Hypermobility Spectrum Disorder (HSD): Symptoms, Diagnosis, and Management

What is Hypermobility Spectrum Disorder (HSD)?

Hypermobility Spectrum Disorder (HSD) is a connective tissue disorder characterized by joint hypermobility and associated musculoskeletal or non-musculoskeletal symptoms that do not meet the diagnostic criteria for a more specific connective tissue disorder, such as Ehlers-Danlos Syndrome (EDS).

Understanding Joint Hypermobility

Joint hypermobility refers to the ability of a joint to move beyond its normal anatomical range of motion. This increased laxity is often due to variations in the structure or composition of connective tissues, particularly collagen, which provides strength and elasticity to ligaments, tendons, and joint capsules. While some degree of hypermobility can be asymptomatic, when it leads to pain, instability, or other systemic issues, it falls under the umbrella of hypermobility disorders.

Generalized vs. Localized Hypermobility:

• Generalized Joint Hypermobility (GJH): This describes hypermobility present in multiple joints throughout the body. It is typically assessed using standardized tools like the Beighton Score, which evaluates nine specific joint movements. A score of 4/9 or more (depending on age and sex) often indicates GJH.
• Localized Joint Hypermobility (LJH): This refers to hypermobility affecting only one or a few specific joints, such as a single shoulder or knee, without generalized laxity.

The Spectrum of Hypermobility Disorders

The understanding and classification of hypermobility have evolved significantly.

Historical Context: Benign Joint Hypermobility Syndrome (BJHS): Previously, many individuals with symptomatic generalized hypermobility were diagnosed with Benign Joint Hypermobility Syndrome (BJHS). The term "benign" often downplayed the chronic pain, fatigue, and other debilitating symptoms many patients experienced, leading to a lack of appropriate recognition and management.

The Shift to Hypermobility Spectrum Disorder (HSD): In 2017, the International Consortium on Ehlers-Danlos Syndromes and Hypermobility Spectrum Disorders introduced a new nosology, replacing BJHS with Hypermobility Spectrum Disorder (HSD). This change emphasizes that hypermobility exists on a spectrum of severity and presentation, ranging from asymptomatic joint laxity to complex multisystemic involvement. HSD is a diagnosis of exclusion, meaning it is made when a person presents with symptomatic joint hypermobility but does not meet the full diagnostic criteria for hypermobile Ehlers-Danlos Syndrome (hEDS) or other more specific connective tissue disorders.

Relationship to Ehlers-Danlos Syndromes (EDS): EDS are a group of heritable connective tissue disorders characterized by joint hypermobility, skin hyperextensibility, and tissue fragility. Hypermobile Ehlers-Danlos Syndrome (hEDS) is the most common type of EDS and is considered the most severe end of the hypermobility spectrum. HSD shares many features with hEDS, but individuals with HSD do not meet the strict criteria for hEDS, particularly regarding the extensive systemic manifestations often seen in hEDS. However, both conditions require similar management approaches, focusing on symptom alleviation and functional improvement.

Signs and Symptoms of HSD

The symptoms of HSD can vary widely in type and severity, affecting both the musculoskeletal system and other body systems.

Musculoskeletal Manifestations:

• Chronic Joint Pain: Often widespread and disproportionate to activity levels, stemming from joint instability, muscle overuse, and compensatory patterns.
• Joint Instability: A feeling of joints "giving way," leading to frequent sprains, subluxations (partial dislocations), and full dislocations.
• Fatigue: Profound and debilitating fatigue, often related to the increased muscular effort required to stabilize joints and systemic energy drain.
• Proprioception Deficits: Reduced awareness of body position in space, increasing the risk of falls and injuries.
• Muscle Weakness and Imbalance: Muscles may become weak or imbalanced as they struggle to compensate for ligamentous laxity.
• Early Onset Osteoarthritis: Chronic joint stress can accelerate degenerative changes.

Non-Musculoskeletal Manifestations (Systemic Symptoms): While less prominent than in hEDS, individuals with HSD can experience systemic symptoms due to widespread connective tissue involvement:

• Autonomic Dysfunction: Including Postural Orthostatic Tachycardia Syndrome (POTS), manifesting as dizziness, lightheadedness, palpitations, and fainting upon standing.
• Gastrointestinal Issues: Such as dysmotility, reflux, constipation, or irritable bowel syndrome (IBS)-like symptoms.
• Skin Manifestations: While typically not as severe as in EDS, skin may be soft, velvety, or show easy bruising.
• Anxiety and Depression: Chronic pain and fatigue can significantly impact mental health.
• Pelvic Floor Dysfunction: Due to laxity of supporting tissues.
• Headaches and Migraines: Often related to craniocervical instability or autonomic dysfunction.

Diagnosis of HSD

The diagnosis of HSD is primarily clinical, based on a thorough medical history, physical examination, and the exclusion of other conditions.

Clinical Evaluation:

• Beighton Score: This nine-point scoring system assesses the range of motion in the pinky finger, thumb, elbows, knees, and trunk. A higher score indicates greater joint laxity.
• Patient History: Detailed information about joint pain, instability episodes, fatigue, and any systemic symptoms. The clinician will look for patterns consistent with hypermobility-related issues.
• Physical Examination: Beyond the Beighton Score, a comprehensive musculoskeletal examination assesses muscle strength, joint stability, posture, and gait.

Exclusion of Other Conditions: A crucial step in diagnosing HSD is to rule out other connective tissue disorders, particularly hEDS, and other conditions that can cause joint pain or hypermobility. This often involves genetic testing or specific clinical criteria for other EDS types, Marfan syndrome, or rheumatological conditions.

Management and Treatment Strategies for HSD

Management of HSD is highly individualized and focuses on symptom management, improving function, and preventing further complications. It often requires a multidisciplinary approach.

Physical Therapy and Exercise: This is the cornerstone of HSD management.

• Strengthening: Focusing on core stability and muscles surrounding hypermobile joints to provide active support and improve joint stability.
• Proprioceptive Training: Exercises to enhance body awareness and joint position sense, reducing the risk of injury.
• Balance Training: To improve stability and reduce falls.
• Low-Impact Activities: Encouraging activities like swimming, cycling, or elliptical training that minimize joint stress.
• Posture and Ergonomics: Education on maintaining optimal posture and using ergonomic principles in daily activities to reduce strain.
• Pacing and Energy Conservation: Learning to manage activity levels to prevent post-exertional malaise and fatigue.

Pain Management:

• Pharmacological: Over-the-counter pain relievers (NSAIDs), neuropathic pain medications, or muscle relaxants may be used under medical supervision.
• Non-Pharmacological: Heat/cold therapy, transcutaneous electrical nerve stimulation (TENS), massage, and acupuncture can provide relief.

Lifestyle Modifications:

• Activity Modification: Adapting daily tasks to reduce stress on vulnerable joints.
• Assistive Devices: Braces, splints, or orthotics may be used to support unstable joints during activity.
• Nutrition: A balanced diet and adequate hydration support overall health and connective tissue integrity.

Multidisciplinary Approach: Collaboration among healthcare professionals is vital:

• Physicians: Rheumatologists, geneticists, or general practitioners for diagnosis and overall medical management.
• Physical Therapists: For exercise prescription, pain management, and functional rehabilitation.
• Occupational Therapists: To assist with daily living activities and adaptive strategies.
• Psychologists/Counselors: For managing chronic pain, anxiety, and depression.
• Other Specialists: Depending on systemic symptoms (e.g., cardiologists for POTS, gastroenterologists for GI issues).

Living with HSD

Living with HSD requires ongoing self-management and a proactive approach to health.

Prognosis and Long-Term Outlook: HSD is a chronic condition, but with appropriate management, individuals can significantly improve their quality of life. The prognosis varies widely depending on the severity of symptoms and the effectiveness of management strategies. Early diagnosis and intervention can help prevent long-term complications.

Empowerment and Self-Management: Education about HSD is crucial for empowering individuals to understand their body's unique needs. Learning to listen to one's body, pace activities, and consistently engage in prescribed exercises are key to managing symptoms and maintaining function. Support groups and patient advocacy organizations can also provide valuable resources and community.

Conclusion

Hypermobility Spectrum Disorder (HSD) represents a significant advancement in understanding and classifying symptomatic joint hypermobility. Moving beyond the "benign" label, HSD acknowledges the diverse and often debilitating symptoms experienced by individuals with connective tissue laxity. While distinct from Ehlers-Danlos Syndromes, HSD requires a similarly comprehensive, multidisciplinary approach focused on strengthening, stability, pain management, and lifestyle adjustments. With proper education and tailored interventions, individuals with HSD can effectively manage their condition and lead fulfilling, active lives.