1. Myotonic Dystrophy (DM1) A Multi-System Condition
Kirsten Patterson (Genetic Specialist Nurse)
24th October 2018

2. Jacqueline Donachie Scottish artist Sister has myotonic dystrophy
Short film "Hazel," which highlights several different sets of sisters like the Donachie’s.

3. Classification
Mild DM1 (symptoms usually after 40 years) - cataracts and mild myotonia (sustained muscle contraction); life span is normal.
Classic DM1 (symptoms years) - muscle weakness and wasting, myotonia, cataracts, and often cardiac conduction abnormalities; adults may become physically disabled and may have a shortened life span.
Juvenile DM1 (symptoms between birth and adolescence) –muscle hypotonia, tiredness after physical exercise. gastrointestinal problems and learning difficulties, will likely become physically disabled and may have a shortened life span.
Congenital DM1 (symptoms at birth) - muscle hypotonia and severe generalized weakness, often with respiratory insufficiency and early death; learning disability is common.

6. Muscles Symptoms range from mild to severe.
Particularly involving face, jaw, neck, distal limb muscles.
Pain may be an issue.
Myotonia can lead to problems with grip.
Can affect speech and swallowing.
Can give a lack of facial expression
Referrals can include SLT, PT and OT.

7. Heart May be involved even without symptoms
Annual ECG advised for early detection of conduction defects.
Symptoms suggestive of cardiac arrhythmia:
Palpitations, syncope, blackouts, fainting, dizzy spells.
Referrals may include holter monitor (R test), Echo, Cardiology Consultant

8. Respiratory System
Chest infections may result from diaphragm weakness/ aspiration
Impaired ventilation (especially at night)
Signs of nocturnal hypoventilation:
Morning headache, lethargy, disturbed sleep, noisy sleep (snoring)
Referrals may include to Respiratory consultant/ sleep clinic
Flu and pneumonia vaccinations advised

9. Anaesthetic and Sedation
Increased sensitivity to sedatives, inhaled anaesthetics and neuromuscular blockade
Essential for anaesthetist to be aware of diagnosis for risk assessment and post operative planning
Detailed anaesthetic guidance is available on the Scottish Muscle Network website -
Alert card and Key Ring for all patients, as well as electronic alerts – Trak/ ACP/ KIS.

10. GI/ Liver/ Endocrine
Constipation, diarrhoea, indigestion and abdominal pain are common but might need further assessment to rule out other causes.
LFTs may be abnormal – recommend further investigation – annual LFTs
Risk of Diabetes – annual HbA1c
Risk of Hypothyroidism – annual TFT
Onward referral depends on symptoms

11. Cognition
Excessive day time sleepiness (CNS involvement) – Epworth Score
Apathy and lack of initiative
Executive function can become affected - leading to greater difficulty in organising and performing routine activities (paying bills, keeping appointments, arranging schedules, etc.)

12. Epworth Score:
Would never dose 1
Slight chance of dozing 2
Moderate chance of dozing 3
High chance of dozing
> 12 refer to sleep clinic
Sitting reading:
Watching TV:
Sitting in a public place:
Passenger in car > 1 hour:
Lying to rest in afternoon:
Sitting and talking to someone:
Sitting quietly after lunch (no alcohol):
In a car stopped for a few minutes in traffic:

13. Genetic Counselling – Autosomal dominant
A parent with an autosomal dominant condition has a 50% chance of having a child with the condition. This is true for each pregnancy.
The signs and symptoms of some genetic conditions tend to become more severe and appear at an earlier age as the disorder is passed from one generation to the next.
Anticipation
A mother with DM1 is more likely to have a baby with congenital DM.