Differential Diagnosis for 2-year-old Female with Fever, Vomiting, and Fussiness
- Single Most Likely Diagnosis
- Viral gastroenteritis: This is the most likely diagnosis given the symptoms of fever, vomiting, and fussiness, especially with negative tests for influenza A and B, RSV, and COVID-19. The elevated white blood cell count (WBC) with a predominance of segmented neutrophils (seg neut absolute 12.9) can be seen in viral infections, and the absence of specific findings on the chest X-ray and urinalysis supports a gastrointestinal cause.
- Other Likely Diagnoses
- Bacterial gastroenteritis: Although less common than viral causes, bacterial gastroenteritis could present similarly and should be considered, especially if the vomiting persists or if there's blood in the stool, which is not mentioned here.
- Urinary tract infection (UTI): Despite a normal urinalysis, UTIs can sometimes present with non-specific symptoms like fever and fussiness in young children. A normal urinalysis does not completely rule out a UTI, especially if the sample was not a clean catch or if the infection is very early.
- Pneumonia: Although the chest X-ray shows no acute findings, pneumonia can sometimes present with minimal or no radiographic findings early in the course, especially in young children. The clinical presentation of fever and fussiness could still suggest pneumonia, particularly if there are respiratory symptoms not mentioned.
- Do Not Miss Diagnoses
- Appendicitis: This condition can present with non-specific symptoms like fever, vomiting, and abdominal pain (which might manifest as fussiness in a 2-year-old). Although less common in this age group, appendicitis is a surgical emergency and must be considered.
- Intussusception: A condition where a part of the intestine slides into an adjacent part, which can cause intestinal obstruction. It's a medical emergency and can present with vomiting, fever, and abdominal pain.
- Sepsis: Although the child's WBC is elevated, which could indicate infection, sepsis is a life-threatening condition that requires immediate recognition and treatment. The presence of fever, elevated WBC, and signs of potential organ dysfunction (e.g., low hemoglobin) necessitate consideration of sepsis.
- Rare Diagnoses
- Kawasaki disease: An acute febrile illness of childhood that can present with fever, vomiting, and irritability, among other symptoms. It's less common but important to consider due to the risk of cardiac complications if not treated.
- Hemolytic uremic syndrome (HUS): Typically follows a bacterial infection (like E. coli) and can cause renal failure, hemolytic anemia, and thrombocytopenia. The low hemoglobin (10.1) might raise suspicion, but other findings like thrombocytopenia and renal dysfunction would be expected.
- Inborn errors of metabolism: Certain metabolic disorders can present with non-specific symptoms like vomiting and fussiness, especially during episodes of metabolic decompensation. These are rare but critical to diagnose early for appropriate management.