Changes

**[[Exocrine Pancreatic Insufficiency]] results in an inability to digest fat, protein and carbohydrate, leaving these substrates in the intestinal lumen.  This is thought to be the major cause of secondary ARD

**[[Exocrine Pancreatic Insufficiency]] results in an inability to digest fat, protein and carbohydrate, leaving these substrates in the intestinal lumen.  This is thought to be the major cause of secondary ARD

**[[Lymphangiectasia]] leads to increased luminal concentrations of fat and protein.

**[[Lymphangiectasia]] leads to increased luminal concentrations of fat and protein.

**[[Villous atrophy with intact/hypertrophic crypt glands|Villous atrophy]] leads to the loss of digestive enzymes on the brush borders of enterocytes.

**[[Villus atrophy with intact/hypertrophic crypt glands|Villous atrophy]] leads to the loss of digestive enzymes on the brush borders of enterocytes.

**[[Biliary Tract - Obstruction|Extrahepatic Biliary Obstruction]] leads to an inability to digest and absorb fat because bile salts do not pass into the intestine.

**[[Biliary Tract - Obstruction|Extrahepatic Biliary Obstruction]] leads to an inability to digest and absorb fat because bile salts do not pass into the intestine.

**Congenital deficiencies of brush border enzymes are very rare in animals.

**Congenital deficiencies of brush border enzymes are very rare in animals.

===Trial Therapy===

===Trial Therapy===

Ideally, if the history and clinical signs provide no obvious localisation, a full diagnostic investigation is recommended to define the cause of the condition.  This would involve analysis of blood samples, examination of faecal and urine samples, diagnostic imaging and endoscopy and is therefore beyond the reach of most clients.  Although less clinically rigorous, it may be justified to begin trial antimicrobial (antibacterial and antiparasitic) therapy at the outset instead to determine whether the condition does respond.  This approach may still be appropriate if further diagnostic work is intended as the presence of secondary ARD may impede the diagnosis of any underlying cause.  A suitable regime would include:

Ideally, if the history and clinical signs provide no obvious localisation, a full diagnostic investigation is recommended to define the cause of the condition.  This would involve analysis of blood samples, examination of faecal and urine samples, diagnostic imaging and endoscopy and is therefore beyond the reach of most clients.  Although less clinically rigorous, it may be justified to begin trial antimicrobial (antibacterial and antiparasitic) therapy at the outset instead to determine whether the condition does respond.  This approach may still be appropriate if further diagnostic work is intended as the presence of secondary ARD may impede the diagnosis of any underlying cause.  A suitable regime would include:

*Antiparasitic treatment to rule out helminths and protozoa (particularly ''[[Giardia duodenalis]]''. [[Anthelmintic Drugs|Fenbendazole]] is often used for this purpose.

*Antiparasitic treatment to rule out helminths and protozoa (particularly ''[[Giardia|Giardia duodenalis]]''. [[Anthelmintic Drugs|Fenbendazole]] is often used for this purpose.

*Antibacterial treatment with [[Macrolides and Lincosamides|tylosin]] or [[Nitroimidazoles|metronidazole]], continued for one month.     

*Antibacterial treatment with [[Macrolides and Lincosamides|tylosin]], [[Nitroimidazoles|metronidazole]] or [[Tetracyclines|oxytetracycline]], continued for one month.     

If this treatment does not result in any improvement, further investigations would be indicated to detect a primary GI disease.  If the clinical signs respond to the therapy but recur when this is withdrawn, a diagnosis of ARD can be made with some confidence.   

If this treatment does not result in any improvement, further investigations would be indicated to detect a primary GI disease.  If the clinical signs respond to the therapy but recur when this is withdrawn, a diagnosis of ARD can be made with some confidence.   

==Treatment==

==Treatment==

As suggested by its name, the major treatment option for ARD is antimicrobial therapy.

As suggested by its name, the major treatment option for ARD is antimicrobial therapy.

===Idiopathic ARD===

===Idiopathic Antibiotic Responsive Diarrhoea===

*Antimicrobial for an initial period of 4 weeks

Antimicrobial therapy should be instituted for an initial period of 4-6 weeks and the patient should then be reassessed to determine whether further treatment is necessary.  Some dogs will improve spontaneously after this initial course, either because bacterial population dynamics have returned to a more stable form or because of maturation of the mucosal immune system.  Animals that do not respond or which relapse after initial treatment may require long-term or permanent treatment.

**Suitable drugs include [[Tetracyclines|oxytetracycline]], [[Macrolides and Lincosamides|tylosin]], [[Nitroimidazoles|metronidazole]].  [[Tetracyclines|oxytetracycline]] is the drug of first choice for idiopathic ARD but its use for secondary ARD is controversial.  In addition, resistance is fast to develop with [[Tetracyclines|oxytetracycline]].  [[Macrolides and Lincosamides|Tylosin]] and [[Nitroimidazoles|metronidazole]] may be more appropriate at targeting bacteria that are likely to be present in secondary ARD.

===Secondary ARD===

 

 

===Secondary Antibiotic Responsive Diarrhoea===

The underlying cause of the disease should be treated and the ARD should then resolve.

The underlying cause of the disease should be treated and the ARD should then resolve.

===Dietary modification===

===Dietary modification===

A highly digestible and fat restriction diet, with added prebiotics is recommended.  Fructo-oligosaccharides.  This may be useful in both idiopathic and secondary ARD.

A highly digestible diet with high quality protein, low fibre content and low fat content should be used limit the availability of excess substrate for bacterial growth.  '''Fructo-oligosaccharides''' may be added to the diet as 'pre-biotics' to encourgae the growth of only normal host flora and, in one study of their use in German shepherd dogs, they produced a reduction in bacterial numbers on duodenal juice culture <ref>Willard MD, Simpson RB, Delles EK, Cohen ND, Fossum TW, Kolp D, Reinhart G. '''Effects of dietary supplementation of fructo-oligosaccharides on small intestinal bacterial overgrowth in dogs.''' ''Am J Vet Res. 1994 May;55(5):654-9.''</ref>.

 

==Prognosis==

==Prognosis==

For cases of secondary ARD, the prognosis depends on the underlying cause and success of treatment.  For cases of idiopathic ARD, the prognosis is guarded and many of them are likely to relapse when treatment is stopped, which may require a prolonged or life-long treatment.  Some cases, however, do resolve and only require a short term treatment.

For cases of secondary ARD, the prognosis depends on the underlying cause and success of treatment.  For cases of idiopathic ARD, the prognosis is guarded and many of them are likely to relapse when treatment is stopped, which may require prolonged or life-long treatment.  Some cases, however, do resolve and only require short term treatment.

 

==References==

==References==