Duchenne muscular dystrophy symptoms
Reviewed by Duchenne muscular dystrophy (DMD) is one of the most common types of inherited neuromuscular diseases, affecting about one in 3,500 boys.
DMD’s progression is relatively rapid compared with other types of muscular dystrophy. Boys typically begin showing signs of the disease in early childhood and usually need to use a wheelchair before they reach their early teens.
DMD is caused by a lack of dystrophin, a protein that supports muscle fibers. Without it, muscle contractions damage the fibers, leading to progressive muscle weakness.
What are the early signs of Duchenne?
In Duchenne muscular dystrophy (DMD), the earliest signs usually start in infancy and early childhood, as selective muscle weakness begins in the proximal muscles and legs. Noticeable developmental delays will accompany these.
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| Early signs of Duchenne muscular dystrophy | Manifestations |
|---|---|
| Delayed developmental milestones | Toddlers may take longer to lift their head, sit, walk, and talk. |
| Difficulty standing, running, and climbing stairs | Preschoolers may struggle in these areas. |
| Changes in walking and balance | Children may fall frequently, waddle, walk on their toes, or push their bellies out and shoulders back for balance. |
| Gowers’ sign | Children use their hands to push themselves upright from the floor because of hip and thigh weakness. |
| Enlarged calf muscles | Fat and connective tissue replace muscle, making calves and thighs appear larger despite reduced strength. |
How does Duchenne muscle weakness progress?
Muscle deterioration in DMD gets worse over time. Weakness gradually progresses from the lower limbs to the upper body, increasingly affecting mobility throughout childhood and adolescence. DMD progression occurs in the following pattern:
- Early symptoms affect muscles closest to the trunk, called proximal muscles, and can be hard to spot.
- Most patients need a wheelchair by their early teens.
- During adolescence, arm, trunk, and neck weakness limit daily activities, often requiring assistive devices or adaptive support.
From late childhood to young adulthood, fatigue due to increasing muscle weakness can make walking long distances and keeping up with peers challenging. A scooter, carriage, or manual wheelchair may help to reduce fatigue.
Scoliosis, or curvature of the spine, commonly develops as patients spend more time in a wheelchair. Contractures, or tight and rigid joints, may also surface as the disease progresses, further limiting the patient’s range of motion.
Here is the most common progression of DMD symptoms, grouped by developmental stage.
Infancy and toddlerhood
- takes longer to reach early milestones, including lifting the head, sitting up, walking, and talking
- initial disease signs start to show in early childhood
Preschool and early school age
- frequent stumbling or clumsiness
- difficulty running, climbing stairs, or getting up from the floor
- Gowers’ sign
- waddling or toe walking
- belly pushed out and shoulders pulled back for balance
- muscle loss around the hips and shoulders
- enlarged calves due to fat and scar tissue replacing muscle
- tiring faster than other children
- learning and social difficulties in about one-third of boys
- wheelchair use for longer distances
- increasing muscle fatigue and weakness
Teenage years and later
- full wheelchair reliance by the early teens
- scoliosis associated with prolonged wheelchair use
- contractures that limit movement
- heart muscle weakness that may cause irregular heartbeats and heart failure
- breathing muscle weakness that increases the risk of lung infections, respiratory failure, and ventilator use
What other physical symptoms can Duchenne cause?
Beyond skeletal muscle weakness, DMD can lead to postural adaptations and other body-wide concerns, including:
- Changes in posture and spinal curvature: Scoliosis, or a curved spine, is more likely in children who use wheelchairs and can make positioning difficult. Steroids have significantly reduced its occurrence in boys with DMD.
- Muscle tightness and joint contractures: Muscle changes and tightening tissues around joints can cause contractures that limit movement.
- Bone weakness and fractures: Fragile bones lead to fractures in about two to four in every 10 people with DMD, sometimes after minor bumps or position changes. Regular screening should check for vertebral compression fractures.
- Swallowing and digestive symptoms: Swallowing difficulties worsen during young adulthood and may cause meals to take more than 30 minutes. Constipation is also a common DMD symptom.
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| Duchenne muscular dystrophy can affect: | Symptoms |
|---|---|
| The heart | Feeling more fatigued than usual, unwanted or unexpected weight loss, vomiting, stomach pain, sleep problems, difficulties getting through daily tasks, chest pains. |
| Breathing | Shallow breathing and a weak cough that does not clear mucus as it should. |
| Speech and language | Difficulties processing complex verbal information, following instructions with several steps, or expressing ideas clearly. |
| Learning | Difficulties with working and short-term memory, attention and processing, and executive function. The risk of learning disabilities is also increased. |
| Behavior | Impulsive outbursts, difficulty managing emotions, anxiety, depression, adjustment difficulties, obsessive-compulsive traits, sensory issues, and social difficulties |
How can Duchenne affect the heart?
In addition to skeletal muscle atrophy, DMD patients also experience weakening of the heart muscles, known as cardiomyopathy. Duchenne heart problems can be life-threatening.
Most people with DMD have no heart failure symptoms, making screening with a cardiologist vital. Call a cardiologist upon noticing the following symptoms:
- feeling more fatigued than usual
- unwanted or unexpected weight loss
- vomiting
- stomach pain
- sleep problems
- difficulties getting through daily tasks
- chest pains
Women who carry a mutation in the DMD gene that causes Duchenne muscular dystrophy may develop heart problems, even without muscle symptoms. Regular heart screening is important to detect these problems early.
How can Duchenne affect breathing?
DMD does not directly affect the lungs. Instead, it weakens the muscles that support breathing and coughing, such as the diaphragm. This can lead to shallow breathing and a weak cough that does not clear mucus as it should.
This can increase the risk of lung infections and breathing-related illnesses. In later stages of the disease, patients may need a ventilator to help them breathe.
Pressure on the chest wall from scoliosis can also contribute to Duchenne’s breathing symptoms. Constipation might also make it challenging to take deep breaths.
Can Duchenne affect learning and behavior?
About 1 in 3 DMD patients experiences some degree of cognitive impairment. Dystrophin’s absence from the brain as well as the muscles can mean that nerves in the brain communicate less efficiently. This can lead to difficulties with learning, including with reading, math, and written communication, as well as social interactions.
Dystrophin loss in the brain can increase the risk of developmental, learning, and behavioral challenges, but not every child with DMD experiences them.
Speech and language development
DMD can affect how a person speaks, communicates, and understands language in the following ways:
- Basic vocabulary: This usually remains in the normal range, which can sometimes mask underlying difficulties with understanding language.
- Comprehension and expression: Boys may struggle to process complex verbal information, follow instructions with several steps, or express ideas clearly.
- Phonological processing: Boys may struggle to recognize and manipulate speech sounds. This, in turn, raises the risk of reading difficulties.
Learning, attention, and executive function
DMD can increase a boy’s risk of developing attention-deficit/hyperactivity disorder (ADHD) and cause memory issues. This can manifest as follows:
- Working and short-term memory: Boys with DMD might have an impaired capacity to hold and manipulate verbal information in working memory. This is the most prevalent cognitive issue.
- Learning disabilities: DMD increases the risk of learning disabilities in spelling, math, and written communication.
- Attention and processing: DMD is linked to higher rates of ADHD, distractibility, and slower processing speed.
- Executive functioning: Boys with DMD may experience challenges with planning, organization, starting tasks, and mental flexibility. They may also struggle to move from one idea to another.
Behavior, emotions, and social development
Boys with DMD have a higher risk of mental health, behavioral, and emotional regulation problems, such as:
- Behavior: Impulsive outbursts and difficulty managing emotions are more likely and may worsen with fatigue or steroids.
- Emotional health: Anxiety, depression, adjustment difficulties, obsessive-compulsive traits, and sensory issues are more common.
- Social development: About one-third of boys have social difficulties linked to cognitive and communication challenges, fatigue, and physical limitations.
Do symptoms progress the same way for everyone?
Duchenne progresses differently in each person, even among siblings. The DMD variant that causes the disease does not necessarily predict its progression. Symptoms range from earlier, more severe onset to later, milder onset.
Regular visits with a neuromuscular care team help monitor progression and guide treatment.
When should a child be assessed for Duchenne?
The American Academy of Pediatrics guidelines recommend seeking an evaluation after the following early signs become clear:
- not walking independently by 16 to 18 months of age
- the Gowers’ maneuver
- enlarged calves
- physical delays, such as difficulty running, jumping, climbing stairs, or keeping up with peers physically
- a distinct waddling gait, walking consistently on tiptoes, or falling frequently
- unexplained speech delays or cognitive/behavioral differences alongside physical lag
Routine developmental screening at 9, 18, and 30 months can also help identify any potential neuromuscular symptoms that need further investigation.
Which symptoms may need urgent attention?
A primary care physician should be notified of any muscle weakness or mobility issues.
Those with a diagnosis of DMD who experience any of the following symptoms should seek emergency medical care:
- Difficulty breathing: Requires emergency care, even without gasping or other obvious signs.
- Sudden rapid breathing: With or without confusion, this may signal a life-threatening fat embolism, especially after a fracture or limb injury.
- Shortness of breath: May indicate heart failure, particularly during activity or when lying flat.
- Altered consciousness: Requires urgent attention and may result from a head injury, low oxygen, fat embolism, or abruptly stopping steroids.
- Chest pain: Requires emergency evaluation for possible heart complications.
- Persistent vomiting: Inability to keep fluids or steroids down may require intravenous fluids or steroids to prevent dehydration or an adrenal crisis.
People with DMD should bring medical alert identification and advance directives to the hospital to help guide safe emergency care.
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