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Hypotonia
Decreased muscle tone; Floppy infant
Hypotonia means decreased muscle tone.
Considerations
Hypotonia is often a sign of a worrisome problem. The condition can affect children or adults.
Infants with this problem seem floppy and feel like a "rag doll" when held. They rest with their elbows and knees loosely extended. Infants with normal tone tend to have flexed elbows and knees. They may have poor head control. The head may fall to the side, backward, or forward.
Infants with normal tone can be lifted with the adult's hands placed under the armpits. Hypotonic infants tend to slip between the hands.
Causes
Muscle tone and movement involve the brain, spinal cord, nerves, and muscles. Hypotonia may be a sign of a problem anywhere along the pathway that controls muscle movement. Causes may include:
- Brain damage, due to lack of oxygen before or right after birth, or problems with brain formation
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Disorders of the muscles, such as
muscular dystrophy
Muscular dystrophy
Muscular dystrophy is a group of inherited disorders that cause muscle weakness and loss of muscle tissue, which get worse over time.
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- Disorders that affect the ability of nerves to send messages to the muscles
- Infections
Genetic or chromosomal disorders, or defects that may cause brain and nerve damage include:
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Down syndrome
Down syndrome
Down syndrome is a genetic condition in which a person has 47 chromosomes instead of the usual 46.
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Spinal muscular atrophy
Spinal muscular atrophy
Spinal muscular atrophy is a group of disorders of the motor neurons (motor cells). These disorders are passed down through families (inherited) and...
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Prader-Willi syndrome
Prader-Willi syndrome
Prader-Willi syndrome is a disease that is present from birth (congenital). It affects many parts of the body. People with this condition feel hung...
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Tay-Sachs disease
Tay-Sachs disease
Tay-Sachs disease is a life-threatening disease of the nervous system passed down through families.
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Trisomy 13
Trisomy 13
Trisomy 13 (also called Patau syndrome) is a genetic disorder in which a person has 3 copies of genetic material from chromosome 13, instead of the u...
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Other disorders that can lead to the condition include:
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Achondroplasia
Achondroplasia
Achondroplasia is a disorder of bone growth that causes the most common type of dwarfism.
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Being born with hypothyroidism
Being born with hypothyroidism
Neonatal hypothyroidism is decreased thyroid hormone production in a newborn. In very rare cases, no thyroid hormone is produced. The condition is ...
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Marfan syndrome
Marfan syndrome
Marfan syndrome is a disorder of connective tissue. This is the tissue that strengthens the body's structures. Disorders of connective tissue affect...
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Spinal cord injuries that occur around the time of birth
Home Care
Take extra care when lifting and carrying a person with hypotonia to avoid causing an injury.
What to Expect at Your Office Visit
The physical exam will include a detailed examination of the nervous system and muscle function.
In most cases, a neurologist (specialist in brain and nerves) will help evaluate the problem. Geneticists may help diagnose certain disorders. If there are also other medical problems, a number of different specialists will help care for the child.
Which diagnostic tests are done depends on the suspected cause of the hypotonia. Most of the conditions associated with hypotonia also cause other symptoms that can help in the diagnosis.
Many of these disorders require ongoing care and support.
References
Burnette WB. The hypotonic (floppy) infant). In: Daroff RB, Jankovic J, Mazziotta JC, Pomeroy SL, eds. Bradley's Neurology in Clinical Practice . 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 29.
Johnston MV. Encephalopathies. In: Kliegman RM, Stanton BF, St Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics . 20th ed. Philadelphia, PA: Elsevier; 2016:chap 598.
Marcdante KJ, Kliegman RM. Weakness and hypotonia. In: Marcdante KJ, Kliegman RM. Nelson's Essesntials of Pediatrics . 7th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 7.
Sarnat HB. Evaluation and investigation. In: Kliegman RM, Stanton BF, St. Geme JW III, Schor NF, eds. Nelson Textbook of Pediatrics . 20th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 607.
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Hypotonia - illustration
Hypotonia is often a sign of abnormality in the case of a newborn or older infant, and may suggest the presence of central nervous system dysfunction, genetic disorders, or muscle disorders. Hypotonic infants rest with their elbows and knees loosely extended, while infants with normal tone tend to have flexed elbows and knees. Head control may be poor or absent in the floppy infant with the head falling to the side, backward or forward.
Hypotonia
illustration
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Central nervous system - illustration
The central nervous system is comprised of the brain and spinal cord. The peripheral nervous system includes all peripheral nerves.
Central nervous system
illustration
-
Hypotonia - illustration
Hypotonia is often a sign of abnormality in the case of a newborn or older infant, and may suggest the presence of central nervous system dysfunction, genetic disorders, or muscle disorders. Hypotonic infants rest with their elbows and knees loosely extended, while infants with normal tone tend to have flexed elbows and knees. Head control may be poor or absent in the floppy infant with the head falling to the side, backward or forward.
Hypotonia
illustration
-
Central nervous system - illustration
The central nervous system is comprised of the brain and spinal cord. The peripheral nervous system includes all peripheral nerves.
Central nervous system
illustration
Review Date: 10/27/2015
Reviewed By: Chad Haldeman-Englert, MD, FACMG, Fullerton Genetics Center, Asheville, NC. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
