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Sunday April 12, 2009

Managing dengue

The commonplace and inconsistent symptoms of dengue fever have long hampered its early detection, leading to complications in patients and outbreaks in communities nationwide.

EVEN though she lived in a flat where dengue infections are common, the only symptom of dengue fever Vanitha Devi Senagiah knew about before she was admitted to a hospital last October was that “it gives you red spots on your body”.

“It was during the Deepavali period when I started purging and getting diarrhoea. Soon after, I was down with a very high fever.” But the possibility of a dengue infection did not cross her mind, or her doctors’, as the characteristic red spots were not present.

“I went to four different clinics and the doctors there told me that it was probably a normal fever,” she recalls. Finally, after a blood test on her visit to the fifth clinic, the attending doctor suspected a dengue infection due to low platelet levels.

The skin rash described as 'islands of white in a sea of red' is a typical sign of dengue infection, although it may persist in the recovery phase.

“The doctor recommended me to be admitted, but the first hospital I went to also did not find anything. I was eventually discharged,” says the 24-year-old.

By the time she checked in to the second hospital, where she was confirmed to have dengue fever, she was very weak and had difficulty breathing. Her doctors chastised her for coming for treatment late.

“It was only after I was given treatment that the rashes appeared. It took me a month to recover from the infection,” she says.

While Vanitha’s doctor-hopping may have played a part in the delay of her diagnosis, she and her doctors are hardly to be blamed.

The commonplace and inconsistent symptoms of dengue fever have long hampered its early detection, leading to complications in patients and outbreaks in communities nationwide.

Patients down with dengue fever should be advised to rest under a mosquito net or use mosquito repellents to prevent mosquito bites as they can be the source of dengue virus.

With this in mind, the first clinical practise guidelines (CPG) on dengue infection in adults was published by the Ministry of Health and Academy of Medicine Malaysia in 2003.

“The (2003) CPG was a consensus guideline based on expert opinions and literature searches at that time. It provided a general approach to the management of dengue infection,” says senior consultant and infectious disease physician Dr Mahiran Mustafa, the chairperson of the latest dengue CPG development group.

With the results of new studies and clinical trials made available, a new CPG was released in January this year, with more details on the clinical manifestation of the disease and recommendations on how to manage it effectively.

Varying symptoms

In response to the increase in dengue cases earlier this year, health director-general Tan Sri Dr Ismail Merican explained the situation at a press conference: “Now, dengue cases come with different presentations, like epileptic (seizures), jaundice, hepatitis and organ failure, so people don’t realise it is dengue. These atypical presentations are not like the standard cases of fever, bleeding or low-platelet counts.

“Because of this, some of the diagnoses were made very late. That’s why we have informed all our doctors to be aware. If someone has fever and comes from a dengue-infested area, always do extra testing for dengue,” he added.

The infection can be asymptomatic for some, but for others, symptoms can range from mild flu-like illness to severe disease, with or without bleeding, plasma leakage (the loss of fluids from blood vessels into the body) and organ impairment.

“In a specific group of patients with other co-morbid diseases such as diabetes mellitus, heart failure, renal failure, liver failure and blood disorders, the risk of complications due to pulmonary oedema (collection of fluid in the lungs) and bleeding episodes may be more significant,” says Dr Mahiran.

Noteworthy is the fact that symptomatic dengue infection is one that affects the functions of the whole body (systemic and dynamic).

Tight monitoring of a patient is required as the clinical (symptoms), haematological and serological profiles (blood test results) of a patient can change from day to day. These changes can accelerate by the hour, or even minutes, during the critical phase, particularly in those with plasma leakage.

The three-part fever

Typically, the incubation period for dengue infection (the time it takes for symptoms to appear) is about four to seven days. After the incubation period, the illness can begin abruptly and will be followed by three phases: the febrile, critical and recovery phase.

The febrile phase (Day 1 - 7)

In the febrile phase, patients typically develop high fever for about two to seven days. This is often accompanied by facial flushing, redness of the skin (skin erythema), generalised bodyache and headache.

Some patients may also have sore throat, loss of appetite, nausea and vomiting.

It is important for physicians to be able to detect a dengue infection during the febrile phase because this is the phase where the dengue virus is at its highest levels in the blood. Early notification can prevent the disease from spreading further.

While physical symptoms may or may not be present, a progressive decrease in the white blood cell count is a useful indicator of dengue, particularly in a neighbourhood with a history of dengue cases.

“Patients are advised to rest under a mosquito net or use mosquito repellents to prevent mosquito bites as they can be the source of dengue virus during this time,” says Dr Mahiran. Family members should also take precautions to avoid mosquito bites and eliminate mosquito-breeding sites in and around their homes.

While chikungunya, another virus transmitted by mosquitos also causes similar early symptoms, it rarely causes dehydration, shock or other life threatening events, says Dr Mahiran.

The critical phase (Day 3-7)

This phase usually occurs three to seven days after the onset of fever – when the patient’s fever subsides (defervescence) and plasma leakage or bleeding may occur.

By this time, those who have mild disease may experience only transient or minimal circulatory changes. They usually recover spontaneously or after a short period of fluid or electrolyte therapy.

“Patients will generally feel better as the fever subsides, but they should also be careful as their condition could deteriorate in a matter of hours if they have severe disease,” says consultant physician and head of infectious diseases Dr Christopher Lee.

These patients may sweat, become restless, or have cool extremities as a result of plasma leakage. They may also experience abdominal pain, persistent vomiting, liver enlargement and altered levels of consciousness.

An increase in haematocrit (Hct) levels (the concentration of red blood cells) due to fluid loss from blood vessels and a rapid decrease in platelet levels are usually detectable just before the onset of shock.

In this phase, patients should be monitored closely as they can go into profound shock and may die if fluid resuscitation is not given. Patients who experience extensive bleeding may need blood transfusion.

The recovery phase (Day 7-10)

Spontaneously (for mild cases), or with appropriate supportive therapy (for more serious cases), patients enter the recovery phase after the critical phase, which usually lasts for 24 to 48 hours.

It is important to recognise signs of recovery, as supportive therapy such as fluid infusions need to be tapered off as the body regains its normal function.

In recovery, the patient will feel better and experience less gastrointestinal symptoms, although they may have the classical rash of “islets of white in a sea of red” and a generalised pruritus (itchiness).

Their haematocrit levels may stabilise or drop further following the reabsorption of fluids into the blood vessels while their platelet counts will eventually rise, usually after their white cell count (WCC) increases.

Treatment options

According to Dr Mahiran, a majority of patients can be treated at home except those who are:

·Very old, obese, or pregnant

·Not able to take fluids orally

·Showing signs of dehydration (decreased urine output, muscle weakness, headache, lightheadedness)

·Patients with co-morbid diseases (heart, renal and liver failure, bleeding disorders and diabetes mellitus)

·Staying alone and have limited means to sustain a regular follow-up

·Showing signs of severe disease such as those described in the critical phase

If possible, all suspected and confirmed dengue patients should be given the Home Care Advice for Dengue included in the CPG (see sidebars) to guide them towards recovery and remind them to seek immediate treatment if their illnesses worsens.

“They need to be followed up daily at a local clinic with facilities for blood investigation (full blood count) until they have no more fever for 48 hours,” says Dr Mahiran. A dengue follow-up chart provided in the guideline can be printed for patients to keep track of their progress.

As there is currently no cure or vaccine available to treat or prevent dengue, the management of dengue infection is limited to treating the symptoms and offering supportive therapy to avoid complications.

For more information on the latest ‘Clinical Practice Guidelines on the Management of Dengue Infections in Adults’, the full version can be downloaded from the Ministry of Health website www.moh.gov.my.

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