Correct Answer: A

Rationale: A patient with a severe viral infection exhibiting reduced levels of circulating lymphocytes is likely due to the apoptosis of infected lymphocytes. When a virus enters the body, it can infect and replicate within lymphocytes, subsequently triggering the immune system to induce apoptosis in infected cells to prevent further spread of the virus. This process is part of the body's defense mechanism to control the viral infection. As a result, the circulating lymphocyte levels may decrease as infected lymphocytes are targeted for apoptosis. This phenomenon helps to limit viral replication and spread within the body, thereby aiding in the immune response to eliminate the virus.

Correct Answer: B

Rationale: The patient's presentation of severe headache, blurred vision, and fatigue, along with the laboratory findings of elevated white blood cell count, thrombocytosis, and JAK2 V617F mutation, are characteristic of essential thrombocythemia. This is a myeloproliferative neoplasm characterized by the clonal proliferation of megakaryocytes, leading to an increased platelet count. The JAK2 V617F mutation is commonly found in essential thrombocythemia and other myeloproliferative disorders. The symptoms of essential thrombocythemia can be related to the increased blood viscosity and risk of thrombosis due to the elevated platelet count. Polycythemia vera would present with elevated red blood cell count, hemoglobin, and hematocrit, along with other features such as pruritus after a hot bath. Chronic myeloid leukemia (CML

Correct Answer: C

Rationale: Erythropoietin-stimulating agents (ESAs) are prescribed to manage anemia in patients with chronic kidney disease. Monitoring the hemoglobin level closely during ESA therapy is crucial to ensure that the treatment is effective in increasing red blood cell production without causing excessive elevation. Hemoglobin levels should be checked regularly to adjust the ESA dosage accordingly and prevent risks associated with high hematocrit levels, such as increasing blood viscosity and cardiovascular events. Monitoring serum potassium, creatinine, and platelet count are important in the management of chronic kidney disease for different reasons, but for ESA therapy, monitoring hemoglobin is the most essential parameter.

Correct Answer: A

Rationale: The presentation described indicates a candidal infection, which commonly occurs in warm, moist body areas like inguinal folds and gluteal cleft. The pruritic, erythematous rash with scaly plaques and satellite papules and pustules is characteristic of cutaneous candidiasis. The recent antibiotic use for urinary tract infection likely disrupted the normal skin flora, predisposing the patient to a Candida overgrowth. Tinea cruris (jock itch) can also present similarly, but the presence of satellite papules and pustules is more indicative of candidiasis. Erythrasma typically presents as well-defined brown-red patches without satellite lesions, and intertrigo is a more generic term referring to inflammation of skin folds that can have various causes, including candidiasis.

Correct Answer: A

Rationale: A patient with a severe viral infection exhibiting reduced levels of circulating lymphocytes is likely due to the apoptosis of infected lymphocytes. When a virus enters the body, it can infect and replicate within lymphocytes, subsequently triggering the immune system to induce apoptosis in infected cells to prevent further spread of the virus. This process is part of the body's defense mechanism to control the viral infection. As a result, the circulating lymphocyte levels may decrease as infected lymphocytes are targeted for apoptosis. This phenomenon helps to limit viral replication and spread within the body, thereby aiding in the immune response to eliminate the virus.