Editing Tropical sprue

{{Other uses|Sprue (disambiguation){{!}}Sprue}}
{{Infobox medical condition (new)
| name            = Tropical sprue
| image           =
| caption         =
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| pronounce       =
| field           =
| synonyms        = Postinfectious tropical malabsorption<ref name="Wanke2015" />
| symptoms        = Diarrhoea, abdominal pain, weight loss
| complications   = Malabsorption, anaemia
| onset           =
| duration        =
| types           =
| causes          =
| risks           =
| diagnosis       = Intestinal histology
| differential    = Coeliac disease, environmental enteropathy
| prevention      =
| treatment       = Antibiotics, folate replacement
| medication      =
| prognosis       =
| frequency       =
| deaths          =
}}
'''Tropical sprue''' is a [[malabsorption]] disease commonly found in tropical regions, marked with abnormal flattening of the [[Intestinal villus|villi]] and [[inflammation]] of the lining of the [[small intestine]].<ref name="Wanke2015">{{cite book| author=Wanke, Christine A. | chapter=Tropical Sprue: enteropathy |title=Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases|editor1=Bennett, John E.|editor2=Dolin, Raphael|editor3=Blaser, Martin J.| edition=8| date=2015| pages=1297–1301 | doi=10.1016/B978-1-4557-4801-3.00104-1 | pmc=7151975|chapter-url=https://books.google.com/books?id=73pYBAAAQBAJ&pg=PA1298}}</ref><ref name="pmid17148698">{{cite journal |vauthors=Ramakrishna BS, Venkataraman S, Mukhopadhya A |title=Tropical malabsorption |journal=Postgrad Med J |volume=82 |issue=974 |pages=779–87 |year=2006 |pmid=17148698 |pmc=2653921 |doi=10.1136/pgmj.2006.048579 }}</ref> It differs significantly from [[coeliac sprue]]. It appears to be a more severe form of [[environmental enteropathy]].<ref name="pmid22633998">{{cite journal |vauthors=Korpe PS, Petri WA |title=Environmental enteropathy: critical implications of a poorly understood condition |journal=Trends Mol Med |volume=18 |issue=6 |pages=328–36 |year=2012 |pmid=22633998 |pmc=3372657 |doi=10.1016/j.molmed.2012.04.007 }}</ref><ref name="pmid24781741">{{cite journal |vauthors=Ghoshal UC, Srivastava D, Verma A, Ghoshal U |title=Tropical sprue in 2014: the new face of an old disease |journal=Curr Gastroenterol Rep |volume=16 |issue=6 |pages=391 |year=2014 |pmid=24781741 |doi=10.1007/s11894-014-0391-3 |pmc=7088824 }}</ref>

==Signs and symptoms==
The illness usually starts with an attack of acute [[diarrhoea]], [[fever]] and [[malaise]] following which, after a variable period, the patient settles into the chronic phase of diarrhoea, [[steatorrhoea]], [[weight loss]], [[anorexia (symptom)|anorexia]], malaise, and nutritional deficiencies.<ref name="Wanke2015" /><ref name="pmid17148698"/><ref name="pmid22633998"/>
The symptoms of tropical sprue are:
* Diarrhoea
* Steatorrhoea or fatty stool (often foul-smelling and whitish in colour)
* [[Indigestion]]
* [[Cramps]]
* [[Weight loss]] and [[malnutrition]]
* [[Fatigue (physical)|Fatigue]]

Left untreated, nutrient and [[vitamin deficiency|vitamin deficiencies]] may develop in patients with tropical sprue.<ref name="Wanke2015" /><ref name="pmid17148698"/>  These deficiencies may have these symptoms:
* [[Vitamin A]] deficiency: [[hyperkeratosis]] or skin scales
* [[Vitamin B12|Vitamin B<sub>12</sub>]] and [[folic acid]] deficiencies: [[anaemia]], [[numbness]], and [[tingling sensation]]
* [[Vitamin D]] and [[calcium]] deficiencies: [[spasm]], [[bone pain]], muscle weakness
* [[Vitamin K]] deficiency: [[bruises]]

==Cause==
The cause of tropical sprue is not known.<ref name="pmid17148698"/>  It may be caused by persistent bacterial, viral, amoebal, or [[parasitic infection]]s.<ref name="pmid9135537">{{cite journal |vauthors=Cook GC |title='Tropical sprue': some early investigators favoured an infective cause, but was a coccidian protozoan involved? |journal=Gut |volume=40 |issue=3 |pages=428–9 |year=1997 |pmid=9135537 |pmc=1027098 |doi= 10.1136/gut.40.3.428}}</ref>  [[Folic acid deficiency]], effects of malabsorbed fat on [[intestinal motility]], and persistent [[small intestinal bacterial overgrowth]] may combine to cause the disorder.<ref name="pmid6143049">{{cite journal |vauthors=Cook GC |title=Aetiology and pathogenesis of postinfective tropical malabsorption (tropical sprue) |journal=Lancet |volume=1 |issue=8379 |pages=721–3 |year=1984 |pmid=6143049 |doi= 10.1016/s0140-6736(84)92231-1|s2cid=41146323 }}</ref> A link between [[small intestinal bacterial overgrowth]] and tropical sprue has been proposed to be involved in the etiology of post-infectious [[irritable bowel syndrome]] (IBS).<ref name="pmid28513629">{{cite journal |vauthors=Ghoshal UC, Gwee KA |title=Post-infectious IBS, tropical sprue and small intestinal bacterial overgrowth: the missing link |journal=Nat Rev Gastroenterol Hepatol |volume=14 |issue=7 |pages=435–441 |year=2017 |pmid=28513629 |doi=10.1038/nrgastro.2017.37 |s2cid=33660302 }}</ref> Intestinal immunologic dysfunction, including deficiencies in secretory immunoglobulin A (IgA), may predispose people to malabsorption and bacterial colonization, so tropical sprue may be triggered in susceptible individuals following an acute enteric infection.<ref name="Wanke2015" />

==Diagnosis==
Diagnosis of tropical sprue can be complicated because many diseases have similar symptoms.  The following investigation results are suggestive:<ref name="Wanke2015" />
* Abnormal flattening of [[Intestinal villus|villi]] and inflammation of the lining of the small intestine, observed during an [[endoscopy|endoscopic]] procedure.
* Presence of inflammatory cells (most often lymphocytes) in the [[biopsy]] of small intestine tissue.
* Low levels of vitamins [[vitamin A|A]], [[vitamin B12|B<sub>12</sub>]], [[vitamin E|E]], [[vitamin D|D]], and [[vitamin K|K]], as well as [[serum albumin]], [[calcium]], and [[folate]], revealed by a blood test.
* Excess fat in the [[feces]] ([[steatorrhoea]]).
* Thickened small bowel folds seen on [[medical imaging|imaging]].

Tropical sprue is largely limited to within about 30 degrees north and south of the [[equator]].  Recent travel to this region is a key factor in diagnosing this disease in residents of countries outside of that geographical region.<ref name="pmid17148698"/>

Other conditions which can resemble tropical sprue need to be differentiated.<ref name="pmid24781741"/>  [[Coeliac disease]] (also known as ''[[coeliac sprue]] or gluten sensitive enteropathy''), has similar symptoms to tropical sprue, with the flattening of the [[Intestinal villus|villi]] and [[small intestine inflammation]] and is caused by an [[autoimmune disorder]] in genetically susceptible individuals triggered by ingested [[gluten]].  Malabsorption can also be caused by [[protozoan infections]], [[tuberculosis]], [[HIV/AIDS]], [[immunodeficiency]], [[chronic pancreatitis]] and [[inflammatory bowel disease]].<ref name="pmid17148698"/>  [[Environmental enteropathy]] is a less severe, subclinical condition similar to tropical sprue.<ref name="pmid17148698"/>

==Prevention==
Preventive measures for visitors to tropical areas where the condition exists include steps to reduce the likelihood of [[gastroenteritis]].  These may comprise using only [[bottled water]] for drinking, brushing teeth, and washing food, and avoiding fruits washed with tap water (or consuming only peeled fruits, such as [[bananas]] and [[orange (fruit)|oranges]]).  Basic sanitation is necessary to reduce fecal-oral contamination and the impact of environmental enteropathy in the developing world.<ref name="pmid17148698"/>

==Treatment==
Once diagnosed, tropical sprue can be treated by a course of the antibiotic [[tetracycline]] or [[co-trimoxazole|sulphamethoxazole/trimethoprim (co-trimoxazole)]] for 3 to 6 months.<ref name="pmid17148698"/><ref name="pmid20805939">{{cite journal |vauthors=Batheja MJ, Leighton J, Azueta A, Heigh R |title=The Face of Tropical Sprue in 2010 |journal=Case Rep Gastroenterol |volume=4 |issue=2 |pages=168–172 |year=2010 |pmid=20805939 |pmc=2929410 |doi=10.1159/000314231 }}</ref>
Supplementation of vitamins B<sub>12</sub> and folic acid improves appetite and leads to a gain in weight.<ref name="pmid24781741"/><ref name="pmid910746">{{cite journal |vauthors=Klipstein FA, Corcino JJ |title=Factors responsible for weight loss in tropical sprue |journal=Am. J. Clin. Nutr. |volume=30 |issue=10 |pages=1703–8 |year=1977 |pmid=910746 |doi= 10.1093/ajcn/30.10.1703|doi-access=free }}</ref>

==Prognosis==
The prognosis for tropical sprue may be excellent after treatment.  It usually does not recur in people who get it during travel to affected regions.  The recurrence rate for natives is about 20%,<ref name="pmid17148698"/> but another study showed changes can persist for several years.<ref name="pmid5009590">{{cite journal |vauthors=Rickles FR, Klipstein FA, Tomasini J, Corcino JJ, Maldonado N |title=Long-term follow-up of antibiotic-treated tropical sprue |journal=Ann. Intern. Med. |volume=76 |issue=2 |pages=203–10 |year=1972 |pmid=5009590 |doi= 10.7326/0003-4819-76-2-203}}</ref>

==Epidemiology==
Tropical sprue is common in the [[Caribbean]], Central and [[South America]], and [[India]] and southeast [[Asia]].  In the Caribbean, it appeared to be more common in Puerto Rico and Haiti.  Epidemics in southern India have occurred.<ref name="pmid17148698"/>

==History==
The disease was first described by [[William Hillary (physician)|William Hillary]]<ref name="pmid2691344">{{cite journal | author = Bartholomew C | title = William Hillary and sprue in the Caribbean: 230 years later | journal = Gut | volume = 30 | issue = Special issue | pages = 17–21 |date=November 1989 | pmid = 2691344 | pmc = 1440696 | doi = 10.1136/gut.30.spec_no.17}}</ref> in 1759 in [[Barbados]].<ref>{{Cite book |url=https://books.google.com/books?id=pvb7v8slz2sC&pg=PA278 |pages=277–281|title=Observations on the Changes of the Air and the Concomitant Epidemical Diseases in the Island of Barbados: To which is Added a Treatise on the Putrid Bilious Fever, Commonly Called the Yellow Fever|last1=Hillary|first1=William|year=1759}}</ref> Tropical sprue was responsible for one-sixth of all casualties sustained by the Allied forces in India and Southeast Asia during World War II.<ref name="pmid17148698"/> The use of folic acid and vitamin B<sub>12</sub> in the treatment of tropical sprue was promoted in the late 1940s by Dr. [[Tom Spies]] of the [[University of Alabama]], while conducting his research in Cuba and Puerto Rico.<ref name="pmid17769104">{{cite journal |vauthors=Spies TD, Suarez RM, Suarez RM, Hernandez-Morales F |title=The Therapeutic Effect of Folic Acid in Tropical Sprue |journal=Science |volume=104 |issue=2691 |pages=75–6 |year=1946 |pmid=17769104 |doi=10.1126/science.104.2691.75 |bibcode=1946Sci...104...75S }}</ref><ref name="pmid18139385">{{cite journal |vauthors=SUAREZ RM, SPIES TD |title=A note on the effectiveness of vitamin B12 in the treatment of tropical sprue in relapse |journal=Blood |volume=4 |issue=10 |pages=1124–30 |year=1949 |pmid=18139385 |doi= 10.1182/blood.V4.10.1124.1124|doi-access=free }}</ref><ref>{{Cite journal |doi = 10.1001/jama.1957.02980080048013|title = Dr. Spies Receives Distinguished Service Medal|journal = Journal of the American Medical Association|volume = 164|issue = 8|pages = 878|year = 1957}}</ref>

==References==
{{Reflist}}

{{Medical resources
|  ICD10 = {{ICD10|K|90|1}}
|  ICD9 = {{ICD9|579.1}}
|  DiseasesDB = 13393
|  MedlinePlus = 000275
|  eMedicineSubj = med
|  eMedicineTopic = 2162
|  MeshID = D013182
}}

{{Gastroenterology}}

{{DEFAULTSORT:Tropical Sprue}}
[[Category:Ailments of unknown cause]]
[[Category:Gastrointestinal tract disorders]]
[[Category:Malnutrition]]
[[Category:Steatorrhea-related diseases]]