From the Guidelines
To investigate the cause of persistent polyphagia, I recommend a comprehensive laboratory assessment including a complete blood count, comprehensive metabolic panel, electrolytes, liver enzymes, and renal function tests, as suggested by the American Psychiatric Association 1. These tests can help identify underlying medical conditions that may be contributing to excessive hunger, such as diabetes, hyperthyroidism, or metabolic disorders. Additional tests that may be helpful include:
- Thyroid function tests (TSH, free T3, free T4) to evaluate for hyperthyroidism
- Fasting glucose and hemoglobin A1C to assess for diabetes or insulin resistance
- Fasting insulin levels to evaluate for insulin resistance or hyperinsulinemia
- Leptin and ghrelin levels to assess for hormonal imbalances affecting appetite regulation
- Cortisol levels to evaluate for Cushing's syndrome or other adrenal disorders
- Vitamin D status to assess for deficiency or insufficiency It is essential to note that these tests should be interpreted in the context of the patient's overall clinical presentation and medical history. Before ordering these tests, it may be helpful to have the patient keep a food diary for 1-2 weeks to document their eating habits, hunger levels, and any patterns or triggers that may be contributing to their excessive hunger. This information can help guide the selection of laboratory tests and ensure that the most relevant evaluations are performed. In some cases, additional tests such as a glucose tolerance test or screening for specific conditions like Prader-Willi syndrome may be warranted based on the patient's symptoms and medical history 1.
From the Research
Laboratory Tests for Investigating Persistent Polyphagia
To investigate the cause of persistent polyphagia (excessive hunger), several laboratory tests can be recommended based on the available evidence.
- Complete Blood Count (CBC): A CBC is a fundamental test that can help identify various conditions, including anemia, infection, and blood cell disorders 2. It includes parameters such as red blood cell count, hemoglobin, hematocrit, white blood cell count, and platelet count.
- Comprehensive Metabolic Panel (CMP): A CMP is a group of tests that measure different substances in the blood to assess various bodily functions, including glucose metabolism, electrolyte balance, and liver and kidney function 3. This panel can help identify conditions such as diabetes, hypoglycemia, and thyroid dysfunction.
- Thyroid Function Tests: Thyroid function tests, including thyroid-stimulating hormone (TSH), free tri-iodothyronine (FT3), and free thyroxine (FT4), can help diagnose thyroid dysfunction, which can cause excessive hunger 4, 5.
- Fasting and Post-prandial Blood Glucose: Measuring blood glucose levels after fasting and after eating can help diagnose diabetes and other glucose metabolism disorders 5.
- Insulin and C-peptide Levels: Measuring insulin and C-peptide levels can help assess insulin resistance and glucose metabolism 4, 5.
- Lipid Panel: A lipid panel can help assess lipid metabolism and identify conditions such as hyperlipidemia, which can contribute to excessive hunger 6.
These laboratory tests can help healthcare providers identify underlying conditions that may be contributing to persistent polyphagia and guide appropriate treatment and management.