Dan was feeling terrible! He knew he should have worn more sunscreen on that tri
ID: 127726 • Letter: D
Question
Dan was feeling terrible! He knew he should have worn more sunscreen on that trip to Haiti. Sitting on the plane waiting to be allowed off was torture! He was burning up and felt exhausted. And sitting still so long on the plane had made his ankles and shoulders start to ache too. If only they would let him off the plane! He was beginning to feel nauseous and hoped he didn’t vomit all over his fellow passengers.
After they finally let him off the plane he rushed to the bathroom to put some cool water on his face and inspect this horrible sunburn. But it didn’t look normal in the mirror…. His skin was covered in red blotchy spots, especially his chest and all the way up his neck. Maybe he was allergic to something? Can allergies cause this heat (he assumed now it was a fever)? He had to go to the doctor, now. LA General was a short cab ride away.
As the PA on duty you ask Dan a few questions before making some theories about what’s causing his symptoms. You discover he just got back from Haiti where he visited friends for 2 weeks. His doctor had given him enough doxycycline for the whole trip and he had taken it religiously. His vaccination history included immunizations to typhoid, hepatitis B and tetanus. He also took Bumex. His major complaints were joint pain, nausea, and the growing rash on his trunk. His fever was 101.8. But as you were talking with him you noticed his speech began to slur a bit. This was deeply concerning.
1) What are the top four suspects for Dan’s infectious disease? Justify your answers.
2) You send off for some laboratory tests right away and find the information below. Interpret each of these findings. Does this change your diagnosis?
3) Dan’s speech became even more slurred and he could no longer move his arms, flaccid paralysis. You ordered an emergency CT scan that revealed encephalitis. Finally the molecular results came back. Has your tentative diagnosis been confirmed? Interpret the test and describe how it works.
a. Real time reverse transcriptase PCR (rRT-PCR)
i. The probe Cy5-ATGCAAACGGCGACCATGCCGTCA—BBQ at E1 position 10433-10456 was detected after 10 cycles
ii. The probe JOE-AAGGACTAGMGGTTAGWGGAGACCC—BBQ at 3’UTR position 10610-10634 was not detected after 300 cycles
iii. The probe FAM-CTYAGACCAGCTGAAR-BBQ at NS5 position 9304-9320 was not detected after 300 cycles.
4) What is this infectious agent doing in Dan’s body to cause disease? (pathogenesis, virulence factors, detail)
5) How did Dan’s innate immune system try to protect him from the infection? (make sure it is specific for this type of attack)
6) Please describe the acquired immune reaction that occurred in response to this infection. (make sure it is specific for this type of attack)
7) What treatment would you prescribe after confirming your original diagnosis? How does each part of that treatment work?
Leukocytes Lymphocytes Neutrophis Platelets 400) 76 140,000 mm3 562 pg/ml 379 pg/ml IL-1Explanation / Answer
1. Top four suspects:
Dengue hemorrhagic fever, Chikungunya fever, Zika virus, Yellow fever. Also Japanese encephalitis can be considered.
2. Yes, this shows it is a viral based fever most likely dengue or chikungunya. Platelets are also low. Hemorrhagic fevers to be suspected here.
3. The molecular results favour Chikungunya hemorrhagic fever with encephalitis complication.
4. Chikungunya virus is transmitted via mosquitoes - Aedes genus. Following transmission, the virus multiplies in the skin and travels via the blood stream to joint spaces. In the acute phase, the patient will present with fever, nausea, rash and joint pain. In severely complicated cases - the virus can also cause encephalitis like picture overlapping with other diseases like Japanese encephalitis.
5, 6. Disease onset will coincide with rising viral load. Here the trigger causes the increase in interferons. Later - T cell and antibody-mediated responses predominate.
7.Treat the encephalitis first with close monitoring, later patient can be stabilized with intravenous fluids to maintain hydartion status. NSAIDs to control pain and inflammation. Respiratory support if required.
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