warning signs of dengue fever



Dengue Fever : Clinical Presentation, Pathogenesis, Diagnostic Methods, Treatment & Management

Dengue fever is the most common and important arthropod borne viral disease in human that is transmitted by the mosquitoes of genesis. two species of ed's mosquitoes have been identified as vectors of dengue virus beads,egypt and ed's alphabetics. these mosquitoes are widely distributed in tropical and subtropical areas and most recently,in more temperate areas.

dengue is a serious disease,which affects more than one hundred twenty countries in the world in twenty nineteen.it is named as one of the top ten threats to human health by the world health organization. disease spectrum can range from a mild flu like illness,which is usually seen in classic dengue fever to a severe ,life threatening disease called severe dengue, which is previously known as dengue hemorrhagic fever.

And it is characterized by coagulopathy increased vascular fragility,and permeability has not closely monitored and managed hemorrhagic fever is more likely to progress into a state of hypovolemic show. which is known as dengue shock syndrome,or d s s. dengue virus belongs to the group of flavour viruses,which contain a single stranded,non segmented rna molecules,genetic material.there are four zero types of dengue virus have been identified.

And several zero types can be in circulation during an epidemic infection with one zero type gives a lifelong immunity against that particular zero type.however,secondary infection with another zero. can cause severe dengue and dengue shock syndrome within the same person.ultimately an individual could be infected by all four zero types of virus. first,let's see. what are the signs and symptoms of a dengue infection incubation period of the virus is about four to ten days on average,following onset.

Symptoms usually last for about two to seven days,many patients with dengue virus infection are asymptomatic. approximately one in four people with dengue infection become symptomatic. symptomatic infection commonly presents as a mile to moderate,non specific acute february illness,about one in twenty patients with symptomatic disease develop severe dengue.

Most of the time, these patients have a history of a prior dengue infection. there are three phases of the clinical course of a dengue viral infection. february phase. critical phase and convalescent or recovery phase.let's discuss about them in detail in the following sections. first,let's discuss about the february phase.high grade fever is the predominant symptom in this period.in addition,patient may complain of severe headaches, along with retro orbital.

Severe arthritis or joint pains,severe mild geez or muscle pain,bone pain and some people may present with a macula,or macula,popular rash. predominantly seen on flexed services. in addition,patient may present with nausea and vomiting and mild hemorrhagic manifestations like pitti ki purpura,bleeding gums. episodes or bleeding from nose, hematuria or blood and urine. and attorney case test is positive in most patients. let's see what is attorney test in the next slide.

The tourniquet test is performed by inflating a blood pressure cuff around the upper arm to a midway between systolic and diastolic blood pressure for five minutes after removing the cut. the number of petit key per square inch is calculated that it is more than twenty than it is a positive turn. a gay test,in addition to above signs and symptoms, patient may have anorexia.

Or loss of appetite,sore throat,altered taste,sensation and limb,fat and apathy as patient reaches the late days of february,face fever starts to drop. this is known as death,or vessels,and it is due to the cessation of the remedia.however,some patients may show some warning signs of progression into severe dengue around the time of death.

Now let's see,what are those warning signs?as i told before,these signs begin to appear around the time of death or vessels.these include persistent vomiting. severe abdominal pain,fluid accumulation in spaces like plural and paratonia,cavity mucus or bleeding,difficulty in breathing,restlessness mhm. postural hypotension happen immediately,and progressive increase in humanitarian due to him a concentration.the clinicians should always monitor the patience with dengue for these warning signs.

And must provide,with appropriate supportive care to reduce the risk of developing hypothermic shock. now let's come to the critical phase.it begins after depressants and usually lasts for about twenty four to forty eight hours,most patients clinically improved during this period. however,some patients with a considerable plasma leakage can develop severe dengue within a few hours during this phase.and in these patience,fever starts to reappear. this pattern of fever is known as saddleback fever,or by basic fever.this graph shows the reappearance of fever during the critical phase increased vascular permeability is the cause of extensive plasma leakage in these patients.

Due to the plasma leakage,blood volume starts to drop,which ultimately results in hypo olympic shock due to the plasma leakage,patient may have conditions like plural effusion. and s i t s and due to the reduced blood volume,patient may have hypotension,tactical cardia to kidney,reduced level of consciousness.and him,a. in addition,these patients will show severe hemorrhagic manifestations,including hematomas,or vomiting of blood,g eye bleeding.

And hematuria,which also reduced the blood volume and ultimately result in shock,some uncommon manifestations of severe dengue during this phase include hepatitis. mio carditis,pancreatitis.and in satellite's. during the convalescent or recovery phase,blood volume tends to stabilize by reabsorbing extra vacated fluid into the bloodstream.hemodynamics status stabilizes. h.y.m.medical stabilizes or may fall in some patients due to the dialogue of reabsorbed fluid.white blood cell count starts to rise,as well as the platelet count.

Now let's discuss about the pathogenesis of dengue infection.it starts when an infected female leads mosquito bites a person for a blood male. during mosquito feeding,the virus is inoculated into the blood.female leads,mosquito requires blood for their egg maturation.unlike other mosquitoes,they are daytime feature. they usually bite on the back of the neck and ankle area primary reservoir of the virus as human when an infected person is bitten by a non infected ed's mosquito.the virus is transmitted into mosquito.

And it becomes infected when this mosquito bites on another non infected person,the person also becomes infected.this is the main method of viral

transmission.patients who are hospitalized for suspected dengue infection. are advised to stay within bed nets to avoid transmission during an outbreak,because an individual with dengue infection can transmit the disease for about four to five days.a. cell and tissue trophism of the virus plays a major role in pathogenesis of dengue infection.three major organ systems are affected by the virus.the immune system.

Liver and the endothelial lining of blood vessels during a mosquito bite virus enters through the skin and infects him.mature dendritic cells,which are located in the skin.and the. then these infected dendritic cells will reach the lymph nodes at the lymph nodes.monocytes and macrophages recruit to halt the infection.however,these cells also get infected by the virus. when these cells become infected,they secrete large amounts of cytokines into the bloodstream,which mediate the early nonspecific symptoms of the infection.

Not only that,when the monocytes and macrophages get infected,they are unable to hold viral replication.and this will result in increased viral load,while the host monocytes and macrophages undergo death by appetites. increased viral load will result in dissemination of the virus via bloodstream and reach the vital organs,including bone marrow and the liver.direct destructive action of the virus on bone marrow,precursor cells,will cause drump acid opinion.

and look,opinion,and due to the cellular destruction,patient gets a severe bone pain.and because of its severity,this pain is also called break bone pain.hypnotized damage will give rise to elevated transaminases in blood. and due to anti thereal cell damage and thrombus it opinion patient will have minor hemorrhagic manifestations.we discussed. as we discussed before,secondary infection with another serotype will give rise to a more severe clinical presentation than the primary infection.immunology behind this condition is not well understood.in the. currently accepted theory as as follows,almost all the patients with severe dengue have a previous history of dengue infection with one or more zero types during a secondary infection.

T cells produce small amounts of non neutralizing antibodies,which are directed to the surface proteins of dengue virus.when these antibodies bind to the surface proteins,macro phages and monocytes. get attached to the fc portion of the antibodies in order to neutralize the virus and halt the infection.however,as the serotype is different from the previous infection,macrophages and monocytes are unable to hold the infection. instead,they formatted in antibody complexes,and the virus continues to proliferate unchecked.this will result in the production of large amounts of cytokines and complement system activation and which are the main causes of extensive vascular effects in severe dengue?and this whole process is called antibody dependent enhancement.also,the nonstructural protein one.

Or n s one antigen of the virus can directly activate the complement system,which also contributes to the vascular effects. Early detection of dengue infection is extremely important to prevent the patient from developing hypothermic shock,therefore dengue should be suspected in a patient with compatible signs and symptoms.in. who lives or travel to a dengue endemic area,recently,patients with dengue infection typically present with acute onset of fever,headache,body aches a nd sometimes rash.

Nucleic acid amplification tests are the preferred method of diagnosis.real time reverse transcript as polymers.chain reaction is the technique used to detect viral genomic material in this method. it has to be done within the first week of symptom onset because with cessation of berrima,the virus will no longer available in the bloodstream. detection of viral n s one antigen by immunoassays,is another reliable method of diagnosis.and it also has to be done within the first week of illness,even though the n s one antigen presence within blood for about twelve days after symptom.

onset,in addition,serologic tests can detect the antibodies produced against a virus.i g m antibodies against a virus present in the blood from four days after symptom onset. for the patients who present within the first week after symptom onset,both i g m and n s one or nucleic acid amplification test should be done for the patients who present more than after a week of symptom onset.

I g m tests should be done,however serologic tests may give false positive results due to their cross reactivity between other flavour viruses like zika virus and japanese and safaris. Clinicians should be able to rule out those other causes of the same clinical presentation and come to a precise diagnosis testing for igg antibodies is not useful in diagnosing a present infectious. Because they present during life after a dengue infection enzyme linked to muno,sorbent assay,or alisa is the technique used to detect antibodies against dengue virus.

Some common laboratory findings of dengue infection include the following trump acid opinion,lucca pina,and mild to moderate increase in serum transaminases. and severe infection patient may have increased him adequate hypo protonema prolonged p t and a p t t and decreased for british levels. finally,let's come to the treatment of dengue fever.unfortunately,there is no specific anti viral drug available to treat this disease.supportive care is advised to reduce signs and symptoms.

Patients are advised to stay well hydrated to prevent dehydration caused by vomiting and high fever,aspirin and other types of non steroidal anti-inflammatory drugs like ibuprofen. should not be used to reduce fever because they have anticoagulin properties to control fever. a settlement off a named tepid sponging or indicated and patients should be advised to avoid mosquito bites to prevent transmission.

For severe dengue,closed monitoring and observation is required to prevent the patient from developing hypothermic shock for dehydration. iv fluid administration may be required. for patients with coagulopathy,fresh,frozen plasma is given,prophylactic platelet infusion is not beneficial. in these patients,can cause fluid,overloaded. See you again Thank you.