Medical Officers’ Handbook for Clinical Management of Dengue & Malaria Department of Health & Family Welfare Government of West Bengal
Medical Officers’ Handbook for Clinical Management of Dengue & Malaria
Jun 28, 2022
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Management of Dengue & Malaria
iii
FOREWORD
Over the last decade, dengue has emerged globally as a critical threat to health of people. The World Health Organization (WHO) estimates that 50-100 million dengue infections occur each year and almost half the world’s population lives in countries where dengue is endemic. Dengue also ranks as one of the most challenging mosquito-borne viral diseases in the world including malaria. While dengue is a global concern, West Bengal is not untouched.
To work upon these concerns, the training of Medical Officers at health facility levels will be undertaken with the aim to reduce Dengue mortality & Malaria Mortality by improved clinical management of patients. We already have worked on Vector Borne Diseases Surveillance Joint Action Plan to tackle and take measures on outbreak prediction, epidemiological and entomological surveillance and develop locally-adapted vector control programme.
The Guidelines – “Medical Officers Handbook for Clinical Management of Dengue & Malaria” will provide critical inputs to Medical Officers to enhance the quality of patient management at the point of health care delivery. Such management practices with timely intervention will also ensure early recovery and restrict unnecessary referral.
I express my gratitude to the experts, WHO-NTD Division and compliment the Public Health Division of the Directorate of Health Services, WB on this initiative. I wish all success to the programme.
(Anil Verma)
Government of West Bengal Health & Family Welfare Department Swasthya Bhavan, 3rd Floor, Wing ‘B’
GN-29, Sector-V, Salt Lake, Kolkata-700091
Ph. : (033) 2357-5899, Fax : (033) 2357-7907
No. HS-352/2018 Dated : 23/05/2018
v
Dr. Ajoy Kumar Chakraborty Government of West Bengal Director of Health Service Department of Health and Family Welfare
Swasthya Bhawan, Wing- “A” 4th Floor, GN-29 Sector-V, Salt Lake City, Kolkata-700091
PREFACE
Dengue & Malaria both are major public health challenges among vector borne diseases in West Bengal. There has been a recent upsurge of fever cases. Dengue cases are reported but the proportionate mortality is less in our State. This can be further reduced with timely case management specially maintaining the critical fluid balance even in the primary tier set up. More alarming is Malaria situation where at National level we have less Falciparum cases but higher case fatality in the country and also single largest contributor of malaria deaths in the country. This needs further focus since prompt diagnosis and intervention can prevent many of such deaths.
An urgent need was felt to sensitize the Medical Officers on Dengue and Malaria so that all of them are sensitized on recent updates of treatment guideline, have a clear clarification on approaches to be adopted and provide timely best possible treatment available at that facility, even in a primary setting.
“Medical Officers Handbook for Clinical Management of Dengue & Malaria” developed by Health & Family Welfare Department, Govt of West Bengal is not intended to replace national treatment training materials and guidelines but is developed based upon that to give practical contextual information and helpful to build up confidence of Medical Officers in our State.
This handbook has been produced and made widely available to health-care practitioners at all levels. This deals with different aspects of management even severe cases of dengue & malaria at different levels of health care. The focus is to build up the confidence of Medical Officers and bring uniformity in case management of dengue & malaria in West Bengal. I hope, with help of this training there will be a great improvement of quality of management of both the cases and many lives will be saved in future.
We are most grateful to all the contributors without whose active support it was not possible to prepare this module in such a short time.
DATE : 23.05.2018 (Dr. A.K. Chakraborty)
vii
CONTENTS
Critical phase 5
Recovery phase 6
Worsening hypovolemic shock 6
Prolonged hypotensive shock 6
Medical complications seen in the febrile, critical and recovery phases of dengue. 7
Risk factors associated with severe disease of dengue 7
Clinical evaluation 7
History taking 7
Clinical examination 8
Undifferentiated dengue Fever (UDF) 9
Severe dengue Fever 10
Clinical Criteria for DF/ DHF/ DSS 11
Differential Diagnosis of DF/ DHF 11
Clinical Management 12
Management of DHF Grade I and II 14
Management of Shock (DHF Grade III/IV) 15
Flow diagrams 15
Choice of intravenous fluids for resuscitation 17
Summary of IV fluid therapy in Dengue 19
Management of severe bleeding 21
Management of DF/ DHF with co-morbid illness. 22
viii
Management of dengue in pregnancy 24
Management of dengue in infants 26
Suggested Admission & Discharge criteria 27
Nursing advice in admitted patient 27
Practices to be kept in mind 28
Annexure 28
References 31
Management in specific situation
Treatment of mixed infections (P. vivax + P. falciparum) cases: 37
Antimalarials for severe malaria cases: 37
Treatment of patients co-infected with HIV: 38
Additional consideration for clinical management: 38
Points to Note –
Primaquine therapy: Caution 39
Annexure 41
Introduction
Dengue is a major public health concerns globally, a common cause of illness seen in primary care settings in tropical and subtropical countries. It is endemic in more than 100 countries of Africa, America, Eastern Mediterranean, South-East Asia and Western Pacific. It is the most rapidly spreading mosquito-borne viral disease of mankind, with a 30-fold increase in global incidence over the last five decades. According to World Health Organization (WHO), about 50-100 million new dengue infections are estimated to occur annually in more than 100 endemic countries, with a steady increase in the number of countries reporting the disease.
Every year, during the period July - November, an upsurge in the cases of dengue/DHF has been observed in India. The disease has a seasonal pattern; the cases peak after the monsoons. It is transmitted by Aedes aegypti and Aedes albopictus.
Literature shows that case fatality in Dengue can be minimized by early treatment attention. Medical Officers play a pivotal role in the early recognition and management of dengue fever when patients progress through the different phases of illness.
Dengue virus
The agent of dengue,i.e. dengue viruses, are categorized under the genus Flaviviridae. They are single stranded RNA virus. The dengue virus genome is composed of three structural protein genes encoding the nucleocapsid of core protein(C), a membrane associated protein (M), an envelope protein (E) and seven non-structural (NS) proteins — NS1, NS2A, NS2B, NS3, NS4A, NS4B and NS5. The functions for all the individual NS-proteins are not well characterized. However,NS1 protein has been shown to interact with the host immune system, and known to evoke T cell responses. In dengue virus infection, patients have measurable levels of NS1 protein in the blood, which are utilized as a diagnostic marker of the infection.There are four dengue virus serotypes which are designated as DENV-1, DENV-2, DENV-3 and DENV- 4. These serotypes can co-exist in the endemic areas because the immunity to one serotype does not afford protection from the infection by a heterotopous serotype. Although all four serotypes are antigenically similar, they are different enough to elicit cross- protection only for a few months after infection by any one of them. Infection with any one serotype confers lifelong immunity to that virus serotype. The ability of all DENV serotypes to utilize pre-existing heterotypic flavivirus antibody to enhance antigen antibody reaction, a unique feature of DENV, distinguishes it from all other flaviviruses and is considered to be the primary basis of DENV pathogenesis.Individual variations occur in antibody responses to the dengue virus. Secondary infections are associated with elevated risks of severe disease outcomes. Primary and secondary infections are distinguishable based on their antibody responses.
Understanding dengue fever
Dengue viruses cause symptomatic infections or asymptomatic seroconversion. Patients with asymptomatic infection are viraemic and thus may be a source of infection. Symptomatic dengue infection is a systemic and dynamic disease. The incubation period lasts for 5 to 7 days and the onset of the illness is abrupt. It has a wide clinical spectrum, which includes both severe and non-severe clinical manifestations.
Common presenting symptoms include high-grade fever, headache, retro-orbital pain, myalgia, arthralgia, nausea, vomiting and rash. The symptoms usually last for 2-7 days. As the symptoms are relatively nonspecific in early stages, other differential diagnoses need to be considered in the first 72 hours. In patients with moderate-to-severe disease, the course of the illness follows three phases: febrile, critical and recovery.
4
The severity of the disease usually becomes apparent during defervescence, that is, during transition from the febrile to the afebrile phase. This often coincides with the onset of the critical phase, usually occurs on days 3 to 8 of illness. The critical phase is distinguished by the pathophysiological phenomenon of increased capillary permeability, which lasts approximately for 24 to 48 hours and is more common in secondary dengue infections. This phase is followed by the recovery phase. The key to achieve a good clinical outcome is to have an understanding of the different phases of the disease and be alert to the clinical problems that could arise during these phases.
Figure 1: Course of Dengue illness
Febrile phase of dengue
After the incubation period, the illness starts abruptly with high fever accompanied by non-specific symptoms such as facial flushing, skin erythema, generalised body aches and headache. This febrile or viraemia phase usually lasts for 2 to 7 days. It can be clinically difficult to distinguish dengue from other viral febrile illnesses in the early febrile phase.
In addition to a recent history of dengue within the family or neighborhood, the three early clinical predictors of dengue at 72 hours of fever were nausea and/or vomiting, postural dizziness and lower total white cell count compared to patients with other febrile illnesses (OFI). Symptoms such as headache, myalgia, arthralgia and retro-orbital pain that were frequently reported by patients with dengue fever were also observed in patients with OFI with no significant differences. Similarly, children with dengue were more likely to report anorexia, nausea and vomiting. They had a positive tourniquet test, lower total white cell counts, absolute neutrophil and monocyte counts and higher plasma ALT and AST than the children with OFI. Symptoms of upper respiratory tract infections such as injected pharynx and enlarged tonsils did not exclude dengue.
After 2 to 3 days of high fever, anorexia and nausea, most patients may have varying degrees of dehydration and lethargy. The quality of life decreases to approximately 40% to 50% at the onset of fever with experiences of somatic pain and discomfort and difficulties in cognition, sleep, mobility, self-care and anxiety or depression. Mild haemorrhagic manifestations such as petechiae and mucosal membrane bleeding (e.g., nose and gums) may be seen. Easy bruising and bleeding at venipuncture sites are present in some cases. Massive vaginal bleeding (in women of childbearing age) and gastrointestinal bleeding may occur during this phase, although this is not common. The liver may be enlarged and tender after a few days of fever. The earliest change in the full blood count is a progressive decrease in white blood cell count, which should alert the physician to a high probability of dengue. This leucopenia is most likely due to a virus-induced down-regulation of haematopoiesis.
5
Critical phase
During the transition from febrile to afebrile phase, usually after day 3 or as late as day 7 of fever, patients without an increase in capillary permeability improve without going through the critical phase. Their appetites improve and they feel better. Patients with increased capillary permeability, however, experience worsening of symptoms with the subsidence of high fever. Defervescence usually occurs on days 3 to 8 of illness when temperature drops to 38°C or less and remains below this level. Patients may have warning signs, mostly as a result of plasma leakage. Warning signs usually precede the manifestations of shock and appear towards the end of the febrile phase, usually between days 3 and 7 of illness.
Warning and danger signs and symptoms of dengue fever
Bleeding: epistaxis, scanty haemoptysis, haematemesis, gum bleeding, black coloured stools, excessive menstrual bleeding, dark-coloured urine or haematuria.
Lethargy and/or restlessness, sudden behavioural changes.
Convulsions.
Persistent vomiting >3 times a day.
Severe abdominal pain
Pale, cold clammy hands and feet.
Not able to drink and no urine output for 4-6 h/ urine output less than 0.5 ml/kg/h.
Rising HCT (>45%)together with rapid fall in platelet count.
Metabolic acidosis.
Pleural effusion/ ascites/ gall bladder oedema on imaging.
It is important to note that the warning signs should not be randomly applied without making a clinical diagnosis of dengue.
In the full blood count picture, progressive leucopenia followed by a rapid decrease in platelet count usually precedes plasma leakage. An increasing haematocrit (HCT) above the baseline is another early sign. The period of clinically significant plasma leakage usually lasts 24-48 h. The degree of plasma leakage varies. A rising haematocrit precedes changes in blood pressure (BP) and pulse volume. The degree of haemoconcentration above the baseline haematocrit reflects the severity of plasma leakage; however, this can be masked by early intravenous fluid therapy. Usually pleural effusion and ascites are clinically detectable only after an intravenous fluid therapy unless the plasma leakage is significant, which is a case of patient in a state of shock. A right lateral decubitus chest radiograph, ultrasound detection of free fluid in the chest or abdomen or gall bladder wall oedema may precede clinical detection. In addition to the plasma leakage, haemorrhagic manifestations such as easy bruising and bleeding at venepuncture sites occur frequently. Shock occurs when a critical volume of plasma is lost through leakage; it is often preceded by warning signs. Some patients progress to the critical phase of plasma leakage and shock before defervescence. In these patients, a rising haematocrit and rapid onset of thrombocytopenia or the warning signs indicate the onset of plasma leakage. Most patients with dengue having warning signs recover from intravenous rehydration, although some will deteriorate to severe dengue.
6
Recovery phase
As the patient survives the 24- to 48-hour critical phase, a gradual reabsorption of extravascular compartment fluid takes place in the following 48 to 72 hours. During this time, patient’s general well-being improves, appetite returns, gastrointestinal symptoms abate, haemodynamic status stabilizes and diuresis ensues. Some patients may exhibit a confluent erythematous or petechial rash in small areas of normal skin described as “isles of white in the sea of red”. Some may experience generalised pruritus. Bradycardia and electrocardiographic changes are common during this stage. The hematocrit stabilizes or may become lower due to the dilutional effect of reabsorbed fluid. The white blood cell count usually starts to rise soon after defervescence but the recovery of the platelet count is typically later than that of the white blood cell count. Respiratory distress from massive pleural effusion and ascites, pulmonary oedema or congestive heart failure may occur during the critical and/or recovery phases if excessive intravenous fluids have been administered.
Worsening hypovolemic shock
Worsening hypovolemic shock manifests as increasing tachycardia and peripheral vasoconstriction. Not only are the extremities cold and cyanosed but the limbs become mottled, cold and clammy. By this stage the breathing becomes more rapid and increases in depth, a compensation for the metabolic acidosis (Kussmaul’s breathing). Finally, there is decompensation, both systolic and diastolic BPs decrease suddenly and dramatically, and the patient is said to have hypotensive or decompensated shock.
At this time the peripheral pulses disappear while the central pulse (femoral) will be weak. Hypotension develops when physiologic attempts to maintain systolic BP and perfusion are no longer effective.
One key clinical sign of this deterioration is a change in mental state as brain perfusion declines. The patient becomes restless, confused and extremely lethargic. Seizures may occur and agitation may alternate with lethargy. On the other hand, children and young adults have been known to have a clear mental status even in profound shock. Adults have been known to be able to work until the stage of profound shock is reached.
The failure of infants and children to recognize, focus or make eye contact with parents may be an early ominous sign of cortical hypo perfusion, as is the failure to respond to painful stimuli such as venepuncture. Parents may be the first to recognize these signs, but they may be unable to describe them, other than to say something is wrong. Listen to parents! Hypotension is a late finding and signals an imminent total cardiorespiratory collapse.
Prolonged hypotensive shock
Prolonged hypotensive shock and hypoxia lead to severe metabolic acidosis, multiple organ failure and an extremely difficult clinical situation. It may take a few hours for patients to progress from warning signs to compensated shock and another few hours for compensated shock to progress to hypotensive shock, but only minutes for hypotensive shock to progress to cardiorespiratory collapse and cardiac arrest.
Hypotension is associated with prolonged shock which is often complicated by major bleeding. Patients with severe dengue have varying degrees of coagulation abnormalities, but these are usually not sufficient to cause major bleeding. When major bleeding does occur, it is almost always associated with profound shock since this, in combination with thrombocytopenia, hypoxia and acidosis, can lead to multiple organ failure and advanced disseminated intravascular coagulation.
Massive bleeding may occur without prolonged shock in instances when acetylsalicylic acid(aspirin), ibuprofen, or corticosteroids have been taken. Bleeding may occur in patients with previous peptic or duodenal ulcers. Acute liver and renal failure and encephalopathy may be present in severe shock; these have been described even in the absence of severe plasma leakage or shock. Cardiomyopathy and encephalitis
7
have also been reported in a few dengue case series. However, most deaths from dengue occur in patients with profound and prolonged shock resulting from plasma leakage and complicated by bleeding and/or fluid overload.
Table 1
Medical complications seen in the febrile, critical and recovery phases of dengue.
Phase Complication
Febrile phase Dehydration: High fever may cause neurological disturbances and febrile seizures in young children
Critical phase Shock from plasma leakage: Severe haemorrhage and organ impairment
Recovery phase Hypervolemia (only if intravenous fluid therapy has been excessive and/ or has extended into this period) and acute pulmonary oedema
The various risk factors associated with severe disease of dengue are listed as below :
Infants.
1. History taking,
2. Clinical examination,
3. Investigations and
Step 1 : A patient’s history should include-Ask
Date of onset of fever (date is preferable to the number of days of fever)
Other symptoms and severity
Oral fluid intake-quantity and types of fluids
Urine output-quantify in terms of frequency and estimated volume and time of most recent voiding
Types of activities performed during this illness (e.g., can the patient go to school, work, market, etc?)
8
These questions, though not specific to dengue, give a good indication of patient’s hydration status and how well the patient copes with his illness.
Other fluid losses-such as vomiting or diarrhoea
Presence of warning signs, particularly after the first 72 hr of fever
Family or neighbor having dengue or travel to dengue-endemic areas
Medications (including non-prescription or traditional medicine) in use
List of medications and the time they were last taken
Risk factors
Mental state
Hydration status
Peripheral perfusion done by holding the patient’s hand, assessing the colour, capillary refill time, temperature of the extremities, pulse volume and pulse rate (CCTVR)
Haemodynamic status
Rash and bleeding manifestations
Tourniquet test (repeat if previously negative or if there is no bleeding manifestation)
Step 3 : Investigation
For confirmation of dengue infection, Government of India (Gol) recommends use of ELISA—based antigen detection test (NS1) for diagnosing the cases from the first day of fever onwards and antibody detection test lgM capture ELISA (MAC-ELISA) for diagnosing the cases after the fifth day of onset of disease.
(NS1 for samples collected from day-1…
iii
FOREWORD
Over the last decade, dengue has emerged globally as a critical threat to health of people. The World Health Organization (WHO) estimates that 50-100 million dengue infections occur each year and almost half the world’s population lives in countries where dengue is endemic. Dengue also ranks as one of the most challenging mosquito-borne viral diseases in the world including malaria. While dengue is a global concern, West Bengal is not untouched.
To work upon these concerns, the training of Medical Officers at health facility levels will be undertaken with the aim to reduce Dengue mortality & Malaria Mortality by improved clinical management of patients. We already have worked on Vector Borne Diseases Surveillance Joint Action Plan to tackle and take measures on outbreak prediction, epidemiological and entomological surveillance and develop locally-adapted vector control programme.
The Guidelines – “Medical Officers Handbook for Clinical Management of Dengue & Malaria” will provide critical inputs to Medical Officers to enhance the quality of patient management at the point of health care delivery. Such management practices with timely intervention will also ensure early recovery and restrict unnecessary referral.
I express my gratitude to the experts, WHO-NTD Division and compliment the Public Health Division of the Directorate of Health Services, WB on this initiative. I wish all success to the programme.
(Anil Verma)
Government of West Bengal Health & Family Welfare Department Swasthya Bhavan, 3rd Floor, Wing ‘B’
GN-29, Sector-V, Salt Lake, Kolkata-700091
Ph. : (033) 2357-5899, Fax : (033) 2357-7907
No. HS-352/2018 Dated : 23/05/2018
v
Dr. Ajoy Kumar Chakraborty Government of West Bengal Director of Health Service Department of Health and Family Welfare
Swasthya Bhawan, Wing- “A” 4th Floor, GN-29 Sector-V, Salt Lake City, Kolkata-700091
PREFACE
Dengue & Malaria both are major public health challenges among vector borne diseases in West Bengal. There has been a recent upsurge of fever cases. Dengue cases are reported but the proportionate mortality is less in our State. This can be further reduced with timely case management specially maintaining the critical fluid balance even in the primary tier set up. More alarming is Malaria situation where at National level we have less Falciparum cases but higher case fatality in the country and also single largest contributor of malaria deaths in the country. This needs further focus since prompt diagnosis and intervention can prevent many of such deaths.
An urgent need was felt to sensitize the Medical Officers on Dengue and Malaria so that all of them are sensitized on recent updates of treatment guideline, have a clear clarification on approaches to be adopted and provide timely best possible treatment available at that facility, even in a primary setting.
“Medical Officers Handbook for Clinical Management of Dengue & Malaria” developed by Health & Family Welfare Department, Govt of West Bengal is not intended to replace national treatment training materials and guidelines but is developed based upon that to give practical contextual information and helpful to build up confidence of Medical Officers in our State.
This handbook has been produced and made widely available to health-care practitioners at all levels. This deals with different aspects of management even severe cases of dengue & malaria at different levels of health care. The focus is to build up the confidence of Medical Officers and bring uniformity in case management of dengue & malaria in West Bengal. I hope, with help of this training there will be a great improvement of quality of management of both the cases and many lives will be saved in future.
We are most grateful to all the contributors without whose active support it was not possible to prepare this module in such a short time.
DATE : 23.05.2018 (Dr. A.K. Chakraborty)
vii
CONTENTS
Critical phase 5
Recovery phase 6
Worsening hypovolemic shock 6
Prolonged hypotensive shock 6
Medical complications seen in the febrile, critical and recovery phases of dengue. 7
Risk factors associated with severe disease of dengue 7
Clinical evaluation 7
History taking 7
Clinical examination 8
Undifferentiated dengue Fever (UDF) 9
Severe dengue Fever 10
Clinical Criteria for DF/ DHF/ DSS 11
Differential Diagnosis of DF/ DHF 11
Clinical Management 12
Management of DHF Grade I and II 14
Management of Shock (DHF Grade III/IV) 15
Flow diagrams 15
Choice of intravenous fluids for resuscitation 17
Summary of IV fluid therapy in Dengue 19
Management of severe bleeding 21
Management of DF/ DHF with co-morbid illness. 22
viii
Management of dengue in pregnancy 24
Management of dengue in infants 26
Suggested Admission & Discharge criteria 27
Nursing advice in admitted patient 27
Practices to be kept in mind 28
Annexure 28
References 31
Management in specific situation
Treatment of mixed infections (P. vivax + P. falciparum) cases: 37
Antimalarials for severe malaria cases: 37
Treatment of patients co-infected with HIV: 38
Additional consideration for clinical management: 38
Points to Note –
Primaquine therapy: Caution 39
Annexure 41
Introduction
Dengue is a major public health concerns globally, a common cause of illness seen in primary care settings in tropical and subtropical countries. It is endemic in more than 100 countries of Africa, America, Eastern Mediterranean, South-East Asia and Western Pacific. It is the most rapidly spreading mosquito-borne viral disease of mankind, with a 30-fold increase in global incidence over the last five decades. According to World Health Organization (WHO), about 50-100 million new dengue infections are estimated to occur annually in more than 100 endemic countries, with a steady increase in the number of countries reporting the disease.
Every year, during the period July - November, an upsurge in the cases of dengue/DHF has been observed in India. The disease has a seasonal pattern; the cases peak after the monsoons. It is transmitted by Aedes aegypti and Aedes albopictus.
Literature shows that case fatality in Dengue can be minimized by early treatment attention. Medical Officers play a pivotal role in the early recognition and management of dengue fever when patients progress through the different phases of illness.
Dengue virus
The agent of dengue,i.e. dengue viruses, are categorized under the genus Flaviviridae. They are single stranded RNA virus. The dengue virus genome is composed of three structural protein genes encoding the nucleocapsid of core protein(C), a membrane associated protein (M), an envelope protein (E) and seven non-structural (NS) proteins — NS1, NS2A, NS2B, NS3, NS4A, NS4B and NS5. The functions for all the individual NS-proteins are not well characterized. However,NS1 protein has been shown to interact with the host immune system, and known to evoke T cell responses. In dengue virus infection, patients have measurable levels of NS1 protein in the blood, which are utilized as a diagnostic marker of the infection.There are four dengue virus serotypes which are designated as DENV-1, DENV-2, DENV-3 and DENV- 4. These serotypes can co-exist in the endemic areas because the immunity to one serotype does not afford protection from the infection by a heterotopous serotype. Although all four serotypes are antigenically similar, they are different enough to elicit cross- protection only for a few months after infection by any one of them. Infection with any one serotype confers lifelong immunity to that virus serotype. The ability of all DENV serotypes to utilize pre-existing heterotypic flavivirus antibody to enhance antigen antibody reaction, a unique feature of DENV, distinguishes it from all other flaviviruses and is considered to be the primary basis of DENV pathogenesis.Individual variations occur in antibody responses to the dengue virus. Secondary infections are associated with elevated risks of severe disease outcomes. Primary and secondary infections are distinguishable based on their antibody responses.
Understanding dengue fever
Dengue viruses cause symptomatic infections or asymptomatic seroconversion. Patients with asymptomatic infection are viraemic and thus may be a source of infection. Symptomatic dengue infection is a systemic and dynamic disease. The incubation period lasts for 5 to 7 days and the onset of the illness is abrupt. It has a wide clinical spectrum, which includes both severe and non-severe clinical manifestations.
Common presenting symptoms include high-grade fever, headache, retro-orbital pain, myalgia, arthralgia, nausea, vomiting and rash. The symptoms usually last for 2-7 days. As the symptoms are relatively nonspecific in early stages, other differential diagnoses need to be considered in the first 72 hours. In patients with moderate-to-severe disease, the course of the illness follows three phases: febrile, critical and recovery.
4
The severity of the disease usually becomes apparent during defervescence, that is, during transition from the febrile to the afebrile phase. This often coincides with the onset of the critical phase, usually occurs on days 3 to 8 of illness. The critical phase is distinguished by the pathophysiological phenomenon of increased capillary permeability, which lasts approximately for 24 to 48 hours and is more common in secondary dengue infections. This phase is followed by the recovery phase. The key to achieve a good clinical outcome is to have an understanding of the different phases of the disease and be alert to the clinical problems that could arise during these phases.
Figure 1: Course of Dengue illness
Febrile phase of dengue
After the incubation period, the illness starts abruptly with high fever accompanied by non-specific symptoms such as facial flushing, skin erythema, generalised body aches and headache. This febrile or viraemia phase usually lasts for 2 to 7 days. It can be clinically difficult to distinguish dengue from other viral febrile illnesses in the early febrile phase.
In addition to a recent history of dengue within the family or neighborhood, the three early clinical predictors of dengue at 72 hours of fever were nausea and/or vomiting, postural dizziness and lower total white cell count compared to patients with other febrile illnesses (OFI). Symptoms such as headache, myalgia, arthralgia and retro-orbital pain that were frequently reported by patients with dengue fever were also observed in patients with OFI with no significant differences. Similarly, children with dengue were more likely to report anorexia, nausea and vomiting. They had a positive tourniquet test, lower total white cell counts, absolute neutrophil and monocyte counts and higher plasma ALT and AST than the children with OFI. Symptoms of upper respiratory tract infections such as injected pharynx and enlarged tonsils did not exclude dengue.
After 2 to 3 days of high fever, anorexia and nausea, most patients may have varying degrees of dehydration and lethargy. The quality of life decreases to approximately 40% to 50% at the onset of fever with experiences of somatic pain and discomfort and difficulties in cognition, sleep, mobility, self-care and anxiety or depression. Mild haemorrhagic manifestations such as petechiae and mucosal membrane bleeding (e.g., nose and gums) may be seen. Easy bruising and bleeding at venipuncture sites are present in some cases. Massive vaginal bleeding (in women of childbearing age) and gastrointestinal bleeding may occur during this phase, although this is not common. The liver may be enlarged and tender after a few days of fever. The earliest change in the full blood count is a progressive decrease in white blood cell count, which should alert the physician to a high probability of dengue. This leucopenia is most likely due to a virus-induced down-regulation of haematopoiesis.
5
Critical phase
During the transition from febrile to afebrile phase, usually after day 3 or as late as day 7 of fever, patients without an increase in capillary permeability improve without going through the critical phase. Their appetites improve and they feel better. Patients with increased capillary permeability, however, experience worsening of symptoms with the subsidence of high fever. Defervescence usually occurs on days 3 to 8 of illness when temperature drops to 38°C or less and remains below this level. Patients may have warning signs, mostly as a result of plasma leakage. Warning signs usually precede the manifestations of shock and appear towards the end of the febrile phase, usually between days 3 and 7 of illness.
Warning and danger signs and symptoms of dengue fever
Bleeding: epistaxis, scanty haemoptysis, haematemesis, gum bleeding, black coloured stools, excessive menstrual bleeding, dark-coloured urine or haematuria.
Lethargy and/or restlessness, sudden behavioural changes.
Convulsions.
Persistent vomiting >3 times a day.
Severe abdominal pain
Pale, cold clammy hands and feet.
Not able to drink and no urine output for 4-6 h/ urine output less than 0.5 ml/kg/h.
Rising HCT (>45%)together with rapid fall in platelet count.
Metabolic acidosis.
Pleural effusion/ ascites/ gall bladder oedema on imaging.
It is important to note that the warning signs should not be randomly applied without making a clinical diagnosis of dengue.
In the full blood count picture, progressive leucopenia followed by a rapid decrease in platelet count usually precedes plasma leakage. An increasing haematocrit (HCT) above the baseline is another early sign. The period of clinically significant plasma leakage usually lasts 24-48 h. The degree of plasma leakage varies. A rising haematocrit precedes changes in blood pressure (BP) and pulse volume. The degree of haemoconcentration above the baseline haematocrit reflects the severity of plasma leakage; however, this can be masked by early intravenous fluid therapy. Usually pleural effusion and ascites are clinically detectable only after an intravenous fluid therapy unless the plasma leakage is significant, which is a case of patient in a state of shock. A right lateral decubitus chest radiograph, ultrasound detection of free fluid in the chest or abdomen or gall bladder wall oedema may precede clinical detection. In addition to the plasma leakage, haemorrhagic manifestations such as easy bruising and bleeding at venepuncture sites occur frequently. Shock occurs when a critical volume of plasma is lost through leakage; it is often preceded by warning signs. Some patients progress to the critical phase of plasma leakage and shock before defervescence. In these patients, a rising haematocrit and rapid onset of thrombocytopenia or the warning signs indicate the onset of plasma leakage. Most patients with dengue having warning signs recover from intravenous rehydration, although some will deteriorate to severe dengue.
6
Recovery phase
As the patient survives the 24- to 48-hour critical phase, a gradual reabsorption of extravascular compartment fluid takes place in the following 48 to 72 hours. During this time, patient’s general well-being improves, appetite returns, gastrointestinal symptoms abate, haemodynamic status stabilizes and diuresis ensues. Some patients may exhibit a confluent erythematous or petechial rash in small areas of normal skin described as “isles of white in the sea of red”. Some may experience generalised pruritus. Bradycardia and electrocardiographic changes are common during this stage. The hematocrit stabilizes or may become lower due to the dilutional effect of reabsorbed fluid. The white blood cell count usually starts to rise soon after defervescence but the recovery of the platelet count is typically later than that of the white blood cell count. Respiratory distress from massive pleural effusion and ascites, pulmonary oedema or congestive heart failure may occur during the critical and/or recovery phases if excessive intravenous fluids have been administered.
Worsening hypovolemic shock
Worsening hypovolemic shock manifests as increasing tachycardia and peripheral vasoconstriction. Not only are the extremities cold and cyanosed but the limbs become mottled, cold and clammy. By this stage the breathing becomes more rapid and increases in depth, a compensation for the metabolic acidosis (Kussmaul’s breathing). Finally, there is decompensation, both systolic and diastolic BPs decrease suddenly and dramatically, and the patient is said to have hypotensive or decompensated shock.
At this time the peripheral pulses disappear while the central pulse (femoral) will be weak. Hypotension develops when physiologic attempts to maintain systolic BP and perfusion are no longer effective.
One key clinical sign of this deterioration is a change in mental state as brain perfusion declines. The patient becomes restless, confused and extremely lethargic. Seizures may occur and agitation may alternate with lethargy. On the other hand, children and young adults have been known to have a clear mental status even in profound shock. Adults have been known to be able to work until the stage of profound shock is reached.
The failure of infants and children to recognize, focus or make eye contact with parents may be an early ominous sign of cortical hypo perfusion, as is the failure to respond to painful stimuli such as venepuncture. Parents may be the first to recognize these signs, but they may be unable to describe them, other than to say something is wrong. Listen to parents! Hypotension is a late finding and signals an imminent total cardiorespiratory collapse.
Prolonged hypotensive shock
Prolonged hypotensive shock and hypoxia lead to severe metabolic acidosis, multiple organ failure and an extremely difficult clinical situation. It may take a few hours for patients to progress from warning signs to compensated shock and another few hours for compensated shock to progress to hypotensive shock, but only minutes for hypotensive shock to progress to cardiorespiratory collapse and cardiac arrest.
Hypotension is associated with prolonged shock which is often complicated by major bleeding. Patients with severe dengue have varying degrees of coagulation abnormalities, but these are usually not sufficient to cause major bleeding. When major bleeding does occur, it is almost always associated with profound shock since this, in combination with thrombocytopenia, hypoxia and acidosis, can lead to multiple organ failure and advanced disseminated intravascular coagulation.
Massive bleeding may occur without prolonged shock in instances when acetylsalicylic acid(aspirin), ibuprofen, or corticosteroids have been taken. Bleeding may occur in patients with previous peptic or duodenal ulcers. Acute liver and renal failure and encephalopathy may be present in severe shock; these have been described even in the absence of severe plasma leakage or shock. Cardiomyopathy and encephalitis
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have also been reported in a few dengue case series. However, most deaths from dengue occur in patients with profound and prolonged shock resulting from plasma leakage and complicated by bleeding and/or fluid overload.
Table 1
Medical complications seen in the febrile, critical and recovery phases of dengue.
Phase Complication
Febrile phase Dehydration: High fever may cause neurological disturbances and febrile seizures in young children
Critical phase Shock from plasma leakage: Severe haemorrhage and organ impairment
Recovery phase Hypervolemia (only if intravenous fluid therapy has been excessive and/ or has extended into this period) and acute pulmonary oedema
The various risk factors associated with severe disease of dengue are listed as below :
Infants.
1. History taking,
2. Clinical examination,
3. Investigations and
Step 1 : A patient’s history should include-Ask
Date of onset of fever (date is preferable to the number of days of fever)
Other symptoms and severity
Oral fluid intake-quantity and types of fluids
Urine output-quantify in terms of frequency and estimated volume and time of most recent voiding
Types of activities performed during this illness (e.g., can the patient go to school, work, market, etc?)
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These questions, though not specific to dengue, give a good indication of patient’s hydration status and how well the patient copes with his illness.
Other fluid losses-such as vomiting or diarrhoea
Presence of warning signs, particularly after the first 72 hr of fever
Family or neighbor having dengue or travel to dengue-endemic areas
Medications (including non-prescription or traditional medicine) in use
List of medications and the time they were last taken
Risk factors
Mental state
Hydration status
Peripheral perfusion done by holding the patient’s hand, assessing the colour, capillary refill time, temperature of the extremities, pulse volume and pulse rate (CCTVR)
Haemodynamic status
Rash and bleeding manifestations
Tourniquet test (repeat if previously negative or if there is no bleeding manifestation)
Step 3 : Investigation
For confirmation of dengue infection, Government of India (Gol) recommends use of ELISA—based antigen detection test (NS1) for diagnosing the cases from the first day of fever onwards and antibody detection test lgM capture ELISA (MAC-ELISA) for diagnosing the cases after the fifth day of onset of disease.
(NS1 for samples collected from day-1…
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