Differential Diagnosis for 2-year-old Male with Congenital Conditions and Acute Symptoms
- Single Most Likely Diagnosis
- Urinary Tract Infection (UTI): The presence of positive nitrites in the urine analysis (UA) is a strong indicator of a UTI, especially in a child with a history of congenital hydronephrosis, which can predispose to urinary stasis and infection. The symptoms of vomiting and diarrhea could be secondary to the UTI or a concurrent gastrointestinal infection.
- Other Likely Diagnoses
- Gastroenteritis: Although the UA suggests a UTI, the symptoms of vomiting and diarrhea without fever could also be indicative of a viral or bacterial gastroenteritis. The negative leukocyte esterase (leuk est) might suggest a lower likelihood of a UTI, but it does not rule it out, especially in young children where the urine dipstick may not always be reliable.
- Dehydration: Given the symptoms of vomiting and diarrhea, dehydration is a likely complication that needs to be addressed, regardless of the underlying cause.
- Do Not Miss Diagnoses
- Sepsis: Although the child does not have a fever, sepsis can present atypically in young children, and the history of congenital heart defects (PDA and PFO) might increase the risk of bacterial endocarditis or other severe infections.
- Pyelonephritis: This is a serious infection of the kidney that can occur in the setting of UTI, especially in children with underlying urinary tract abnormalities like hydronephrosis. It requires prompt diagnosis and treatment to prevent long-term kidney damage.
- Rare Diagnoses
- Uretero-pelvic junction obstruction (UPJO) exacerbation: Given the history of congenital hydronephrosis, an exacerbation of UPJO could potentially cause acute symptoms, although this would more likely present with flank pain and possibly vomiting rather than diarrhea.
- Other congenital anomalies causing intestinal obstruction: Although less likely, other congenital anomalies could potentially cause the symptoms of vomiting and diarrhea, especially if there's an intestinal obstruction. However, this would typically be associated with more significant abdominal distress and possibly blood in the stool.