A Case of Malaria | Department of Emergency Medicine

A Case of Malaria – Presenting to a Canadian Emergency Department

Medical Student Clinical Pearl

Matthew Kenney, Med 2

Dalhousie Medicine New Brunswick, Class of 2018

Abstract

A 65 year old male presented to the Saint John Regional Hospital Emergency Department with nausea and vomiting over the last 72 hours. The patient had recently returned from a trip overseas in Africa. A differential was developed after a thorough history and physical examination. Appropriate laboratory tests were conducted and revealed that the patient tested positive for Plasmodium falciparum. The diagnosis of Malaria was made.

Background

Description

Malaria is due to an infection from plasmodium protozoa which affects the erythrocytes of the host. The most common type of transmission through mosquito transmission. The life cycle of the Plasmodium species responsible for this condition is complex and an overview of is covered in Figure 1. Plasmodium falciparum is the most common species implicated in Malaria and will be the focus of this paper.

Figure 1- 1. Infected Anopheles mosquito bites human and the plasmodia sporozoites within the mosquito saliva are transferred to the host. 2. Sporozoites go into the hepatocytes of the host. 3. The infected hepatocytes develop into the hepatic schizont. 4. When the schizont ruptures, it releases merozoites into the bloodstream.These merozoites penetrate the human erythrocytes. They can become become nonmultiplying gametocytes or enter into the asexual reproductive forms. 5. The gametocytes can be transmitted to mosquitoes for future spread.

Reference: (Breman, JG, 2016)¹

Epidemiology

According to the World Health Organization (WHO), active Malaria transmission is occurring in 106 countries ². Figure 2 shows a map of the currently affected countries within the Eastern Hemisphere. Malaria is a particular concern in the tropics and subtropics where it is common and life-threatening. Many of these countries are visited by millions of tourists each year which increases the risk of exposure. The WHO estimates that there were 214 million cases worldwide in 2015; in particular, the African region is of concern as 88% of the cases were reported in these regions ². Certain individuals are more at risk of developing severe malarial complications and special counselling should be done when these groups travel to endemic areas. These groups include children between the ages of 6 and 36 months, those susceptible to developing severe illness, as well as pregnant women ¹.

Figure 2. Map displaying current Malaria endemic countries in the Eastern Hemisphere.

Photo Reference: (Daily, J, 2016) ¹⁰

Etiology

There are 5 Plasmodium species that are responsible for causing Malaria. The five include Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale, and Plasmodium knowlesi ^3,4. The species most commonly found in malaria infections is P. falciparum and is also considered to be the most lethal. P. ovale and P. vivax can cause recurrent attacks of malaria as these two species are able to produce hypnozoites that can reenter the erythrocyte cycle months later ⁵

Pathogenesis

The most common mode of transmission is through an infected mosquito; however, malaria less commonly may be spread congenitally, by blood transfusion, by sharing an intravenous (IV) drug needle with an infected individual, or by liver transplantation ⁶. The life cycle of the protozoa in the human body is described in Figure 1. When the protozoa enters the hepatocytes, it has an incubation period between 7-35 days ¹. When an erythrocyte becomes infected with P. falciparum, it induces erythrocyte alterations and microcirculatory abnormalities. When the parasite reaches its late stage of infection in the circulatory system, it can cause adhesion and can lead to sequestration to the endothelial cells, platelets, and uninfected erythrocytes ⁷. This adherence can cause microvascular occlusion, intravascular hemolysis, and metabolic derangements⁷.

Clinical Presentation

Patients infected with P. falciparum have a range of presentations based on the progression of the disease. In uncomplicated P. falciparum, patients tend to present with flu-like symptoms along with periods of a high spiking fever and chills. Initially, the fevers are sporadic¹. These patients may also present with abdominal pain, diarrhea, headaches, or a cough ¹. Individuals presenting with complicated P falciparum may vary. In some cases of complicated malaria, patients can have central nervous system involvement, or cerebral malaria resulting in seizures and a coma ^1,5,8. These patients may also have severe anemia, acute kidney injury, as well as acute respiratory distress syndrome ⁷.

Investigations

Microscopic evaluation of blood smears should be done or a rapid diagnostic test (RDT). The RDTs can be used to detect histidine-rich protein 2, Plasmodium lactate dehydrogenase, or aldolase ⁹. These tests can be done in 15-20 minutes and the detection of one or more of these is confirmatory for malaria. In general, if in a region where P. falciparum is the suspected species, performing a test detecting HRP2 are more sensitive and more cost effective for detecting this species ⁹. The RDTs provide a confirmatory presence of the parasite; however, RDTs do not provide the count or density of the parasite. The density presence is determined by analyzing blood smears with microscopy⁹. Blood smears can be used to determine the species as well as the density of the parasites in the blood. The density of the Plasmodium parasite in the blood is important to determine as it directly correlates with the severity of the infection ⁹.

Management

Malaria is a potentially life-threatening condition and should be diagnosed and treated quickly. Those patients with non-complicated P. falciparum can be treated with the drug regimens listed in Appendix 1. Malaria can also be approached prophylactically for any patients potentially travelling to malaria endemic countries. The prophylactic treatment for malaria is country dependent. Countries have different recommendations based on particular Plasmodium species and the degree of drug resistance. These individual country recommendations are beyond the scope of this paper. General mosquito avoidance and insect repellent is recommended in addition to prophylactic treatment when travelling to malaria-endemic areas.

Case Study

(Whilst the stimulus for this report was a real case of Malaria, the following case report is purely fictional, and based on a number the similar presentations seen by the author’s supervisor)

History of Presenting Illness

A 65-year-old male presented to an emergency department in Canada with complaints of nausea and vomiting for 72 hours. The patient had been overseas on business where he travelled throughout South Africa, Zimbabwe, and the Mauritius region. He stated that his vaccines were up to date but that he was not taking anti-malarial medication as he was only briefly travelling through these African countries. He also noted that he had many “bug bites”. The patient further stated that he also had a questionable meal before he started feeling nauseous. There was no evidence of blood in the vomit and no diarrhea. The patient’s past medical history and family history was unremarkable. The patient was on no medication and had no known allergies.

Physical Examination

Patient appears diaphoretic and flush in the face. No signs of respiratory distress. GI exam in normal with no abdominal tenderness or evidence of organomegaly; however, the patient complained of extreme nausea during examination. Respiratory exam is normal with no evidence of accessory muscle use to adventitious breath sounds.

Differential Diagnosis

Hepatitis A
Malaria
Typhoid toxin ingestion

Laboratory examinations:

Complete blood count
Malaria Rapid Diagnostic Test and Blood Smear
Hepatitis A and B immunological status

Laboratory Results

Increased PT and INR
Elevated ALT
Positive Rapid Diagnostic Test for falciparum

Diagnosis and Management

The patient was diagnosed with uncomplicated falciparum malaria. The patient was admitted to internal medicine and Infectious Disease was notified. The patient was started on Atovaquone-proguanil 4 tabs qd for three days. Patient was discharged 5 days later.

References

Breman, JG. Clinical Manifestations of malaria is nonpregnant adults and children. In: UpToDate, Daily, J (Ed), UpToDate, Waltham, MA. (Accessed on March 28, 2016.)

“Fact Sheet: World Malaria Report 2015”. World Health Organization. N.p., 2016. Web. 12 Apr. 2016.

Arguin, PM, Keystone JS. Prevention of malaria infection in travelers. In: UpToDate, Daily, J (Ed), UpToDate, Waltham, MA. (Accessed on April 12, 2016.)

Maguire, JD. Overview of non-falciparum malaria. In: UpToDate, Daily, J (Ed), UpToDate, Waltham, MA. (Accessed on April 1, 2016.)

Suh, KN et al. (2004). Malaria. Canadian Medical Association Journal, 170(11), 1693-1702. doi: 10.1503/cmaj.1030418.

Centers for Disease Control and Prevention. (2011). Malaria. Retrieved from http://www.cdc.gov/malaria/about/faqs.html

Buffet PA, Safeukui I, Deplaine G, et al. The pathogenesis of Plasmodium falciparum malaria in humans: insights from splenic physiology. Blood. 2011;117(2):381-392. doi:10.1182/blood-2010-04-202911.

Taylor, TE. Treatment of severe falciparum malaria. In: UpToDate, Daily, J (Ed), UpToDate, Waltham, MA. (Accessed on April 2, 2016.)

Hopkins, H. Diagnosis of Malaria. In: UpToDate, Daily, J (Ed), UpToDate, Waltham, MA. (Accessed on April 18, 2016.)

Daily, J. Treatment of uncomplicated falciparum malaria in nonpregnant adults and children. In: UpToDate, Leder, K (Ed), UpToDate, Waltham, MA. (Accessed on April 22, 2016.)

Centers for Disease Control and Prevention. (2013). Guidelines for Treatment of Malaria in the United States. Retrieved from http://www.cdc.gov/malaria/resources/pdf/treatmenttable.pdf