Severe Haemolysis in Patients with Glucose-6-Phosphate Dehydrogenase Deficiency Secondary to Dengue Fever: Analysis of 3 cases from Oman

TL;DR

Three patients in Oman with G6PD deficiency developed severe haemolysis after contracting dengue fever, leading to fatal or severe outcomes.

Contribution

This paper reports the first cases of dengue fever-induced haemolysis in G6PD-deficient patients, highlighting a novel clinical interaction.

Findings

Three G6PD-deficient patients in Oman developed severe haemolysis after dengue fever.

One case was fatal and another required dialysis due to irreversible renal damage.

The combination of dengue fever and G6PD deficiency may increase morbidity and mortality.

Abstract

Dengue fever (DF) is a viral fever transmitted by the Aedes species of mosquitoes. Globalisation has led to worldwide spread of DF including Oman. High incidence of glucose-6-phosphate dehydrogenase (G6PD) deficiency is present in Oman's population but is often undiagnosed. We report 3 G6PD-deficient patients admitted in a tertiary care hospital in Muscat, Oman in 2023 with DF that later triggered haemolysis. It proved fatal in 1 case and caused irreversible renal damage requiring dialysis in the other case. Both DF and G6PD deficiency can cause bleeding. Both need supportive treatment. G6PD deficiency with concomitant viral infections have been reported to increase morbidity and mortality. Haemolysis triggered due to DF in G6PD deficient patients has not been reported in the literature. If the clinical course or haemolytic pattern in DF patients deviates from what is to be expected, an associated haemolytic disorder should be considered especially in regions with high prevalence.

Tables

Table 1.. Laboratory blood results of case 1.

Investigation	Day 0*	Maximum change (days 5–7)	Discharge home (day 10)
Dengue test	+ve
G6PD	171 (i.e., deficient)
Haemoglobin in g/dL	13.8	9.7	9.3
Platelets in ×109/L	237	85	240
WBC in ×109/L	9.2	12	9
Methemoglobin in % (normal range: 0–1.5%)	1.2	5.9	2.6
Serum creatinine in μmols/L (normal range: 62–110 μmols/L)	170	104	71
eGFR in mL/min/1.73 m2 (normal = eGFR > 90; kidney injury = eGFR < 90)	43	77	>90
ALT in IU/L (normal range: 10–40 IU/L)	114	129	59
AST in U/L (normal range: 0–34 U/L)	-	343	99
Bilirubin in μmols/L (normal range: 5–21 μmols/L)	29	81	55
Conjugated bilirubin in μmols/L (normal range: 0–5 μmols/L)	-	55	-
LDH in IU/L (normal range: 126–246 IU/L)	3,189	-	-
Haptoglobin in mg/L (normal range: 400–2,800 mg/L)	-	100	-
Serum sodium in mmol/L (normal range: 135–145 mmol/L)	129	140	141
Serum potassium in mol/L (normal range: 3–5.5 mol/L)	3.8	4	3.4
Serum urea in mmol/L (normal range: 2.6–6.2 mmol/L)	12.9	8.0	6.4

Table 2.. Laboratory blood results and interventions of case 2.

Investigation	Day 0*	Maximum admission values (days 5–15)	At discharge (day 26)	Intervention
Dengue test	+ve
G6PD		150
Haemoglobin in g/dL	14	11	-	Blood transfusion
Platelets in ×109/L	55	113	163
WBC in ×109/L	11	10	5.1
Methemoglobin in % (normal range: 0–1.5%)	1.2	7.3 (day 10)	0.09
Serum urea in mmol/L (normal range: 2.6–6.2 mmol/L)	9.2	19 (day 8)	6.3
Serum creatinine in μmols/L (normal range: 62–110 μmols/L)	33	361(day 8)	431	Dialysis at 3 months
eGFR in mL/min/1.73 m2 (normal = eGFR > 90; kidney injury = eGFR < 90)	56	17	13
ALT in IU/L (normal range: 10–40 IU/L)	47	806 (day 6)	27
AST in U/L (normal range: 0–34 U/L)	-	5,564 (day 6)	-
Bilirubin in μmols/L (normal range: 5–21 μmols/L)	22	512 (day 10)	80
Conjugated bilirubin in μmols/L (normal range: 0–5 μmols/L)	-	426 (day 10)	-
Ammonia in μmols/L (normal range: 11–32 μmols/L)	-	136 (day 6)	-
PT/INR in sec (normal range: 9.8–11.9 sec)	13.6/1.22	13.8	13.4
APTT in sec (normal range: 26.4–38.9 sec)	58	41	40
Fibrinogen in g/L (normal range: 1.6–4 g/L)	2.02	1.24	2.56
Haptoglobin in IU/L (normal range: 400–2,800 IU/L)	-	176	-
LDH in IU/L (normal range: 126–246 IU/L)	-	6,459 (day 10)	358

Table 3.. Laboratory blood results and interventions of case 3.

Investigation	Day 0*	Day 1	Day 3	Intervention
Dengue test	+ve
G6PD	289 (i.e., deficient)
Haemoglobin in g/dL	10	8	7	Blood transfusion
Platelets in ×109/L	79	71	63
WBC in ×109/L	35	27	21
Methemoglobin in % (normal range: 0–1.5%)
Serum creatinine in μmols/L (normal range: 62–110 μmols/L)	332	265	222	On dialysis
Bilirubin in μmols/L (normal range: 5–21 μmols/L)	164	175	243
Conjugated bilirubin in μmols/L (normal range: 0–5 μmols/L)	-	-	-	Haemolyzed
ALT in IU/L (normal range: 10–40 IU/L)	1,651		1,070
GGT (0-38 IU/L)	5,812
AST in IU/L (normal range: 0-34 IU/L)	5,812	Icteric
PT/INR in sec (normal range: 9.8–11.9 sec)	24/2.39	19/1.9	28/2.9	FFP
APTT in sec (normal range: 26.4–38.9 sec	65	40	55
Fibrinogen in g/L (normal range: 1.6–4 g/L)	0.5	<0.5	<0.5	(0-34)Cryoprecipitate
Haptoglobin in IU/L (normal range: 400–2,800 IU/L)	320
LDH in IU/L (normal range: 126–246 IU/L)	>7,500		>7,500
Ammonia in μmols/L (normal range: 11–32 μmols/L)	200

Full text

1. Introduction

Dengue fever (DF) is an arthropod borne viral fever reported worldwide. Though relatively new to Middle East there has been a steady rise in DF cases annually; initially a disease of the immigrant population, DF has been indigenous to Oman since 2013.^1^ DF is usually self-limiting with fever followed by thrombocytopenia, mild haemolysis with haematuria and bleeding.^2^

Severe cases may progress to dengue haemorrhagic fever (DHF) or dengue shock syndrome (DSS) which can be fatal.^34^ Viral infections are known to trigger intravascular haemolysis in glucose-6-phosphate dehydrogenase (G6PD) deficient patients.^5678^ Dual effect of haemolysis contributed by DF and G6PD can prove fatal.

During a DF outbreak in 2023 in Oman, 3 patients were admitted in an intensive care unit (ICU) of a tertiary care hospital in Muscat, Oman. We report the details of each of these 3 cases.

2. Case 1

A 47-year-old diabetic, hypertensive male patient was admitted with 4 days history of fever, myalgia, abdominal pain and reduced urine output. Clinically, the patient had hypotension and required inotropes along with fluid resuscitation. Blood investigations showed thrombocytopaenia, transaminitis and acute kidney injury (AKI). Dengue RNA-PCR was positive. The patient responded to supportive care with hydration, fluid intake-output and haemodynamic monitoring. By the fourth day, platelet count and AKI had improved however, the patient continued to feel unwell and was drowsy. Clinical examination showed evidence of encephalopathy with right hypochondriac and epigastric tenderness. A decrease in haemoglobin with near normal mean cell haemoglobin concentration and mean cell haemoglobin values, elevated serum lactate dehydrogenase (LDH) and normal haptoglobin was suggestive of acute haemolysis. Haemoglobin levels dropped significantly and blood film showed microcytic hypochromia, blister cells, elliptocytes and few tear drop cells suggestive of haemolysis. Ultrasound abdomen showed a fatty liver. History of exposure to medications, alternative herbal therapies, infections and travel was negative. As both clinical and laboratory parameters associated with dengue infection were improving, the acute hepatic derangement was thought to be triggered secondary to DF. Furthermore, the patient was found to be G6PD deficient. Serum glucose, hepatic and renal haemogram along with hydration were closely monitored for 10 days until normalisation [Table 1].

3. Case 2

A 52-year-old diabetic male patient was referred from a healthcare centre with history of fever followed by thrombocytopaenia, AKI, transaminitis and low urine output. Dengue RNA-PCR was positive prior to admission. The patient was noted to have bradycardia, oliguria and haematuria with steady a rise in serum creatinine and reduction in estimated glomerular filtration rate. By day 3 of admission, oliguria and haematuria persisted despite optimisation of haemodynamic parameters. A drop in haemoglobin disproportionate to haematuria was noted requiring blood transfusions (3 g/dL). Platelet count improved but he developed pulmonary oedema requiring non-invasive ventilation. Echocardiography showed calcified aortic valve with moderate aortic stenosis (ejection fraction = 55%) and no regional wall motion abnormality. Cardiac cause of oedema was ruled out.

A blood gas analysis showed rising lactates and methemoglobinemia. The methemoglobin levels rose from normal values at admission to 15% before normalising after 10 days. Raised bilirubin, LDH and low haptoglobin along with peripheral blood film suggested haemolysis. Based on this, G6PD levels was assessed and found to be low [Table 2].

The patient required blood transfusions and oxygen therapy and intermittent haemodialysis. Hospital stay was complicated by healthcare-associated pneumonia that required intubation and mechanical ventilation. Management was primarily supportive with avoiding incriminated medication. As the haemolysis stopped, methemoglobin levels normalised. He was successfully extubated and discharged. However, he had irreversible renal failure and became dialysis dependent.

4. Case 3

A 56-year-old male patient with no known comorbidities, presented with 1 day history of self-limiting fever; 10 days later he visited the regional hospital with generalised fatigability and myalgia. He was afebrile but icteric and was admitted for further evaluation. Initial blood tests showed thrombocytopaenia, elevated liver enzymes, raised ammonia and deranged kidney function. DF was suspected. Within hours of admission, the patient showed features of encephalopathy, suggesting acute liver failure. In view of rapidly worsening liver functions, he was transferred on the next day to the current tertiary care hospital for possible liver transplant. He was intubated prior to transfer for low level of consciousness and needed inotropes. Computed tomography of his head was normal. On arrival to the ICU, he was on vasopressors, ventilator support and needed renal replacement therapy. Dengue RNA-PCR result was positive. A diagnosis of DF related acute liver failure was made and treatment started. Plasma exchange was initiated to support his liver.^1011^ Adequate partial pressure of oxygen in blood gas analysis despite low peripheral saturations (88%) was noted. Elevated methemoglobin levels explained this. Raised LDH, low haptoglobin and blood film with occasional spherocytosis and Howell-Jolly bodies confirmed haemolysis [Table 3]. In addition, the patient was found to be G6PD deficient. Supportive treatment was continued. However, the patient was already in multiorgan failure and expired within 48 hours of admission. G6PD-related haemolysis triggered by DF was suspected to be the cause of death.

5. Discussion

Dengue fever (DF) is an arthropod borne viral disease reported globally. In the majority of cases the presentation is like other viral fevers. Within 1–10 days of infection, fever may be followed with thrombocytopaenia and haemolysis with a self-limiting course. A small percentage progress to DHF and DSS which can be fatal and is characterised by bleeding from various sites, AKI, liver dysfunction, deranged coagulation and third space fluid extravasation.^2346^

Initially considered a disease of tropical and subtropical regions, the disease is now reported globally due to easy movement of population and rapid urbanisation. Though the climatic conditions in the Middle East are not suitable for the spread of DF it has been declared endemic in many countries in the region.^6^ Large immigrant population is another major contributory factor. Since 2008, a steady rise in the number of DF patients is being reported in Oman. Since 2018, DF has been found to be endemic with an incidence of 2.34 per 100,000 population reported in 2022.^15^

Patients with severe illness, documented bleeding, thrombocytopaenia or clinical manifestations of organ dysfunction are admitted to hospital. Severe cases may require intensive care admission and multiorgan support.

The case report presents 3 patients who were G6PD-deficient and contracted DF during an outbreak in 2023 which later triggered haemolysis, despite normalisation of platelets. All 3 patients were unaware of their G6PD-deficient status. As a search for the probable causes of haemolysis proved unsuccessful it was concluded that the oxidative stress produced by DF triggered haemolysis in these cases. All patients showed elevated liver enzymes, raised haemolytic markers, methemoglobinemia and peripheral blood film suggestive of haemolysis. The first patient had elevation of liver enzymes, developed hepatic encephalopathy and responded to supportive therapy. The other 2 patients showed elevated methemoglobin levels. The second patient showed persistent haematuria, developed renal failure and required long term dialysis. The third patient developed acute hepatic failure requiring multiorgan support including plasma exchange. Organ dysfunction, permanent organ damage and death have all been described as complications of G6PD induced haemolysis.^6789^ Delay in diagnosing the G6PD deficient status resulted in deviation of management strategy. Though treatment in both DF and G6PD is supportive, awareness will help to decrease morbidity and mortality.

Raised conjugated bilirubin disproportionate to enzyme elevation, renal failure secondary to haemoglobinuria and massive intravascular haemolysis, associated methemoglobinemia and fatal liver failure are all described as manifestations of G6PD deficient haemolysis.^35789^

The incidence of G6PD is documented in 25% of the Omani male population and 10% in the female population.^1^ Being an X-linked recessive disorder, males manifest the symptoms. Females may show evidence of haemolysis only if homozygous. Not all are aware about their G6PD status.^12^

The enzyme G6PD is involved in the pentose monophosphate shunt. It helps glucose-6-phosphatase to reduce nicotinamide adenine dinucleotide phosphate (NADPH) which in turn helps in scavenging oxidative metabolites in red cells. Its deficiency thus increases the free oxygen radicles which damage cellular structures. Iron in the heme of red blood cells (RBCs) is in the ferrous form (Fe^+2^). This is oxidised to its ferric form (Fe^+3^) which is poor in oxygen uptake leading to hypoxaemia. Methemoglobinemia is often seen in patients with G6PD.^3^ Hypoxaemia occurs when its levels exceed 10%.^5^

There are more than 300 variants of the gene coding for glucose-6-phosphate enzyme and severity of haemolysis depends on the level of enzyme activity.^312^ Based on the level of enzyme deficiency and severity of haemolysis, the World Health Organization has classified G6PD variants in I–V. Those with low enzyme levels produce massive haemolysis with various triggers, while some such as G6PD (A-) produce haemolysis in presence of oxidative stresses only. Certain variants cause haemolysis of old RBCs in the presence of oxidative stress.

Most patients are asymptomatic and may develop acute haemolysis within 24–72 hours after exposure to triggers. The episodes are usually self-limiting for 8–14 days when new RBCs replace the old ones; blood transfusions are rarely required. In some cases, chronic haemolytic anaemia persists.^9^

G6PD is required to maintain the redox potential in the Embden–Meyerhof–Parnas pathway. The well-known stressors are drugs, chemicals, infections and fava bean ingestion. There are case reports where G6PD-deficient patients, when affected by certain viral infections (e.g., influenzas, hepatitis, herpes simplex virus and COVID-19), have been shown to have increased morbidity.^2341112^ In the presence of oxidative stressors, the RBCs, especially the older ones, are unable to generate adequate NADPH which is a percussor for glutathione. Decreased glutathione decreases the ability of RBCs to metabolise oxidant radicles and their breakdown increases.^5^ Increased incidence of diabetes has also been seen in these patients. The oxidative stressors may cause methemoglobinemia which impairs tissue oxygenation and impairs cellular functioning.^6^

6. Conclusion

The combination of DF and G6PD-induced haemolysis may complicate diagnosis and line of therapy as the duration of disease progresses. Treatment of both DF and G6PD is supportive. Awareness of G6PD-deficient status may help to avoid potential triggers and guide supportive treatment, thereby reducing potential morbidity and mortality.

Ethics Statement

Hospital ethics committee clearance (MoH/CSR/CR #2023/36) was obtained after approval of patients for publication.

Authors' Contribution

AG contributed to conception and design, acquisition of data, analysis and interpretation of data and drafting the manusciprt/revising it critically. HAK contributed to conception and design, interpretation of data and revising the manuscript critically. MAA contributed to analysis, interpretation of data and revising the manuscript. All authors approved the final version of the manuscript.

Data Availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.