Malaria Flashcards

1
Q

What is Malaria?

A

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

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2
Q

Epidemiology of Malaria?

A
  • 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
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3
Q

Incubation period of malaria?

A

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.

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4
Q

Symptoms of malaria?

A

nonspecific symptoms like fever, nausea, and vomiting

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5
Q

Gold standard for diagnosing malaria?

A
  1. identification of parasites in RBCs on a blood smear
  2. although rapid diagnostic tests to identify Plasmodium antigens are used with increasing frequency
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6
Q

Classification of malaria?

A
  1. severe
  2. uncomplicated
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7
Q

Signs of severe malaria?

A

characterized by severe organ dysfunction

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8
Q

Treatment of severe malaria?

A

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

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9
Q

Treatment for uncomplicated malaria?

A

treated with oral antimalarials

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10
Q

Pathogen that causes malaria?

A

plasmodia
- eukaryotic parasite belonging to the sporoza group

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11
Q

Name the different types of plasmodia?

A
  1. plasmodium falciparum - most virulent
  2. plasmodium vivax
  3. plasmodium ovale
  4. plasmodium knowlesi
  5. plasmodium malariae
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12
Q

Malaria vector?

A

the female anopheles mosquito

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13
Q

What conditions offer partial resistance against malaria?

A
  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)
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14
Q

Pathophysiology - asexual development in humans?

A
  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
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15
Q

Pathophysiology - sexual development in female Anopheles mosquito?

A

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

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16
Q

Describe the course of the malaria illness?

A

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

17
Q

General malaria symptoms?

A
  1. Flu‑like symptoms, headache
  2. Diaphoresis
  3. High fever
18
Q

Blood specific symptoms of malaria?

A
  1. Thrombocytopenia: increased bleeding risk
    - DIC might occur in severe cases
  2. Hemolytic anemia: weakness, paleness, dizziness
19
Q

Gastrointestinal specific symptoms of malaria?

A

Nausea, vomiting
Diarrhea, abdominal pain

20
Q

Liver specific symptoms of malaria?

A
  1. hepatosplenomegaly
  2. discrete jaundice
21
Q

CNS specific symptoms of malaria?

A
  1. hallucinations
  2. confusion
  3. impaired consciousness
  4. seizures
  5. coma
22
Q

Diagnostic approach to malaria?

A
  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
23
Q

What are the routine lab studies done in malaria?

A
  1. FBC
  2. CMP/Urea and electrolytes
  3. Urinalysis
24
Q

CBC of a malaria patient?

A
  1. Hemolytic anemia
    - ↓ Hb, ↓ haptoglobin, ↑ LDH, ↑ indirect bilirubin, ↑ reticulocytes
  2. Thrombocytopenia
    Leukocytosis or leukopenia are uncommon except in severe disease
25
Q

CMP/Urea and electrolytes of a malaria patient?

A

hypoglycemia can occur in severe malaria

26
Q

Urinalysis of a malaria patient?

A

hemoglobinuria may occur with intravascular hemolysis

27
Q

What is a MRDT?

A
  • Detects specific malaria antigens
  • Allows for quick diagnosis if high‑quality microscopy is unavailable or delayed
28
Q

What is a blood smear in malaria testing?

A

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

29
Q

Why is a blood smear good in malaria testing?

A
  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
30
Q

What is found on a blood smear in malaria testing?

A
  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
31
Q

Classification of malaria?

A
  1. uncomplicated malaria
  2. severe malaria
32
Q

Describe uncomplicated malaria?

A

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

33
Q

Describe severe malaria?

A

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.

34
Q

Criteria for severe malaria?

A

≥ 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

35
Q

Lab findings in severe malaria?

A

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

36
Q

Treatment for severe malaria?

A

Start IV artesunate

37
Q

Treatment for uncomplicated malaria?

A

lumefantrine-artemethar - LA