Vagus Indigestion or Hoflund Syndrome is a chronic disease of fore stomach and abomasum that is clinically characterised by prolonged anorexia, scanty feces, and a papple-shaped abdomen due to gradual distension and weight loss.
Etiology
- Sequelae of TRP: In the majority of cases, either FB or the lesions associated with FB cause damage to the vagus nerve, especially the ventral branch, which ramifies the ventral part of the reticulum.
- Abscess near the reticulo-omasal junction.
- Actinobacillosis of the rumen and reticulum.
- Lymphadenopathies: Due to EBL, TB adjoining the vagus nerve in the thoracic cavity.
Pathogenesis
Vagus indigestion can be caused by two mechanisms, depending on the part of the vagus nerve affected:
- Anterior functional stenosis: Achalasia is the dysfunction of the reticulo-omasal sphincter; this is called anterior functional stenosis. No outflow of reticular contents to the omasum leads to accumulation of contents in the rumen and reticulum, and results in ruminal hypermotility and develops into frothy bloat, leading to distension of the abdomen. Similar pathogenesis is observed in diaphragmatic hernia. Over a period of time, because of this chronic vagus indigestion, there is a typical appearance of the abdomen. If the animal is observed from the rear side, it is sagging on the right side, which looks like a pear-shaped and capped prominence on the left side. This is called papple abdomen, followed by uniform distension of the abdomen in later stages.
- Posterior functional stenosis: which results because of pyloric stenosis. There is no outflow of abomasal contents to duodenum and regurgitation of abomasal contents in the anterior chambers (internal vomition). Low pH in the rumen is due to hydrochloric acidosis, called latent hydrochloric acidosis. This is called abomasal reflux syndrome.
Varying degrees of dehydration and metabolic alkalosis due to hypochloremia are major systemic changes.
Clinical findings
Prolonged inappetence, unresponsiveness to treatment, recurrent episodes of frothy bloat, typical appearance of the (papple-shaped) abdomen, and passing of scanty faeces. Initially, hypermotility of the rumen (4-5 contractions per 2 minutes) was followed by hypomotility of the rumen. Bradycardia with a systolic murmur audible during inspiration is characteristic sign of the Vagus Indigestion or Hoflund Syndrome.
Diagnosis
- Based on the clinical signs: papple-shaped abdomen, unresponsive prolonged anorexia, and recurrent bloat.
- Based on the laboratory investigation: It reveals hypochloremia and hypokalemia; the pH of the ruminal fluid is acidic due to elevated chloride, which indicates abomasal reflux.
Differential Diagnosis
- Diaphragmatic Hernia: Most of the signs are similar except for displaced heart sounds.
- Omasal impaction: impacted firm mass can be palpated per rectally.
Treatment
Usually, the prognosis is unfavourable because the extent of damage to the vagus nerve is unpredictable.
- Rumenotomy and lavage with warm water.
- Nervine tonics: improve the functioning ability of the nerves. Ex: B1, B6, and B12.
- Administration of DOSS: Dioctile sodium sulfo-succinate acts as a motility modifier, dispenses substances, causes segregation of contents, and helps in evacuation. It is administered as 120–130 ml in 5–6 L of mineral oil.
- The efficacy of cisapride, also a motility modifier, is not yet ascertained in large animal practice.
