Question
A 26-year-old traveler comes to clinic after returning from South Asia. He complains of extremely intense pain in his left wrist and both ankles, rating it as 10/10. Over the past 4 days, he has also experienced high fever, headache, fatigue, and a general feeling of being unwell.
On examination, his temperature is 39.2°C. He has a diffuse blanching maculopapular rash. His joints are very painful to move, but there is no obvious swelling or redness. Other systemic examination is unremarkable.
What is the most likely underlying cause?
a) Dengue fever
b) Septic arthritis
c) Yellow fever
d) Chikungunya infection
e) Malaria
Answer
Chikungunya infection
Detailed Explanation
This is a classic presentation of Chikungunya, a mosquito-borne alphavirus infection.
Key diagnostic clues:
- Recent travel to endemic region (South Asia)
- High fever + rash
- Severe debilitating polyarthralgia (hallmark feature)
- Joint pain out of proportion to examination findings
- No significant joint swelling (distinguishes from septic arthritis)
Why Chikungunya?
Chikungunya is transmitted by Aedes mosquitoes (same as dengue). It presents with:
- Abrupt high fever
- Severe symmetrical joint pain (wrists, ankles, small joints)
- Rash (maculopapular)
- Fatigue, headache, myalgia
👉 The joint pain is the key differentiator — often severe enough to cause immobility.
Why NOT the other options?
- Dengue fever
- More: thrombocytopenia, bleeding tendency
- Less prominent joint pain
- Septic arthritis
- Usually monoarticular
- Joint is hot, swollen, red
- Yellow fever
- Associated with jaundice and liver failure
- Not endemic in Sri Lanka
- Malaria
- Presents with fever patterns, chills, anemia
- Does not cause severe joint pain
Cheat Sheet (Exam Ready)
Chikungunya – High Yield Points
- Virus: Alphavirus
- Vector: Aedes mosquito
- Geography: Asia, Africa, Indian subcontinent
Key Features
- Sudden high fever
- Severe polyarthralgia (hallmark)
- Maculopapular rash
- Fatigue, headache
Labs
- Lymphopenia
- Mild thrombocytopenia
Diagnosis
- PCR (early)
- IgM antibodies
Management
- Supportive (fluids, paracetamol, NSAIDs)
- No antiviral
Flashcards
Q1: What is the hallmark feature of Chikungunya?
A: Severe debilitating joint pain (polyarthralgia)
Explanation: Pain is often disproportionate and may persist for months.
Q2: Which mosquito transmits Chikungunya?
A: Aedes mosquito
Explanation: Same vector as dengue.
Q3: How to differentiate dengue from chikungunya clinically?
A: Chikungunya has more severe joint pain; dengue has more bleeding tendency
Explanation: Platelet drop is more marked in dengue.
Q4: Is there a specific antiviral treatment for Chikungunya?
A: No
Explanation: Management is supportive only.
Q5: What type of rash is seen in Chikungunya?
A: Maculopapular rash
Explanation: Similar to other viral exanthems.
MCQs (High-Level)
MCQ 1
A returning traveler presents with fever, rash, and severe symmetrical joint pain without swelling. Most likely diagnosis?
a) Dengue
b) Chikungunya
c) Malaria
d) Septic arthritis
Answer: b) Chikungunya
Explanation: Severe polyarthralgia is the defining feature.
MCQ 2
Which of the following is FALSE regarding Chikungunya?
a) Caused by an alphavirus
b) Transmitted by Aedes mosquito
c) Causes severe joint pain
d) Commonly leads to hemorrhagic shock
Answer: d) Commonly leads to hemorrhagic shock
Explanation: That is more typical of severe dengue.
MCQ 3
Which investigation confirms Chikungunya in early disease?
a) IgG antibodies
b) PCR for viral RNA
c) Blood culture
d) ESR
Answer: b) PCR for viral RNA
Explanation: PCR is useful in early phase; IgM later.
MCQ 4
A patient with fever and joint pain has one swollen, hot knee joint. Most likely diagnosis?
a) Chikungunya
b) Dengue
c) Septic arthritis
d) Malaria
Answer: c) Septic arthritis
Explanation: Monoarticular hot swollen joint → infection.
MCQ 5
Which feature best distinguishes chikungunya from dengue?
a) Fever
b) Rash
c) Severe joint pain
d) Thrombocytopenia
Answer: c) Severe joint pain
Explanation: Joint pain is much more prominent in chikungunya.
MCQ 6
Which of the following is TRUE?
a) Chikungunya commonly causes jaundice
b) Malaria presents with severe polyarthralgia
c) Yellow fever is common in Sri Lanka
d) Chikungunya may cause prolonged joint pain
Answer: d) Chikungunya may cause prolonged joint pain
Explanation: Chronic arthralgia may persist for months.
Summary for Quick Exam Revision
Chikungunya is an alphavirus transmitted by Aedes mosquitoes and is endemic in Asia and Africa. It presents with sudden high fever, a maculopapular rash, and most importantly severe debilitating polyarthralgia, which is often symmetrical and affects small joints such as wrists and ankles. This joint pain is the key distinguishing feature from dengue, which instead shows more bleeding tendency and thrombocytopenia. Septic arthritis typically presents with a single hot, swollen joint, unlike the multiple painful but non-swollen joints seen here. Yellow fever is characterized by jaundice and hepatic involvement and is not endemic in Sri Lanka. Malaria presents with cyclical fever and systemic symptoms but not severe joint pain. Diagnosis of chikungunya is confirmed by PCR in early stages or IgM serology later. Management is supportive, including fluids and analgesics, as there is no specific antiviral therapy. A key exam point is that joint pain in chikungunya can persist for weeks to months even after acute illness resolution.