CLINICAL MATTER

“Na-lepto,” is not an uncommon reply when someone dies unexpectedly in a community.

Colloquially known as “lepto,” leptospirosis is a disease that is typically associated with rainy days and floods. While most leptospirosis infections are mild, those who develop severe disease can end up with kidney failure that may require dialysis. Some develop liver failure, which can be fatal. But the most dreaded complication of leptospirosis is bleeding in the lungs (pulmonary hemorrhage), which can have more than a 90 percent mortality rate. As an infectious diseases doctor who has taken care of hundreds of leptospirosis patients, I have a very healthy respect for this disease, which has killed quite a number of Filipinos.

Leptospirosis is caused by the bacteria Leptospira. It is a type of bacteria known as a spirochete because it looks like a spiral when seen under the microscope. Leptospirosis is a zoonosis, meaning that it is usually transmitted from animals to humans. Leptospira can infect almost all mammals, but the most common source of human infections is from rodents, specifically rats and mice. Humans most often get leptospirosis from exposure to contaminated urine. Floodwaters are a common source of leptospirosis because when these mix with infected rat urine, the leptospires swim freely and can penetrate human skin. Leptospirosis can also be contracted by eating food and drink contaminated with urine or feces from infected rats and mice.

Most leptospirosis infections are either asymptomatic or mildly symptomatic. Usual symptoms of leptospirosis are fever, muscle aches and pains (especially in the calf muscles), headache, and malaise. Conjunctival suffusion, which is characterized by redness and swelling of the white part of the eyes, is highly suggestive of leptospirosis but may not always be present. The symptoms start a few days after exposure and most people recover after a few days without any problems. Some patients, however, proceed to the so-called “immune phase,” where the body has an exuberant reaction, almost like an allergy, to the leptospires. The resulting severe inflammation can cause the kidneys and the liver to fail. Signs of severe leptospirosis are decreasing urine output with a dark color and jaundice (yellowing of the eyes and skin). Without proper treatment, many of those who develop the immune phase of leptospirosis will die. An unfortunate few develop pulmonary hemorrhage, which is almost always fatal.

There is currently no effective human vaccine for leptospirosis. The best way to prevent leptospirosis is by avoiding exposure. This includes making sure there are no rodent infestations in your house and in the community, along with proper hygiene and sanitation. During the rainy season, the use of rain boots to avoid skin contact with flood water is very effective. If exposure does occur despite these precautions, there are antibiotics that can be used to prevent infection or progression to severe disease. One such antibiotic is doxycycline, a prescription drug that needs to be given by a licensed physician. If you are exposed to flood waters, immediately talk to your doctor if antibiotic prophylaxis is right for you.

If you do develop symptoms of leptospirosis, it is important to see a doctor right away. Starting the proper antibiotics in the early phase of leptospirosis significantly decreases the risk of progression to severe disease. Your doctor may order some blood tests, including a CBC (complete blood count), creatinine (a test of kidney function), AST and ALT (tests of liver function), and a leptoMAT (an antibody test for leptospirosis). There is no single perfect test for leptospirosis. The leptoMAT is not always available and may not be positive early in the course of the infection. Mild leptospirosis can be treated with oral antibiotics and close clinic follow-up.

Without early treatment, some patients progress to severe leptospirosis, which can be life-threatening. Intravenous antibiotics will need to be given in the hospital. Kidney failure may require urgent dialysis. Some patients can recover their kidney function with just a few dialysis sessions. Unfortunately, especially if diagnosed late, some patients may become dependent on dialysis for life or require a kidney transplant. Patients who develop liver failure may need to be admitted to the intensive care unit to help them recover. If pulmonary hemorrhage develops, the patient may need to be placed on a ventilator. Steroids and blood products can be given as deemed necessary by the team. Several subspecialties typically care for a patient with severe leptospirosis, including infectious diseases, pulmonary/critical care, and nephrology.

Due to its nonspecific symptoms at the start of illness, leptospirosis may be mistaken for other common infectious diseases in the Philippines. Both dengue fever and typhoid fever can mimic leptospirosis in its early stages. Distinguishing leptospirosis from these diseases isn’t easy since all of them present with fever and muscle aches. There are some features that are more prominent with leptospirosis compared to the other diseases, although sometimes they can overlap. Aside from the typical conjunctival suffusion, one of the most helpful clues for diagnosing leptospirosis is the recent exposure to floodwaters.

Dengue is a viral disease transmitted by mosquitoes. It typically presents with a skin rash and usually doesn’t cause changes in the urine and kidneys, unlike leptospirosis. It can usually be diagnosed with a blood test (dengue IgG, IgM, NS1 antigen) and a CBC that shows low platelets. While leptospirosis can lower the platelet count, this usually happens in severe disease when the liver is failing. Since dengue is caused by a virus, antibiotics aren’t needed for treatment and the main treatment is supportive care with good hydration.

Typhoid, on the other hand, is caused by the bacteria Salmonella typhi. It is usually acquired by ingesting contaminated food or water. The fever in typhoid is typically very high and there can be accompanied by abdominal discomfort or pain. Most patients become constipated at the start but can develop diarrhea later in its course. Diagnosis of typhoid is with an antibody test (IgM, IgG), which isn’t always positive early in the disease. Blood cultures and stool cultures sometimes become positive as well. Typhoid fever requires antibiotic treatment and may need hospitalization in more severe cases.

To make things worse, we’ve sometimes diagnosed leptospirosis patient with concurrent dengue or typhoid infections. Dengue and leptospirosis cases typically peak at the same time during the rainy season so it isn’t impossible to get them both at the same time. The important thing is that if you are exposed to floodwaters or if you develop a fever, talk to your doctor as soon as possible so that you can get treatment early and avoid preventable complications.

Finally, we all need to work together as a community to limit the impact of leptospirosis in our country. The risk of leptospirosis is exacerbated by poverty and poor sanitation. Improving living conditions, controlling rodents and other pests, and good flood control will go a long way in minimizing the scourge of leptospirosis in our communities.