7.4 Neurological & Gastrointestinal Disease
Key Takeaways
- An upper motor neurone facial weakness spares the forehead because the frontalis receives bilateral cortical innervation, whereas Bell's palsy is a lower motor neurone lesion that involves the forehead — this distinction separates a stroke from a facial palsy
- Phenytoin causes gingival overgrowth in a substantial proportion of users, sodium valproate can impair platelet function and cause thrombocytopenia, and carbamazepine can suppress the bone marrow
- Trigeminal neuralgia in a patient under 40, or with bilateral symptoms or any sensory deficit, is a red flag for multiple sclerosis or a space-occupying lesion and requires imaging
- Coeliac disease can present with recurrent aphthous ulceration, symmetrical enamel defects and iron or folate deficiency long before gastrointestinal symptoms are recognised
- Oral Crohn's disease produces cobblestoned buccal mucosa, linear ulcers in the sulci, mucosal tags and lip swelling, and may precede intestinal symptoms
Cerebrovascular Disease
Stroke is a focal neurological deficit of vascular origin lasting more than 24 hours; a transient ischaemic attack resolves within 24 hours and is a warning of impending stroke. Recognition in the chair uses FAST — Face, Arms, Speech, Time to call 999 — and any suspected stroke is a 999 emergency because thrombolysis and thrombectomy are strictly time-critical.
Dental implications of established stroke:
- Elective treatment is usually deferred for about six months after a cerebrovascular event, with earlier care discussed with the medical team.
- Almost all survivors take antiplatelet or anticoagulant therapy, which should not be stopped for dental treatment; manage bleeding with local measures.
- Facial weakness causes food pooling in the affected buccal sulcus, drooling and denture instability.
- Dysphagia raises the risk of aspiration: work with the patient upright, use high-volume suction and avoid rinsing.
- Dysphasia is a communication difficulty, not a cognitive one — allow time, use closed questions and written or pictorial aids, and do not assume incapacity.
- Reduced manual dexterity requires adapted brush handles, electric brushes and carer support.
Upper versus lower motor neurone facial weakness
The forehead has bilateral cortical innervation, so an upper motor neurone lesion such as a stroke spares the forehead while the lower face is weak. A lower motor neurone lesion — Bell's palsy, Ramsay Hunt syndrome, parotid malignancy, or iatrogenic facial nerve injury — weakens the whole side including the forehead. Bell's palsy is treated with early high-dose corticosteroids and eye protection, and the patient needs urgent medical review; a facial weakness that spares the forehead is a stroke until proven otherwise.
Epilepsy
| Aspect | Dental relevance |
|---|---|
| Seizure triggers | Missed medication, sleep deprivation, stress, flickering lights (operating light and some equipment), alcohol, infection, hypoglycaemia |
| Chair safety | Establish seizure type, frequency, last seizure, aura and triggers; keep the chair low, remove sharp instruments, do not restrain, do not force anything into the mouth |
| Status epilepticus | A seizure of five minutes or more, or repeated seizures without recovery: buccal midazolam 10 mg and call 999 |
| Phenytoin | Gingival overgrowth in a substantial minority of users, worse with poor plaque control; intensive hygiene, and gingivectomy if function or aesthetics are affected |
| Sodium valproate | Thrombocytopenia and impaired platelet function — check a full blood count before surgery; also teratogenic, so relevant to female patients of childbearing age |
| Carbamazepine | Bone marrow suppression, hyponatraemia, and a raft of interactions; also the first-line drug for trigeminal neuralgia |
| Trauma | Seizure-related dental and facial trauma is common; fixed rather than removable prostheses are preferred where possible to avoid inhalation |
Parkinson's Disease and Movement Disorders
Bradykinesia, rigidity and tremor produce loss of manual dexterity, drooling from reduced swallowing frequency rather than excess saliva, dysphagia and denture difficulty. Practical management: appointments timed for the patient's "on" period, usually 60–90 minutes after a levodopa dose; short appointments; support for the head; adapted or electric toothbrushes; and awareness that postural hypotension is common, so raise the chair slowly.
Multiple Sclerosis and Other Neurological Disease
- Multiple sclerosis — relapsing-remitting demyelination. Trigeminal neuralgia in a patient under 40, bilateral trigeminal neuralgia, or any objective sensory deficit is a red flag for MS or a posterior fossa lesion and warrants imaging rather than a simple carbamazepine trial. Fatigue makes short morning appointments preferable.
- Myasthenia gravis — fatigable weakness affecting bulbar and respiratory muscles. Short morning appointments, careful use of sedation, and caution with drugs that worsen weakness, notably macrolides, aminoglycosides and quinolones.
- Motor neurone disease — progressive weakness with dysphagia and eventual respiratory failure; prevention-led, prosthesis-cautious, and planned early while the patient can still tolerate treatment.
- Cerebral palsy — covered in the special care chapter.
Gastrointestinal Disease
| Condition | Oral features | Dental management |
|---|---|---|
| Gastro-oesophageal reflux disease | Palatal erosion of upper teeth, halitosis, burning mouth | Treat semi-upright, avoid fully supine positioning, refer for medical management, prevention for erosion, do not brush immediately after reflux |
| Coeliac disease | Recurrent aphthous ulceration, symmetrical enamel hypoplasia and defects of the permanent incisors and first molars, glossitis, iron or folate deficiency anaemia | Consider coeliac disease in unexplained recurrent aphthae with abnormal haematinics; refer for serology rather than diagnosing it yourself |
| Crohn's disease | Cobblestoning of the buccal mucosa, linear ulcers in the buccal sulci, mucosal tags, diffuse lip swelling, pyostomatitis vegetans; oral features may precede intestinal disease | Refer for gastroenterology assessment; deficiency screen; topical corticosteroid for symptomatic lesions |
| Ulcerative colitis | Pyostomatitis vegetans, aphthous-like ulceration | As above; note steroid and immunosuppressant therapy |
| Orofacial granulomatosis | Persistent lip swelling, cobblestoning, mucosal tags in the absence of intestinal disease | Exclude Crohn's disease, particularly in children; dietary exclusion (benzoates, cinnamaldehyde) is used in some centres |
| Peptic ulcer disease | None specific | Avoid NSAIDs; use paracetamol, and consider gastroprotection if an NSAID is unavoidable |
Pattern to recognise: recurrent aphthous ulceration with low ferritin, B12 or folate is a haematinic-deficient ulcer pattern until proven otherwise, and the deficiency itself demands a cause. Coeliac disease, occult gastrointestinal blood loss and malabsorption all sit behind it — the dentist's job is to identify the pattern and refer, not to prescribe iron.
A 68-year-old develops sudden weakness of the right side of the face during a dental appointment. The forehead moves normally on the affected side and his speech is slurred. What is the most likely diagnosis and the correct action?
A patient with epilepsy taking sodium valproate is scheduled for three surgical extractions. Which pre-operative investigation is most relevant to the drug?
A 34-year-old woman presents with lancinating pain in the left V2 distribution and describes similar episodes on the right side last year. Examination shows reduced sensation over the left cheek. What is the correct next step?
A 22-year-old has recurrent aphthous ulceration, ferritin below the reference range and symmetrical enamel defects on the permanent incisors and first molars. Which underlying diagnosis should be considered?