Page 167 - Medical Parasitology_ A Textbook ( PDFDrive )

160 14 Case Reports

Case 4: Hyperparasitaemia of Plasmodium knowlesi Infection in Human
Case report: A 56-year-old Chinese man was admitted to the hospital with a his-
tory of 5 days of high-grade fever, 2 days of yellowish discolouration of the skin and
extreme tiredness. He worked as a sawmill supervisor in Kluang, Johor. He had no
history of travelling overseas or trekking into deep jungles. However, he often vis-
ited a recreational park at the foothill of Gunung Lambak, Kluang, Johor.
Upon admission, he was alert, conscious but appeared lethargic. There was nei-
ther neck stiffness nor papilloedema. He was febrile with temperature of 38 °C. He
had mild pallor, deep jaundice but no petechiae. He was haemodynamically stable,
with well-perfused peripherals, no signs of tachypnea and good oxygenation.
Physical examinations of cardiovascular and respiratory systems were normal. He
had hepatomegaly, but no splenomegaly.
The initial haematological investigations revealed mild anaemia (Hb level 10.0 g/
dL), thrombocytopaenia (48,000 platelets/μL) with normal total white count and
haematocrit. Dengue tests were negative. Serology tests for Hepatitis B, Anti-HCV
and HIV tests were negative. Renal function was abnormal as evidenced by high
urea and creatinine levels. Liver enzymes were elevated with hyperbilirubinaemia
of a mixed picture. Lactate dehydrogenase (LDH) level was elevated but reticulo-
cyte count was normal and Coombs test was negative. The initial chest radiography
revealed normal lung field and no pulmonary congestion.
Rapid diagnostic test for malaria showed infection caused by non-Plasmodium falci-
parum. Thick and thin Giemsa-stained blood smears examination unravelled abundant
parasitized erythrocytes. Presence of numerous golden brown pigments with no enlarge-
ment of infected erythrocytes was indicative of P. knowlesi infection. The parasitemia
level was 27%. Nested PCR of the blood sample was positive for P. knowlesi infection.
The patient was treated with 4 doses of intravenous (IV) artesunate at 2.4 mg/kg
at 0, 12, 24, and 48 h in combination with oral doxycycline 100 mg BD for 1-week
duration. Packed cell transfusions were given to the patient for the anaemia.
Unfortunately, the patient went into the oliguric phase of acute kidney injury. He
needed 7 sessions of hemodialysis before his renal function recovered. On the sec-
ond day, a repeat blood smear showed dead and unhealthy parasites. The parasite
count declined by 4 to 5 fold for every 24 h after treatment. No malaria parasite was
noted in the peripheral blood film from day 5 onwards.

Source: Lee, Wenn-Chyau, Pek-Woon Chin, Yee-Ling Lau, Lit-Chein Chin,
Mun- Yik Fong, Chee-Jiek Yap, Raymond Raj Supramaniam, and Rohela
Mahmud. “Hyperparasitaemic human Plasmodium knowlesi infection with atyp-
ical morphology in peninsular Malaysia.” Malaria Journal 12, no. 1 (2013): 88.

Learning Points
1. In a patient with a febrile illness, a history of trekking into jungle/recreational
park is important to help in the diagnosis of P. knowlesi infection.
2. The presence of fever, anaemia, thrombocytopaenia and acute renal failure should
prompt the attending clinician to include malaria as a differential diagnosis.
3. When malaria is suspected, its confirmation needs to be pursued to minimize
delay in treatment.