A 4-month-old boy is brought to clinic by his mother for routine follow-up. He was last seen at his 2-month checkup. The mother reports that the patient continues to feed well but has noticed that his head is larger than other infants'. He can roll from front to back, sit straight when propped, and hold his head steady without support. The patient can bring objects to his mouth and make babbling sounds. The patient was born at 37 weeks gestation and adopted at birth. Temperature is 37.2 C (99 F), pulse is 130/min, and respirations are 30/min. Examination shows a symmetrical head with an open and soft fontanelle. Pupils are equal and reactive, and extraocular movements are intact. Eyes and ears are in the normal positions. The neck is supple. Abdominal and skin examination is unremarkable. Extremities appear normal. Growth charts are shown in the exhibit. Head ultrasound shows normal ventricles and brain parenchyma. Which of the following is the best next step in management of this patient?

Question

A 4-month-old boy is brought to clinic by his mother for routine follow-up.  He was last seen at his 2-month checkup.  The mother reports that the patient continues to feed well but has noticed that his head is larger than other infants'.  He can roll from front to back, sit straight when propped, and hold his head steady without support.  The patient can bring objects to his mouth and make babbling sounds.  The patient was born at 37 weeks gestation and adopted at birth.  Temperature is 37.2 C (99 F), pulse is 130/min, and respirations are 30/min.  Examination shows a symmetrical head with an open and soft fontanelle.  Pupils are equal and reactive, and extraocular movements are intact.  Eyes and ears are in the normal positions.  The neck is supple.  Abdominal and skin examination is unremarkable.  Extremities appear normal.  Growth charts are shown in the exhibit.  Head ultrasound shows normal ventricles and brain parenchyma.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d6f1_55e6_bc81_5dfc323b1973_MD0003_00 Head circumference (HC), an important marker for growth, is routinely measured from birth to age 2-3 because brain growth is greatest during this period. Macrocephaly is defined as an HC ?98th percentile for age and sex and may be the presenting sign of hydrocephalus (ie, increased cerebrospinal fluid) or signify an underlying genetic disorder (eg, cerebral gigantism). However, the most common cause is benign familial macrocephaly due to megaloencephaly (increased brain parenchyma volume), a condition characterized by a large head in both an otherwise normal patient and a first-degree relative. Examination findings that are reassuring for benign macrocephaly include the following: Normal development No syndromic features No signs of increased intracranial pressure (eg, bulging fontanelle) No signs of infection (eg, fever, lethargy) An enlarged parental HC supports a diagnosis of benign familial macrocephaly. Head ultrasound, which may be performed to exclude other causes of macrocephaly (eg, increased cerebral blood flow, cerebrospinal fluid, bone mass), is also typically normal in benign macrocephaly. This developmentally normal patient with macrocephaly and an otherwise normal examination warrants no further workup. Management is reassurance and continued observation of HC. (Choice A) A cranial molding helmet may be considered for positional plagiocephaly, which is seen as occipital flattening and is not present in this patient. (Choice B) Karyotype analysis is indicated in patients with macrocephaly who also have dysmorphic features (eg, midface hypoplasia, large ears) concerning for a genetic disorder such as fragile X syndrome. In contrast, this patient has normal facial features. (Choice C) Lumbar puncture for opening pressure may be indicated to diagnose increased intracranial pressure, which is unlikely in this patient without a bulging fontanelle on examination or ventriculomegaly on ultrasound. (Choice D) MRI of the brain is performed in patients with macrocephaly and either an abnormal neurologic examination or abnormal findings on head ultrasound. MRI is used to assess ventricle size, mass lesions, or vascular malformations. This patient's examination and ultrasound are normal. Educational objective: Macrocephaly is a head circumference ?98th percentile. The condition is most likely benign (eg, familial) in a patient with normal development and normal examination (eg, no syndromic features, no signs of increased intracranial pressure). Management is reassurance and observation. References: Macrocephaly diagnosed during well child visits. (http://www.ncbi.nlm.nih.gov/pubmed/29498760)

A 4-Month-Old Boy Is Brought to Clinic by His Mother