Presenting Complaint

• You are worried as you have been tripping involuntarily while walking your dog.

History of Presenting Complaint

• Site: Difficulty lifting both legs on walking but predominantly on the left. Wife feels that you lift your legs much higher than usual when walking
• Onset: First tripped 3 months ago. 
• Character: Legs feel weak and heavy
• Timing: Last week tripped 3 times on different days. It has worsened since onset (Student must specifically ask if symptoms have worsened).
• Associated features: No sensory changes (only if specifically asked), no joint pain, no pain in legs or back. Sometimes, have difficulty holding the cup of tea and once dropped it accidentally.
• Exacerbating/Relieving factors: No provoking factors. Tripping happens unexpectedly. You sit more often, but this does not help.

Systems Review

• Neurological: apart from leg weakness, no other neurological deficits
• GI: No change in bladder or bowel function
• Otherwise well, no other problems
• Red flags: as below
  • Trousers feel looser around the calf and thigh.
  • Feel more tired recently but no night sweats, change in appetite, fevers or recent infection

Previous Medical History

• Well controlled Asthma
• No known hospital admissions or recent surgeries

Drug History

• Blue Salbutamol inhaler PRN

Allergies

• NKDA

Social History

• Stopped smoking 5 years ago – smoked 5 a day for 20 years (only if asked).
• Drink alcohol on social occasions only.
• Never taken recreational drugs.
• Works as a chef at a renowned restaurant.
• Live with your wife with no problems at home.

Family History

• Father has Parkinson’s Disease
• Mother has Breast Cancer

ICE

Expectations: Want to know the diagnosis and if you should do anything to improve the symptoms.

Ideas: Thinks this might be Parkinson’s disease

Concerns: Worried about Parkinson’s and if symptoms will impact your ability to work

Vitals

• HR: 76 bpm
• BP: 126/84 mmHg
• SpO₂: 98%
• Temperature: 36.6℃
• Respiratory Rate: 14 breaths per min

Neurological Examination

Pin-prick, vibration and proprioception sensation normal.

Upper limbs:

Mild atrophy of thenar eminence. 

Normal tone. 

Normal power on all joint movements. 

Reflexes normal. 

Pin-prick, vibration and proprioception sensation normal.

Lower limbs:

Prominent atrophy of tibialis anterior in the left leg compared to the right. Fasiculations are seen bilaterally.

Reduced tone bilaterally.

Reduced power on dorsiflexion of both feet but prominent on the left. Reduced power on hip flexion bilaterally but normal power in other joint movements.

Increased reflexes on tapping the patellar and Achilles tendon. Babinski’s sign is negative bilaterally.

Examiner Questions

1. What is the most likely diagnosis and explain why?

• Motor neuron disease (MND) – a mix of upper and lower motor neuron signs in the absence of sensory deficits is characteristic of MND. A bilateral foot drop suggests a systemic problem rather than a local one. Patients often present with involuntary tripping or difficulty holding objects due to reduced muscle strength

2. What are the types of MND?

• Amyotrophic Lateral Sclerosis (ALS is the commonest type). Subtypes include:
  • Spinal ALS → classic MND
  • Bulbar ALS → Tongue, muscles involved in chewing and swallowing are affected causing difficulty talking, chewing and swallowing
• Progressive Muscular Atrophy – Only lower motor neuron signs. Distal muscles affected before proximal muscles
• Primary Lateral Sclerosis – Only upper motor neuron signs

3. What blood tests would you consider doing in primary care?

• Bloods:
  • Vitamin B12, Folate – to exclude subacute combined degeneration (although unlikely as there are no sensory deficits, it can cause both upper and lower motor neuron signs)
  • FBC and Iron studies – assess for microcytic anaemia, which can cause tiredness. If iron deficient, consider bowel cancer due to patient’s age
  • Thyroid Function Tests – hypothyroidism can cause tiredness

4. Given the suspected diagnosis of MND, how would you manage this patient in primary care?

• Urgent referral to neurologist informing about a suspected diagnosis of MND (as per NICE guidance).
• Provide the patient with a leaflet about the diagnosis and direct them to local support groups or national charities that can help them through their diagnosis.
• Discuss legal rights, including social care support, occupational therapy input, physiotherapy, employment rights and benefits.
• Notify the Driver and Vehicle Licensing Agency (DVLA).
• Opportunities for advance care planning e.g. LPA

5. What treatment may be provided in secondary care?

Prognosis is poor: 50% of patients die within 3 years of diagnosis

Riluzole

Glutamate receptor antagonist

Prolongs life by about 3 months

Respiratory care – Use BIPAP (non-invasive ventilation) at night

Nutrition support – Percutaneous endoscopic gastrostomy tube (PEG) is preferred due to impaired swallow