Benign Hypotonia Is Not a Diagnosis
The diagnosis of Benign Hypotonia in infants and children, sometimes called Benign Congenital Hypotonia, has not been an accurate diagnosis since the early 1960s. It is well known now by neuromuscular specialists that there are several disorders which cause hypotonia or muscle weakness in infants and children. These are principally the Congenital Myopathies and Infantile Spinal Muscular Atrophy.
Unfortunately, the diagnosis of benign hypotonia is still found on patients’ charts, in medical articles and textbooks, on the Internet and there is even a parents’ group of children who carry this diagnosis.
It is extremely important that a muscle biopsy be done under a local anesthetic to establish the correct diagnosis. One a specific diagnosis is made; a child’s prognosis can be discussed, as well specific problems that may be encountered. The diagnosis of Central Core disease is a particularly important one to establish since this disorder and Malignant Hyperthermia are at the same gene location.
Thus, a child with this disorder who receives an anesthetic is greatly at risk if the necessary precautions are not taken.
Some of the other Congenital myopathies are: Minicore disease, Fibre-type Disproportion, Myotubular Myopathy, and Nemaline Myopathy. Each of these has specific characteristics and muscle biopsy changes.
Written by Charlotte E. Thompson, M.D.