Situs inversus totalis

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Situs inversus totalis in a dog, showing inverted cardiac silhouette, stomach on right side and complete inversion of intestines[1]

Situs inversus totalis (Kartagener’s syndrome) is a rare congenital malformation characterized by a complete reversal of organ placement within the body, producing an anatomical mirror-image of normal placement.

During the embryological development, a 270 degree clockwise rotation instead of normal 270 degree anti-clockwise of the developing thoraco-abdominal organs results in mirror image positioning of the abdominal and thoracic viscera from the normal (Situs solitus) to the abnormal position[2].

The cause of this disease is presently unknown, but in the English Springer Spaniel, it is thought to be due to an autosomal-recessive mutation[3].

In dogs, it has been reported in association with primary ciliary dyskinesia, hydrocephalus internus and cardiac malformations[4]. In these cases, the dogs had severe respiratory abnormalities due to bronchitis, rhinitis, sinusitis and short survival times[5].

In one case, congestive heart failure ensued due to an underlying ventricular septal defect, severe subaortic stenosis and tricuspid dysplasia.

In some cases, diagnosis is established incidentally during routine laparotomy and as a consequence, this disease may be more prevalent than realized[6].

Although situs inversus totalis is not life-threatening per se, concurrent genetic anomalies usually result in elective euthanasia due to poor quality of life.

References

  1. Piantedosi D et al (2011) Situs inversus totalis associated with subaortic stenosis, restrictive ventricular septal defect, and tricuspid dysplasia in an adult dog. Can Vet J 52(11):1237-1242
  2. Song JY et al (2004) Laparoscopic appendicectomy in a female patient with situs inversus: Case report and literature review. JSLS 8:175–177
  3. Edwards DF et al (1989) Familial immotile-cilia-syndrome in English springer spaniel dogs. Am J Med Genet 33:290–298
  4. Reichler IM et al (2001) Primary ciliary dyskinesia with situs inversus totalis, hydrocephalus internus and cardiac malformations in a dog. J Small Anim Pract 42(7):345-348
  5. Durant AM et al (2008) What is your diagnosis? Thoracic and abdominal situs inversus totalis. J Am Vet Med Assoc 232(2):197-198
  6. Witsberger TH et al (2009) Situs inversus totalis in a dog with a chronic diaphragmatic hernia. J Am Anim Hosp Assoc 45(5):245-248