A patient presents with flank pain, hematuria, and a palpable mass in the abdomen. Imaging reveals a solid renal mass with calcifications. Which of the following conditions is most likely?

Correct Answer: A

Rationale: The presentation of flank pain, hematuria, and a palpable mass in the abdomen is characteristic of renal cell carcinoma. Renal cell carcinoma is a common type of kidney cancer that often presents with these symptoms. The presence of a solid renal mass with calcifications on imaging further supports this diagnosis, as renal cell carcinoma is known to have this appearance on imaging studies. It is important to promptly evaluate and manage patients with suspected renal cell carcinoma to optimize outcomes.

Correct Answer: B

Rationale: Nephrotic syndrome is a kidney disorder characterized by increased glomerular permeability, leading to protein loss in the urine. One of the hallmarks of nephrotic syndrome is hypoalbuminemia, which refers to low levels of albumin in the blood due to its excessive loss in the urine. This loss of albumin results in decreased oncotic pressure, leading to edema and ascites. Hematuria (choice A) is not typically found in nephrotic syndrome but may be present in other kidney conditions. Hyperkalemia (choice C) is not specific to nephrotic syndrome and may be more common in conditions affecting potassium regulation. Hypocalcemia (choice D) is also not a characteristic feature of nephrotic syndrome.

Correct Answer: C

Rationale: The presentation described in the question, including the skin lesion resembling a "bull's eye" rash at the site of a tick bite, is characteristic of Lyme disease. Lyme disease is caused by the spirochete bacterium Borrelia burgdorferi, which is transmitted to humans through the bite of infected black-legged ticks (Ixodes scapularis). The symptoms of Lyme disease include fever, headache, myalgia, and the erythema migrans rash, which appears as a red circular rash with central clearing resembling a bull's eye.

Correct Answer: C

Rationale: The patient is likely infected with Cryptosporidium parvum based on the symptoms of watery diarrhea, abdominal cramps, and nausea after consuming contaminated water. Cryptosporidium is a protozoan parasite that can be transmitted through contaminated water sources, such as streams. Laboratory tests revealing oocysts in the stool sample further support the diagnosis of Cryptosporidium infection, as these oocysts are characteristic of this parasite. Giardia lamblia is another common protozoan parasite that can cause similar symptoms but is usually associated with more foul-smelling, greasy diarrhea. Entamoeba histolytica causes amoebic dysentery, which presents with bloody diarrhea and abdominal pain. Cyclospora cayetanensis also causes watery diarrhea, but it is usually associated with foodborne outbreaks rather than waterborne transmission.

Correct Answer: D

Rationale: Complete abortion is the most likely cause of the symptoms described. In a complete abortion, all products of conception are expelled from the uterus. Symptoms include vaginal bleeding, passage of tissue, and dilation of the cervix. In this scenario, the presentation of a dilated cervix with visualized products of conception is classic for a complete abortion at 10 weeks gestation.