Differential Diagnosis for Pediatric Patient with Low-Grade Fever, Nausea, Abdominal Pain, Right Upper Quadrant, and Diarrhea

Single Most Likely Diagnosis

• Viral Gastroenteritis: This is the most common cause of the symptoms described, especially in pediatric patients. The presence of diarrhea, nausea, and abdominal pain, along with a low-grade fever, strongly suggests a viral etiology.

Other Likely Diagnoses

• Acute Appendicitis: Although the pain is in the right upper quadrant, appendicitis can sometimes present with pain in this area, especially if the appendix is retrocecal. The presence of fever, nausea, and abdominal pain makes this a plausible diagnosis.
• Mesenteric Lymphadenitis: This condition, often caused by viral infections, can mimic appendicitis and presents with fever, abdominal pain, and sometimes diarrhea.
• Hepatitis: Viral hepatitis can cause right upper quadrant abdominal pain, nausea, fever, and sometimes diarrhea, especially in the prodromal phase.

Do Not Miss Diagnoses

• Intussusception: A condition where a part of the intestine telescopes into another, which can cause severe abdominal pain, vomiting, and sometimes diarrhea. It's a surgical emergency and must be considered in pediatric patients with these symptoms.
• Pneumonia: Right lower lobe pneumonia can cause referred pain to the right upper quadrant of the abdomen. Given the symptoms of fever and nausea, pneumonia should be considered, especially if there are respiratory symptoms.
• Biliary Disease (e.g., Cholecystitis): Although less common in pediatric patients, biliary disease can cause right upper quadrant pain, fever, and nausea. It's crucial to consider this, especially if the patient has risk factors like gallstones.

Rare Diagnoses

• Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can present with chronic diarrhea, abdominal pain, and fever. While less likely to present acutely, they should be considered in the differential diagnosis, especially if symptoms persist.
• Pancreatitis: Acute pancreatitis can cause severe abdominal pain, nausea, and sometimes diarrhea. It's less common in pediatric patients without risk factors like gallstones or a family history of pancreatitis but should be considered if other symptoms like vomiting are prominent.
• Food Poisoning: Certain types of food poisoning (e.g., from Salmonella or E. coli) can cause severe symptoms, including diarrhea, abdominal pain, and fever. The history of recent food intake can help in diagnosing this condition.