Please answer questions in short answer or paragraphs. Write enough to provide c
ID: 212718 • Letter: P
Question
Please answer questions in short answer or paragraphs. Write enough to provide clarity and answer each questions thoroughly in the sake of brevity. Answers should be type-written and submitted through Canvas or turned in at the beginning of class on the specified date.
(True story- as mentioned in class) A 74 year old woman walks into a Baltimore clinic with an enlarged spleen but no other physical symptoms. She had been previously diagnosed with lymphoma and prescribed drug treatment accordingly, but during the course of drug treatment she began having symptoms of a cyclical fever. These subsided after the treatment course, but the enlarged spleen remained. Based on the cyclical fevers, her doctor decides to check and see if she has malaria. He was not able to see parasites on a blood smear, but was able to detect parasites by PCR proving that she had malaria. She had been living in the US for decades and had not traveled abroad. However, she did have malaria when she was 3 when living in a foreign country, suggesting that she had a malaria infection for 71 years! What malaria parasite did this woman have? How does this explain her enlarged spleen? How could it have maintained an active infection for that long?
Explanation / Answer
The malarial parasite may be Plasmodium vivax or Plasmodium ovale. The dormant stage (hypnozoits) of these two plasmodum species can persist in liver for long time even in many years.
Enlarged spleen. Spleen is the main organ which provides a immunological response against malaria. In case of malaria the RBCs are infected. Spleen produced white blood cells (immune cells) which remove infected RBCs from the blood. In case of malaria more and more RBCs are infected and thus, spleen becomes highly engaged in destruction of infected cells which involve more and more production of immune cells and more destruction of infected RBCs. This highly engagment of spleen is the reason to make it enlarge.
Maintenence of an active infection for long time. Plasmodium vivax or Plasmodium oval has a hypnozoites dormant stage in the liver which shows a long latency period. This hypnozoite does not become active till the immune system is properly working. Here in this case, patient is suffering from lymphoma and taking corresponding medication which may suppress the immune system and also the elder age may be the reason for suppression of immune system.