ARTICLE MALARIA DIAGNOSIS
an antipodean case study
Plasmodium falciparum malaria was the subject of a case and poster
presentation given by Jayachandran Radhakrishnan at an Australian
Institute of Medical Scientists meeting in Bunbury, Western Australia.
A 47-year-old male presented to his GP tests required at least a week for the results
complaining of intermittent fever, diarrhoea to be returned, as they were performed in a
and vomiting. The GP noted that the patient reference laboratory in Perth.
had travelled to the Ivory Coast in West Africa However, a very low platelet count did
a month previously to attend a job interview. give the GP reason to request further blood
In view of the patient’s condition, the GP investigations. Meanwhile, on the following
decided to refer him to Kalgoorlie Regional day, the patient was feeling extremely unwell
Hospital for further tests and a complete and was admitted to the Kalgoorlie Regional
check. This short study illustrates the Hospital.
importance of diagnostic methods in the early
detection of Plasmodium falciparum malaria LABORATORY FINDINGS
and subsequent treatment outcomes. Initial full blood count on the samples
collected by the GP gave a low platelet count
PRELIMINARY INVESTIGATION (38 x 109/L) and a haemoglobin (Hb) value Fig 1. A fresh blood test on Day 2 using a
Prior to referring the patient, the GP had asked of 126 g/L (Table 1). The peripheral smear malaria kit yielded a positive result for
him to undergo a series of blood investigations examination undertaken in the laboratory to Plasmodium falciparum.
including full blood picture, electrolytes, liver detect the cause of the low platelet level failed
function tests (LFTs), C-reactive protein to detect any platelet clumps. The CRP was Fresh bloods were collected from the
(CRP), erythrocyte sedimentation rate (ESR), elevated to 154 mg/L and LFTs showed an patient and the laboratory performed a
and serology for influenza, dengue fever and increase in alanine transaminase (ALT) or malarial investigation that included a serology
atypical pneumonia. γ-glutamyl transpeptidase (GGT) values. test and also peripheral smear examination
Initial laboratory results from these tests However, the low platelet count and Hb gave using thick and thin films. Noting the
yielded little information on which the GP enough cause for concern for the clinician patient’s history of diarrhoea and vomiting
could base a diagnosis. Most of the serology to order a malaria investigation. and also his recent travel to Africa, a Widal
test and blood culture were also requested to
Table 1. Initial results on the bloods collected by the GP. investigate the possibility of typhoid fever.
Blood counts were performed on an
Hb (g/L) RBC (x1012/L) Platelets (x109/L) CRP LH500 analyser (Beckman Coulter), and
(135–180) (4.5–5.5) (150–400) (<10) thick and thin blood films were stained with
126 4.07 38 154 Leishman.
Table 2. Results over the four days following commencement of antimalarial treatment. P. FALCIPARUM MALARIA
Fresh blood tests undertaken of Day 2 using
Day Platelet count Infected RBCs Absolute count a malaria kit (BinaxNow, Inverness Medical)
(x109/L) (%) (x109/L) (Fig 1) yielded a positive result for
3 51 4.6 150.6 P. falciparum. The thick (Fig 2a) and thin
4 89 2.4 78.3
blood films (Figs 2b and 2c) showed a number
of P. falciparum trophozoites and the level
5 119 <0.5 NA of infected red cells was estimated at 7%.
6 211 <0.5 NA Absolute count of the infected red cells was
estimated at 261.1 x 109 cells/L. The blood
2 THE BIOMEDICAL SCIENTIST OCTOBER 2009
Fig 2. Thick (a) and thin (b and c) blood films showed a number of Plasmodium falciparum trophozoites.
cell counts correlated well with the clinical patient was advised to visit his GP regularly co-existing typhoid infection. Serology
picture. Platelet count was 45 x 109 cells/L for blood tests to monitor the reduction in investigations for dengue, influenza and
and the patient was anaemic (Hb 113 g/L). infected red cells to an absolute count of zero. Epstein-Barr virus were negative.
Neutrophils showed mild left shift and Timely laboratory detection of the
moderate toxic granulation. OUT OF AFRICA P. falciparum parasite improved the condition
The condition of the patient improved of the patient; however, this case study also
TREATMENT AND FOLLOW-UP considerably after administration of the highlights the need for travellers to take
The patient was started on intravenous (iv) antimalarial drug. His platelet count precautionary measures when visiting regions
antibiotics and was given an antimalarial increased and the illness began to subside. of the world in which malaria is endemic.
drug, which over a period of days decreased It would seem apparent that he contracted
the percentage of infected red cells to the malarial disease while on his visit to the
<0.5% and increased the platelet count to Ivory Coast. The Widal and blood culture Jayachandran Radhakrishnan
211 x 109/L. On discharged from hospital, the results were negative, which ruled out is a medical scientist working
at Kalgoorlie Regional
Hospital, Piccadilly Street,
‘In view of recent travel to Africa, a Widal test and blood culture Kalgoorlie, Western Australia.
were requested to investigate the possibility of typhoid fever’
OCTOBER 2009 THE BIOMEDICAL SCIENTIST 3