Tropical sprue is an acquired chronic diarrheal disorder of unclear etiology affecting residents of and visitors to tropical regions. Patients usually present with . English Spanish online dictionary Term Bank, translate words and terms with different pronunciation options. ESPRUE TROPICAL trastorno de diarrea crónica con mala absorción y deficiencia nutricional etiología desconocida regiones tropicales.
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Malabsorption is an important clinical problem both in visitors to the tropics and in native residents of tropical countries. Infections of the small intestine are the most important cause of tropical malabsorption. Protozoal infections cause malabsorption in immunocompetent hosts, but do so more commonly in the setting of immune deficiency.
Tropical malabsorption
In recent years, inflammatory bowel disease and coeliac disease have become major causes of malabsorption in the tropics. Sporadic tropical sprue is still an important cause of malabsorption in adults and in children in South Asia.
Investigations to exclude specific infective, immunological or mo causes are important before considering tropical sprue as tropial diagnosis. This tropicall briefly reviews the management of tropical sprue and presents an algorithm for its investigation and management. Malabsorption is an important clinical problem eslrue tropical countries, typically presenting with chronic diarrhoea, glossitis, weight loss and multiple nutritional deficiencies.
The aetiological profile of malabsorption in tropical countries often differs from that in temperate zones. A description in the ancient Indian medical treatise, Charaka samhitaof an illness characterised by chronic diarrhoea and weight loss and attributed to failure of the digestive system 1 suggests that the malabsorption syndrome was clinically recognised in eslrue tropics two millennia ago.
InWilliam Hillary described a malabsorption syndrome in expatriates tropcal in Barbados, 2 but the first case that he described may have been due to giardiasis rather than tropical sprue. Initially thought to be confined to visitors to the tropics, it became apparent in the early 20th century that indigenous residents of the tropics were afflicted with similar illnesses.
In the past two decades, the profile of malabsorption has changed in tropical countries, probably related to changes in hygiene and sanitation. This review considers tropical malabsorption as any syndrome of malabsorption that affects indigenous residents of tropical countries and also travellers visiting or residing in the tropics. Protozoal infections of the small intestine are particularly common in tropical countries and may be associated with malabsorption.
Protozoa are an important cause of traveller’s diarrhoea. Chronic diarrhoea and malabsorption are seen in a small proportion of infected people.
Giardia intestinalis is the protozoan parasite most commonly associated with malabsorption. Infection with this protozoan is common in the tropics and is often a cause of diarrhoeal illness in visitors to the tropics.
The presence of Espdue cysts in the stool indicates infection. In patients with diarrhoea, trophozoites in stool are usually present. Examination of at least three faecal specimens is recommended for optimal diagnosis of the infection. Other protozoa box 1 associated with malabsorption include Cryptosporidium parvumIsospora belliCyclospora cayetanensis and Microsporidia species Enterocytozoon bieneusi and Encephalitozoon intestinalis.
However, immunocompetent people also sometimes show prolonged symptoms. Before the AIDS epidemic, these protozoa were recognised as the causes of malabsorption mainly in patients with primary immunodeficiency syndromes such as common variable immunodeficiency, and were thus relatively uncommon. Since the advent of AIDS, protozoal infections have become seprue causes of tropical malabsorption, 2021 although they are now uncommon in the developed countries as a result of antiretroviral treatment.
For instance, C parvum is the most important diarrhoeal pathogen in Zaire and Uganda, whereas I belli is the most common pathogen causing chronic diarrhoea and malabsorption in south India. Algorithms for the management of malabsorption in the tropics require that HIV illness be first excluded by appropriate testing. Helminth infections are an occasional cause of tropical malabsorption. The most common of these are Strongyloides stercoralis and Capillaria philippinensis. Infection with S stercoralis is common in the tropics and may cause chronic diarrhoea and malabsorption in immunocompetent people.
Intermittent or persistent diarrhoea occurs, while steatorrhoea, anaemia and hypoproteinaemia are common. Treatment with thiabendazole, albendazole or ivermectin has been found to be effective. Intestinal tuberculosis is common in tropical countries. It may manifest with many clinical syndromes, including obstruction and malabsorption syndromes. Biochemical evidence of malabsorption can be found in many patients with intestinal tuberculosis, even though the patient may not present with a clinical diagnosis of the malabsorption syndrome.
The improvement in diarrhoea and malabsorption with antiretroviral treatment lends credence to this theory. Crohn’s disease is increasingly being diagnosed in tropical countries, 535455 and is an important differential diagnosis for tgopical. Malabsorption in Crohn’s disease may occur as a result of several factors. Terminal ileal resections can lead to vitamin B 12 deficiencies and bile salt malabsorption, whereas ileocaecal valve resections result in bacterial overgrowth causing malabsorption.
Common variable immunodeficiency occurs sporadically in residents of the tropics, and may present primarily as a malabsorption syndrome. The most common infection noted in these patients is with the protozoan G intestinalis.
Esprje protozoa may also colonise the small bowel and lead to malabsorption. These include I belliC parvum and microsporidia.
Tropical malabsorption
Selective immunoglobulin Ig A deficiency is less common and can be associated with a flat mucosa and giardiasis. Symptomatic chronic infection of the small bowel leads to malabsorption. Bacterial colonisation of the upper small bowel may also occur in some patients with primary immunodeficiency and cause malabsorption.
This is identified by quick response to treatment with tetracycline or other antibiotics. Immunoproliferative small intestinal disease IPSID was traditionally esprrue Mediterranean lymphoma but is not uncommon in the tropics. Patients present with chronic diarrhoea and malabsorption in the second and third decades of life. Abdominal pain may be a major complaint. Clubbing of the fingers is characteristic and abdominal masses may be palpated on physical examination.
Nutritional deficiencies and a marked weight loss are troical. Clonal proliferation may occur secondary to chronic trlpical recurrent infections of the intestine in childhood. Mucosal biopsy of the small intestine is characteristic and shows a dense cellular lymphoplasmacytic infiltrate in the lamina propria leading to effacement of the crypts.
Three stages of the disease are noted, ranging fsprue an apparently benign disease stage A to a clear lymphoma stage C. The disease progresses over variable periods of time to the development of lymphoplasmacytic and immunoblastic lymphoma. Staging of the disease by laparoscopy or laparotomy should precede chemotherapy or radiation therapy.
Recently, IPSID was shown to be associated with Campylobacter jejuni infection, trolical suggesting that this was one potential antigenic stimulus driving the uncontrolled proliferation of B cells. Incidence of IPSID is reducing in areas where it was previously prevalent, probably owing nno improving hygiene.
Idiopathic chronic calcific pancreatitis is endemic in several tropical regions including the Tropicql subcontinent and southern Africa. Symptoms typically develop in adolescence and the usual presentation is with recurrent abdominal pain attributable to pancreatitis.
In some patients, presentation is solely with features of chronic diarrhoea and malabsorption due to the exocrine pancreatic insufficiency.
Xylose absorption is usually normal in these patients, and faecal fat is grossly increased. Vitamin B 12 malabsorption may be noted in some people due to lack of pancreatic proteolytic activity and failure to cleave the R protein—vitamin B 12 complex.
Occasionally, endoscopic retrograde pancreatography or endoscopic ultrasonography is used to establish the diagnosis. Malabsorption can be treated by an oral dose of a pancreatic enzyme preparation such as Creon with every meal. The mucosa of the small intestine of residents of the tropics is structurally different from that of residents of temperate countries. The villi are shorter, crypts are more elongated and trppical are increased tropiccal of lymphocytes in the lamina propria.
Malabsorption of fat, vitamin B 12 and xylose, as well as increased mucosal permeability, has been noted in a large number of healthy residents of the tropics. Tropical enteropathy may represent an adaptation of the gut to frequent intestinal infection.
T cells possibly have a role in the development of enteropathy. Tropical sprue is an acquired disease of unknown aetiology, characterised by malabsorption, multiple nutritional deficiencies and mucosal abnormalities in the small bowel. The definition of the various clinical syndromes that are together termed tropical sprue is still controversial. Baker and Klipstein 78 suggested that the diagnosis of tropical sprue should be made only when there is tropival of two or more unrelated nutrient groups eg, fat and carbohydrateand after other known causes of malabsorption trkpical been excluded.
Tropical sprue – Wikipedia
The aetiology of tropical sprue remains unknown. The need for prolonged residence in the tropics and the response to antibiotics suggested that persistent intestinal infection was responsible. Bacterial contamination of the small bowel was described in returning expatriates who developed tropical sprue, 89 as well as in the indigenous population from several regions with endemic tropical sprue.
The issue of whether this bacterial colonisation could lead to tropical sprue in those with a genetic predisposition has not been considered, especially as earlier studies predated current understanding on innate immune responses in the gastrointestinal tract. In this study, 10 of 13 patients with sprue had aerobic bacteria in the small intestine in larger numbers median 3.
Similar slowing of small intestinal transit in coeliac disease can be reversed with gluten withdrawal. Viral particles resembling human enteric corona viruses have been identified in the stool of patients with tropical sprue. Coccidian parasites such as Cyclospora cayetanensis might have a role in the initiation of tropical sprue in some patients. Nutrient malabsorption in tropical sprue arises from involvement of both the proximal and distal small intestine.
Ultrastructural studies show degenerating cells in the crypts of the small intestine, suggesting stem cell damage. Bile acid malabsorption occurs as a result of terminal ileal involvement and may contribute to diarrhoea.
Colonic malabsorption of water and electrolytes contributes considerably to diarrhoea in patients with sprue, and may result from the action of unabsorbed bile acids and free unsaturated fatty acids. Villus atrophy, crypt elongation and inflammatory cell infiltration of the lamina propria can be seen. Images courtesy of Professor Anna Pulimood.
A typical patient with tropical sprue is an adult who presents with chronic diarrhoea, glossitis, bloating, prominent bowel sounds and weight loss. The signs of nutritional deficiency include pallor due to anaemia; angular stomatitis, cheilitis and glossitis due to vitamin B deficiency; and peripheral oedema and skin and hair changes secondary to hypoproteinaemia.
Rarely, vitamin A deficiency may manifest with night blindness and corneal xerosis, while vitamin B 12 deficiency leads to subacute combined degeneration of the spinal cord. In expatriates, the illness is heralded by acute diarrhoea associated with fever and malaise in the first week. A milder form of chronic diarrhoea, steatorrhoea and a marked weight loss follows this. Some patients may present solely with a specific nutritional deficiency such as megaloblastic anaemia or hyperpigmentation of the skin due to vitamin B 12 deficiency.
Fever, uncommon in Caribbean patients, has been noted in almost a quarter of patients from southern India.
Two abnormal tests in the appropriate setting are consistent with tropical sprue in the absence of other causes of malabsorption.
Quantitative stool fat estimation is the most reliable test of malabsorption in the tropics. Although this is useful to detect the increased faecal fat triglyceride in patients with chronic pancreatitis, Sudan stain is not sensitive in the diagnosis of tropical sprue, where the faecal fat is in the form of fatty acids rather than triglycerides.