Hypermobility Spectrum Disorder (HSD)

Joint hypermobility means a joint has a greater range of motion than usual. There are different types of joint hypermobility based on which joints are hypermobile.

In generalized joint hypermobility (GJH), joint hypermobility is present in many different joints throughout the body.

In peripheral joint hypermobility, joint hypermobility is limited to the hands and feet.

In localized joint hypermobility, joint hypermobility is present in a single joint or group of joints in the same area.

A joint is the point where two or more bones connect. Joint instability means the bones of a joint are not held in place securely. This can lead to joint subluxations, dislocations, sprains, and other injuries. 

A joint dislocation occurs when two bones at a joint separate completely and are no longer touching. A subluxation is a partial dislocation in which two bones at a joint are out of place but are still touching each other. 

Most people with HSD have chronic pain that persists over a long period of time. HSD can also cause acute pain that lasts for a shorter period due to something specific, like an injury.

Ligaments are bands of connective tissue that can connect two bones in a joint. Sprains occur when ligaments are stretched or torn, which can cause pain, swelling, and bruising. 

Tendons are bands of connective tissue that connect muscles to bones and other structures. Strains occur when muscles or tendons are stretched or torn, which can cause pain, swelling, and muscle spasms.

Cartilage is a connective tissue that protects the joints by cushioning the bones and preventing them from rubbing together. Osteoarthritis (OA) occurs when the cartilage in a joint wears away. Osteoarthritis can cause joint pain, swelling, and stiffness.

Osteoarthritis is common as people age because it is caused by wear on the joints over time. Osteoarthritis may start at a younger age in people with HSD because joint hypermobility causes increased wear on the joints.

People with HSD may have some of the skin features seen in hypermobile Ehlers-Danlos syndrome (hEDS).

Local anesthesia is a medicine used to numb parts of the body before a medical procedure. Local anesthetics, such as lidocaine, are not as effective in some people with HSD.

Dysautonomia, also called autonomic dysfunction, is a group of disorders that affect the autonomic nervous system. The autonomic nervous system regulates many involuntary bodily processes that we do not consciously think about, including heart rate, blood pressure, body temperature, sweating, digestion, metabolism, and bladder control.

Common symptoms of dysautonomia include:

• Tachycardia (fast heart rate)
• Hypotension (low blood pressure)
• Dizziness/lightheadedness
• Gastrointestinal dysmotility (problems moving food through the digestive system)
• Bladder issues
• Temperature and sweating dysregulation
• Sleep problems

Each type of dysautonomia causes different symptoms. Many people with HSD have a type of orthostatic intolerance, which means the symptoms occur when upright or standing. The two most common types of orthostatic intolerance are:

• Orthostatic hypotension (OH) — low blood pressure on being upright ⁠
• Postural orthostatic tachycardia syndrome (POTS) — an abnormal increase in heart rate when standing without a drop in blood pressure

Proprioception is the ability to sense the body’s position and movement. Research shows that people with HSD have decreased proprioception. Reduced proprioception may make a person seem clumsy or uncoordinated and increase the risk of injury.

Neuropathic pain is a type of persistent (or chronic) nerve pain caused by problems with the nervous system. Nerve pain may feel like burning, stabbing, shooting, numbness, or tingling.

Nerve entrapment occurs when a nerve is compressed or pinched by surrounding tissues. Nerve entrapment can cause pain, numbness, tingling, and weakness in the affected area.

Small fiber neuropathy (SFN) occurs when small nerve fibers are damaged. Small nerve fibers regulate bodily processes and carry sensations like pain and temperature to the brain. Symptoms of SFN include pain, numbness, tingling, and burning in the feet and hands.

Thoracic outlet syndrome (TOS) occurs when nerves or blood vessels in the lower neck and upper chest are compressed.

Symptoms of TOS include:

• Pain in the neck and shoulder
• Numbness and tingling of the fingers
• Weakness in the arms
• Cold hands
• Swelling
• Skin color changes

Kyphosis is an abnormal forward curve in the spine that causes the upper back to look more rounded. Some people with HSD develop postural kyphosis due to poor posture and loose connective tissues.

Craniocervical instability (CCI) is increased movement where the spine meets the skull. This can happen when the surrounding tissues are too weak or loose to properly support the joint between the skull and the first vertebra of the spine.

Symptoms of CCI include:

• Headaches
• Neck pain
• Dizziness
• Balance and coordination issues
• Nausea
• Numbness and tingling in the hands and feet
• Bladder or bowel issues
• Vision and hearing problems
• Swallowing issues

The atlantoaxial joint connects the first (C1) and second (C2) vertebrae in the neck. Atlantoaxial instability (AAI) is increased movement in the atlantoaxial joint. This can happen when the surrounding tissues cannot properly support this joint.

Symptoms of AAI include:

• Neck pain
• Headaches
• Restricted neck movements
• Vision changes
• Dizziness
• Nausea
• Facial pain
• Swallowing issues

The spine is made up of bones called vertebrae. The vertebrae are separated by discs of connective tissue that support and cushion them and allow the spine to move. Degenerative disc disease happens when the spinal discs wear down and no longer properly cushion the vertebrae.

Degenerative disc disease becomes more common as people age due to wear on the joints over time. Joint hypermobility and instability can increase wear on the joints, which may contribute to the development of degenerative disc disease in people with HSD.

Fatigue is severe tiredness or lack of energy that prevents a person from functioning normally. Many people with HSD have chronic fatigue, which is constant or recurring fatigue that lasts for more than six months.

People with HSD may get headaches for several different reasons, including:

• Migraines
• Muscle tension
• Idiopathic intracranial hypertension
• Dysautonomia
• Craniocervical instability
• Temporomandibular joint dysfunction
• Cerebrospinal fluid leaks
• Cervical spine disorders

People with HSD may sometimes feel lightheaded or dizzy, particularly when standing. Lightheadedness is often due to dysautonomia in people with HSD.

People with HSD may have issues with sleep initiation (falling asleep), sleep maintenance (staying asleep), and sleep restoration (getting refreshing sleep).

Obstructive sleep apnea (OSA) is when breathing stops repeatedly during sleep due to a partial or complete airway blockage.

Anxiety is a feeling of worry, nervousness, or unease about something. Anxiety can cause physical symptoms, such as fast heart rate, rapid breathing, and sweating.

Depression is a constant feeling of sadness and loss of interest in activities.

Attention deficit hyperactivity disorder (ADHD) is a condition that causes people to be inattentive, hyperactive, and impulsive.

• Inattentive means someone is easily distracted and has trouble focusing their attention
• Hyperactive means someone moves around a lot and has a hard time sitting still
• Impulsive means someone acts quickly without thinking their actions through

Autism spectrum disorder, also called autism or ASD, is a neurodevelopmental disorder that affects how people communicate and interact with the world. Autism is a “spectrum disorder,” which means there is wide variation in both the type and severity of symptoms. Autism is often associated with difficulties with social and communication skills, repetitive behaviors, restricted interests, and sensory sensitivities.

The temporomandibular joint (TMJ) connects the lower jaw to the skull. Problems with the TMJ and the ligaments and muscles that control it are more common in people with HSD.

Some people with HSD have trouble producing or sustaining their voice, also known as dysphonia.

Some people with HSD have a hard time swallowing, also known as dysphagia.

Tachycardia occurs when the heart beats too fast, at more than 100 beats per minute at rest. Many people with HSD experience tachycardia due to dysautonomia.

Gastrointestinal motility is the movement of food through the digestive system. Problems with this process are known as dysmotility. Dysmotility occurs when the muscles or nerves of the digestive system don’t work properly. This can cause symptoms such as reflux, nausea, vomiting, abdominal pain, bloating, constipation, and diarrhea.

The esophagus is a tube that connects the throat to the stomach. Gastroesophageal reflux disease (GERD) occurs when stomach acid regularly flows backward into the esophagus. This backward flow of acid can cause burning in the chest, which is known as heartburn. GERD can also cause swallowing and voice problems.

Gastroparesis, also called delayed gastric emptying, occurs when the stomach either slows down or stops working, causing food to remain in the stomach for longer. Symptoms of gastroparesis include nausea, vomiting, feeling full at the beginning of a meal, and feeling full long after a meal.

Irritable bowel syndrome (IBS) is a condition that causes abdominal pain and changes in bowel movements.

People with HSD may feel uneasy and feel the need to vomit.

Some people with HSD experience pain in the abdomen, the midsection of the body that contains the gastrointestinal system and other organs.

Bloating is feeling fullness, tightness, or pressure in the abdomen. It is usually caused by a buildup of air or gas in the stomach or intestines. Bloating may be uncomfortable and make the abdomen look larger.

People with HSD may have infrequent or difficult bowel movements.

People with HSD may have loose, watery, or more frequent bowel movements.

Mast cells are part of the immune system that cause inflammation and allergic reactions when activated. Mast cell activation syndrome (MCAS) refers to an increased number of mast cells, increased activity of mast cells, or both.

MCAS can cause many different symptoms throughout the body, including typical allergic responses (such as hives, itchiness, and anaphylaxis), gastrointestinal symptoms (such as nausea and abdominal pain), and bladder issues (such as pain and inflammation).

People with HSD may experience changes in their symptoms during pregnancy. This may include the worsening of the following:

• Pain
• Joint instability
• Gastrointestinal issues
• Dysautonomia
• Mast cell activation syndrome