Situs Inversus

Situs Inversus is a very rare condition that is marked by “mirror image” positioning of major organs within the human body. Read on to know all about this condition including its various forms, causes and symptoms.

Situs Inversus Definition

This is a rare disease that leads to a mirror image organization of the organs in the stomach and chest. The term “Situs Inversus” is an abbreviation of “Situs Inversus Viscerum” which is a Latin phrase that stands for “inverted placement of the internal organs”.

Situs Inversus Incidence

The prevalence of this disease varies among various populations. However, it has been estimated to affect less than 1 in 10,000 individuals.

Situs Inversus Causes

The exact cause of Situs inversus has not yet been determined. However, approximately 25% individuals with this disorder have been estimated to be having a congenital condition known as Kartagener’s Syndrome that is also characterised by lung and sinus infections. Kartagener’s Syndrome is also referred to as Primary Ciliary Dyskinesia (PCD) and is regarded to be an underlying causative factor for this syndrome.

Kartagener’s Syndrome is characterized by extremely discomforting signs like

• Increased secretion of mucous from the lungs
• Chronic infections of the sinus
• Heightened susceptibility to Infections of the respiratory system

PCD has been found to be a result of a defect in the cilia that affects the normal movements of these hair-like structures.

Most cases of this disease are sporadic, apart from Kartagener Syndrome. Once it appears in pregnancy, it does not show any sign of recurrence in later maternities. In such cases, there can be a new, self-generated mutation or participation of multiple genes in association with environmental factors that collectively influence the appearing of this disease. Several genes of different varieties involved in the procedure of determining the normal intrauterine development direction have been located. Damage to any of these can give rise to Situs Inversus.

Situs Inversus Symptoms

This congenital disorder leads to a reversal of the major visceral organs. The organs get positioned in a manner that is a mirror image of their original posture. The normal position of the organs is known as “Situs Solitus”. Situs Inversus is the contrary of Situs Solitus.

Situs Inversus and Heart

This condition usually results in the heart positioning itself in the other side of the chest. This condition is known as Mirror Image Dextrocardia.

In rare cases, however, there is not a complete heart movement to the opposite side. This is known as Levocardia.

Situs Inversus Complications

This condition does not give rise to complications very frequently. The infrequent complications that usually arise from this disorder include lung complications, organ donation problems and heart disease. Complications may also arise due to wrong diagnosis of this condition.

Heart Disease

A small population with this condition may also suffer from congenital heart ailments. Most patients do not have major problem due to this alignment. However, it is an abnormal phenomenon to have everything in reverse posture.

Primary Ciliary Dyskinesia

According to medical professionals, some people with this disorder also have an underlying disease that is known as Primary Ciliary Dyskinesia. The condition is associated with the posture of the cilia or the small hairs that may be found within the lungs. The Cilia extends protection to the lungs and the body from infection by acting as a filter and removing dust and other particles that can be found in the air. People with this condition may suffer from an impaired functioning of the cilia that affects normal motion of these hairy structures, leading to the accumulation of a greater amount of mucus in the lungs. This can cause respiratory infections and also make a patient with Situs Inversus highly susceptible to chronic sinus infections.

Organ Donation

This disorder can also give rise in patients who undergo an operation for organ donation. This is a rare condition and organs from most donors come from healthy people who have their organs located in normal position. The problem arises due to difficulties in setting an organ into a cavity which is exactly opposite in shape and has the reverse blood vessel orientation.

Situs Inversus and Genetics

Situs inversus is usually an autosomal recessive genetic disorder. However, it can be linked to X-chromosomes. It may also be found in “Identical Twins” or “Mirror Twins”.

Situs Inversus with Dextrocardia

Dextrocardia with Situs Inversus is a type of heart condition that arises only rarely and is marked by unusual positioning of the heart. In this disorder, the apex (tip) of the heart is placed on the right area of the chest. Moreover, the placement of the visceral organs like the spleen and liver as well as the position of the cardiac chambers is transposed (Situs Inversus). However, most sufferers can lead a normal life without suffering from disabilities or related symptoms.

Situs Inversus Totalis is another name for Situs inversus with Dextrocardia. Inversus refers to the inverted position of the abdominal viscera, atrial chambers and the heart. All these organs are located in a posture that is a mirror image of their normal anatomical location. Complete Situs Inversus or Situs Inversus Totalis has been found to appear once in approximately 6,000 to 8,000 births.

Abdominal Situs Inversus

This is the name given to a condition that is characterized by the reverse positioning of the intra-abdominal organs such as the liver and the spleen in the abdominal cavity. In this condition, the liver and the spleen can be found in the left side and the right side respectively. The disorder is also characterized by multiple congenital defects.

Situs Inversus with Levocardia

This is a very rare condition that is also known by the name “Situs Inversus Incompletus”. This Partial Situs Inversus arises when the heart is positioned in the left area of the thorax. It is a case of Dextrocardia without Situs Inversus and may be found only in one out 22,000 individuals. It is associated with higher cases of congenital defects than Situs Inversus Totalis.

Visceral Situs Inversus

It is a health disorder that arises when the viscera are positioned on an opposite side. This condition may vary in range. There may only be ten to twenty cases. The disease may also be present in as high a population as one hundred thousand individuals.