第36回："A Chilly Fever"
悪寒戦慄，悪心，重度の頭痛を伴う発熱が 1 週間続いた 30 歳の男性の症例で、結論は「マラリア」でした。
Word Count：2792語 (Time: 16'20'', 171 wpm)
参加人数：５名
クリニカル・パール：
- In 2010, a total of 1691 cases were reported to the Centers for Disease Control and Prevention (CDC), the largest number reported since 1980; P. falciparum, P. vivax, P. malariae, and P. ovale were identified in 58%, 19%, 2%, and 2% of cases, respectively.
- Given the patient's delayed presentation, years after presumed exposure, P. falciparum can be ruled out, since it does not give rise to relapses.
- Primaquine, the only effective drug against dormant hypnozoites, has not been approved by the Food and Drug Administration for primary prophylaxis, but the CDC endorses its use for prophylaxis in Latin American countries where P. vivax predominates, because the drug can prevent both primary attacks and relapses caused by all species that are a source of malarial infection.
- P. falciparum is resistant to chloroquine in most regions in which it is endemic and resistant to mefloquine in parts of Southeast Asia. In contrast, nonfalciparum malaria parasites do not have substantial resistance to mefloquine, and the distribution of chloroquine-resistant P. vivax malaria is limited, occurring primarily in Indonesia and Papua New Guinea.
- This patient's travel to Uganda merits consideration for infections that can be acquired in East Africa and are manifested long after acquisition. These diseases include malaria, tuberculosis, filariasis (although this infection is unlikely after short-term travel), visceral leishmaniasis, and Q fever. Malaria relapses are more likely to begin with rigors than are primary infections. The physical examination should focus on the liver and spleen (since hepatosplenomegaly can develop in association with malaria, visceral leishmaniasis, or Q fever), the lungs (particularly the upper lobe, which is often involved in tuberculosis), the heart (since pericardial rubs or murmurs can be detected in association with Q fever), and the extremities and the scrotum (since lymphangitis and lymphedema can develop in association with filarial fevers).
- In malaria, the febrile pattern is initially irregular but subsequently regularizes if a dominant brood of synchronously replicating parasites develops. Typically, the periodicity of fever is 72 hours with P. malariae and 48 hours with other species.
- The average time to relapse is approximately 9 months, but it can range from weeks to years.
感想：
- 旅行医学の分野では、まず除外すべき疾患だが、日本ではリソースの乏しさから診断の遅れが危惧される。（かえって途上国のほうがリソースが揃っているかもしれない。）
- 温暖化が進めば、沖縄、九州あたりで復興するかもしれない。
- 「研修医当直御法度」では、chillの程度を「 mild chills: 寒気：上着を羽織りたくなるくらい 、moderate chills: 悪寒：分厚い毛布を羽織りたくなるくらい 、shaking chills: 悪寒戦慄：分厚い毛布を羽織っていても全身が震えるくらい」と定義している。
