What is Tropical Sprue?
Tropical sprue is a condition that makes it difficult for the body to absorb nutrients properly and is often marked by sudden or long-lasting diarrhea. It usually occurs in tropical regions and scientists think it’s caused by an infection along with some environmental factors, but the exact cause is unknown. This condition primarily affects the small intestine and leads to various nutritional shortages, particularly in vitamin B12 and folic acid.
This disease was first pointed out by a man named William Hillary in 1759 who noticed it in people from Barbados suffering from chronic diarrhea. Later in 1880, a man named Patrick Manson added the term “sprue” to refer to the persistent diarrhea seen in Asian countries.
What Causes Tropical Sprue?
Despite extensive research, we still don’t fully understand what exactly causes tropical sprue. The most commonly accepted theory is that it occurs when an initial gut infection leads to damage to the lining of the small intestine. This damage affects the structure and function of the cells lining the intestine, resulting in an overgrowth of bacteria and slowed-down movement of food and waste matter through the intestine. Several studies have shown a link between an overgrowth of bacteria in the small intestine and tropical sprue.
When it comes to understanding the underpinnings of tropical sprue, some factors seem to play a role in causing the damage that leads to the condition. These include exposure to a toxic substance, nutritional deficiencies, or an infection.
- Toxic substances: There’s no solid evidence that any specific toxin is responsible for causing tropical sprue. Some theories suggested that harmful fats might be the cause, but the evidence doesn’t support this idea.
- Nutritional deficiencies: Some have suggested that a lack of certain vitamins or minerals could trigger tropical sprue, but research has suggested that any deficiencies are likely a result of the disease rather than a cause.
- Infections: Some studies suggest that a prior infection might be the cause of tropical sprue. The fact that there’s often a long gap between exposure to the infection and the start of symptoms suggest that it’s unlikely to be due to toxins or nutritional deficiencies.
Despite the many research efforts, there is no solid proof pointing to any specific cause for tropical sprue. Some studies have suggested that certain bacterial or viral infections might be the culprit.
Bacterial infections are one possibility. The fact that symptoms often improve with antibiotics supports this idea. However, attempts to find bacterial infections in stool samples from patients with tropical sprue haven’t been successful. Moreover, tissue samples from the damaged areas of the intestine haven’t shown any bacterial growth.
Viral infections are another possibility, as these can cause damage to the cells lining the intestine. While some viruses can cause diarrhea, they don’t typically lead to the long-term, chronic diarrhea seen in tropical sprue. One virus, called Reovirus, has been shown to cause diarrhea lasting several weeks in monkeys, but it has not yet been isolated from patients with tropical sprue. While there’s some evidence pointing to a viral cause, more research and better techniques are needed to prove this theory.
Risk Factors and Frequency for Tropical Sprue
Tropical sprue is a disease that primarily affects countries in the tropical region, specifically between the latitudes of 30°N to 30°S. However, not all countries in this region are impacted. It’s common in Puerto Rico, Haiti, Cuba, India, and Pakistan, but the disease is hardly seen in places like the African continent, China, the Middle East, and the USA. This condition typically impacts local populations and visitors who stay more than a month in the affected areas. It’s quite rare in people who visit these areas for less than two weeks. The number of cases in India and Pakistan is decreasing, probably due to better sanitation and the widespread use of antibiotics. The disease affects both men and women equally and can occur in adults and children, though it’s typically seen in adults.
- Tropical sprue is mostly seen in countries between latitudes 30°N to 30°S.
- Not all countries in this area are affected.
- It’s prevalent in Puerto Rico, Haiti, Cuba, India, and Pakistan.
- It is rare in the African continent, China, the Middle East, and the USA.
- The disease usually impacts locals and visitors who stay more than a month in these regions.
- It is rarely seen in people who visit for less than two weeks.
- The incidence is declining in India and Pakistan, likely due to improved hygiene and antibiotic use.
- Both males and females are equally affected.
- It’s usually seen in adults but can happen in children too.
Signs and Symptoms of Tropical Sprue
Tropical sprue is a disease often seen in people living in or traveling to certain areas. It often starts with traveler’s diarrhea but doesn’t get better. Persistent, stinky, watery poops continue, along with bloating, stomach pain, and loud noises from the gut.
Fever is not usually a common symptom. However, the person affected may pass fatty stools (steatorrhea), lose their appetite, and lose weight. They may also feel tired, look pale, and get out of breath easily because they can’t properly absorb vitamins B12 and folate, leading to anemia.
On physical examination, the doctor may find changes in the mouth such as inflamed tongue (glossitis), cracks at the corners of the mouth (cheilitis), mouth sores (stomatitis), swollen feet (pedal edema), or a big belly. The person may also show signs that their body isn’t getting enough nutrients, like not being able to focus, feeling cold, being tired and grumpy, wounds taking a long time to heal, and catching infections frequently.
- Traveler’s diarrhea that doesn’t get better
- Continual watery and foul-smelling stools
- Bloating
- Abdominal pain
- Loud noises from the gut
- No fever normally
- Fatty stools (steatorrhea)
- Loss of appetite
- Weight loss
- Tiredness, paleness and shortness of breath due to anemia
- Inflamed tongue, cracks at the corners of the mouth, mouth sores
- Swollen feet
- Protuberant abdomen
- Signs of malnutrition such as difficulty concentrating, feeling cold, being grumpy, delay in healing wounds, and catching infections frequently
Testing for Tropical Sprue
Tropical sprue is a condition that can cause prolonged diarrhea and other problems, and it can be mistaken for other infections or inflammation-related illnesses. To diagnose this condition, other similar diseases must first be ruled out.
Doctors can work out if you have tropical sprue by doing a series of laboratory and stool tests. They may look for indicators such as megaloblastic anemia (a type of anemia where you have fewer but larger than normal red blood cells), and low levels of vitamin B12 and folate (types of vitamins) in a complete blood count (CBC). They may also find high levels of homocysteine (a type of amino acid), which can be a sign of vitamin B12 or folate deficiency. Similarly, high levels of methylmalonic acid may point to a specific vitamin B12 deficiency. The comprehensive metabolic panel (a more detailed kind of blood test that looks at your body’s metabolism) may reveal imbalances in electrolytes like potassium, chloride, and sodium (kinds of salts the body needs to function correctly).
Because certain infections can mimic tropical sprue, it’s important to conduct stool tests to rule out these infections like Giardia, Entamoeba, Strongyloides, and Cryptosporidium. Doctors also use serological tests, which use your blood to look for antibodies against conditions, to rule out Celiac disease, which can have similar symptoms.
To see if you’re absorbing food the way you should be, tests can be done for malabsorption, which looks for signs you’re not absorbing certain nutrients. These could include a stool test that measures the fat content, or a D-xylose test. This is a simple test where you drink a liquid containing a sugar called D-xylose, then your blood and urine is tested to see if your body is absorbing it correctly.
In some cases, doctors might use a barium study, a test involving X-rays and a metallic liquid called barium, which helps to highlight the gastrointestinal tract. They would look for things like changes in size and thickening of the lining of your intestines.
Another tool used to diagnose tropical sprue is endoscopy, a procedure where a doctor uses a flexible lighted tube to see the inside of your digestive tract. They would be looking for any abnormalities in the small intestine like duodenum (part of the small intestine) and jejunum (the middle part of the small intestine).
The diagnosis of tropical sprue may be confirmed if there is evidence of steatorrhea (fat in the stool), malabsorption of two substances (like D-xylose and fat), and abnormal biopsy findings like villous atrophy (damage to the lining of the small intestine). Treatment’s effectiveness has also been used in some occasions to confirm the diagnosis.
Treatment Options for Tropical Sprue
Tropical sprue is typically managed using a variety of techniques. Most often, individuals with tropical sprue are treated in an outpatient setting, meaning they don’t have to stay overnight in a hospital. The key focus is on treating malnutrition, which involves providing the patient with necessary minerals and vitamins and finding and addressing the root cause of the issue.
In some cases, patients may need severe, immediate care, such as when they experience extreme weight loss and dehydration. In these situations, the patient might need to be urgently evaluated, and treatment to replace lost fluids and electrolytes get underway quickly. Under particularly complicated circumstances, such as severe dehydration, imbalances in electrolyte levels, and noticeable anemia symptoms, they could need to be admitted to the hospital.
The usual treatment plan includes antibiotics, injecting vitamins (specifically vitamin B12 and folate) directly into the bloodstream, replacing fluids and electrolytes, and in some cases, blood transfusions. A combined treatment with tetracycline, an antibiotic, and folic acid, a type of vitamin B, is often necessary for three to six months. It’s important to note that not getting treated or stopping the treatment prematurely may lead to a recurrence of tropical sprue, causing malabsorption. Malabsorption means that your body is unable to absorb nutrients properly.
In areas where tropical sprue is common, and for patients who have experienced the disease repeatedly, the treatment period could extend until a year. After treatment, it is crucial for patients to be regularly assessed for a few months to monitor their progress. The healthcare provider will be looking for signs of improvement, such as a lessening of symptoms and weight gain, along with changes to blood counts and electrolyte levels.
What else can Tropical Sprue be?
When a patient has tropical sprue, a digestive disease often caused by a bacterial or viral infection, many other conditions could also be causing their symptoms. So, doctors need to be sure to check for these before diagnosing tropical sprue.
- Infectious diseases, such as E. histolytica, G. lamblia, S. stercoralis, C. parvum, I. belli, and C. cayetanesis.
- Other chronic diarrhea causes like lactose intolerance, short bowel syndrome, and bile salt deficiency.
- Diseases that cause fat malabsorption, which include small intestinal bacterial overgrowth, pancreatic insufficiency, and celiac disease.
What to expect with Tropical Sprue
The outlook is usually positive for people with tropical sprue, a disease that affects your body’s ability to absorb nutrients from food. Treatment has proven to be very effective, especially for people who contract the disease while traveling to areas where it’s common. In these cases, relapses or recurrence of the disease are infrequent or non-existent.
However, if you live in these areas (known as endemic regions) where the disease is common, the chances of the disease coming back are higher — around 20%. This could mean repeated bouts of the disease over a period of time. That said, recent studies suggest a positive shift in trends, meaning treatment strategies for tropical sprue are improving and becoming more effective.
Possible Complications When Diagnosed with Tropical Sprue
Tropical sprue, a disease of the intestines, usually presents slightly harmful health side effects and very few cases result in death. The most worrying symptom is often acute or sudden diarrhea. Such diarrhea is not only discomforting but also can cause severe electrolyte imbalances and dehydration, which can be dangerous and lead to poor health outcomes if not properly managed. Common complications that could arise include heightened anemia, vitamin deficiencies, and malnutrition. If not addressed swiftly, these issues can cause tissue damage and organ dysfunction. More so, if the disease lingers while malnutrition turns severe, it can lead to death, particularly in patients with existing health issues.
Possible Health Problems:
- Sudden onset diarrhea
- Severe electrolyte imbalances
- Dehydration
- Increased anemia
- Vitamin deficiencies
- Malnutrition
- Tissue damage
- Organ dysfunction
- Potential death in people with pre-existing health conditions
Preventing Tropical Sprue
People who are planning to travel to areas known for certain diseases, particularly in tropical regions, should be informed about the risks. It’s important for everyone to take the right steps to avoid being exposed to harmful germs that can cause intestinal diseases. If someone has been experiencing diarrhea for a long time, they shouldn’t put off getting help. They should go see a doctor right away.
