Hypotonic infant | Medical Council of Canada
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Hypotonic infant

Version: February 2017
Legacy ID: 71-2


Hypotonia in an infant can be an indication of severe systemic disease requiring urgent intervention, or neurological disease potentially requiring long-term multidisciplinary care.

Causal Conditions

(list not exhaustive)

  1. Neurologic (e.g., perinatal asphyxia, spinal muscular atrophy, myasthenia gravis)
  2. Disorders of skeletal muscle (e.g., muscular dystrophy)
  3. Genetic/metabolic (e.g., Prader-Willi, hypothyroidism)
  4. Systemic illness (e.g., sepsis, dehydration)

Key Objectives

The candidate will recognize hypotonia in an infant as a finding requiring urgent attention. Considering the presence or absence of other clinical findings, the candidate will formulate an appropriate differential diagnosis, assess the severity of the condition, and will initiate an appropriate management plan.

Enabling Objectives

Given a hypotonic infant, the candidate will

  1. list and interpret critical clinical findings, including
    1. assessment of physiologic stability (e.g., oxygenation, cardiovascular function);
    2. a thorough history including a perinatal history;
    3. a complete physical examination, including a detailed neurological and musculoskeletal examination;
  2. list and interpret critical investigations appropriate to the clinical condition, which may include
    1. urgent investigations relevant to an acutely ill infant (e.g., electrolytes, blood glucose, arterial blood gas);
    2. diagnostic investigations (e.g., computerized tomography scan, creatine kinase, electromyogram, genetic studies);
  3. construct an effective initial management plan, including:
    1. immediate supportive care (when required);
    2. supportive communication with family;
    3. referral for specialized care, if necessary.