis (HSP), also called familial spastic paraplegia
• It is a group of inherited disorders causing progressive spastic weakness in the legs 🦵.
• Genetically heterogeneous – many different mutations can lead to a similar phenotype 🧬.
• Hallmark = slowly progressive spasticity + weakness of lower limbs, often with gait disturbance 🚶‍♂️.

🧬 Aetiology

• Genetics: Mutations found on chromosomes X, 2, 3, 8, 11, 12, 14, 15, 19.
• Most cases = autosomal dominant (AD), but AR and X-linked recessive (XLR) forms also exist.
• The commonest gene = SPAST (encodes spastin, important for microtubule stability and axonal transport).
• Pathology: defective microtubules → impaired axonal transport, especially in long corticospinal tract neurons ⚡.

🩺 Clinical Presentation

• Gradually worsening weakness + stiffness in legs.
• Scissor gait 🚶 due to hip adductor spasticity.
• Stiff, awkward gait with increased tone.
• Brisk reflexes, extensor plantar responses, exaggerated abdominal reflexes.
• No cerebellar signs (helps distinguish from ataxias).

🔎 Investigations

• Family history: Often diagnostic clue 👨‍👩‍👧.
• MRI spine: Usually normal – helps exclude cord compression or other structural myelopathies.
• EMG: Typically normal, since HSP affects central motor pathways, not peripheral nerves.

🧾 Differential Diagnosis

• Cord compression: Spasticity + weakness but usually with sensory loss/pain 🚨.
• Vitamin B12 deficiency: Subacute combined degeneration – look for sensory changes and anaemia 🩸.
• Infective myelopathy: e.g., HTLV-1 associated myelopathy / tropical spastic paraparesis 🌍.

💊 Management

• Spasticity control: Baclofen, Tizanidine, or targeted Botulinum toxin injections 🎯.
• Physiotherapy: Maintain mobility, prevent contractures, gait training 🏃.
• Genetic counselling: Essential for affected families 🧬.
• Although progressive and incurable, symptom control + supportive care greatly improves quality of life 💙.

Cases — Hereditary Spastic Paraparesis (HSP)

• Case 1 — Pure HSP in a Young Adult 👣: A 22-year-old man reports gradually worsening leg stiffness and difficulty walking over 5 years. Exam: bilateral spastic paraparesis, brisk knee reflexes, ankle clonus, extensor plantar responses. No sensory loss. Family history: father with similar gait. Diagnosis: Pure hereditary spastic paraparesis (autosomal dominant). Management: Physiotherapy, baclofen for spasticity, genetic counselling.
• Case 2 — Complicated HSP with Neuropathy 🧠: A 30-year-old woman develops progressive leg stiffness and weakness since her teens. Exam: spastic gait, brisk reflexes, distal wasting, mild glove-and-stocking sensory loss. MRI spine: normal. Diagnosis: Complicated HSP with associated peripheral neuropathy. Management: Supportive — physiotherapy, orthotics, neuropathic pain medication, MDT care.
• Case 3 — Childhood-Onset with Cognitive Features 🧬: A 12-year-old boy presents with delayed walking, increasing leg stiffness, and learning difficulties. Exam: spastic paraparesis, scoliosis, mild dysarthria. Strong family history in siblings. Diagnosis: Complicated HSP (childhood onset, cognitive involvement). Management: Supportive neurorehabilitation, spasticity control (baclofen, botulinum toxin), special educational needs support, genetic testing for family.

Teaching Commentary 🧠

Hereditary spastic paraparesis (HSP) = group of genetic disorders causing progressive spasticity and weakness of the legs due to corticospinal tract degeneration. - Pure HSP: only lower limb spastic paraparesis ± bladder symptoms. - Complicated HSP: additional features (neuropathy, ataxia, seizures, cognitive impairment, optic atrophy). Inheritance: autosomal dominant most common; recessive and X-linked forms exist. Diagnosis: clinical + family history, genetic testing (SPG mutations), exclusion of mimics (MS, structural cord lesions, HTLV-1 myelopathy). Management: no disease-modifying therapy — focus on spasticity control, physiotherapy, orthotics, and genetic counselling. Life expectancy usually normal.