Motor Neuron Disease — DCE Clinical Case

DCE Long Case — Bulbar-Onset ALS with Respiratory Failure

Patient summary

Mrs R is a 66-year-old retired librarian referred by her general practitioner with a 14-month history of progressive slurred speech and difficulty swallowing, a 6-month history of progressive right-hand weakness and difficulty writing, and a 2-month history of breathlessness when lying flat, morning headaches, and daytime sleepiness. She has lost 10 kilograms in weight over 6 months. She was commenced on riluzole 50 mg twice daily one month ago by her GP. She lives with her husband, who is her main carer. She has no other past medical history and takes no other regular medications. ^[1]

Key examination findings

• Bulbar: wasted, fasciculating tongue at rest; brisk jaw jerk; spastic, poorly moving palate; mixed spastic-flaccid dysarthria; weak, bovine cough.
• Upper limbs: wasting and fasciculation of the right first dorsal interosseous and thenar muscles with reduced grip power; reflexes brisk in the right arm including the finger jerks; mild spasticity. Left arm normal. Sensation intact.
• Lower limbs: spastic tone, brisk reflexes, sustained clonus at both ankles, extensor plantar responses; power reduced in ankle dorsiflexion. Sensation intact.
• Respiratory: forced vital capacity 52 per cent predicted erect, 35 per cent supine; sniff nasal inspiratory pressure 36 cmH2O; weak cough; using accessory muscles at rest.
• Other: BMI 19. Arterial blood gas (room air): pH 7.37, pCO2 48 mmHg, pO2 86 mmHH, bicarbonate 28 mmol/L. ^[1]

Investigations performed

• EMG: active denervation (fibrillations, positive sharp waves) and chronic reinnervation (large polyphasic motor units, reduced recruitment) in bulbar, cervical and lumbar regions; normal sensory studies; no conduction block.
• MRI cervical spine: normal — no cord compression or signal change.
• Bloods: normal full blood count, electrolytes, creatine kinase (mildly elevated at 320), vitamin B12 410 pmol/L, thyroid function normal, glucose normal. Anti-GM1 negative. ^[1]

Candidate's opening statement (SASPOP)

"This is Mrs R, a 66-year-old retired librarian presenting with a 14-month history of progressive dysarthria and dysphagia, 6 months of right-hand weakness, and 2 months of orthopnoea and morning headache, with significant weight loss. Her principal problems are clinically definite bulbar-onset amyotrophic lateral sclerosis with established respiratory muscle weakness, nutritional decline requiring urgent gastrostomy, distressing pseudobulbar symptoms, and the need to begin advance care planning while she retains capacity." ^[1]

Structured problem list and integrated management

1. Clinically definite ALS (bulbar onset). Combined UMN and LMN signs in bulbar, cervical and lumbar regions meet the revised El Escorial criteria for clinically definite ALS ^[5][4]. The EMG confirms widespread active denervation with chronic reinnervation and excludes conduction block; the normal MRI excludes cervical myelopathy; the bloods exclude B12 deficiency. Continue riluzole 50 mg twice daily with monitoring of liver function and full blood count — it provides a modest median survival benefit of about 3 months ^[2].

2. Symptomatic respiratory muscle weakness — urgent NIV. She has orthopnoea and morning headache, a SNIP of 36 cmH2O (below 40), a supine FVC of 35 per cent predicted (below 50), and established hypercapnia. She meets the criteria to be OFFERED non-invasive ventilation immediately — the single intervention with the largest survival benefit (median 7 to 13 months) ^[1][3]. Initiate bilevel positive airway pressure, titrated to symptoms and nocturnal capnography, with intensive patient and family education on mask management. The hypercapnia is a late sign; do not allow further decompensation.

3. Nutritional decline — urgent PEG/RIG. BMI 19, 10 kg weight loss, dysphagia, and bulbar disease all indicate gastrostomy. Because her FVC has already fallen below the 50 per cent predicted safety threshold, coordinate periprocedural NIV and prefer a radiologically inserted gastrostomy (RIG), which is safer in respiratory compromise ^[3]. The principle is that PEG timing is determined by respiratory surveillance — ideally before FVC falls below 50 per cent — and her window is closing.

4. Symptom management.

   • Sialorrhoea: hyoscine hydrobromide 1 mg patch every 72 hours, or glycopyrrolate; botulinum toxin into salivary glands if refractory.
   • Pseudobulbar affect: dextromethorphan-quinidine 20 mg/10 mg twice daily after an ECG (QT interval) ^[6]; or an SSRI as an alternative.
   • Spasticity: baclofen, titrated from 5 mg three times daily.
   • Communication: speech therapy, voice banking, and augmentative and alternative communication set up before speech is lost.
   • Pain, constipation, mood: address proactively.

5. Multidisciplinary care and advance care planning. Refer to the specialist multidisciplinary MND clinic (independently prolongs survival). Begin advance care planning now while capacity is intact: goals and fears, advance directive, substitute decision-maker (her husband), the future role of tracheostomy ventilation, and the transition to palliative care. Screen cognition with the ECAS — ALS-FTD coexists in 15 per cent and predicts poor NIV adherence and shorter survival. Involve palliative care from diagnosis. Provide psychological support for the patient and her husband, and refer to the MND association for equipment and peer support. ^[1]

Communication and shared decision-making

The respiratory and nutritional decisions are the shared-decision-making fulcrum. I would frame NIV honestly as the intervention most likely to extend her life and improve her sleep and daytime symptoms, while being clear that it does not halt the disease and will become an increasing part of her day. I would frame PEG as a means of maintaining nutrition, hydration and medication safely, timed now because of her respiratory status. I would return to advance care planning at intervals, respecting that her priorities may shift as the disease progresses, and I would document her decisions in an advance directive with her husband as substitute decision-maker. ^[1]