Malaria is transmitted through the bite of Anopheles mosquitoes infected with Plasmodium. Clinically, it is characterized by paroxysmal high fever, chills, sweating, splenomegaly, and anemia. In recent years, large-scale prevention and treatment efforts in China have significantly reduced the incidence rate.

bubble_chart Clinical Manifestations

1. The incubation period for tertian malaria is 10–12 days, for quartan malaria 14–25 days, and for malignant malaria 9–16 days. In the late stage [third stage] of the incubation period, prodromal symptoms such as mild fever, mental fatigue, and soreness in the limbs and back may occur.
2. The attack cycle for tertian malaria and ovale malaria occurs every other day, for quartan malaria every two days, while the fever pattern of malignant malaria is often irregular or remittent. The younger the child, the more atypical the symptoms; after 5–6 years of age, the manifestations resemble those of adult malaria.
3. A typical attack begins with the shivering stage, where the patient suddenly feels cold, shivers, has a pale complexion, a thready and rapid pulse, and often experiences nausea and vomiting, lasting about 20–30 minutes. This is followed by the fever stage, with body temperature rising to 40–41°C, accompanied by thirst, headache, a rapid and full pulse, and generalized soreness, lasting 4–8 hours. Then comes the sweating and defervescence stage, with profuse sweating all over the body, a sudden drop in temperature, and immediate relief of discomfort but accompanied by fatigue. Prolonged attacks may lead to anemia and splenomegaly.
4. Malignant malaria, caused by Plasmodium falciparum, is severe and life-threatening. Apart from shivering and high fever, clinical manifestations can be categorized based on the organs affected by the parasites: cerebral type (manifested as severe headache, restlessness, unconsciousness, delirium, convulsions, paralysis, hyperreflexia, meningeal irritation signs, and encephalopathy), gastrointestinal type (manifested as vomiting, diarrhea, and severe abdominal pain), renal failure type (manifested as progressive oliguria, anuria, and uremia), jaundice remittent type (manifested as remittent fever, jaundice, vomiting bile, anemia, hepatomegaly, and unconsciousness), and shock-collapse type (manifested as hypothermia, cold extremities, hypotension, and a thready, rapid pulse).
5. In infants and young children, acute malaria attacks are atypical. The shivering stage may only present with cold limbs, pale complexion, and cyanosis of the lips. Despite high fever during the fever stage, the limbs remain cold. Vomiting and diarrhea are common. Profuse sweating during the defervescence stage is rare. Anemia progresses rapidly, and splenomegaly is pronounced. However, rapid recovery can be achieved with treatment.
6. Congenital malaria occurs when the mother is infected with malaria before delivery, and the newborn develops symptoms within 5–6 days after birth, with the same malaria parasites found in the blood as the mother. The mortality rate is high.

bubble_chart Auxiliary Examination

1. In addition to anemia, there is a decrease in the total white blood cell count.
2. Diagnosis requires the identification of malaria parasites in a blood smear. Malaria parasites are easier to find before the acute attack and during the stage of attack. Thick blood smears have a higher detection rate than thin blood smears. For suspected cases where malaria parasites are not found after multiple tests, a subcutaneous injection of 0.1% adrenaline (0.01mg/kg) can be administered, followed by thick blood smears taken at 15 and 30 minutes post-injection to further search for malaria parasites. If necessary, a bone marrow puncture can be performed at the iliac crest to prepare thick bone marrow smears and thin smears, which are then examined under a microscope for malaria parasites.
3. Immunological tests: For epidemiological surveys or to assess parasite carriage in blood donors, indirect fluorescent antibody tests, indirect hemagglutination tests, and enzyme-linked immunosorbent assays (ELISA) can be used.

bubble_chart Diagnosis

(1) Medical and Epidemiological History: A history of previous malaria infection, recent blood transfusion, or travel to or residence in an endemic area during the transmission season.

bubble_chart Treatment Measures

﹝Treatment﹞

(1) General treatment: Bed rest is advised during symptom onset to prevent febrile convulsions. Provide a nutritious and easily digestible diet. Iron supplements can be given to anemic children. (2) Antimalarial drug therapy: Antimalarial drugs vary in their ability to kill different Plasmodium species and stages of schizonts, thus differing in their effects on stopping attacks, preventing relapses, and interrupting transmission. They can be broadly categorized into three types: (1) Primarily used to control attacks and eliminate schizonts, such as chloroquine, quinine, and atabrine; (2) Primarily used to prevent relapses and transmission, such as primaquine; (3) Primarily used for prophylaxis, such as pyrimethamine. These drugs can be used alone or in combination for different purposes.

1. Chloroquine can kill Plasmodium at all developmental stages within red blood cells, thereby controlling symptoms of all types of malaria. The pediatric dose is a total of 50mg/kg, with 25 mg/kg administered on the first day, and 12.5 mg/kg on the second and third days, not exceeding a total of 1.5g. Gastrointestinal reactions are common during treatment but subside after discontinuation. During a malaria attack, a large single dose may trigger a Herxheimer reaction, requiring caution. High doses can cause bradycardia, arrhythmia, and hypotension, so it is contraindicated in elderly patients and those with heart disease. Long-term use may lead to retinitis, rash, dermatitis, even exfoliative dermatitis, and leukopenia. 2. Quinine has schizonticidal effects and can usually control attacks within 1–2 days but does not provide a radical cure. The usual oral dose is 10mg/kg per dose, three times daily for 7 days. Side effects include tinnitus, vertigo, nausea, vomiting, visual impairment, and purpura. In severe cases, it can be administered via deep intramuscular injection at 1/20 of the oral dose. For unconscious patients or cerebral malaria, quinidine dihydrochloride can be diluted to 0.1% with 5–10% glucose solution and infused slowly intravenously at 5–10mg/kg per dose, repeatable once after 8 hours but no more than three times in 24 hours. Monitor for cardiac depression and collapse during IV infusion. ?
2. Primaquine has no schizonticidal effect but can destroy gametocytes. It is often used alongside or after the above drugs to kill gametocytes and prevent relapse. The dose is 0.5 tablets (6.6mg) daily for children under 1 year, 1 tablet for ages 3–6, 2.5 tablets for ages 7–10, 2 tablets for ages 11–12, and 3 tablets for ages >12, taken for 6–8 days. Side effects may include fatigue, dizziness, nausea, vomiting, and abdominal pain. Overdose or use in G6PD-deficient individuals may trigger acute hemolysis and cyanosis, requiring immediate discontinuation and emergency treatment.
3. Pyrimethamine is effective against the pre-erythrocytic stage of tertian malaria and is used for prophylaxis. It is easily absorbed and excreted with minimal side effects, but overdose or prolonged use may cause nausea, vomiting, megaloblastic anemia, cyanosis, or even convulsions. Children in malaria-endemic areas can take this drug prophylactically every 10–14 days: 25 mg for older children and 12.5 mg for preschoolers. Its sweet taste poses a risk of accidental overdose in children. Caution is advised in patients with renal impairment due to potential accumulation.
4. Artemisinin has a highly potent schizonticidal and trophozoiticidal effect on Plasmodium in red blood cells. Oral administration leads to rapid metabolism and relapse, so it is often combined with primaquine to reduce recurrence. Oil-based injections are more effective than oral administration and lower relapse rates. The oral dose for children is 6mg/kg initially, followed by 3mg/kg at 6–8 hours and on days 2 and 3, totaling 15mg/kg. The artemisinin oil injection follows the same dose and schedule as oral administration.
5. Pyronaridine (Malaridine) is primarily used to kill schizonts. It can treat malaria that has developed resistance to chloroquine. Its water-soluble {|###|} injection is used for emergency treatment of severe malaria cases, characterized by high efficacy, rapid action, and low toxicity. The total intramuscular injection dose for children is 2-4mg/kg, administered in 2 divided doses within one day. For intravenous drip {|###|} injection, the dosage is 3-6mg/kg each time, diluted in 200-500ml of 5-10% glucose {|###|} solution and administered slowly, with a total of 2-3 doses given. The oral total dose is 20mg/kg, divided into 3 doses: 2 doses on the first day and 1 dose on the second day. Combining antimalarial drugs can enhance efficacy, control symptom recurrence, and achieve radical cure or consolidate preventive effects. Additionally, if hemoglobinuria and hemolysis occur during treatment, such as symptoms of blackwater fever like {|###|} fever, jaundice, cyanosis, anemia, or anuria, the use of primaquine and quinine should be stopped immediately. Attention should be paid to correcting dehydration and acidosis, and adrenal corticosteroids should be administered to control acute hemolysis.

bubble_chart Prevention

(1) Control the source of pestilence by treating current patients and preventing relapse. Collective medication for prevention can be administered during epidemic seasons. Establish an epidemic reporting system. (2) Eliminate mosquitoes through patriotic health campaigns. Strengthen personal protection by using mosquito nets, repellent oil, or mosquito coils. (3) Preventive medication Yaodui for residents or visitors in high malaria-endemic areas should include regular intake of pyrimethamine.

bubble_chart Differentiation

It should be differentiated from febrile diseases with splenomegaly such as cold-damage disease, sepsis, schistosomiasis, leptospirosis, etc. Malignant malaria needs to be distinguished from encephalitis, meningitis, toxic dysentery, severe pneumonia, foxtail millet subcutaneous nodules, nephropathy, cold-damage disease, etc.