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PREVALENCE AND SEVERITY OF HYPOGLYCAEMIA AND LACTIC ACIDOSIS IN CHILDREN DIAGNOSED WITH Plasmodium falciparum MALARIA

Bio Chemistry Project Topics & Materials

 

ABSTRACT

The prevalence and severity of hypoglycaemia and lactic acidosis in Nigerian children diagnosed with Plasmodium falciparum malaria were determined in 100 outpatient children aged 3-144 months (12 years). The children were grouped into 2 categories: 3-59 month old and 60-144 month old. The results obtained indicated that out of the 100 children recruited into this study, seventy-five (75%) were infected while twenty-five (25%) were uninfected with Plasmodium falciparum malaria. On the basis of age group, higher incidence of malaria was recorded in children under 5 years of age with prevalence rate of 85.3%, while those above 5 years had low prevalence rate of 14.7%. The mean blood glucose concentration of malaria-infected children below 5 years (3.80 ± 0.73 mmol/l) was lower than that of malaria-infected children above 5 years (4.21 ± 1.34 mmol/l); however, the difference was not significant (p>0.05). Comparatively, the mean glucose concentrations of the corresponding uninfected subjects were 4.10 ± 0.87 and 4.26 ± 0.51 mmol/l respectively. The mean blood lactate concentration of children below 5 years of age (2.59 ± 1.63 mmol/l ) was significantly (p<0.05) higher than those above 5 years (2.30 ± 1.75 mmol/l). The mean values for both groups were also above the normal range of 1.0 – 2.0 mmol/l while the mean haemoglobin concentration of malaria-infected children below 5 years (16.11 ± 2.24 g/dl) was slightly lower than that of malaria-infected children above 5 years (16.36 ± 2.64g/dl) though not significant (p> 0.05). The prevalence rates of 14.7% were recorded for both hypoglycaemia and lactic acidosis in malaria-infected subjects while 16.0% was recorded for anaemia. There was no significant correlation between blood lactate concentration and blood glucose concentration (r= 0.032, p=0.751) but there was significant positive correlation between haemoglobin level and glucose concentration (r=0.401, p=0.0001). The results suggest that the risk of hypoglycaemia, lactic acidosis and anaemia is higher in younger children, particularly among those below five years of age and also confirmed the knowledge that malaria is a major cause of hospital visits by children.

TABLE OF CONTENTS

PAGE

Title Page                                                                                                                           i

Certification                                                                                                                       ii

Dedication                                                                                                                         iii

Acknowledgements                                                                                                            iv

Abstract                                                                                                                              v

Table of Contents                                                                                                               vi

List of Figures                                                                                                                    x

List of Tables                                                                                                                     xi

List of Abbreviations                                                                                                         xii

 

CHAPTER ONE: INTRODUCTION

1.1        Malaria                                                                                                                                   2

1.1.1     World malaria report                                                                                                       3

1.1.2     Malaria in children                                                                                                            5

1.1.3     Malaria parasite life cycle                                                                                               5

1.1.3.1 Sporogony within the mosquitoes                                                                             5

1.1.3.2 Schizogony in the human host                                                                                     6

1.1.3.3 Pre-erythrocytic phase-schizogony in the liver                                                                     6

1.1.3.4 Erythrocytic schizogony-centre stage in red cells                                                                 7

1.1.4     Pathogenic basis of malaria                                                                                           9

1.1.5     Pathophysiology of severe malaria in children                                                                      11

1.1.6     Cytokine-associated neutrophil extracellular traps and antinuclear

antibodies in Plasmodium falciparum                                                                        12

1.2        Biochemistry of Plasmodium falciparum                                                                 13

1.2.1     Detoxification of heme and reactive oxygen intermediates                                           17

1.2.2     Biochemistry and molecular biology of malaria parasite:

pyrimidine biosynthetic pathway                                                                                 18

1.2.3     Complication of Plasmodium falciparum malaria                                                                 20

 

1.2.4      Prevalence and management of Plasmodium falciparum malaria

among infants and children                                                                                            22

1.3        Hypoglycaemia in childhood malaria                                                                          22

1.3.1     Sublingual sugar for hypoglycaemia in children with severe malaria                            24

1.4        Lactic acidosis in childhood malaria                                                                             24

1.4.1    Lactate levels in severe malarial anaemia                                                                                25

1.5       Transport of lactate and pyruvate in Plasmodium falciparum malaria                          26

1.6       Anaemia in childhood malaria                                                                                        27

1.6.1    Severity of anaemia in children diagnosed with Plasmodium falciparum

malaria                                                                                                                                     28

1.7       Typhoid and malaria co-infection                                                                                 28

1.8       Aim and objectives of the study                                                                                   29

1.8.1    Aim of the study                                                                                                                 29

1.8.2    Specific objectives of the study                                                                                   29

 

CHAPTER TWO: MATERIALS AND METHODS

2.1       Materials                                                                                                                                30

2.1.1    Subjects and location                                                                                                       30

2.1.2    Instruments/Equipment                                                                                                 30

2.1.2.1 Accutrend plus meter                                                                                                      30

2.1.2.2 Crista haemoglobinometer                                                                                           31

2.1.3    Reagent kit/ Test strips                                                                                                    31

2.1.3.1 Malaria diagnostic rapid test kit                                                                                   31

2.1.3.2 Glucose reagent strip                                                                                                      31

2.1.3.3 Lactate reagent strip                                                                                                        31

2.2       Methods                                                                                                                                31

2.2.1    Preparation of 70% (v/v) ethanol                                                                                31

2.2.2    Experimental design                                                                                                         32

2.2.3    Malaria diagnostic test                                                                                                     32

2.2.4    Biochemical parameters determined                                                                       33

2.2.4.1 Determination of blood glucose concentration                                                                    33

2.2.4.2 Determination of blood lactate concentration                                                                      34

2.2.5    Haematological parameter determined                                                                                   35

2.2.5.1 Estimation of haemoglobin concentration                                                                 35

2.3       Statistical analysis                                                                                                      35

 

CHAPTER THREE: RESULTS

3.1   Prevalence of Plasmodium falciparum malaria according to age of subjects                 36

3.2   Blood glucose levels in malaria-infected and uninfected subjects                                     37

3.3   Blood lactate levels in malaria-infected and uninfected subjects                                       38

3.4   Haemoglobin levels in malaria-infected and uninfected subjects                                      39

3.5   Variation of glucose concentration with age of malaria-infected

subjects                                                                                                                                        40

3.6   Variation of lactate concentration with age of malaria-infected

subjects                                                                                                                                       41

3.7   Variation of haemoglobin concentration with age of malaria-infected

subjects                                                                                                                                      43

3.8   Effect of Plasmodium falciparum parasite load on the blood glucose

concentration of subjects                                                                                                    44

3.9   Effect of Plasmodium falciparum parasite load on the blood lactate

concentration of subjects                                                                                                    46

3.10 Effect of Plasmodium falciparum parasite load on haemoglobin

concentration of subjects                                                                                                    47

3.11 Comparison of glucose concentration of malaria-infected and

uninfected subjects                                                                                                                48

3.12 Comparison of lactate concentration of malaria-infected and

uninfected subjects                                                                                                                49

3.13 Comparison of haemoglobin concentration of malaria-infected and

uninfected subjects                                                                                                                50

3.14 Correlations matrix                                                                                                                51

CHAPTER FOUR: DISCUSSION

4.1    Discussion                                                                                                                         53

4.2   Conclusion                                                                                                                          56

4.3   Suggestions for further studies                                                                                           56

REFERENCES                                                                                                                           57

APPENDICES                                                                                                                            76

 

LIST OF FIGURES

 

Fig 1: World malaria burden (World Malaria Report, 2011)                                                      4

Fig. 2: Ingestion of host cytoplasm                                                                                             15

Fig. 3: Variation of glucose concentration with age of malaria-infected

subjects                                                                                                                            40

Fig. 4: Variation of lactate concentration with age of malaria-infected

subjects                                                                                                                            42

Fig. 5: Variation of haemoglobin concentration with age of malaria-infected

subjects                                                                                                                            43

Fig. 6: Effect of Plasmodium falciparum parasite load on the blood glucose

concentration of subjects                                                                                                  45

Fig. 7: Effect of Plasmodium falciparum parasite load on the blood lactate

concentration of  subjects                                                                                                 46

Fig. 8: Effect of Plasmodium falciparum parasite load on haemoglobin

concentration of  subjects                                                                                                 47

Fig. 9: Comparison of glucose concentration of malaria-infected and

uninfected subjects                                                                                                          48

Fig. 10: Comparison of lactate concentration of malaria-infected and

uninfected subjects                                                                                                          49

Fig. 11: Comparison of haemoglobin concentration of malaria-infected and

uninfected subjects                                                                                                         50

LIST OF TABLES

Table 1: Indicators of severe malaria and poor prognosis                                                       21

Table 2: Prevalence of Plasmodium falciparum malaria according to age of subjects           36

Table 3: Blood glucose concentration (BGC) in malaria-infected and uninfected

subjects                                                                                                                       37

Table 4: Blood lactate concentration (BLC) in malaria-infected and uninfected

subjects                                                                                                                       38

Table 5: Haemoglobin concentration (HC) in malaria-infected and uninfected

subjects                                                                                                                        39

Table 6: Correlations matrix                                                                                                    52

 

LIST OF ABBREVIATIONS

 

µl:                                           Microlitre

ABC:                                      ATP-binding cassette

ANOVA:                               Analysis of Variance

ATC:                                       Aspartate transcarbamylase

ATP:                                       Adenosine triphosphate

BGC:                           Blood glucose concentration

BLC:                           Blood lactate concentration

CPS :                          Carbamyl phosphate synthase

CRP:                           C-reactive protein

DBL:                          Duffy binding-like

de novo:                      From the beginning

DHO:                         Dihydroorotase

DHOD:                      Dihydroorotate dehydrogenase

DNA:                         Deoxyribonucleic acid

DPAP:                       Dipeptidyl aminopeptidase

DRC:                         Democratic Republic of the Congo

Fe2+:                          Ferrous ion

Fe3+:                          Ferric ion

GSH:                         Reduced glutathione

H+:                            Hydrogen ion

HC:                           Haemoglobin concentration

HCl:                          Hydrochloric acid

HCM:                        Hz-containing monocytes

HCN:                        Hz-containing neutrophils

HCO3:                                  Bicarbonate

HRP:                         Histidine-rich protein

Hz:                            Haemozoin

IFN-y:                       Interferon gamma

IgG:                           Immunoglobulin G

IgM:                              Immunoglobulin M

IL:                                 Interleukin

LED:                             Light-emitting diode

MCTs:                          Monocarboxylate transporters

NAD+:                          Nicotinamide adenine dinucleotide

NADH:                         Reduced form of nicotinamide adenine dinucleotide

NETs:                            Neutrophil extracellular traps

OMPDC:                      Orotidine 5’-monophosphate decarboxylase

OPRT:                          Orotate phosphoribosyltransferase

pCMBS:                       p chloromercuribenzenesulphonate

Pfmdr-1:                       Plasmodium falciparum multidrug resistance protein/gene

pHi:                              Intracellular pH

pLDH:                         Plasmodium lactate dehydrogenase

ppm:                             Parasite plasma membrane

PVM:                           Parasitophorous vacuole membrane

RBC:                            Red blood cell

RNA:                           Ribonucleic acid

ROI:                             Reactive oxygen intermediates

SD:                              Standard deviation

SEARO/WPRO:         South-East Asia and Western Pacific Regional Office

SOD:                           Superoxide dismutase

SPPS:                          Statistical product and service solutions

TNF-α:                        Tumor necrosis factor alpha

TRAP:                        Thrombospondin-related anonymous protein

UMP:                          Uridine 5’ monophosphate

WHO/AFRO:             World Health Organization Regional Office for Africa

CHAPTER ONE

                                            

                                             INTRODUCTION

 

Plasmodium falciparum is the most common cause of severe and life-threatening malaria, which causes over 2 million deaths every year (Bruneel et al., 2003; Njuguna and Newton, 2004). In Africa, a vast majority of these deaths occur in children under five years of age (WHO, 2012). Lactic acidosis complicates 35% of severe childhood malaria (Krishna et al., 1994) and hypoglycaemia is present in 20% of children with cerebral malaria (Newton and Krishna, 1998). Both acidosis and hypoglycaemia commonly coexist but each is considered separately as a cause of fatality in children and adults due to severe complicated malaria. Hypoglycaemia is known to be an independent risk factor for death in both severe malaria (Gray et al., 1985; Molyneux et al., 1989) and other severe childhood infections in the tropics (Kawo et al., 1990). Despite its importance, its pathogenesis is not well understood (English et al., 1998). Hypoglycaemia is associated with a poor prognosis in severe malaria (krishna et al, 1994).

In African children with malaria, impairment in hepatic gluconeogenesis in the presence of adequate levels of precursors (glycerol) has been considered the most likely mechanism (White et al., 1987). Irreversible coma may quickly develop if the condition is not effectively treated. Hyperlactataemia is often associated with a poor outcome in severe malaria in African children (Krishna et al, 1994). The pathophysiology of metabolic acidosis is complex. The direct contribution of P. falciparum to the final lactate concentration, through anaerobic glycolysis in the parasite itself, is likely to be small (Vander et al., 1990). More significantly, an inadequate supply of oxygen to tissues may follow from severe anaemia and provoke a metabolic shift within host cells to anaerobic glucose metabolism and increased lactic acid production. In addition, the flow of blood through the microcirculation may be impeded by adherence of infected erythrocytes to the endothelium of post-capillary venules and/or increased rigidity of uninfected cells (Dondrop et al., 1997). Lactate may not in itself be sufficient to cause acidaemia but the inhibition of oxidative metabolism in the context of an ongoing inflammatory response will cause protons (H+) to accumulate and eventually lead to metabolic acidosis (English et al.,1997). These pathophysiological pathways suggest that the syndrome of lactic acidosis may be associated with the total parasite burden during acute infection.

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