What is the differential diagnosis for abdominal pain in a patient undergoing inpatient refeeding, to distinguish between refeeding-related gastrointestinal (GI) symptoms and other causes of abdominal pain?

From the Guidelines

When evaluating abdominal pain in a patient undergoing inpatient refeeding, it is crucial to differentiate between expected refeeding symptoms and those requiring further workup, with warning signs warranting immediate investigation including severe localized pain, peritoneal signs, fever, hemodynamic instability, significant electrolyte abnormalities, or new-onset vomiting. To approach this differentiation, consider that mild to moderate abdominal discomfort, bloating, and altered bowel habits are common refeeding symptoms that typically resolve within 3-5 days 1. Refeeding-related pain is usually diffuse, mild to moderate, and improves with slower feeding advancement. Key factors to assess include:

• Pain severity and timing
• Associated features such as fever, vomiting, or significant electrolyte abnormalities
• Presence of peritoneal signs or hemodynamic instability Initial evaluation should encompass:
• Vital signs
• Physical examination focusing on abdominal tenderness and peritoneal signs
• Laboratory tests including complete blood count, comprehensive metabolic panel, phosphate, magnesium, and calcium levels If concerning features are present, consider:
• Abdominal imaging, such as ultrasound or CT scan, as guided by the clinical context and the need for rapid diagnosis 1
• Consultation with gastroenterology for further guidance Management involves:
• Slowing the refeeding rate if symptoms are mild and consistent with refeeding syndrome
• Providing appropriate electrolyte replacement, particularly phosphate, potassium, and magnesium, to mitigate the risk of refeeding syndrome complications 1 This approach aims to balance the need for continued nutritional rehabilitation with the necessity of investigating potentially serious abdominal pathology, prioritizing the patient's morbidity, mortality, and quality of life outcomes.

From the Research

Abdominal Pain Workup in Inpatient Refeeding

• The workup for abdominal pain in patients undergoing inpatient refeeding should consider the possibility of refeeding-related GI symptoms versus other causes of abdominal pain 2, 3, 4.
• Refeeding syndrome (RFS) is a life-threatening metabolic condition that can occur after nutritional replenishment, and its diagnosis and management are crucial in the inpatient setting 2, 3, 4.
• A risk assessment for RFS should be performed before starting nutritional therapy, and patients at high risk should receive adapted energy and fluid support during the replenishment phase 2, 3.

Differential Diagnosis

• The differential diagnosis for abdominal pain in patients undergoing inpatient refeeding includes:
  • Refeeding-related GI symptoms (e.g., nausea, vomiting, diarrhea, abdominal cramps) 2, 3, 4
  • Other causes of abdominal pain (e.g., acute pancreatitis, gastrointestinal obstruction, inflammatory bowel disease) 5
• The diagnosis of RFS is made in patients with moderate to severe malnutrition who develop electrolyte imbalance after beginning nutritional support 4.
• The National Institute for Health and Clinical Excellence criteria represent the best clinical assessment tool for RFS, and a multidisciplinary metabolic team can help with diagnosis and management 4.

Laboratory Tests

• Laboratory tests, such as complete blood count (CBC), can aid in the diagnosis and monitoring of patients with abdominal pain and suspected RFS 6.
• The CBC includes components such as red blood cell count, hemoglobin, hematocrit, and white blood cell count, which can help identify underlying conditions that may be contributing to abdominal pain 6.

Clinical Assessment

• Clinical assessment, including history, physical examination, and laboratory tests, is essential for differentiating between refeeding-related GI symptoms and other causes of abdominal pain 2, 3, 4, 5.
• Patients with mild acute pancreatitis, for example, may experience pain relapse during oral refeeding, which can be related to higher serum levels of lipase and C-reactive protein, and presence of peripancreatic fluid collections 5.