UNDERSTANDING SITUS INVERSUS: BORN WITH "FLIPPED" ORGANS
Medically Reviewed by Dr. Sony Sherpa, (MBBS)
Have you ever wondered if your internal organs are in the same position as everyone else's? The answer may surprise you. While most people have their organs typically arranged, a rare condition called Situs Inversus causes the organs to be flipped or mirrored.
This article will explore situs inversus, its types and causes, symptoms and associated conditions, diagnosis, treatment and management, and the latest developments in understanding this condition.
What is Situs Inversus?
Situs inversus is a shorter version of situs inversus viscerum, which refers to an inversion of the heart and organs in the abdominal cavity. The typical arrangement of internal organs is called Situs Solitus.[1]
Also known as Flipped Organs or Mirror Image Anatomy, it is a rare congenital condition where the internal organs develop in utero in a mirror image of their normal position. This means that the organs on the left side of the body are on the right side, and vice versa.[2]
There are three main types of situs inversus:
- Situs inversus totalis: The placement of all the organs is in a complete mirror-image reversal of situs solitus. This is the most common type of situs inversus.
- Situs inversus incompletus or partialus: This type only affects some abdominal organs. It most commonly involves the inversion of the placement of the heart, known as dextrocardia or situs inversus with levocardia.
- Situs ambiguous (heterotaxy): Organs are positioned abnormally without a consistent right-left pattern.
Situs inversus affects 1 in 6,500-25,000 live births, with a slightly higher male prevalence (1.5:1). While this condition may sound alarming, it is usually harmless and does not cause health problems.
Many people with situs inversus may only know they have it if they undergo medical imaging or surgery. In some cases, situs inversus can be associated with other health conditions, particularly congenital heart deformities.
Causes of Situs Inversus
The exact cause of situs inversus is still being investigated, yet it correlates strongly with genetic factors. During early embryonic development, specific genes and proteins guide the left-right positioning of organs. Disruptions in this process can lead to situs inversus.
While poorly understood, researchers have uncovered more than 100 genetic mutations responsible for multiple forms of situs inversus[3], specifically in genes involved in cilia (hair-like structures on cells). Ciliary dysfunction often disrupts the signaling that determines left-right orientation in the embryo.[4]
The condition sometimes causes the incidence of mirror image twins, in which one twin develops organ inversion due to a later-than-usual embryonic split during early pregnancy.[5]
In some cases, situs inversus follows an autosomal recessive inheritance pattern, meaning both parents carry the gene and have a 25% chance of passing it on to their child[6]. However, situs inversus occurs randomly and is not usually inherited.
Symptoms and Associated Conditions
In most cases, situs inversus does not cause any symptoms or health problems.
It can sometimes be associated with other conditions that may cause symptoms. These conditions include:
Congenital Heart Defects
Some of the most common conditions associated with situs inversus are congenital heart defects, present in 5-10% of people with the condition.[7] These are structural problems with the heart that are present at birth.
In those with situs inversus, the heart is flipped, affecting how the blood flows through the heart and the rest of the body. This can lead to several outcomes, such as transposition of the great vessels like an inverted aorta and pulmonary artery, or dextrocardia, where the heart is on the right side of the body.[8]
Primary Ciliary Dyskinesia (PCD)
Primary Ciliary Dyskinesia (PCD) is a rare hereditary disorder that affects the cilia, microscopic hair-like structures that line various tissues, including the respiratory tract.
The changes that cause cilia dysfunction can lead to situs inversus totalis, which affects up to 50% of people with PCD.[9] The combined condition is known as Kartagener Syndrome, and it can cause chronic respiratory infections, sinus problems, and infertility. Roughly 20% of those with situs inversus have Kartagener syndrome, which results in sinusitis and bronchiectasis.[10]
Symptoms can include:
- Ongoing nasal blockage featuring dense nasal discharge and sinusitis
- A persistent cough that produces mucus
- Shortness of breath
- Chronic middle ear infections
- Frequent bouts of pneumonia or chest infections
Other Associated Conditions
Other conditions associated with situs inversus include liver and spleen abnormalities, intestinal malrotation, and kidney abnormalities.
Rarely, mirror image anatomy is associated with asplenia (absence of the spleen) and polysplenia (more than one spleen).
These health conditions may cause additional symptoms, including abdominal pain, digestive problems, and urinary tract infections.
Diagnosis
Situs inversus is usually accidentally diagnosed during medical imaging, such as X-rays, MRI scans, CT scans, or ultrasounds.[11] These imaging techniques reveal the organs' position and determine their orientation.
A doctor may suspect situs inversus when listening to the heartbeat, as they will struggle to hear the heart on the usual left-hand side.
In some cases, situs inversus may be diagnosed during surgery, where the surgeon may notice that the organs are in a different position than expected.
Risks of Situs Inversus
Having situs inversus does not necessarily mean you are at a higher risk of developing health problems. However, you should be aware of some risks associated with this condition.
One of the main risks of having situs inversus is misdiagnosis.
Since most medical professionals are used to seeing organs in regular positions, they may not recognize the patient has inverted organs. This can result in misdiagnosis, incorrect treatment, and further complications, such as failure to detect potentially life-threatening situations and inappropriate prescriptions.
Appendicitis is a typical example of a possibly life-threatening condition where the appendix becomes inflamed and requires prompt treatment. The diagnosis often involves blood tests, a physical examination, and imaging, such as an x-ray.[12]
In situs inversus, the inverted appendix is on the left side of the body instead of the right. A doctor may miss the appendix or diagnose the condition as an abnormal growth, as the appendix looks like a small extension of the gastrointestinal tract. This is a potentially life-threatening scenario for a patient with an inverted appendix requiring treatment.
Where the patient is aware of his or her condition, it is important to inform the doctor to avoid any potential misdiagnosis or delays in treatment.
Treatment and Management
In most cases, situs inversus does not require any treatment or management. However, if you have associated conditions, such as congenital heart defects or PCD, these conditions will need appropriate treatment. This may involve medications, lifestyle modifications, or frequent follow-up appointments for monitoring and surgery.
If you are aware that you have situs inversus and need surgery, it is crucial to inform your surgeon beforehand so they can prepare optimally for the flipped organs.
In some instances, the surgeon may need to adjust their usual surgical techniques to accommodate the flipped organs. For example, laparoscopic cholecystectomy (gallbladder removal) in a patient with situs inversus might require adjustments in the surgeon's positioning and port placement.
Living with Situs Inversus
It is normal to feel anxious about having situs inversus. However, life expectancy is not affected for most individuals, and those with the condition can live optimal, healthy lives.
Open communication with your healthcare providers can help alleviate concerns and ensure you receive adequate treatment for any associated conditions.
However, there are some things to remember if you have this condition.
Athletes with Situs Inversus
If you are an athlete with situs inversus, you may need to inform your coach or trainer about your condition. This is especially important if you participate in contact sports, as your flipped organs may be more vulnerable to injury.
Pregnancy
If you have situs inversus and are pregnant, you may need to inform your doctor about your condition. Situs inversus may affect the baby's position in the womb, which may require special care during delivery.
Can you have children with Situs Inversus?
Having situs inversus does not affect your ability to have children. However, if you have Primary Ciliary Dyskinesia (PCD), it may affect fertility. It is important to relay any concerns you have about fertility to your doctor.
Latest Developments
Researchers are constantly studying situs inversus to better understand its causes and associated conditions. In recent years, there have been advancements in understanding the genetic mutations that cause situs inversus and the role of cilia in this condition. These developments may lead to better diagnosis and treatment options in the future.
Conclusion
Situs inversus is an uncommon condition that affects the position of the internal organs. While it may sound alarming, it is usually harmless and does not cause any health problems. However, it is essential to be aware of any associated conditions and inform your doctor if you are aware that you have situs inversus to avoid potential misdiagnosis. With advancements in research, we may better understand this condition and its impact on our health.
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