Silamut K, White N J
Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
Trans R Soc Trop Med Hyg. 1993 Jul-Aug;87(4):436-43. doi: 10.1016/0035-9203(93)90028-o.
Admission blood films from 72 patients who died of severe falciparum malaria (50 Thai adults, 22 Gambian children) were matched retrospectively for parasitaemia with equal numbers of survivors. The peripheral blood parasites from fatal cases were more mature than those from survivors. Tiny rings (TR) comprised > 50% of parasites in 47/72 (65%) survivors but only 12/72 (17%) of fatal cases (P < 0.001). Parasites containing visible pigment (MTS: mature trophozoites and schizonts) comprised < 20% of the total parasite count in 10/72 (14%) survivors compared with 31/72 (43%) fatal cases (P < 0.001). Of the 39 patients with > 10(4) MTS/microL, 30 (81%) died. These findings were confirmed in a prospective study of 279 adult Thai patients admitted sequentially with acute falciparum malaria. Only 4 of the 19 fatal cases (21%) had > 50% TR, compared with 130 of 260 (50%) survivors, whereas > 20% MTS were found in 10/19 (53%) fatal cases, compared with 28/108 (27%) severe malaria survivors, and 26/155 (17%) patients with moderately severe malaria (P = 0.001). As a predictor of fatal outcome, the finding of either > 10(4) MTS/microL or > 5 x 10(5) parasites/microL in severe malaria had a sensitivity of 90% (95% confidence interval [CI] = 75-97%) and a specificity of 72% (95% CI = 59-86%). These observations are consistent with the hypothesis that a predominance of mature parasites in the peripheral blood reflects a greater sequestered biomass, and thus more severe disease. Simple microscopical assessment of parasite maturity on an admission blood slide provides important pathophysiological and prognostic information in severe falciparum malaria.
对72例死于严重恶性疟的患者（50名泰国成年人，22名冈比亚儿童）的入院血涂片进行回顾性分析，根据疟原虫血症情况与同等数量的幸存者进行匹配。致命病例的外周血寄生虫比幸存者的更成熟。微小环状体（TR）在47/72（65%）的幸存者中占寄生虫的比例超过50%，但在致命病例中仅占12/72（17%）（P<0.001）。含有可见色素的寄生虫（MTS：成熟滋养体和裂殖体）在10/72（14%）的幸存者中占总寄生虫计数的比例不到20%，而在致命病例中为31/72（43%）（P<0.001）。在39例每微升MTS超过10⁴个的患者中，30例（81%）死亡。在一项对279例因急性恶性疟连续入院的泰国成年患者的前瞻性研究中证实了这些发现。19例致命病例中只有4例（21%）的TR超过50%，而260例幸存者中有130例（50%）；10/19（53%）的致命病例中发现MTS超过20%，而严重疟疾幸存者中为28/108（27%），中度严重疟疾患者中为26/155（17%）（P = 0.001）。作为致命结局的预测指标，在严重疟疾中发现每微升MTS超过10⁴个或每微升寄生虫超过5×10⁵个，敏感性为90%（95%置信区间[CI]=75 - 97%），特异性为72%（95%CI = 59 - 86%）。这些观察结果与以下假设一致，即外周血中成熟寄生虫占优势反映了更多的隐匿生物量，从而导致更严重的疾病。对入院血涂片上寄生虫成熟度进行简单的显微镜评估可为严重恶性疟提供重要的病理生理和预后信息。
