In hypotonia, the muscles lack tone or strength, resulting in poor posture, difficulty performing certain activities, and reduced resistance to passive movement. A hypotonia can affect the whole body or specific parts, such as the arms, legs, trunk, or face. Hypotonia can develop from birth or develop later in life.
Hypotonia can be caused by various factors that affect the development or function of the muscles, nerves, brain, or spinal cord. Some possible causes include:
Genetic disorders, such as Down syndrome, Prader-Willi syndrome, or muscular dystrophy
Neuromuscular disorders, such as spinal muscular atrophy, myasthenia gravis, or Guillain-Barré syndrome
Brain or spinal cord injuries, such as cerebral palsy, stroke, or spinal cord trauma
Metabolic disorders, such as hypothyroidism, rickets, or mitochondrial disease
Infections, such as meningitis, encephalitis, or sepsis
Medications, such as muscle relaxants, sedatives, or anticonvulsants
Hypotonia may vary in severity depending on the cause, extent, and duration of the condition. The symptoms of hypotonia may include:
Floppy or limp limbs, body, or head
Delayed or impaired motor skills, such as crawling, walking, or grasping
Poor balance, coordination, or reflexes
Difficulty feeding, swallowing, or breathing
Reduced facial expressions or speech
Fatigue or weakness
Joint hypermobility or dislocation
Hypotonia can be diagnosed by a physical examination and a medical history of the patient. The doctor may also order other tests to determine the cause and extent of the condition, such as:
Blood tests, which measure the levels of hormones, enzymes, electrolytes, and antibodies in the blood and detect any signs of infection, inflammation, or metabolic disorder
Urine tests, which analyze the chemical composition of the urine and detect any signs of kidney dysfunction, dehydration, or metabolic disorder
Muscle biopsy, which involves taking a small sample of muscle tissue and examining it under a microscope for any abnormalities or damage
Nerve conduction studies, which measure the speed and strength of the electrical signals that travel along the nerves and detect any nerve damage or dysfunction
Electromyography (EMG), which records the electrical activity of the muscles and detects any muscle damage or dysfunction
Imaging tests, such as magnetic resonance imaging (MRI) or computed tomography (CT) scan, which create images of the brain, spinal cord, and muscles and detect any injuries, lesions, or defects
The main goal of treatment for hypotonia is to improve muscle tone and strength, prevent or correct any complications, and enhance the quality of life of the patient. Treatment may include:
Medications, such as antibiotics, anti-inflammatory drugs, or hormone replacement therapy, which may be prescribed to treat the underlying cause or condition that causes hypotonia
Physical therapy, which involves exercises, stretches, massages, and devices that help improve the muscle function, mobility, and posture of the patient
Occupational therapy, which involves activities, tools, and adaptations that help improve the daily living skills, such as feeding, dressing, or writing, of the patient
Speech therapy, which involves exercises, techniques, and devices that help improve the oral-motor skills, such as chewing, swallowing, or speaking, of the patient
Orthotics, which are braces, splints, or casts that support the joints and muscles and prevent or correct any deformities or injuries
Surgery, which may be performed to repair or replace any damaged or defective muscles, nerves, or joints
Hypotonia cannot be prevented, but some steps can be taken to reduce the risk of having a child with hypotonia, such as:
Getting regular prenatal care and screening tests, such as fetal ultrasound, amniocentesis, or chorionic villus sampling, to detect any genetic or chromosomal abnormalities or infections that may affect the baby’s muscle development
Avoiding exposure to any medications, substances, or infections that may harm the baby’s muscle development during pregnancy
Seeking genetic counseling or testing if there is a family history of hypotonia or other muscle disorders
Following the doctor’s advice and treatment plan for any condition that may cause or worsen hypotonia, such as hypothyroidism, rickets, or mitochondrial disease
Providing proper diagnosis and treatment can improve the condition of hypotonia. One can cope with the challenges and complications of hypotonia by following the doctor's advice and treatment plan, and by getting support from family, friends, and health care professionals.
