Tetralogy of Fallot

Tetralogy of Fallot

is the most common Cyanotic heart disease in children. The condition causes mixing of deoxygenated blood with the oxygenated blood being pumped out of the heart and into the circulatory system of blood vessels, Causing-

• hypoxemia.
  
  
• cyanosis, a bluish color of the skin, lips, and membranes inside the mouth and nose.

The 4 abnormalities (tetralogy) of the heart described by Fallot include the following:

• Right ventricular hypertrophy: Narrowing or blockage of the pulmonary valve and/or muscle under the pulmonary valve coming out of the right ventricle. This restriction to blood outflow causes an increase in right ventricular work and pressure, leading to right ventricular thickening or hypertrophy.
  
  
• Ventricular septal defect (VSD): This is a hole in the heart wall (septum) that separates the 2 ventricles. The hole is usually large and allows oxygen-poor blood in the right ventricle to pass through, mixing with oxygen-rich blood in the left ventricle. This poorly oxygenated blood is then pumped out of the left ventricle to the rest of the body. The body gets some oxygen, but not all that it needs. This lack of oxygen in the blood causes cyanosis.
  
  
• Abnormal position of the aorta: The aorta, the main artery carrying blood out of the heart and into the circulatory system, exits the heart from a position overriding the right and left ventricles. (In the normal heart, the aorta exits from the left ventricle.) This is not of major importance in infants.
  
  
• Pulmonary valve stenosis (PS): The major issue with tetralogy of Fallot is the degree of pulmonary valve stenosis, since VSD is always present. If the stenosis is mild, minimal cyanosis occurs, since blood still mostly travels to the lungs. However, if the PS is moderate to severe, a smaller amount of blood reaches the lungs, since most is shunted right-to-left through the VSD

Investigations:

CXR - baseline
ECG - yearly to assess rhythm and QRS duration
TTE - regularly (yearly or more frequent if severe PR and RV dysfunction, can be 2 or 3 yearly if very good surgical result and no new symptoms) (NB. It is easy to under estimate the degree of PR by colour follow alone) To assess pulmonary valve function, proximal PA anatomy, RV size and function, LV function, aortic root size and degree of aortic regurgitation.
Catheterisation - for dilatation / stenting of pulmonary arteries
MRI - becoming investigation of choice for proximal pulmonary artery anatomy, RV size and function and assessment of pulmonary regurgitation
Holter - for symptoms and screening for VT or high grade ectopy in those with marked RV dilatation or QRS > 180ms
Exercise test / CPEX - exercise capacity serial assessment, pre-pregnancy counselling

Additional investigations - EP studies for those with symptomatic atrial or ventricular arrhythmias or unexplained syncope or pre-syncope


Indications for intervention

Unrepaired tetralogy of Fallot (at any age)
Significant RVOT or branch PA stenosis (RV pressure > half systemic)
Severe pulmonary regurgitation with dilatation and dysfunction of the RV
Aortic regurgitation
Arrhythmias in presence of repairable haemodynamic sequela

TREATMENT OPTIONS
Surgery (+/- anti-arrhythmia procedures)

Percutaneous pulmonary valve implantation (for those with an RV to PA conduit of suitable size only)

Percutaneous pulmonary artery angioplasty and stenting

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ANENCEPHALY

Marfan Syndome: Tall is not always Gold

Marfan syndrome

is an autosomal dominant genetic disorder of the connective tissue characterized by disproportionately long limbs, long thin fingers, a typically tall stature, and a predisposition to cardiovascular abnormalities, specifically those affecting the heart valves and aorta. The disorder may also affect numerous other structures and organs — including the lungs, eyes, dural sac surrounding the spinal cord, and hard palate. It is named after Antoine Marfan, the French pediatrician

Symptoms

Three systems are predominantly affected.

Ocular:
upward lens dislocation
retinal detachment

Skeletal:
arachnodactyly
tall with disproportionately long legs and arms - the span of the arms is greater than the height
pectus excavatum
spinal abnormalities - spondylolisthesis, scoliosis
increased incidence of slipped upper femoral epiphysis
generalised joint laxity with predisposition to flat feet or dislocation of patella or shoulder

Cardiovascular
- affecting the aortic and mitral valves and the ascending aorta:
dilatation of the aorta may be noted at any age, beginning at the aortic valve and usually confined to the ascending aorta
aortic insufficiency may result from stretching of the aortic valve ring and a dissecting aneurysm of the aorta may be a terminal event. Rarely, it occurs during pregnancy
mitral insufficiency results from redundant cusps and chordae tendineae
other cardiac malformations have occasionally been reported
Mental development is normal.

The average lifespan of an affected individual is 40 to 50 years.



Skeletal system
The most readily visible signs are associated with the skeletal system. Many individuals with Marfan Syndrome grow to above average height. Some have long slender limbs with fingers and toes that are also abnormally long and slender (arachnodactyly). This long, slender body habitus and long, slender limbs are known as dolichostenomelia. An individual's arms may be disproportionately long, with thin, weak wrists. In addition to affecting height and limb proportions, Marfan syndrome can produce other skeletal signs. Abnormal curvature of the spine (scoliosis) is common, as is abnormal indentation (pectus excavatum) or protrusion (pectus carinatum) of the sternum. Other signs include abnormal joint flexibility, a high palate, malocclusions, flat feet, stooped shoulders, unexplained stretch marks on the skin and thin wrists. Some people with Marfan have speech disorders resulting from symptomatic high palates and small jaws.


Eyes
Marfan syndrome can also seriously affect the eyes and vision. Nearsightedness and astigmatism are common, but farsightedness can also result. Periodic eye exams can lead to an ophthalmologist or optometrist discovering dislocation, or subluxation, of the crystalline lens in one or both eyes (ectopia lentis) by carefully observing these structures using a slit-lamp biomicroscope. This can be differentiated from the similar condition homocystinuria, where the dislocation is inferonasal; in Marfan's the dislocation is superotemporal. Sometimes eye problems appear only after the weakening of connective tissue has caused detachment of the retina.Early onset glaucoma can be another complication.


Cardiovascular system
The most serious conditions associated with Marfan syndrome involve the cardiovascular system. Undue fatigue, shortness of breath, heart palpitations, racing heartbeats, or pain in the left chest, back, shoulder, or arm, can bring a person into the doctor's office. Cold arms, hands and feet can also be seriously linked to marfan syndrome because of a loss of blood circulation. A heart murmur heard on a stethoscope, an abnormal reading on an electrocardiogram, or symptoms of angina can lead a doctor to order an echocardiogram. This can reveal signs of leakage or prolapse of the mitral or aortic valves that control the flow of blood through the heart. (See mitral valve prolapse.) However, the major sign that would lead a doctor to consider an underlying condition is a dilated aorta or an aortic aneurysm. Sometimes, no heart problems are apparent until the weakening of the connective tissue in the ascending aorta causes an aortic aneurysm or even aortic dissection.



Lungs
Marfan syndrome is a risk factor for spontaneous pneumothorax. In spontaneous unilateral pneumothorax, air escapes from a lung and occupies the pleural space between the chest wall and a lung. The lung becomes partially compressed or collapsed. This can cause pain, shortness of breath, cyanosis, and, if not treated, death. Marfan syndrome has also been associated with sleep apnea and idiopathic obstructive lung disease.


Central nervous system
Another condition that can reduce the quality of life for an individual, though not life-threatening, is dural ectasia, the weakening of the connective tissue of the dural sac, the membrane that encases the spinal cord. Dural ectasia can be present for a long time without producing any noticeable symptoms. Symptoms that can occur are lower back pain, leg pain, abdominal pain, other neurological symptoms in the lower extremities, or headaches. Such symptoms usually diminish when the individual lies flat on his or her back. These types of symptoms might lead a doctor to order an X-ray of the lower spine. Dural ectasia is usually not visible on an X-ray in the early phases. A worsening of symptoms and the lack of finding any other cause should eventually lead a doctor to order an upright MRI of the lower spine. Dural ectasia that has progressed to the point of causing these symptoms would appear in an upright MRI image as a dilated pouch that is wearing away at the lumbar vertebrae. Other spinal issues associated with Marfan include degenerative disk disease and spinal cysts.