Tropical sprue overview

# Overview
Tropical sprue is a chronic diarrheal disorder of unclear etiology affecting the people in endemic and tropical regions.

# Historical Perspective
The description of tropical sprue like disease was reported for the first time in Belgium. The name tropical sprue was coined by Sir Patrick Manson.

# Classification
Tropical sprue is classified based on the duration of symptoms into acute phase and a chronic phase.

# Pathophysiology
The exact pathophysiology of tropical sprue is unclear but is thought to be related to intestinal inflammation following an episode of diarrhea. The inflammation damages the intestinal villi and also result in lymphocytosis in the intestinal wall. Deficiency of lactase enzyme in results in malabsorption of carbohydrates and the dysfunctional enterocytes cause steatorrhea.

# Causes
The exact etiological agent causing tropical sprue is unknown, but different bacteria types are identified in patients with tropical sprue.

# Differentiating Tropical Sprue from other Diseases
Tropical sprue is a diagnosis of exclusion therefore it must be be differentiated from other diseases causing malabsorption such as celiac disease.

# Epidemiology and Demographics
Tropical sprue is a rare diagnosis nowadays, and the highest prevalence is seen in the tropical countries.

# Risk Factors
The risk factors for the development of tropical sprue include an episode of infectious diarrhea and visit to endemic areas.

# Screening
Tropical sprue is a rare disease and a diagnosis of exclusion therefore no screening is recommended.

# Natural History, Complications and Prognosis
Tropical sprue has an acute and a chronic phase and usually follows an episode of infectious diarrhea. The patients present with chronic non bloody diarrhea with malabsorption. The chronic phase can result in malabsorption and the patients will develop symptoms of vitamin B12 and vitamin A deficiency. The prognosis is excellent with treatment.

# History and Symptoms
Patients with tropical sprue present with diarrhea, bloating, flatulence, fever and myalgias in the acute phase. Patients in the chronic phase present with features of malabsorption.

# Physical Examination
The physical examination findings in acute phase can be significant for dehydration. In the chronic phase, features of sub acute combined degeneration of spinal cord and visual field defects are present.

# Laboratory Findings
Tropical sprue is a diagnosis of exclusion and there are no specific laboratory findings. Blood smear will show megaloblastic changes in chronic phase of tropical sprue. All the etiologies of malabsorption must be ruled out to consider the diagnosis of tropical sprue.

# Electrocardiogram
There are no ECG findings associated with tropical sprue.

# X-Ray
X-Ray is not useful for the diagnosis of tropical sprue.

# CT
CT has no role in the diagnosis of tropical sprue, however it is useful to rule out conditions such as inflammatory bowel disease and chronic pancreatitis.

# MRI
MRI is not required for the diagnosis of tropical sprue.

# Other Imaging Findings
Imaging studies are not required for the diagnosis of tropical sprue.

# Other Diagnostic Studies
Upper GI endoscopy should be done to obtain a duodenal biopsy and the histological features suggestive of tropical sprue include intestinal villous blunting and intestinal lymphocytosis.

# Medical Therapy
Folic acid and antimicrobial therapy are the mainstay of treatment for tropical sprue. Supportive therapy includes adequate hydration and replacement of nutrients such as iron and vitamin B12. Oral tetracycline is contraindicated among pregnant and lactating women and among children < 8 years of age. The main aims of treatment include: control of diarrhea, correction of existing vitamin deficiencies and cure of the disease.

# Surgery
Surgery is not required for patients with tropical sprue. Antibiotic therapy alone is the modality of treatment.

# Primary Prevention
The primary preventive measures include drinking clean water and maintaining good hygiene.

# Secondary Prevention
There are no secondary preventive measures for tropical sprue.