Diaphragmatic Hernia (DH)
Diaphragmatic Hernia (DH) is the herniation of the GI parts through the diaphragm into the thoracic cavity. The majority of the time, it is a consequence of TRP in ruminants. It is clinically characterised by recurrent tympani, which is of the frothy type, prolonged anorexia, and displacement of the heart sound anteriorly.
Etiology
- It is a sequelae to TRP. Most of the cases are the result of weakening of the diaphragm due to the lesions or injury caused by TRP.
- DH is common in buffaloes because there is inherent weakness at the centre of the diaphragm, just opposite the reticulum. The incidence is higher in pregnant animals due to the gravid uterus, which causes increased intra-abdominal pressure, facilitating herniation.
- Sometimes severe strain during the act of parturition also precipitates herniation.
Epidemiology
The incidence is more common in buffaloes, especially in pregnancy or immediately after parturition.
Pathogenesis
Lesions of TRP or foreign body (FB) weaken the diaphragm, and sometimes it may cause laceration, leading to herniation of the reticulum into the thoracic cavity. The possibility is greater during advanced pregnancy and immediately after parturition. Increased intra-abdominal pressure due to the gravid uterus and forceful contractions during calving facilitate herniation.
Outcome
Reticulum causes adhesion with the diaphragm and thoracic organs, leading to decreased contractions. Fixation of the reticulum causes closure of the reticulo-omasal orifice, which interferes with the outflow of contents into the omasum, resulting in the accumulation of contents. There by forming stable froth (frothy bloat). Intra-ruminal pressure in the advanced stage of DH becomes so high that the contents are sometimes regurgitated through the mouth and nostrils.
Clinical Signs
Capricious type of appetite (variable type), there is loss of condition, persistent abdominal distension/tympani, grinding of teeth, faeces usually are scanty, and most of the time it is pasty. Regurgitation of ruminal contents is noticed in the advanced stage of DH. Most of these cases have a history of earlier treatment for prolonged inappetite without success or improvement. On auscultation, heart sounds are displaced anteriorly coupled with a systolic murmur. The reticular sounds are audible just behind the cardiac area (5-8th inter-coastal space).
Adhesions formed between the reticulum and thoracic organs make the prognosis unfavourable, and most of the cases die in about 3–4 weeks after the onset of bloating.
Diagnosis
History of signs of TRP:
- History of discomfort, pain at xiphoid, recurrent tympani, and arched back.
- History of pregnancy or recent parturition.
Based on the clinical signs: chronic recurrent tympani, which is a frothy type confirmed by paracentesis, displaced heart sounds and reticular sounds, prolonged inappetite, unresponsiveness to treatment, and regurgitation of ruminal contents are suggestive.
Radiography of the thorax (500 mA skiagram):
- Barium-meal contrast radiography reveals a herniated reticulum.
- A plane radiograph reveals a displaced heart and a discontinuity in the diaphragm.
Exploratory laparotomy can diagnose the condition of diaphragmatic hernia (DH).
Differential Diagnosis
Vagus indigestion: here also chronic recurrent bloat and hypermotility of the rumen, but displacement of the heart and reticular sounds are absent.
Treatment
A transabdominal ventrolateral laprotomy on the right or left side is done in dorsal recumbency:
- Surgical intervention is taken along with the coastal arch.
- Adhesions are removed.
- Reticulum is pulled back.
- Herniorrhaphy or hernioplasty is done.
Thoracotomy:
- It is indicated when too many adhesions are found.
- 1/3rd of the ribs are resected, and provision is made to approach hernial ring. Adhesions are removed, the reticulum is pushed back, and herniorrhapy is done to close the defect in the diaphragm.