A 9-month-old boy is brought to the emergency department by his parents as he is not "acting like himself." The parents report that he has always been a fussy baby and often awakens multiple times a night. However, yesterday he cried the entire night and seemed more tired than usual this morning. The infant typically eats yogurt and formula for breakfast but refused to eat this morning and vomited 3 times. His mother says, "He may have hit his head on the floor after climbing onto and then rolling off the couch 2 days ago. He recently started crawling and often bumps into furniture around the house." The infant was born at term via an uncomplicated vaginal delivery. He was evaluated several times in the emergency department between ages 3 and 5 months for fussiness and was diagnosed with colic. His mother is currently taking antibiotics for bacterial pharyngitis; otherwise, there are no sick contacts or contributory family history. Temperature is 37 C (98.6 F) and pulse is 125/min. Height and weight are at the 75th and 50th percentiles, respectively. On examination, the infant is lethargic. The lungs are clear to auscultation and there are no murmurs. The abdomen is soft and nondistended. A small bruise is present on the buttocks; there are no additional rashes, lesions, or bruises. Item 1 of 2
Which of the following additional findings is most likely present in this patient?

Question

Quizplus · Accepted Answer

Explanation: This infant's presentation is suspicious for abusive head trauma (AHT) (previously known as "shaken baby syndrome"), which refers to injury from shaking and/or blunt force to the head. Injuries typically result from repeated acceleration-deceleration forces as the brain collides against the inside of the cranium. Young children (age <1) are at greatest risk, particularly if they are "fussy" with frequent crying/colic, as in this patient. An unstable home environment (eg, single-parent home, parental drug/alcohol abuse) is also a risk factor. Delayed presentation to medical care following the alleged injury and a vague and inconsistent history of events is suspicious for AHT. In this case, a 9-month-old infant typically cannot climb onto a couch, and falling from this height is unlikely to cause a head injury severe enough to alter his mental status. In addition, his frequent emergency department visits for fussiness suggest that this may not be the first time he has been abused. Irritability and vomiting are signs of increased intracranial pressure from AHT that may be overlooked, and medical attention is often not sought until the child is apneic, seizing, or comatose. Physical examination may show suspicious bruising patterns, such as this patient's bruise on the buttocks; however, frequently there is no external sign of injury. In the majority of AHT cases, fundoscopy shows retinal hemorrhages, which are often multilayered and bilateral and are a result of shearing forces on the retinal vessels. Abnormal neurological findings are concerning for intracranial bleeds and diffuse brain injury. (Choice A) Costochondral junction enlargement is characteristic of rickets. Vitamin D deficiency is unlikely in an infant eating yogurt and formula, which is typically fortified with vitamin D. (Choice B) Hepatosplenomegaly may occur with significant abdominal trauma but is less likely in this patient without bruising and with a soft, nondistended abdomen. Retinal hemorrhages are more likely, given this patient's neurological status. (Choice D) Intussusception, causing a sausage-shaped abdominal mass on examination, presents with colicky abdominal pain, vomiting, and "currant jelly" stools. This patient's altered mental status and history of trauma inconsistent with his development is more concerning for AHT. (Choice E) Although the patient's mother has pharyngitis, streptococcal pharyngitis with tonsillar exudates is uncommon in infants. In addition, fever is expected with a streptococcal infection. Educational objective: Abusive head trauma, typically caused by repeated acceleration-deceleration forces on the brain, often presents in an infant with a reported mechanism of injury inconsistent with the patient's development. Retinal hemorrhages, intracranial bleeds, and diffuse brain injury are characteristic. References: Retinal hemorrhage in abusive head trauma. (http://www.ncbi.nlm.nih.gov/pubmed/20921069) Abusive head trauma: past, present, and future. (http://www.ncbi.nlm.nih.gov/pubmed/25316728) Accuracy of the history of injury obtained from the caregiver in infantile head trauma. (http://www.ncbi.nlm.nih.gov/pubmed/27422215)

A 9-Month-Old Boy Is Brought to the Emergency Department by His