Correct Answer: B

Rationale: Urticaria, commonly known as hives, typically presents as raised, red, and itchy welts or wheals that can appear and disappear in various locations on the skin. Each lesion tends to last for many minutes before resolving and may be associated with itching or a burning sensation. Urticaria is often triggered by an allergic reaction to food, medications, insect bites, or other substances. The clinical presentation described in the question, involving an itchy rash that appears and disappears in different areas, is consistent with urticaria.

Correct Answer: C

Rationale: The symptoms described, including decreased air movement, high-pitched whistling (wheezing) on expiration in all lobes, and resonant lungs on percussion, are characteristic findings of asthma. Asthma is a chronic respiratory condition characterized by airway inflammation, bronchoconstriction, and increased mucus production, leading to symptoms like wheezing, shortness of breath, chest tightness, and cough. The presence of wheezing, particularly on expiration, is a classic sign of asthma. In contrast, spontaneous pneumothorax would typically present with sudden chest pain and shortness of breath, accompanied by hyperresonant percussion notes due to trapped air in the pleural space. COPD, a chronic lung condition characterized by progressive airflow limitation, would often present with symptoms such as chronic cough, sputum production, and dyspnea on exertion. Pneumonia is an infection of the lung tissue,

Correct Answer: B

Rationale: The patient described is most likely suffering from an external hemorrhoid. External hemorrhoids are swollen veins located near the opening of the anus, often resulting from increased pressure in the rectal area. The presence of a swollen bluish ovoid mass containing a blood clot is characteristic of an external hemorrhoid. The pain experienced during digital rectal examination further supports this diagnosis, as external hemorrhoids are typically painful when touched. In this case, there are no palpable masses within the anus or rectum, ruling out anorectal cancer or internal hemorrhoids. Anal fissures are small tears in the lining of the anus, which would present differently from the described swollen mass with a blood clot.

Correct Answer: D

Rationale: The presence of a palpable pulsatile abdominal mass in a patient like Mr. Martin, who is a smoker and at risk for vascular diseases, is concerning for an abdominal aortic aneurysm (AAA). Immediate referral to a vascular surgeon is essential for further evaluation and management. AAA can be a life-threatening condition if left untreated, as it can lead to rupture and severe internal bleeding. Therefore, prompt specialist evaluation and monitoring are crucial in such cases. Waiting for 3 or 6 months for reevaluation could potentially lead to a delayed diagnosis and increase the risk of complications. Abdominal ultrasound is typically the diagnostic test of choice to confirm the presence and size of the aneurysm.

Correct Answer: C

Rationale: The clinical presentation described in the scenario is classic for bacterial vaginosis (BV). BV is the most common cause of vaginal discharge in women of childbearing age. Key features of BV include a thin gray-white discharge with a fishy odor, which typically worsens after sexual intercourse and during menstruation. The discharge characteristically has a pH over 4.5, and the presence of clue cells on wet prep is diagnostic. Clue cells are vaginal epithelial cells covered with bacteria, giving them a stippled appearance when viewed under the microscope. These features are consistent with the findings in this patient.