Malarial paroxysm
A typical malarial attack (paroxysm) is the main symptom of the disease. It includes three consecutive phases:
- Chills. Temperature rapidly rises to 39–41 °C. Lasts from 15 minutes to 3 hours (sometimes longer).
- Fever. Skin becomes flushed and hot. The patient is agitated, with tachycardia, blood pressure drop, and decreased diuresis. Lasts 5–8 hours.
- Sweating. Temperature drops, profuse sweating occurs. Lasts 1–2 hours, after which the patient usually falls asleep.
The total duration of the attack ranges from 6–8 to 12–14 hours. At the onset of the disease (initial fever), paroxysms may overlap due to the maturation of different generations of plasmodia, which obscures the typical clinical picture.
Features of different forms of malaria
The clinical presentation varies depending on the species of the pathogen:
- Malaria vivax and ovale (benign course). Incubation period from 12 days to 8–12 months. Attacks occur every other day, usually in the first half of the day. Complications are rare (splenic rupture is possible in vivax).
- Malaria malariae. Incubation 3–6 weeks. Attacks occur strictly every third day (usually at noon) and are characterized by the longest chills. Without treatment, it can last for decades at a low level of parasitemia.
- Malaria falciparum (tropical malaria, malignant course). The most severe form. Incubation 7–16 days. The chill phase is often absent, and fever can last 12–36 hours. The temperature curve is irregular (daily attacks or continuous fever). High risk of fatal outcome.
Pathogenesis of symptoms and complications
In addition to fever, malaria is characterized by:
- Hepatosplenomegaly: enlargement of the liver and spleen begins on days 3–5 due to blood congestion and macrophage hyperplasia.
- Anemia: develops on days 10–14 due to intravascular hemolysis, destruction of erythrocytes in the spleen, suppression of hematopoiesis, and immune reactions.
In the absence of treatment, especially with P. falciparum infection, severe complications develop:
- Cerebral malaria (malarial encephalopathy) — depression of consciousness ranging from drowsiness to coma, seizures, fatal outcome within 1–2 days.
- Infectious-toxic shock (DIC syndrome, adrenal insufficiency).
- Blackwater fever — acute massive hemolysis (dark urine).
- Acute renal failure and pulmonary edema.
Diagnostics
The diagnosis takes into account:
- Clinical data (fever attacks, hepatosplenomegaly, anemia).
- Epidemiological history (visits to endemic regions, blood transfusions, substance abuse).
- Blood microscopy (smear and thick drop). Determines the species of plasmodium and the level of parasitemia. If malaria is suspected and the initial result is negative, the test must be repeated in 12–24 hours.
Briefly: answers to topical questions
What laboratory diagnostic methods are used to confirm the diagnosis of malaria?
Microscopic methods are used for laboratory confirmation of malaria:
- Blood smear microscopy (Romanowsky-Giemsa stain) — essential for the precise identification of the plasmodium species.
- Thick blood film preparation — used to detect the malaria parasite; the species of plasmodium cannot be determined from it. The results of blood smear and thick film microscopy for malaria plasmodia are available within 1–2 hours.
Comprehensive diagnostics also includes a complete blood count (CBC): decreased hemoglobin levels, leukopenia, lymphomonocytosis, elevated ESR.
Which groups of antimalarial drugs are used for etiotropic treatment of the disease?
For etiotropic action on plasmodia, according to their clinical use, the following are distinguished:
- Erythrocytic stage agents (blood schizontocides) — chloroquine, quinine, mefloquine, artemisinin, atovaquone, doxycycline, tetracycline, clindamycin, sulfonamides, pyrimethamine, proguanil.
- Relapse prevention agents (tissue schizontocides) — primaquine, pyrimethamine.
Class and exam questions
Why can malarial paroxysms be atypical at the beginning of the disease?
During the initial fever, several generations of Plasmodium with different cycles mature simultaneously in the blood. Their attacks overlap, obscuring the clinical picture. Later, 1–2 leading generations remain, and the rhythm normalizes.
What form of malaria is the most dangerous and why?
Tropical malaria (caused by P. falciparum). It rapidly leads to severe complications, such as cerebral malaria (coma) and acute hemolysis, frequently resulting in death.
What does the appearance of adult parasite stages in the blood indicate in tropical malaria?
The detection of adult or amoeboid trophozoites and schizonts of P. falciparum in peripheral blood is an extremely unfavorable laboratory sign indicating a severe complicated course.
What else to study on this topic
- Stages of malarial encephalopathy (I, II, III)
- Species-specific features of the gametocytogony stage
- Classification and mechanism of malaria relapses
- Methods for assessing parasitemia levels (thick film)
- Pathogenesis of malarial anemia in detail
Master the complete topic in the «Infectious Diseases» course
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on "Clinical presentation of malaria" and 3,312 more pages of the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 41 video lessons on the subject
Other topics in the "Vector-borne infections" section
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.