CLINICAL MATTERS

Rainy season is back, and with it the plethora of infectious diseases that increase in incidence during this time. These include the dreaded leptospirosis, dengue, and typhoid fever, among many others . How do w e protect ourselves and our loved ones? Most Filipinos are already familiar with these diseases but a quick review is always a good idea.

Leptospirosis

Leptospirosis is caused by a spirochete, a kind of corkscrew-shaped bacteria. It is usually found in rat urine but can also be harbored in the urine of other animals including dogs and cats. When infected rat urine is mixed with flood waters and someone wades through without wearing boots or other protection, the Leptospira organisms can enter the body through wounds and in some cases, even intact skin. Swallowing contaminated water or eating contaminated food can also cause leptospirosis.

Most people who get leptospirosis end up with mild disease. Symptoms of leptospirosis infection include fever and muscle pains and most people recover on their own. About 10 percent of patients do proceed to develop severe leptospirosis. This is characterized by kidney and liver damage and can be fatal. Signs and symptoms of severe leptospirosis include jaundice (yellowing of the skin and the whites of the eyes), dark urine, decreased urine output, and bleeding from the gums and other mucous membranes. Patients with severe leptospirosis affecting the kidneys may need emergency dialysis in order to survive. The worst complication of leptospirosis is pulmonary hemorrhage, which manifest as a sudden shortness of breath and end up with the person choking in his or her own blood. I’ve taken care of several leptospirosis patients with pulmonary hemorrhage and none of them survived.

Treatment of leptospirosis is with antibiotics. Mild leptospirosis can be treated with oral antibiotics like doxycyline. More serious forms may require intravenous antibiotics like penicillin or ceftriaxone. Don’t take antibiotics without a prescription from your doctor. Supportive care, including judicious fluid management, emergency dialysis, and hooking the patient to a ventilator can improve survival. Corticosteroids have been used in pulmonary hemorrhage as a lastditch treatment as well.

There is no vaccine for leptospirosis because there are so many strains of the bacteria. Post-exposure prophylaxis with a single 200mg dose of doxycyline may be prescribed by your doctor if there is a recent high-risk exposure to flood waters. This should be taken as soon as possible to maximize its benefit, so talk to your doctor right away if you have been exposed. Keeping your surroundings clean and rat-free also helps control the spread of leptospirosis.

Dengue

Dengue is a viral infection that is hyperendemic in the Philippines. This means that we see transmission all year round. There are spikes , however, in the number of cases during the rainy season. You can get dengue fever up to four times in your lifetime since there are four different serotypes and they are all present in the Philippines. Most dengue fever is mild but a small percentage of patients on their severe dengue which can be fatal, especially on their second dengue infection. The symptoms of dengue include a fever that lasts for a few days, an itchy rash, and body aches. Platelets, the part of your blood that helps with clotting, begin to go down shortly after infection and continue to drop for a few days after the fever breaks. The fever typically lasts three to seven days with four days being the average length. Respiratory symptoms are rare, so if someone gets a fever without cough or colds, it may be a good idea to see your doctor to check for dengue. Severe dengue is characterized by an unsafe drop in blood pressure. If platelets drop to a critical level, there can be extensive bleeding. Without proper care, a patient can die.

Diagnostics for dengue include dengue NS1 antigen, dengue IgM, IgG (antibody tests), and a complete blood count to check platelets and hemoglobin. We also monitor liver and kidney function through blood tests. Your doctor may ask for some or all these tests and carefully monitor the results. As long as a patient is able to hydrate properly, has stable vital signs, is not having significant bleeding or organ dysfunction, and the platelets remain above 100,000, they can be managed at home. If the patient develops any of the enumerated warning signs, he or she will have to be admitted.

Treatment of dengue is mostly supportive. There are no antivirals that have been proven to work. There is no evidence herbal medications improve outcomes either. Aggressive hydration is the most important intervention since the blood pressure can drop when fluid leaks out of the blood vessels into the surrounding tissues.

Children are the most likely to get severe dengue but we do see bad dengue in adults as well. Dengue is transmitted by the Asian tiger mosquito (Aedes aegypti) with its distinctive stripes. Dengue can be prevented by using mosquito repellant, cleaning out standing water sources where mosquitoes breed, and fumigation. There are at least three dengue vaccines that are proven to work, but after the dengvaxia fiasco there still aren’t any available dengue vaccines locally. This is a shame because so many Filipinos get sick and die from dengue each year. Perhaps the newer and safer dengue vaccines, which can be given even to those who have never had dengue, can be rolled out in the future.

Typhoid fever

Typhoid fever is caused by the bacteria Salmonella typhi. It is characterized by high fever, chills, and gastrointestinal disturbances. Typhoid can be contracted from consuming contaminated food and water. Without proper treatment, typhoid fever can lead to sepsis and death. Treatment of typhoid includes the use of antibiotics. Patients who have less severe disease and are able to tolerate food can be given oral antibiotics. Patients who are very sick and dehydrated may need to be admitted to the hospital for IV antibiotics. Typhoid can be diagnosed with blood tests, either with antibody tests (typhoid IgM and IgG) or through blood and stool cultures. Paradoxically, despite typhoid being a bacterial infection, the white blood cell count for a typhoid patient is low or normal. This is because Salmonella typhi lives inside the body’s white blood cells and does not cause the normal increase in white blood counts seen with other bacterial infections. Typhoid infections can take a while to respond to antibiotics. It is important that the full course of antibiotics be taken to prevent a relapse.

Prevention of typhoid includes good sanitation and hygiene. Washing hands and ensuring clean water and hygienic food practices go a long way in preventing typhoid. There is a typhoid fever vaccine but it is not a routine part of childhood vaccination and protection only lasts for a few years. These are just three of the many infectious diseases that the rainy season brings. If you do get sick, talk to your doctor to get prompt care and to ensure the best possible outcome.