Differential Diagnosis for Failure to Thrive in a 5-year-old

Single Most Likely Diagnosis

• Psychosocial factors: This is often the most common cause of failure to thrive in children, particularly in the absence of any underlying medical condition. Factors such as poverty, neglect, parental substance abuse, or other forms of child maltreatment can lead to inadequate nutrition and care, resulting in failure to thrive.

Other Likely Diagnoses

• Gastrointestinal issues: Conditions like celiac disease, inflammatory bowel disease (IBD), or gastroesophageal reflux disease (GERD) can lead to malabsorption or decreased intake of nutrients, causing failure to thrive.
• Respiratory problems: Chronic conditions such as asthma or cystic fibrosis can increase the body's energy expenditure and lead to failure to thrive if not adequately managed.
• Endocrine disorders: Hypothyroidism or growth hormone deficiency can directly affect growth and development, leading to failure to thrive.
• Chronic infections: Recurrent or chronic infections, especially in immunocompromised children, can consume more energy and nutrients, leading to failure to thrive.

Do Not Miss Diagnoses

• Child abuse or neglect: It is crucial to consider and investigate any signs of child abuse or neglect, as these can have severe and long-lasting consequences on a child's physical and psychological health.
• Inborn errors of metabolism: Although rare, conditions like phenylketonuria (PKU) or other metabolic disorders can lead to severe health issues if not diagnosed and managed early.
• Malignancies: Certain types of cancer, such as leukemia or lymphoma, can present with failure to thrive among other symptoms.
• HIV/AIDS: In areas with high prevalence, HIV infection should be considered, especially if there are other risk factors or symptoms present.

Rare Diagnoses

• Genetic syndromes: Conditions such as Turner syndrome, Prader-Willi syndrome, or other rare genetic disorders can affect growth and development.
• Congenital heart disease: Certain types of heart defects can lead to failure to thrive due to increased energy expenditure or decreased nutrient absorption.
• Neurological disorders: Conditions affecting the brain or nervous system, such as cerebral palsy or muscular dystrophy, can impact feeding, digestion, and overall growth.
• Immunodeficiency disorders: Primary immunodeficiencies, such as severe combined immunodeficiency (SCID), can increase susceptibility to infections, leading to failure to thrive.