Differential Diagnosis for a 9-Year-Old Boy Who Eats Plenty but is Very Skinny
- Single Most Likely Diagnosis
- Hyperthyroidism: This condition, where the thyroid gland produces too much thyroid hormone, can lead to increased appetite and weight loss despite adequate food intake. It's a common endocrine disorder that can affect children and has a significant impact on metabolism.
- Other Likely Diagnoses
- Diabetes Mellitus Type 1: Although typically associated with polyuria and polydipsia, uncontrolled diabetes can lead to weight loss due to the body's inability to utilize glucose properly, resulting in the breakdown of fat for energy.
- Celiac Disease: An autoimmune reaction to gluten can lead to malabsorption of nutrients, causing weight loss and failure to thrive despite adequate caloric intake.
- Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause malabsorption, chronic inflammation, and increased metabolic demand, leading to weight loss.
- Chronic Infections (e.g., Tuberculosis): Certain infections can increase metabolic rate and lead to weight loss.
- Do Not Miss Diagnoses
- Malignancies (e.g., Leukemia, Lymphoma): Although rare, cancers can present with unexplained weight loss and should always be considered to ensure timely diagnosis and treatment.
- HIV Infection: Can cause failure to thrive and weight loss in children due to chronic infection and malabsorption.
- Congenital Heart Disease: Severe cases can lead to increased metabolic demand and failure to thrive due to decreased cardiac output and poor perfusion of tissues.
- Rare Diagnoses
- Genetic Disorders (e.g., Prader-Willi Syndrome): Certain genetic conditions can affect appetite regulation and metabolism, leading to significant weight issues.
- Mitochondrial Disorders: These are a group of disorders caused by dysfunctional mitochondria, affecting energy production within cells, which can lead to a variety of systemic symptoms including failure to thrive.
- Congenital Disorders of Glycosylation: A group of rare genetic disorders affecting protein glycosylation, which can lead to a wide range of symptoms including failure to thrive and malabsorption.