Hypermobility Syndrome in Children: Symptoms, Causes, Diagnosis, and Management

What is Hypermobility Syndrome in Children?

Hypermobility syndrome in children, often referred to as Joint Hypermobility Syndrome (JHS) or now more commonly as Hypermobility Spectrum Disorder (HSD), is a condition characterized by excessive flexibility in multiple joints, accompanied by chronic pain, fatigue, and other associated symptoms that impact daily function.

Understanding Joint Hypermobility

Joint hypermobility describes joints that can move beyond their normal physiological range of motion. While often perceived simply as "being double-jointed," it exists on a spectrum. Many individuals, especially children, possess benign joint hypermobility without experiencing any adverse symptoms. However, when this excessive joint laxity leads to persistent musculoskeletal pain, fatigue, recurrent injuries, or other systemic issues, it transitions into a recognized clinical condition known as hypermobility syndrome or Hypermobility Spectrum Disorder (HSD).

The prevalence of hypermobility varies but is relatively common in children, often decreasing with age as tissues naturally stiffen. From an anatomical and biomechanical perspective, the underlying cause is typically related to variations in the composition and structure of connective tissues, primarily collagen. Collagen is a key protein providing strength and elasticity to ligaments, tendons, skin, and blood vessels. In individuals with hypermobility, the collagen may be more elastic or have a different configuration, leading to looser joints and potentially weaker support structures.

Causes and Risk Factors

Hypermobility syndrome is predominantly a genetically inherited condition, meaning it often runs in families. While the exact genetic mechanisms are complex and still being researched, several factors contribute:

• Genetic Predisposition: The most significant factor is an inherited difference in collagen or other connective tissue proteins. This can range from generalized joint hypermobility without a specific diagnosis to more severe, syndromic forms such as Ehlers-Danlos Syndromes (especially Hypermobile Ehlers-Danlos Syndrome, hEDS), Marfan Syndrome, or Osteogenesis Imperfecta, where hypermobility is one of many systemic features.
• Collagen Abnormalities: Specific alterations in the genes responsible for producing various types of collagen (e.g., Type I, Type III, Type V) can lead to tissues that are less robust and more extensible.
• Muscular Hypotonia: Some children with hypermobility may also exhibit a degree of generalized muscle hypotonia (low muscle tone). While not a direct cause, it can exacerbate joint instability and contribute to fatigue as muscles have to work harder to stabilize joints.
• Physiological Factors: Hormonal influences (e.g., relaxin during puberty in girls) and growth spurts can temporarily increase joint laxity and symptom severity in children.

Signs and Symptoms in Children

Beyond the obvious flexibility, children with hypermobility syndrome often present with a range of symptoms that can significantly impact their quality of life. These include:

• Musculoskeletal Pain: This is the most common and often debilitating symptom. Children may experience chronic or recurrent pain in multiple joints (arthralgia) and muscles (myalgia), particularly after activity or at night. Pain can be diffuse or localized to specific joints like knees, ankles, hips, or the spine.
• Fatigue: Profound and persistent fatigue is very common, often disproportionate to the child's activity level. This is thought to be due to the increased muscular effort required to stabilize joints and potentially autonomic dysfunction.
• Proprioceptive Deficits: Children may appear clumsy, uncoordinated, or have poor balance. This is because their joints provide less feedback to the brain about their position in space, making fine motor skills and complex movements challenging.
• Recurrent Injuries: Due to joint instability, children are prone to sprains (especially ankles), subluxations (partial dislocations), and full dislocations, even from minor trauma.
• Skin Characteristics: The skin may be unusually soft, velvety, stretchy, or bruise easily.
• Autonomic Dysfunction: Symptoms like Postural Orthostatic Tachycardia Syndrome (POTS), characterized by dizziness, lightheadedness, rapid heart rate upon standing, and fainting.
• Gastrointestinal Issues: Common complaints include abdominal pain, bloating, constipation, and reflux.
• Anxiety and Stress: Chronic pain, fatigue, and the challenges of living with a fluctuating condition can contribute to anxiety, depression, and fear of movement (kinesiophobia).
• Flat Feet (Pes Planus): The laxity in ligaments can lead to reduced arch support in the feet.
• Scoliosis: Curvature of the spine can sometimes be associated with connective tissue laxity.

Diagnosis and Assessment

Diagnosing hypermobility syndrome in children is primarily clinical, based on a comprehensive medical history, physical examination, and symptom evaluation. There is no single blood test or imaging study to confirm the diagnosis.

• Clinical Evaluation: A healthcare professional, often a pediatrician, rheumatologist, or geneticist, will assess joint range of motion and look for characteristic signs and symptoms.
• Beighton Score: This is a widely used, simple nine-point scoring system to quantify generalized joint hypermobility. It assesses the ability to perform specific movements like touching thumbs to forearms, hyperextending elbows and knees, and placing palms flat on the floor with knees straight. A higher score indicates greater hypermobility. It's important to note that a high Beighton score indicates hypermobility, but not necessarily hypermobility syndrome; symptoms must also be present.
• Differential Diagnosis: It's crucial to rule out other conditions that can cause joint pain or hypermobility, such as inflammatory arthritis, metabolic disorders, or other genetic syndromes with more severe systemic implications.
• Multidisciplinary Approach: Diagnosis and management often involve a team of specialists, including pediatricians, geneticists, rheumatologists, physical therapists, occupational therapists, and psychologists.

Management and Treatment Strategies

The management of hypermobility syndrome in children is holistic and focuses on symptom relief, functional improvement, injury prevention, and education.

• Education and Awareness: Empowering children and their families with knowledge about the condition is paramount. Understanding that hypermobility is not a weakness but a difference in connective tissue helps alleviate anxiety and promotes self-management.
• Physical Therapy and Exercise: This is the cornerstone of management.
  • Strengthening: Focus on strengthening the muscles surrounding hypermobile joints (e.g., core muscles, hip abductors, quadriceps, hamstrings) to provide active stability.
  • Proprioceptive Training: Exercises that improve body awareness and joint position sense (e.g., balance exercises, single-leg stands, uneven surfaces).
  • Low-Impact Activities: Encouraging activities like swimming, cycling, and elliptical training that provide cardiovascular benefits without excessive joint stress.
  • Movement Pattern Correction: Teaching children to avoid hyperextending joints during daily activities and exercise.
  • Pain Management Techniques: Incorporating gentle stretching (if appropriate and non-aggravating), heat/cold therapy, and massage.
• Pain Management: For persistent pain, non-pharmacological approaches are preferred. Over-the-counter pain relievers (e.g., NSAIDs) may be used under medical guidance for acute flare-ups.
• Occupational Therapy: May be beneficial for adapting daily tasks, improving fine motor skills, and recommending assistive devices if needed.
• Psychological Support: Addressing anxiety, fear of movement, and pain coping strategies through cognitive behavioral therapy (CBT) or other counseling can significantly improve quality of life.
• Nutritional Considerations: While not a cure, a balanced diet rich in protein, Vitamin C (essential for collagen synthesis), and other micronutrients supports overall connective tissue health.
• Orthotics and Bracing: Custom orthotics can provide support for flat feet, and occasional bracing might be used for unstable joints during specific activities, but reliance on external supports should be minimized to encourage muscular engagement.

Long-Term Outlook and Prognosis

The long-term outlook for children with hypermobility syndrome is highly variable. Many children will see an improvement in symptoms as they grow and their joints naturally stiffen. However, a significant number will continue to experience symptoms into adulthood, requiring ongoing management.

Early diagnosis and intervention are crucial. By implementing appropriate physical therapy, pain management strategies, and lifestyle modifications from a young age, children can learn to manage their condition effectively, prevent injuries, and maintain an active, fulfilling life. The focus remains on optimizing function, reducing pain, and enhancing overall quality of life rather than "curing" the hypermobility itself. Regular follow-ups with healthcare providers are essential to adapt management strategies as the child grows and their needs evolve.