What is the condition characterized by repeated head nodding movements in children?

Repeated Head Nodding Movements: Spasmus Nutans

Repeated head nodding movements are called "spasmus nutans" when occurring as part of a classic triad with nystagmus and abnormal head position, typically presenting between 4-10 months of age in otherwise neurologically normal infants. 1, 2, 3

Clinical Presentation and Diagnostic Features

Spasmus nutans consists of three cardinal features:

• Head nodding (horizontal, vertical, or rotatory direction) that is intermittent and occurs in 100% of cases 2
• Nystagmus that is acquired, asymmetrical or unilateral, rapid, fine, pendular, and horizontal in 88% of cases 2, 3
• Abnormal head position (torticollis, head tilt, or chin up/down posture) present in approximately 44% of cases 2, 3

The typical age of onset ranges from 1-15 months (average 7 months), with most cases presenting in the first year of life. 2, 4

Critical Differential Diagnoses to Exclude

Benign Myoclonus of Early Infancy (BMEI)

• Presents between 4-7 months with myoclonic jerks of head and/or upper limbs occurring in clusters 1
• Consciousness is preserved during attacks, distinguishing it from infantile spasms 1, 5
• Ictal EEG must be normal to confirm diagnosis 1, 5
• Resolves spontaneously by age 2 years without developmental abnormalities 1

Respiratory Distress (Medical Emergency)

• Head nodding synchronized with breathing indicates severe respiratory distress requiring immediate intervention 1, 5
• Look for associated signs: grunting, nasal flaring, tracheal tugging, intercostal retractions, or severe tachypnea 1

Intracranial Pathology

• 15.5% of children with isolated nystagmus have abnormal intracranial findings on MRI, including Chiari malformation (3.4%) and optic pathway glioma (2%) 6
• Optic nerve and chiasmal gliomas can mimic spasmus nutans, making neuroimaging essential 7

Diagnostic Workup Algorithm

Step 1: Immediate Assessment

• Assess whether head nodding is synchronized with breathing to exclude respiratory distress 1, 5
• Document consciousness during episodes (preserved in benign conditions, altered in infantile spasms) 5

Step 2: Ophthalmologic Evaluation

• Complete ophthalmologic examination to characterize nystagmus pattern and symmetry 2, 3
• Cycloplegic refraction to identify refractive errors 6
• Evaluate for underlying causes such as albinism, retinal dystrophies, optic nerve hypoplasia 6

Step 3: Neuroimaging

• MRI of the brain without and with IV contrast is mandatory to exclude structural lesions, particularly optic pathway gliomas 6, 2, 7
• Neuroimaging was normal in all 13 cases in one series, but tumors and other pathology have been reported in other studies 2, 7

Step 4: Neurological Assessment

• Complete neurological examination must be normal to confirm benign diagnosis 2, 3
• Video-EEG during episodes if infantile spasms are suspected 5

Prognosis and Management

Natural History:

• Spasmus nutans typically resolves spontaneously within 6 months to 6 years (average 2.5 years) 2
• However, long-term follow-up shows nystagmus persists in 80% of children (16 of 20), torticollis in 86% (6 of 7), and titubations in 30% (3 of 10) 4

Management Approach:

• Once normal neuroimaging and ophthalmologic examination confirm benign spasmus nutans, reassure parents but avoid guaranteeing complete resolution 4
• Regular developmental monitoring to ensure normal neurodevelopmental progression 1, 5
• Continued follow-up throughout childhood for strabismus and amblyopia 4
• No specific treatment is required for the head nodding itself 1, 2

Critical Pitfalls to Avoid

• Do not diagnose spasmus nutans without MRI, as optic pathway gliomas can present identically 6, 7
• Do not assume all head nodding is benign without excluding respiratory distress first 1, 5
• Do not promise parents complete resolution, as nystagmus and other features frequently persist into childhood 4
• Do not confuse spasmus nutans with BMEI—the former has nystagmus as a defining feature, the latter does not 1, 6