Why is She Shaking?

Uncategorized

Patient Presentation
A 2-month-old female came to clinic for her health maintenance visit. Her parents had no concerns, except they noticed that sometimes while sleeping she would suddenly shake. This began after her two-week health maintenance visit. The shaking would occur for 1-2 seconds, occasionally more than 1 shaking episode would occur over 1 minute. Her whole body seemed to shake, but she did not awaken and had no problems breathing. She had no episodes while she was awake. Developmentally her parents reported that she cooed, responded to light and sound, followed faces, would grab their fingers and would hold up her head while prone.

The past medical history showed she was a term infant with no problems pre- or post-natally.

The family history was negative for neurological disorders or genetic syndromes.

The review of systems was negative.

The pertinent physical exam showed her to have a social smile with growth parameters in the 10-50%. Her head circumference was 25% and tracking appropriately. Her examination was normal including her neurological examination.

The diagnosis of benign infantile sleep myoclonus was made. Its benign nature was explained to the parents who were to continue to monitor her and to call if she had changes to the character or frequency of the episodes.

Discussion
Parents often come to a health care provider with concerns about abnormal movements or positioning by their infants. In healthy infants, many of these are episodes are caused by normal development (e.g. startle response) or are benign in nature (e.g. benign neonatal sleep myoclonus). Some herald the possible beginning of a lifelong problem (e.g. infantile spasms or seizures). The diagnosis of many of these episodes can be made by a good clinical history and physical examination.

Myoclonus is a symptom and not a disease. It is the sudden, involuntary jerking of a muscle or group of muscles. A hiccup or “sleep starts” when a person is falling asleep are examples. The sudden muscle contractions are called positive myoclonus. Sudden muscle relaxation can also occur called negative myoclonus.

Myoclonic jerks may occur singularly or in clusters and may have a pattern or none. Sometimes they occur due to sudden sensory input. The patient cannot control them. Simple myoclonus in healthy persons usually is benign. Sometimes myoclonus may be more persistent or so exaggerated that it can limit a person’s ability to do their normal activities. Persistent or exaggerated myoclonus may indicate a more serious underlying nervous system problem.

Learning Point
Common causes of abnormal movements or positioning in infants include:

  • Benign neonatal sleep myoclonus
    • Cause – idiopathic
    • Description – focal or multifocal myoclonic jerks, that restraint does not stop, occurs only during sleep, child is otherwise healthy
    • Age onset – hours of life to one month
    • Age resolution – < or = 6 months
    • Maneuvers to provoke – may increase with gentle stimulation
    • Maneuver to stop – awakening from sleep
    • Duration of movements – 2-3 seconds with clusters of 15-60 minutes
    • Family history – may or may not have a family history
    • Evaluation – clinical diagnosis, EEG is normal during sleep
  • Startle response
    • Cause – normal arousal response
    • Description – sudden extension of arms/legs that are brought to midline
    • Age onset – birth
    • Age resolution – lifetime
    • Maneuvers to provoke – sudden sensory input (e.g. loud noise, pain)
    • Maneuver to stop – none
    • Duration of movements – seconds
    • Family history – none
    • Evaluation – clinical diagnosis
  • Jitteriness
    • Cause – idiopathic
    • Description – rapid movements that are symmetrical, may involve the jaw
    • Age onset – first few days of life to 2 months
    • Age resolution – < or = 6 months
    • Maneuvers to provoke – stimulation
    • Maneuver to stop – gentle flexion of a limb
    • Duration of movements – variable
    • Family history – no
    • Evaluation – clinical diagnosis but rule out a metabolic cause
  • Seizures
    • Cause – abnormal electrical activity in the central nervous system
    • Description – rhythmic movements, often asymmetric with altered consciousness
    • Age onset – any age
    • Age resolution – depends
    • Maneuvers to provoke – none
    • Maneuver to stop – none
    • Duration of movements – variable
    • Family history – may or may not have a family history
    • Evaluation – EEG ideally during the episode
  • Benign familial neonatal convulsions
    • Cause – abnormal electrical activity in the central nervous system
    • Description – tonic-clonic movements, eye deviation
    • Age onset – 1-4 days
    • Age resolution – < 12 months, usually in first 6 months
    • Maneuvers to provoke – none
    • Maneuver to stop – none
    • Duration of movements – usually minutes, usually occurs many times/day
    • Family history – yes. This is an autosomal dominant condition
    • Evaluation – clinical, EEG possibly, genetic testing possibly
  • Infantile spasms
    • Cause – abnormal electrical activity in the central nervous system
    • Description – clustered myoclonic jerks occurring in clusters
    • Age onset – 3-15 months, mean age 5 months
    • Age resolution – < 2 years but may evolve into other seizures
    • Maneuvers to provoke – transition between sleep and wakening
    • Maneuver to stop – none
    • Duration of movements – seconds with clusters of 15-60 minutes
    • Family history – no
    • Evaluation – EEG shows hypsarhythmia
  • Sandifer syndrome
    • Cause – gastroesophageal reflux
    • Description – dystonic posturing of the head and neck, possible arching of the back, irritability, possible emesis
    • Age onset – 3 weeks to years
    • Age resolution – when gastroesophageal reflux is controlled
    • Maneuvers to provoke – possibly related to feeding
    • Maneuver to stop – none
    • Duration of movements – 20 to 30 minute clusters
    • Family history – none
    • Evaluation – empiric treatment for gastroesophageal reflux, pH probe
  • Paroxysmal torticollis
    • Cause – idiopathic
    • Description – head and trunk twisting, often to both sides, may or may not have pallor, sweating and vomiting
    • Age onset – 1 week to 3 years
    • Age resolution – 5 years
    • Maneuvers to provoke – none
    • Maneuver to stop – none
    • Duration of movements – hours to days with several episodes/year
    • Family history – possible migraine history
    • Evaluation – clinical diagnosis
  • Shuddering
    • Cause – idiopathic
    • Description – “like cold water is being poured on you”
    • Age onset – months to years
    • Age resolution – late childhood
    • Maneuvers to provoke – excitement
    • Maneuver to stop – none
    • Duration of movements – 2-3 seconds
    • Family history – possible history of tremor
    • Evaluation – clinical diagnosis
  • Spasmus nutans
    • Cause – idiopathic
    • Description – head tilt, head bobbling and disconjugate nystagmus
    • Age onset – 6-36 months with a mean of 8 months
    • Age resolution – < 2 years
    • Maneuvers to provoke – none
    • Maneuver to stop – none
    • Family history – none
    • Evaluation – clinical diagnosis, but possible evaluation for a central nervous system tumor

Questions for Further Discussion
1. In a neonate with jitteriness when should maternal drug abuse be suspected?
2. What are indications for a neurological consultation?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for these topics: Movement Disorders and Neuromuscular Disorders.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

Mathews K. Twitchy Babies. Lecture Notes. University of Iowa. April 2001.

Pranzatelli MR. Myoclonus in childhood. Semin Pediatr Neurol. 2003 Mar;10(1):41-51.

Meinck HM. Startle and its disorders. Neurophysiol Clin. 2006 Sep-Dec;36(5-6):357-64.

Borg M. Symptomatic myoclonus. Neurophysiol Clin. 2006 Sep-Dec;36(5-6):309-18.

National Institutes of Neurological Diseases and Stroke. Myoclonus Fact Sheet. National Institutes of Health. Available from the Internet at http://www.ninds.nih.gov/disorders/myoclonus/detail_myoclonus.htm (rev. 12/7/2007, cited 1/27/2009).

National Institutes of Neurological Diseases and Stroke. Motor Neuron Diseases Fact Sheet. National Institutes of Health. Available from the Internet at http://www.ninds.nih.gov/disorders/motor_neuron_diseases/detail_motor_neuron_diseases.htm (rev. 09/09/2008, cited 1/27/2009).

ACGME Competencies Highlighted by Case

  • Patient Care
    1. When interacting with patients and their families, the health care professional communicates effectively and demonstrates caring and respectful behaviors.
    2. Essential and accurate information about the patients’ is gathered.
    3. Informed decisions about diagnostic and therapeutic interventions based on patient information and preferences, up-to-date scientific evidence, and clinical judgment is made.
    4. Patient management plans are developed and carried out.
    5. Patients and their families are counseled and educated.
    8. Health care services aimed at preventing health problems or maintaining health are provided.

  • Medical Knowledge
    10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.
    11. Basic and clinically supportive sciences appropriate to their discipline are known and applied.

  • Practice Based Learning and Improvement
    13. Information about other populations of patients, especially the larger population from which this patient is drawn, is obtained and used.

    Author
    Donna M. D’Alessandro, MD
    Professor of Pediatrics, University of Iowa Children’s Hospital

    • Published