DEFINITION OF THE COMPLAINT
The term decreased activity level describes a wide spectrum of existence ranging from boredom to coma. The diagnostic evaluation focuses on encouraging parents to provide a detailed account, particularly with regard to the magnitude and time course of the changes. Clearly, the differential diagnosis of subtle behavioral changes developing during a period of several months differs from that of changes occurring during several hours.
COMPLAINT BY CAUSE AND FREQUENCY
The causes of decreased level of activity in children vary according to age (Table 2-1), and can be placed into several broad categories (Table 2-2). Additional issues to consider include whether there is depressed sensorium indicating an underlying central nervous system (CNS) disorder, weakness indicating a muscular disorder, or endurance problems suggesting a cardiac or pulmonary issue. Systemic illness may manifest with somnolence or lethargy.
TABLE 2-1. Differential diagnosis of decreased activity by age.
TABLE 2-2. Differential diagnosis of decreased activity level by etiology.
The patient who presents for evaluation of decreased level of activity represents a broad differential. Several important historical questions can help classify the underlying etiology:
• What is the time course of decreased level of activity?
—Infectious etiologies typically present during a shorter time course than do other etiologies, such as iron deficiency anemia or certain types of CNS malignancies.
• Is the patient febrile?
—Fever, from an infectious etiology, can cause a decreased level of activity in children. However, hypothermia, particularly in neonates, can also result in decreased level of activity. In the neonate, hypothermia is a common manifestation of perinatally acquired herpes simplex virus infection and sepsis.
• Have the activities of daily living been impacted?
—Cardiac or pulmonary disease may be reflected in decreased activity levels. In older children, this would be evidenced by poor physical play, whereas in infants, poor feeding. Secondary gain in an older child may play a role if school avoidance appears to be an issue.
• Is there a history of decreased oral intake or increased output?
—Younger children are particularly sensitive to the metabolic demands of glucose utilization. Hypoglycemia can occur from increased losses from diarrhea and/or vomiting, and hyperglycemia from diabetes mellitus. In both instances, behavior changes can occur due to abnormal glucose levels.
• Has there been a change in behavior with friends or with school performance in the older child or adolescent?
—Mental health causes, in particular depression, should always be investigated as potential culprit when behavior change impacts relationships and school. Drug and alcohol abuse should also be considered in adolescents.
• Is there any history of trauma?
—In the acute setting, head injury from mild traumatic brain injury to concussion to intracranial bleeds can result in abnormal level of activity.
• Is there any reason to suspect nonaccidental trauma?
—Child abuse should always be taken into consideration in any child presenting with decreased level of activity. Physical, sexual, and neglect could all be demonstrated through a decreased level of activity. Any unusual injuries not consistent with the child's age and mechanism of injury should also raise the clinician's concern for child abuse.
• Is there a history of ingestion?
—Toxins frequently alter mental status in children. The mechanism may be through sedation (hypnotic agents, opiates, alcohols) or hypoglycemia (oral hypoglycemic agents or beta-blockers).
• Is there any history of abdominal pain or vomiting?
—Intussusception can present with depressed mental status in a child between 6 months and 5 years of age.