MedlinePlus Medical Encyclopedia: Hypotonia

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Hypotonia

Contents of this page:
Illustrations Alternative names Definition Considerations	Common Causes Home Care Call your health care provider if What to expect at your health care provider's office

Illustrations

Hypotonia

Central nervous system

Alternative names Return to top

Floppy; Decreased muscle tone; Hypotonic infant

Definition Return to top

Hypotonia involves decreased muscle tone. Infants with hypotonia seem floppy and feel like a "rag doll" does when held.

Considerations Return to top

Hypotonia is often a sign of a worrisome abnormality 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.

Infants with normal tone can be lifted with the parent's hands placed under the armpits, while hypotonic infants tend to slip between the hands as the infant's arms rise unresistingly upward.

Common Causes Return to top

Down syndrome
Myasthenia gravis
Prader-Willi syndrome
Kernicterus
Cerebellar ataxia, congenital
Myotonic dystrophy
Infant botulism
Familial dysautonomia (Riley-Day syndrome)
Marfan's syndrome
Muscular dystrophy
Achondroplasia
Trisomy 13
Sepsis
Aicardi syndrome
Canavan disease
Congenital hypothyroidism
Hypervitaminosis D
Krabbe disease
Menkes syndrome
Metachromatic leukodystrophy
Methylmalonic acidemia
Rickets
Spinal muscular atrophy type 1 (Werdnig- Hoffman)
Tay-Sachs disease
Vaccine reaction

Home Care Return to top

Extra care must be taken when lifting and carrying a hypotonic infant to avoid causing an injury to the child.

Call your health care provider if Return to top

Call if your child appears "floppy", especially if he or she previously seemed to have normal muscle control.

What to expect at your health care provider's office Return to top

The family history and the child's medical history will be obtained. A physical examination will be performed. Most of the disorders associated with hypotonia also cause other symptoms that, when taken together, will suggest a particular disorder.

Medical history questions may include:

When did you first notice that your baby seemed floppy?
Was it apparent at birth?
Did it develop suddenly or gradually?
Have you ever noticed a pattern to the behavior (is it always the same or is it worse at certain times)?
How exactly does the child act?
Is the child generally limp, or only floppy in certain areas?
What other symptoms are present?

The physical examination will probably include a detailed nervous system and muscle function examination.

Diagnostic tests will vary depending on the suspected cause of the hypotonia.

Update Date: 5/4/2004

Updated by: Katrina McPherson, M.D., Department of Pediatrics, Jackson Memorial Hospital, Miami, FL. Review provided by VeriMed Healthcare Network.

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