Differential Diagnosis
- Single most likely diagnosis
- Ureteropelvic junction obstruction or hydronephrosis due to pregnancy: The patient's symptoms of increased urinary frequency, back pain, and sharp pain in the right groin, combined with the ultrasound findings of bilateral kidney enlargement and dilation of the renal pelvis and proximal ureter, are consistent with ureteropelvic junction obstruction or hydronephrosis. The patient's history of recurrent nephrolithiasis also increases the likelihood of this diagnosis.
- Other Likely diagnoses
- Pyelonephritis: Although the patient's urinalysis does not show significant evidence of infection, pyelonephritis is a common cause of back pain and urinary frequency in pregnancy. The patient's history of recurrent nephrolithiasis and the ultrasound findings of kidney enlargement could also be consistent with pyelonephritis.
- Nephrolithiasis: The patient's history of recurrent nephrolithiasis and the presence of back pain and sharp pain in the right groin could suggest a new kidney stone. However, the absence of hematuria and the ultrasound findings of bilateral kidney enlargement make this diagnosis less likely.
- Do Not Miss diagnoses
- Preeclampsia: Although the patient's blood pressure is within normal limits, preeclampsia can present with back pain and urinary frequency. It is essential to monitor the patient's blood pressure and urine protein levels closely to rule out this diagnosis.
- Placenta previa or abruption: The patient's back pain could be a symptom of placenta previa or abruption, especially if the pain is severe and accompanied by vaginal bleeding. Although the patient denies vaginal bleeding, it is crucial to consider these diagnoses and perform a thorough obstetric evaluation.
- Rare diagnoses
- Renal cell carcinoma: Although rare, renal cell carcinoma could present with back pain, urinary frequency, and kidney enlargement. The patient's history of recurrent nephrolithiasis and the ultrasound findings of bilateral kidney enlargement make this diagnosis possible, but it is less likely given the patient's age and the absence of other symptoms such as hematuria or weight loss.
- Polycystic kidney disease: This genetic disorder could cause kidney enlargement and back pain, but it is relatively rare and would typically be associated with a family history and other symptoms such as hematuria or hypertension.