Hipotónia

Hipotónia, or hypotonia, is a medical sign characterized by decreased muscle tone and reduced resistance to passive movement, often described as floppy. It may indicate a range of underlying conditions affecting the central nervous system, peripheral nerves, or muscles. In infants it can present with poor trunk control, delayed motor milestones, a weak suck or cry, and head lag. In older children and adults, it may appear as generalized weakness, fatigue, and a relaxed posture.

Causes are typically grouped as central (brain or spinal cord) or peripheral (nerves, neuromuscular junction, or muscles). Central causes include brain malformations, birth injury, hypoxic-ischemic encephalopathy, metabolic disorders, and certain genetic syndromes. Peripheral causes include spinal muscular atrophy, muscular dystrophies, congenital myopathies, and neuromuscular junction disorders. Prematurity and systemic illnesses can contribute. In many cases hypotonia is part of a broader developmental delay or syndrome.

Diagnosis relies on history and examination of tone, reflexes, and motor development, followed by targeted testing to identify the cause. Tests may include neuroimaging (MRI), genetic testing, metabolic analysis, and, when appropriate, electromyography or nerve conduction studies.

Management focuses on the underlying cause and supportive care. Interventions commonly include physical therapy to improve strength and coordination, occupational therapy, assistive devices, and management of feeding or respiratory issues.

Prognosis varies with etiology; some individuals improve with therapy, while others have persistent impairment.