HETEROTAXY SYNDROMES

-


What is situs solitus?

In situs solitus the viscera are in their normal positions (stomach and spleen on the left, liver on the right), the 3-lobed right lung is on the right, and the 2-lobed left lung on the left;the right atrium is on the right, and the left atrium is on the left. 

What is situs inversus?

The mirror image of situs solitus, in which there is a reversal of placement of the abdominal and thoracic structures resulting in a left-sided liver, right-sided stomach, left-sided IVC, right atria on the left side, and the left atria on the right side. 

With this arrangement, concordance among organs, vessels, and cardiac components is generally conserved.

situs inversus Diagram | Quizlet

What is heterotaxy?

Heterotaxy, derived from Greek (hetero, meaning "different," and taxy, meaning "arrangement"), is also referred to as visceral heterotaxy or heterotaxy syndrome. It is defined as an abnormal arrangement of the internal thoracic-abdominal organs across the left-right axis of the body. 

What is situs ambiguous or indeterminus?

Situs ambiguus is defined as abnormal arrangements of abdominal and thoracic organs that do not include situs inversus. Most cases of situs ambiguus are due to heterotaxy.

What is isomerism?

In a normal human body there is asymmetry of the thoracic and abdominal organs which gets lost in heterotaxy. 

This causes unusual degree of symmetry of organs and veins. 

The term "isomerism," derived from Greek (iso, meaning "equal," and meros, meaning "part"), refers to this abnormal developmental symmetry in which morphologic structures that normally develop on one side are found on both sides of the body and is the currently accepted term used to describe hearts with isomeric atria and atrial appendages.

So, in affected patients, instead of distinct left and right sides, individuals with isomerism will have either two right sides or two left sides resulting in either two right atria or two left atria (atrial isomerism).

What are the variations of heterotaxy?



There are 2 major variations

Asplenia syndrome - Right isomerism or bilateral right sidedness 

Polysplenia syndrome - left isomerism or bilateral left sidedness

What are the differences between asplenia and polysplenia syndrome?


Left sided isomerism


What can be the cause of heterotaxy ?

Human heterotaxia syndromes may be related to disorders in cilia and in utero left-right axis development. Genes involved in the Nodal signaling pathway,including NODAL (known asymmetric gene).

What is ventricular inversion?


Ventricular Inversion - an overview | ScienceDirect Topics


It is a condition in which the anatomic right ventricle of the heart is on the left side of the interventricular septum and the anatomic left ventricle is on the right. In this case, in the presence of situs solitus, the right atrium connects with the left ventricle and the left atrium with the right ventricle.

It results from l-looping of embryonic cardiac tube.

What is dextrocardia and levocardia?

Dextrocardia occurs when the heart is in the right side of the chest. Levocardia (the normal situation) is present when the heart is in the left side of the chest. 

What is dextroposition?

Anatomic or functional abnormalities of the lungs, diaphragm, and thoracic cage may result in displacement of the heart to the right (dextroposition ). In this case, however, the cardiac apex is pointed normally to the left.
Basic Adult Congenital Heart Disease (ACHD) | SpringerLink

Comments

Post a Comment

Popular posts from this blog

HYPOTHYROIDISM CLINICAL FEATURES

-
Image
     1.       What are the clinical features of congenital hypothyroidism in a newborn? The clinical manifestations are commonly subtle in newborns with congenital hypothyroidism (CH).   Newborns with CH may be asymptomatic because of presence of maternal T 4 (which contributes to approximately one-third of circulating T 4 in a newborn) and residual functioning thyroid tissue.   FEATURES AT BIRTH   The classical symptoms of congenital hypothyroidism include ·          lethargy, ·          hoarse cry, ·          feeding difficulty, ·          constipation not responding to treatment, and increased somnolence.   The characteristic signs of CH include ·          Prolonged neonatal jaundice, ·          Macroglossia, ·          Umbilical hernia, ·          Wide posterior fontanelle, ·          Hypotonia, ·          Dry skin, ·          Head circumference may be slightly increased d/t myxedema of brain ·          Hypothermia. ·          Hirsute for
Read more

Congenital Hypertrophic Pyloric Stenosis

-
Image
What are the parts of pylorus? The incisura angularis divides the stomach into a body to the left and a pyloric portion to the right. The sulcus intermedius further divides the pyloric portion of the stomach: the pyloric vestibule to the left, denoted by an outward convexity of the greater curvature. The pyloric antrum or pyloric canal to the right The pyloric antrum is 2.5 cm and terminates in pyloric orifice into duodenum.   What happens to the normal anatomical structural in CHPS? In infants with IHPS, the pyloric ring is no longer identifiable as a clearly definable separation between the normally distensible pyloric antrum and the duodenal cap. Instead, a channel of variable length (1.5–2.0 cm) corresponding to the pyloric canal separates the normally distensible portion of the antrum from the duodenal cap. ·          Infantile hypertrophic pyloric stenosis  was first fully described by  Harald Hirschsprung  in 1888. ·          IHPS VS CHPS - ????? IHPS is would b
Read more

TURNER SYNDROME

-
Image
What is the other name of Turner Syndrome? Ullrich-Turner syndrome  What is the m/c sex chromosome disorder in female? Turner syndrome and occurs in approximately 1 in 2000 to 1 in 2500 live female births. What are the genotypes of Turner syndrome? 45X monosomy in 45% of cases  45X mosaicism with normal cell line in 15% cases  X chromosome anomalies like - Isochromosome, Ring chromosome, Xp or Xq deletion Y chromosome mosaicism in 10-12% cases. What gene is responsible for short stature in Turner syndrome? SHOX (short stature homeobox-containing gene on the X-chromosome) is associated with short stature in Turner syndrome and in Leri-Weill dyschondrosteosis. What gene is responsible for gonadal insufficiency in Turner syndrome? BMP15 (bone morphogenetic protein 15 (BMP15) on the short arm of the X chromosome (Xp)). What is the frequency of the 45X karyotype at conception? 3% approx, but  99% of these are spontaneously aborted, accounting for 5–10% of all abortuses. Mosaics are found to
Read more