Malaria

Question 1

What is Malaria?

Answer 1

a potentially life‑threatening tropical infectious disease caused by Plasmodium parasites, which are transmitted through the bite of an infected female Anopheles mosquito

Question 2

Epidemiology of Malaria?

Answer 2

• Most cases of malaria occur in tropical Africa (West and Central Africa).
• Transmission also occurs in other tropical and subtropical regions such as South and Southeast Asia, and Central and South America

Question 3

Incubation period of malaria?

Answer 3

7-30 days
- The incubation period of malaria is a minimum of seven days; if fever occurs before the seventh day following exposure in an endemic region, it is most likely not due to malaria.

Question 4

Symptoms of malaria?

Answer 4

nonspecific symptoms like fever, nausea, and vomiting

Question 5

Gold standard for diagnosing malaria?

Answer 5

1. identification of parasites in RBCs on a blood smear
2. although rapid diagnostic tests to identify Plasmodium antigens are used with increasing frequency

Question 6

Classification of malaria?

Answer 6

1. severe
2. uncomplicated

Question 7

Signs of severe malaria?

Answer 7

characterized by severe organ dysfunction

Question 8

Treatment of severe malaria?

Answer 8

affected individuals should be admitted to the ICU and receive IV antimalarials immediately

Question 9

Treatment for uncomplicated malaria?

Answer 9

treated with oral antimalarials

Question 10

Pathogen that causes malaria?

Answer 10

plasmodia
- eukaryotic parasite belonging to the sporoza group

Question 11

Name the different types of plasmodia?

Answer 11

1. plasmodium falciparum - most virulent
2. plasmodium vivax
3. plasmodium ovale
4. plasmodium knowlesi
5. plasmodium malariae

Question 12

Malaria vector?

Answer 12

the female anopheles mosquito

Question 13

What conditions offer partial resistance against malaria?

Answer 13

1. carriers of sickle cell mutation
2. Other hemoglobinopathies (e.g., thalassemia, HbC)
3. Infection with malaria subsequently leads to the development of specific Plasmodium antibodies that result in partial immunity for a limited amount of time (less than a year)

Question 14

Pathophysiology - asexual development in humans?

Answer 14

1. Transmission of Plasmodium sporozoites via Anopheles mosquito bite → sporozoites travel through the bloodstream to the liver of the host
2. Liver: sporozoites enter hepatocytes → sporozoites multiply asexually → schizonts are formed containing thousands of merozoites → release of merozoites into the bloodstream
3. Circulatory system: Merozoites enter erythrocytes → maturation to trophozoites → red cell schizonts are formed containing thousands of merozoites → release of merozoites into the bloodstream (which causes fever and other manifestations of malaria) → penetration of erythrocytes recurs
4. Merozoites enter erythrocytes → differentiation into gametocytes (male or female)
5. Gametocytes mature into oocysts in the mosquito → mature into sporozoites

Question 15

Pathophysiology - sexual development in female Anopheles mosquito?

Answer 15

A mosquito bites an infected human and ingests gametocytes → gametocytes mature within the mosquito intestines → sporozoites are formed and these migrate to the salivary glands → transmission of sporozoites to humans via mosquito bite

Question 16

Describe the course of the malaria illness?

Answer 16

Infection → asymptomatic parasitemia → uncomplicated illness → severe malaria → death

Question 17

General malaria symptoms?

Answer 17

1. Flu‑like symptoms, headache
2. Diaphoresis
3. High fever

Question 18

Blood specific symptoms of malaria?

Answer 18

1. Thrombocytopenia: increased bleeding risk
   - DIC might occur in severe cases
2. Hemolytic anemia: weakness, paleness, dizziness

Question 19

Gastrointestinal specific symptoms of malaria?

Answer 19

Nausea, vomiting
Diarrhea, abdominal pain

Question 20

Liver specific symptoms of malaria?

Answer 20

1. hepatosplenomegaly
2. discrete jaundice

Question 21

CNS specific symptoms of malaria?

Answer 21

1. hallucinations
2. confusion
3. impaired consciousness
4. seizures
5. coma

Question 22

Diagnostic approach to malaria?

Answer 22

1. Focused clinical evaluation
   - Time of travel to regions where malaria is endemic and previous chemoprophylaxis
   - Evaluate for signs of severe malaria.
2. Routine laboratory studies
   - CBC, CMP, LFTs, and coagulation panel to evaluate for organ dysfunction
3. Parasitological testing
   - confirms the presence and determines the species of Plasmodia e.g. MRDT, thick and thin blood smears

Question 23

What are the routine lab studies done in malaria?

Answer 23

1. FBC
2. CMP/Urea and electrolytes
3. Urinalysis

Question 24

CBC of a malaria patient?

Answer 24

1. Hemolytic anemia
   - ↓ Hb, ↓ haptoglobin, ↑ LDH, ↑ indirect bilirubin, ↑ reticulocytes
2. Thrombocytopenia
   Leukocytosis or leukopenia are uncommon except in severe disease

Question 25

CMP/Urea and electrolytes of a malaria patient?

Answer 25

hypoglycemia can occur in severe malaria

Question 26

Urinalysis of a malaria patient?

Answer 26

hemoglobinuria may occur with intravascular hemolysis

Question 27

What is a MRDT?

Answer 27

- Detects specific malaria antigens - Allows for quick diagnosis if high‑quality microscopy is unavailable or delayed

Question 28

What is a blood smear in malaria testing?

Answer 28

allows for visualization of parasites within RBCs via microscopy to confirm malaria diagnosis

Question 29

Why is a blood smear good in malaria testing?

Answer 29

1. Allows identification of Plasmodium species 2. Enables calculation of malaria parasitemia: the percentage of RBCs containing a Plasmodium organism; used to classify severity and monitor response to therapy

Question 30

What is found on a blood smear in malaria testing?

Answer 30

1. Schuffner granules (fine, brick-red dots) within RBCs infected with P. vivax and P. ovale 2. Crescent-shaped gametocytes in individuals infected with P. falciparum

Question 31

Classification of malaria?

Answer 31

1. uncomplicated malaria 2. severe malaria

Question 32

Describe uncomplicated malaria?

Answer 32

Definition: symptomatic, diagnostically proven malaria without features of severe malaria Etiology: can be caused by all Plasmodium species

Question 33

Describe severe malaria?

Answer 33

Description: potentially fatal manifestation or complication of malaria Etiology: most commonly a result of falciparum malaria Pathophysiology: Infected erythrocytes occlude capillaries, which can lead to severe organ dysfunction.

Question 34

Criteria for severe malaria?

Answer 34

≥ 1 of the following in a patient with proven malaria: 1. General: prostration 2. CNS: hallucinations, confusion, impaired consciousness, seizures, coma 3. Cardiac: shock (e.g., hypotension, capillary refill time ≥ 3 seconds), heart failure 4. Pulmonary: respiratory distress, pulmonary edema, ARDS 5. Renal: flank pain, oliguria, hemoglobinuria, acute kidney injury 6. Gastrointestinal: jaundice 7. Hematopoietic: significant bleeding

Question 35

Lab findings in severe malaria?

Answer 35

Severe anemia: < 7 g/dL in adults, < 5 g/dL in children Hypoglycemia: < 40 mg/dL Acidosis (with or without lactemia): base deficit > 8 meq/L or bicarbonate < 15 meq/L Hyperlactatemia: lactate > 5 meq/L Acute kidney injury: creatinine > 3 mg/dL or urea > 20 mmol/L Hyperbilirubinemia: bilirubin > 3 mg/dL High malaria parasitemia

Question 36

Treatment for severe malaria?

Answer 36

Start IV artesunate

Question 37

Treatment for uncomplicated malaria?

Answer 37

lumefantrine-artemethar - LA