Hypotonia is a medical term used to describe decreased muscle tone. People with hypotonia have limited resistance to movement, which causes their bodies to become soft and floppy. In a classic example of hypotonia, an infant lifted from the armpits will slide out of the parent's hands, because his or her arms don't have enough muscle tone for the infant to hold itself up. This condition usually occurs as part of another medical condition, although it can also appear on its own.
Most cases of hypotonia occur in infants, although lack of muscle tone can appear at any time in life. The condition may be the result of a congenital disease such as Tay-Sachs or muscular dystrophy, or an acquired condition, like rickets, hypothyroidism, or encephalitis. In all cases, the limbs pose minimal resistance when they are pulled into flexed positions, and the patient is unable to fully flex his or her limbs.
It can be difficult to narrow down the cause of hypotonia, especially in young patients. In some cases, it reflects a neurological problem which can occur anywhere in the brain or spinal cord, but it can also be caused by a myopathy, a problem with the muscles themselves. In cases where the cause is not evident, the condition may be known as “benign congenital hypotonia,” although in fact hypotonia is not always benign in nature.
People with hypotonia experience poor muscle control, and they can have difficulty chewing, swallowing, and talking. The condition may be severe enough to prevent the patient from walking and engaging in other physical activities, and it can become progressively worse over time if the patient is not given adequate supportive care.
When a patient is diagnosed with hypotonia, a doctor will usually recommend consulting a neurologist, along with other medical specialists who can narrow down the cause of the condition and offer treatment recommendations. Hypotonia cannot be cured, but it is possible to use physical therapy to help the patient cope and develop skills which can help him or her live independently. It may also be possible to make improvements in muscle tone with treatment which will help the patient enjoy a more active life.
If someone develops a sudden loss of muscle tone, he or she should be taken to the doctor for medical treatment, because the loss of muscle tone usually reflects an underlying medical problem. This is especially true in the case of infants, as infants cannot communicate with their parents about the symptoms they are experiencing, which means that parents need to be alert to symptoms which they observe in their children.