A 19-year-old construction worker presents for evaluation of a rash. He notes that it started on his back with a multitude of spots and is also on his arms, chest, and neck. It itches a lot. He does sweat more than before because being outdoors is part of his job. On physical examination, you note dark tan patches with a reddish cast that has sharp borders and fine scales, scattered more prominently around the upper back, chest, neck, and upper arms as well as under the arms. Based on this description, what is your most likely diagnosis?

Correct Answer: B

Rationale: The description of dark tan patches with a reddish cast that have sharp borders and fine scales, especially more prominent on the upper back, chest, neck, and upper arms, is classic for tinea versicolor. Tinea versicolor is a superficial fungal infection caused by Malassezia species, which commonly affects individuals who sweat more, such as those working outdoors like the construction worker in this case. The rash is often pruritic (itchy) and can vary in color from tan to pink or red. The fine scales on the patches are a result of the accumulation of the yeast in the affected areas.

Correct Answer: D

Rationale: A subconjunctival hemorrhage is a common and benign condition characterized by blood in the space between the conjunctiva and sclera of the eye. The condition often presents as a painless, sharply demarcated area of redness on the white part of the eye, typically without associated discharge or visual disturbances. In this case, the absence of eye pain, discharge, visual disturbances, and clear cornea make subconjunctival hemorrhage the most likely diagnosis. The history of forceful coughing with a recent cold is also consistent with the increased intraocular pressure leading to a rupture of a small blood vessel, resulting in the hemorrhage. Treatment is not usually required as the condition is self-limiting and resolves on its own over time.

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: C

Rationale: The target heart rate during physical activity is typically calculated as a percentage of maximum heart rate, which is estimated using the formula: 220 - age. For a 30-year-old individual, the estimated maximum heart rate would be 190 beats per minute. Exercising at 60-70% of the maximum heart rate is usually recommended for moderate-intensity physical activity. For this individual, the target heart rate zone would be approximately 114-133 beats per minute. Therefore, achieving a heart rate of 120 beats per minute would fall within the target range and indicate an appropriate level of exertion for effective physical activity.

Correct Answer: C

Rationale: In the context of visual acuity, the numbers in the ratio 20/100 represent a comparison between the patient's vision and normal vision. Specifically, a visual acuity of 20/100 means that the patient can see at 20 feet what a person with normal vision can see at 100 feet. This indicates that the patient's vision is reduced, as she needs to be closer to see the same level of detail compared to someone with normal vision.

Correct Answer: D

Rationale: The scenario described with a strong pulse followed by a weak pulse is characteristic of pulsus paradoxus, a finding often associated with cardiac tamponade. Cardiac tamponade is a medical emergency where there is an accumulation of fluid (such as blood) in the pericardial sac that exerts pressure on the heart, limiting its ability to pump effectively. As a result, patients may exhibit this pulsus paradoxus, where the pulse strength varies with respiration. The other conditions listed (emphysema, asthma exacerbation, severe left heart failure) are not typically associated with this specific pulsatile pattern.

Correct Answer: C

Rationale: In diabetic ketoacidosis (DKA), the body is in a state of metabolic acidosis due to the accumulation of ketones in the blood. One of the compensatory mechanisms to decrease the acidity in the body is increased breathing, known as Kussmaul breathing. This type of breathing is characterized by a rapid and deep pattern to blow off excess carbon dioxide and decrease the acidity of the blood. Therefore, in a patient with DKA, you would expect to observe rapid and deep breathing.

Correct Answer: C

Rationale: The young woman in this scenario is experiencing symptoms consistent with post-traumatic stress disorder (PTSD). PTSD is an anxiety disorder that can develop after a person is exposed to a traumatic event, such as a life-threatening situation like a robbery with a gun involved. The symptoms she is experiencing, including difficulty sleeping, severe nightmares, irritability, hypervigilance, and avoidance of triggers such as driving at night, are all classic features of PTSD. These symptoms have persisted for at least 6 months since the traumatic event occurred, which is a key criterion for making a diagnosis of PTSD. Treatment for PTSD typically involves a combination of medication and therapy to help the individual process and cope with the traumatic experience.

Correct Answer: C

Rationale: Pain in the calf is a common symptom of atherosclerosis in the lower extremities, also known as peripheral artery disease (PAD). Atherosclerosis is the buildup of plaque in the arteries, leading to reduced blood flow. The calf pain associated with PAD is often described as cramping, aching, or fatigue that occurs during walking and is relieved with rest. This is called intermittent claudication. Thigh, knee, and ankle pain could have other causes, but calf pain specifically raises concerns for atherosclerosis in the lower extremities.