Shaken Baby Syndrome

Shaken baby syndrome (SBS), also commonly referred to as abusive head trauma, or less commonly as shaken impact syndrome, is the leading cause of grave neurological injury or death in physically abused children. SBS is the end result of violently shaking infants.

The forces generated create injuries that possess very specific features due to the unique anatomy of infants, whose heads are larger and heavier in proportion to the rest of their bodies.

Retinal and subdural hemorrhages are pathognomonic for SBS. However, other extreme consequences, such as blindness, hearing loss, seizures, mental retardation, and paralysis may also be seen.

Babies with SBS may present with poor feeding, lethargy, vomiting, irritability, and dyspnea (i.e. difficult breathing) among other symptoms.

Scans of the brain with imaging techniques are required to make a definitive diagnosis.

These infants require emergency treatment, because SBS is a life-threatening condition. In addition to emergency surgery to stop hemorrhaging, respiratory support will be required.

Despite treatment, many infants who survive will suffer long-term effects and as a result need medical attention for the rest of their lives. Thus, no matter how much a baby cries, parents should never ever be tempted to shake that baby.

Pathophysiology

In order for abusive head trauma to occur, an infant must receive forces to the head that are either rotational or translational.

Forces are characterized as rotational if they turn the brain on its central axis during the shaking event.

In contrast, translation forces are linear and are generated during falls. They are often less severe and mostly benign in comparison to their rotational counterparts, which rotate the brain at the brainstem attachment.

Infants with SBS will have tearing and stretching of bridging veins in the brain due to its subdural space movement.

The violent shaking causes brain cell destruction and the prevention of adequate oxygenation to the brain.

The resulting hypoxia that ensues, as established by several studies, is the cause of the initial injury to the brain seen in SBS.

Hypoxia is caused initially by difficulties with respiration. It leads to edema and a consequential increase in the intracranial pressure (ICP).

A raised ICP then causes further neurological destruction due to ischemia, which arises as a result of a drop in the perfusion pressure in the brain.

Babies with SBS are observed to have unique brainstem damage due to them having very poor muscle tone in the neck, which has to support a large head.

Epidemiology

The risk of SBS and its consequences increases the younger an infant is. Boys are more likely than girls to be affected with SBS and in 9 out of every 10 cases the perpetrator is a male.

He is typically the biological father of the child, but in some instances the abuser may be the infant’s step-father or the mother’s boyfriend. Female abusers tend to be more often than not a babysitter.

However, biological mothers may also be the cause in a few cases, which usually occur while the mother is attempting to punish the child corporally.

References

• https://www.ninds.nih.gov/Disorders/All-Disorders/Shaken-Baby-Syndrome-Information-Page
• http://my.clevelandclinic.org/childrens-hospital/health-info/diseases-conditions/hic-Shaken-Baby-Syndrome
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3210040/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1757926/pdf/v078p00732.pdf

Further Reading

• All Shaken Baby Syndrome Content
• Symptoms of Shaken Baby Syndrome
• How is Shaken Baby Syndrome Diagnosed?
• How is Shaken Baby Syndrome Treated?
• Preventing Shaken Baby Syndrome

Written by

Dr. Damien Jonas Wilson

Dr. Damien Jonas Wilson is a medical doctor from St. Martin in the Carribean. He was awarded his Medical Degree (MD) from the University of Zagreb Teaching Hospital. His training in general medicine and surgery compliments his degree in biomolecular engineering (BASc.Eng.) from Utrecht, the Netherlands. During this degree, he completed a dissertation in the field of oncology at the Harvard Medical School/ Massachusetts General Hospital. Dr. Wilson currently works in the UK as a medical practitioner.