A 20 year old woman presents with fever, severe myalgia and ahralgia, pain behind the eyes and rash for 3 days. Lab repos show thrombocytopenia and leucopenia. What is the most likely diagnosis?
**Core Concept**
Dengue is a mosquito-borne viral infection caused by a flavivirus, characterized by sudden onset of high fever, severe headache, myalgia, arthralgia, and rash. The infection can lead to hemorrhage and shock in severe cases due to the destruction of platelets and endothelial damage.
**Why the Correct Answer is Right**
The patient's symptoms, such as fever, severe headache, myalgia, arthralgia, and rash, are classic for dengue fever. Thrombocytopenia and leucopenia are also common laboratory findings in dengue infection. Dengue virus infects and destroys platelets, leading to thrombocytopenia, and causes bone marrow suppression, resulting in leucopenia. The patient's presentation is consistent with a dengue fever diagnosis, especially given the presence of thrombocytopenia and leucopenia.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because rubella typically presents with a rash, fever, and lymphadenopathy, but it does not typically cause thrombocytopenia or leucopenia.
**Option B:** This option is incorrect because leptospirosis can present with fever, headache, and myalgia, but it is less likely to cause a rash or thrombocytopenia.
**Option C:** This option is incorrect because malaria can present with fever, chills, and myalgia, but it is less likely to cause thrombocytopenia and leucopenia, especially in the absence of other symptoms such as anemia.
**Clinical Pearl / High-Yield Fact**
Dengue fever is a leading cause of hospitalization and death in tropical and subtropical regions, and its symptoms can mimic those of other viral infections, making it essential to consider dengue fever in the differential diagnosis of patients presenting with fever, myalgia, and thrombocytopenia.
**Correct Answer:** C.