A patient with a history of rheumatoid arthritis presents with acute pain and swelling of the wrist joint. Physical examination reveals ulnar deviation of the fingers and swan-neck deformity of the digits. Which imaging modality is most appropriate for further evaluation of wrist involvement in rheumatoid arthritis?

Correct Answer: A

Rationale: X-ray is the most appropriate imaging modality for evaluating wrist involvement in rheumatoid arthritis. It can show joint space narrowing, erosions, soft tissue swelling, and periarticular osteopenia. X-rays are readily available, cost-effective, and provide valuable information about joint damage and disease progression in rheumatoid arthritis. In this case, X-ray would be able to confirm the presence of erosions, joint deformities, and assess the severity of the disease in the wrist joint. While MRI and ultrasound can also be helpful in evaluating rheumatoid arthritis, X-ray remains the initial imaging modality of choice due to its convenience and ability to assess bony changes. Dual-energy X-ray absorptiometry (DEXA) scan is not indicated for evaluating wrist involvement in rheumatoid arthritis.

Correct Answer: A

Rationale: The clinical presentation of urinary urgency, frequency, and nocturia along with prostate enlargement with a smooth, firm consistency on digital rectal examination (DRE) is classic for benign prostatic hyperplasia (BPH). BPH is a common condition in aging men characterized by non-malignant growth of the prostate gland, which can cause varying degrees of lower urinary tract symptoms due to obstruction of the urethra. In contrast, prostate cancer typically presents with findings like an asymmetric, hard, or nodular prostate on DRE, while prostatitis presents with symptoms like fever, perineal pain, and systemic symptoms. Urinary tract infection (UTI) may present with dysuria, frequency, urgency, and suprapubic pain, but it does not usually cause prostate enlargement.

Correct Answer: A

Rationale: Acute pyelonephritis is the most likely condition based on the patient presentation and urinalysis findings described. Acute pyelonephritis is an infection of the renal parenchyma and pelvis, typically caused by ascending bacteria from the lower urinary tract. The classic symptoms include fever, chills, flank pain, and costovertebral angle tenderness (tenderness over the kidneys). The presence of pyuria (pus in the urine) and bacteriuria (bacteria in the urine) on urinalysis further supports the diagnosis of acute pyelonephritis. It is crucial to diagnose and treat acute pyelonephritis promptly to prevent complications and recurrent infections.

Correct Answer: C

Rationale: The patient's symptoms of watery diarrhea, abdominal cramps, and nausea after consuming contaminated water from a stream during a camping trip suggest an infection caused by Cryptosporidium parvum. Cryptosporidium is a protozoan parasite that is commonly transmitted through contaminated water sources. Laboratory tests detecting oocysts in the stool sample are characteristic of Cryptosporidium infection.

Correct Answer: B

Rationale: In a pregnant woman presenting with severe abdominal pain and vaginal bleeding at 8 weeks gestation with a closed cervix, the most likely cause of these symptoms is a threatened abortion. A threatened abortion is a common complication of early pregnancy characterized by vaginal bleeding and lower abdominal pain without cervical dilation. The cervix remains closed, indicating that the pregnancy is still intact but at risk of potential miscarriage. Placenta previa typically presents with painless vaginal bleeding in the second or third trimester, whereas ectopic pregnancy usually presents with abdominal pain and vaginal bleeding in the setting of a closed cervix but is less likely at 8 weeks gestation. Gestational trophoblastic disease is a rare cause of vaginal bleeding in pregnancy and typically presents in the first trimester with signs of hyperemesis gravidarum, uterine enlargement, and elevated β-hCG levels.