Tetralogy of Fallot

What It Is

Tetralogy of Fallot has four key features. A ventricular septal defect (a hole between the ventricles) and many levels of obstruction from the right ventricle to the lungs (pulmonary stenosis) are the most important. Also, the aorta (major artery from the heart to the body) lies directly over the ventricular septal defect, and the right ventricle develops thickened muscle. Because the aorta overrides the ventricular defect and there's pulmonary stenosis, blood from both ventricles (oxygen-rich and oxygen-poor) is pumped into the body. Sometimes the pulmonary valve is completely obstructed (pulmonary atresia). Infants and young children with unrepaired tetralogy of Fallot are often blue (cyanotic). The reason is that some oxygen-poor blood is pumped to the body. Surgical TreatmentTetralogy of Fallot is treated surgically. A temporary operation may be done at first if the baby is small. Complete repair comes later. Sometimes, the first operation is a complete intracardiac repair. Temporary OperationIn small and very blue infants, a shunt operation may be done first to provide adequate blood flow to the lungs. This lets the baby grow big enough to have a full repair. The shunt is built between the aorta and the pulmonary artery. The shunt is removed when a complete intracardiac repair is done later.

Complete Repair

Complete repair tends to be done early in life. Once it was more common to do a temporary operation first and a complete repair later in childhood. To do a complete repair, the surgeon closes the ventricular septal defect with a patch and opens the right ventricular outflow tract by removing some thickened muscle below the pulmonary valve, repairing or removing the pulmonary valve and enlarging the peripheral pulmonary arteries that go to both lungs. Sometimes a tube is placed between the right ventricle and the pulmonary artery. This is sometimes called a Rastelli repair.

(www.americanheart.org)

Cerebellar Pilocytic Astrocytoma

What is a cerebellar pilocytic astrocytoma?
(grade I pilocytic astrocytoma of the cerebellum)
(grade II fibrillary astrocytoma of the cerebellum)

A cerebellar low-grade glioma is a tumor arising from a type of cell of the central nervous system known as a glial cell. These tumors originate from a specific type of glial cell known as an astrocyte. Astrocytes make up the supportive network of the brain. These cells are named for their star-like appearance.

As you read further below, you will find general information about cerebellar low-grade glioma. If you would like to view summary information about brain tumors first, see the overview on brain tumors.

Cerebellar low-grade gliomas are astrocytomas that arise in the location of the brain known as the cerebellum. The cerebellum is the center of the brain that controls balance and coordination. Of patients with cerebellar low-grade gliomas, 80-85 percent have what is called grade I pilocytic astrocytomas, and the remaining 15-20 percent have what is called grade II fibrillary astrocytomas. These cerebellar astrocytomas account for 10-20 percent of all childhood brain tumors. They tend to occur before the age of 10 years, most commonly between the ages of 6 and 9.

What causes cerebellar low-grade gliomas?
Children with certain genetic syndromes, including neurofibromatosis type I and tuberous sclerosis, are at higher risk of developing tumors of glial origin, including cerebellar low-grade gliomas. The vast majority of children with cerebellar low-grade gliomas however, develop these tumors spontaneously, meaning there is no identifiable cause.

What are the symptoms of a cerebellar low-grade glioma?
Due to the relative slow growth rate of cerebellar low-grade gliomas, children with these tumors tend to present to the doctor with symptoms that have been occurring for many months. Some children, however, have a more sudden onset of symptoms. The following are the most common symptoms of a cerebellar low-grade glioma, however, each child may experience symptoms differently. Common symptoms may include:

Oh more that 90 percent of patients present with symptoms of increased pressure within the brain. These symptoms include:
*headache (generally upon awakening in the morning)
*vomiting
*fatigue
*Oh the majority of children have evidence of difficulty with balance and coordination

The symptoms of a brain tumor may resemble other conditions or medical problems. Always consult your child's physician for a diagnosis.

How is a cerebellar low-grade glioma diagnosed?
Diagnostic procedures for a cerebellar low-grade glioma may include:
*physical examination - the child may demonstrate difficulty walking and coordinating movements of the hands and/or legs
*computerized tomography scan (also called a CT or CAT scan) - a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. CT scans are more detailed than general x-rays. For cerebellar low-grade gliomas, a CT scan of the brain is usually done.
*magnetic resonance imaging (MRI) - a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body. For cerebellar low-grade gliomas, an MRI of the brain is usually done. In rare cases when cerebellar low-grade gliomas spread to the spine, an MRI of the spine may also be ordered.
*biopsy - in many cases, a tissue sample from the tumor will be taken through a needle during a simple surgical procedure performed by a surgeon to confirm the diagnosis

What are the treatments for a cerebellar low-grade glioma?
Specific treatment for a cerebellar low-grade glioma will be determined by your child's physician based on:
*your child's age, overall health, and medical history
*type, location, and size of the tumor
*extent of the disease
*your child's tolerance for specific medications, procedures, or therapies
*how your child's doctors expects the disease to progress
*your opinion or preference

Treatment may include (alone or in combination):
*surgery - the initial treatment is surgery, and complete tumor removal is associated with a very high rate of cure. In cases when the tumor recurs after initial surgical removal, or if the tumor re-grows after partial surgical removal, the recommended treatment would be a second attempt at surgical removal/de-bulking of the tumor.
*radiation and chemotherapy - in cases of residual/recurrent disease, where maximal surgical removal has been achieved, alternative treatment options include chemotherapy and radiation therapy:
*chemotherapy - a drug treatment that works by interfering with the cancer cell's ability to grow or reproduce. Different groups of chemotherapy drugs work in different ways to fight cancer cells and shrink tumors. Often, a combination of chemotherapy drugs is used to fight a specific cancer. Certain chemotherapy drugs may be given in a specific order depending on the type of cancer it is being used to treat.A number of combinations of chemotherapy drugs are being tested to treat cerebellar low-grade gliomas, including vincristine with carboplatin, and vincristine with CCNU, procarbazine and thioguanine. While chemotherapy can be quite effective in treating certain cancers, the agents do not differentiate normal healthy cells from cancer cells. Because of this, there can be many adverse side effects during treatment. Being able to anticipate these side effects can help the care team, parents, and child prepare, and, in some cases, prevent these symptoms from occurring, if possible. Chemotherapy is systemic treatment, meaning it is introduced to the bloodstream and travels throughout the body to kill cancer cells.

Chemotherapy can be given:
*as a pill to swallow
*as an injection into the muscle or fat tissue
*intravenously (directly to the bloodstream; also called IV)
*intrathecally - chemotherapy given directly into the spinal column with a needle
*radiation therapy - using high-energy rays (radiation) from a specialized machine to damage or *kill cancer cells and shrink tumors. Radiation therapy to the tumor bed is also being used for recurrent disease.

The effectiveness of these methods of treatment is still being studied. There is some evidence to suggest that the use of chemotherapy and/or radiation therapy may increase long-term survival in children with incompletely removal tumors.

How are side effects of treatment managed?
Children with cerebellar low-grade gliomas may have side effects related to the tumor itself and its treatment. Symptoms at the time of diagnosis related to increased pressure within the brain, such as headache, vomiting and lethargy, are often relieved by surgical removal of the tumor. Effects on coordination and balance are also often improved with surgical removal of the tumor that is compressing structures that control these functions. Dexamethasone, an oral steroid, is often used, especially in the post-operative period, to assist in controlling these systems as well as any additional tissue swelling that may occur post-operatively.

Common side effects related to chemotherapy include nausea, vomiting and decreased blood counts (i.e. anemia). Anti-emetics (anti-nausea) medications are administered with the chemotherapy to control symptoms of nausea and vomiting. Occasionally, children receiving chemotherapy will require transfusion of red blood cells and/or platelets to replace these cells, since chemotherapy temporarily decreases the body's ability to produce red blood cells and platelets. White blood cells are reduced with chemotherapy, however these cells are not transfused. Occasionally, children will receive a medication to assist the body in producing white blood cells. Radiation therapy may cause swelling related to tissue inflammation. This inflammation may lead to symptoms of headache or difficulty with coordination. These symptoms, if significant, may be treated with the oral medication dexamethasone.

What is the expected outcome after treatment for cerebellar low-grade glioma?
Grade I cerebellar gliomas are associated with a 10-year survival rate of 70-100 percent after surgical removal alone. Grade II cerebellar gliomas are more likely to recur after surgical removal. Recurrent disease may necessitate the use of chemotherapy and/or radiation therapy. Inability to achieve a complete surgical removal and the presence of recurrent disease decreases prognosis and long-term survival.

What about progressive or recurrent disease?
The recommended treatment for progressive or recurrent cerebellar low-grade glioma is reattempt at surgical removal. In cases of progressive/recurrent disease, where maximal surgical removal has been achieved, chemotherapy and/or radiation therapy will be recommended. The Dana-Farber Cancer Institute is one of nine institutes in the nation belonging to the Pediatric Brain Tumor Consortium. The consortium is dedicated to the development of new and innovative treatments for children with progressive/recurrent brain tumors not responsive to standard therapies. Children with progressive/recurrent low-grade glioma of the cerebellum would be eligible for a number of experimental therapies available through the consortium.

(http://www.childrenshospital.org/)

Respiratory Acidosis

Definition
Respiratory acidosis is a condition in which a build-up of carbon dioxide in the blood produces a shift in the body's pH balance and causes the body's system to become more acidic. This condition is brought about by a problem either involving the lungs and respiratory system or signals from the brain that control breathing.

Description
Respiratory acidosis is an acid imbalance in the body caused by a problem related to breathing. In the lungs, oxygen from inhaled air is exchanged for carbon dioxide from the blood. This process takes place between the alveoli (tiny air pockets in the lungs) and the blood vessels that connect to them. When this exchange of oxygen for carbon dioxide is impaired, the excess carbon dioxide forms an acid in the blood. The condition can be acute with a sudden onset, or it can develop gradually as lung function deteriorates.

Causes and symptoms
Respiratory acidosis can be caused by diseases or conditions that affect the lungs themselves, such as emphysema, chronic bronchitis, asthma, or severe pneumonia. Blockage of the airway due to swelling, a foreign object, or vomit can induce respiratory acidosis. Drugs like anesthetics, sedatives, and narcotics can interfere with breathing by depressing the respiratory center in the brain. Head injuries or brain tumors can also interfere with signals sent by the brain to the lungs. Such neuromuscular diseases as Guillain-Barré syndrome or myasthenia gravis can impair the muscles around the lungs making it more difficult to breathe. Conditions that cause chronic metabolic alkalosis can also trigger respiratory acidosis.
The most notable symptom will be slowed or difficult breathing. Headache, drowsiness, restlessness, tremor, and confusion may also occur. A rapid heart rate, changes in blood pressure, and swelling of blood vessels in the eyes may be noted upon examination. This condition can trigger the body to respond with symptoms of metabolic alkalosis, which may include cyanosis, a bluish or purplish discoloration of the skin due to inadequate oxygen intake. Severe cases of respiratory acidosis can lead to coma and death.

Diagnosis
Respiratory acidosis may be suspected based on symptoms. A blood sample to test for pH and arterial blood gases can be used to confirm the diagnosis. In this type of acidosis, the pH will be below 7.35. The pressure of carbon dioxide in the blood will be high, usually over 45 mmHg.

Treatment
Treatment focuses on correcting the underlying condition that caused the acidosis. In patients with chronic lung diseases, this may include use of a bronchodilator or steroid drugs. Supplemental oxygen supplied through a mask or small tubes inserted into the nostrils may be used in some conditions, however, an oversupply of oxygen in patients with lung disease can make the acidosis worse. Antibiotics may be used to treat infections. If the acidosis is related to an overdose of narcotics, or a drug overdose is suspected, the patient may be given a dose of naloxone, a drug that will block the respiratory-depressing effects of narcotics. Use of mechanical ventilation like a respirator may be necessary. If the respiratory acidosis has triggered the body to compensate by developing metabolic alkalosis, symptoms of that condition may need to be treated as well.

Prognosis
If the underlying condition that caused the respiratory acidosis is treated and corrected, there may be no long term effects. Respiratory acidosis may occur chronically along with the development of lung disease or respiratory failure. In these severe conditions, the patient may require the assistance of a respirator or ventilator. In extreme cases, the patient may experience coma and death.

Prevention
Patients with chronic lung diseases and those who receive sedatives and narcotics need to be monitored closely for development of respiratory acidosis.

(www.healthatoz.com)

Childhood Asthma

Definition
Childhood asthma has become more widespread in recent decades. As the most common chronic illness in children, childhood asthma causes more missed school and places more limits on activity than does any other disease in the United States. Childhood asthma and adult asthma have the same underlying cause — inflammation of the airways. This inflammation makes the airways overly sensitive, leading to signs and symptoms that range from minor coughing or wheezing to serious flare-ups that interfere with breathing.
Fortunately, childhood asthma is treatable. Although childhood asthma can't be cured, you and your child can keep symptoms under control with a written plan, monitoring, regular doctor visits and making treatment changes as needed.

Symptoms
Childhood asthma can be very disruptive, causing bothersome daily symptoms that interfere with play, sports, school and sleep. In some children, unmanaged asthma can cause serious or even life-threatening asthma attacks.
Common childhood asthma symptoms include:
*Coughing
*A whistling or wheezing sound when exhaling
*Shortness of breath
*Chest congestion or tightness

Other signs and symptoms of asthma in children include:
*Trouble sleeping caused by shortness of breath, coughing or wheezing
*Bouts of coughing or wheezing that get worse with a respiratory infection such as a cold or the flu
*Delayed recovery or bronchitis after a respiratory infection
*Fatigue or trouble breathing during active play or exercise — signs of exercise-induced asthma

Asthma signs and symptoms vary from child to child, and may get worse or better over time. While wheezing is most commonly associated with asthma, not all children with asthma wheeze. Your child may have only one sign or symptom, such as a lingering cough or chest congestion.
Sometimes it's difficult to tell whether your child's symptoms are caused by asthma. Wheezing episodes and other asthma-like symptoms may be caused by infectious bronchitis or other respiratory problem.

When to see a doctor Take your child to see the doctor as soon as possible if you suspect he or she may have asthma. Early treatment will not only help control disruptive asthma flare-ups, it may also improve breathing every day.

Make an appointment if you notice:
*Coughing that's constant, intermittent or associated with physical activity
*Wheezing or whistling sounds when your child exhales
*Shortness of breath or rapid breathing that may or may not be associated with exercise
*Complaints of chest tightness
*Repeated episodes of suspected bronchitis or pneumonia

Pay attention to cues from a child who says, "My chest feels funny" or "I'm always coughing." Asthma can be worse at night, so listen for coughing during sleep or coughing that wakes your child in the night. Crying, laughing, yelling, or strong emotional reactions and stress also may trigger coughing or wheezing. If your child is diagnosed with asthma, creating an asthma action plan can help you monitor symptoms and be ready if an asthma attack does occur.
When to seek emergency treatment Even if your child hasn't been diagnosed with asthma, seek medical attention immediately if he or she has any trouble breathing. Although episodes of asthma vary in severity, asthma attacks can start with coughing, which progresses to wheezing and rapid breathing.

In severe cases, you may see your child's chest and sides pulling inward as he or she struggles to breathe. Your child may have an increased heartbeat, sweating and chest pain. Seek emergency care if your child is:
*Breathing so hard that he or she has to stop in midsentence to catch his or her breath
*Using abdominal muscles to breathe
*Widening the nostrils when breathing in
*Trying so hard to breathe that the abdomen is sucked under the ribs when he or she breathes in

Causes
In children with asthma, an overly sensitive immune system makes airways become inflamed and swollen when exposed to triggers such as smoke or allergens. Sometimes, asthma symptoms occur with no apparent triggers. When asthma flares up, airway muscles constrict, the lining of the airways swell, and thick mucus fills the bronchial tubes, leading to asthma symptoms.

Asthma triggers differ from child to child and include:
*Viral infections such as the common cold
*Allergens such as dust mites, pet dander, pollen or mold
*Tobacco smoke or other environmental pollutants
*Exercise
*Weather changes or cold air
*Conditions linked to asthma include:
*A chronic runny or stuffy nose (rhinitis)
*Inflamed sinuses (sinusitis)
*Heartburn (gastroesophageal reflux disease)

Risk factors
It isn't clear why some children get asthma and others don't, but it's probably due to a combination of genetic (inherited) and environmental factors. Children with a family history of asthma are at greater risk of developing the disease. Other environmental factors that may increase your child's chances of developing asthma include:
*Exposure to tobacco smoke
*Previous allergic reactions, including skin reactions, food allergies or allergic rhinitis (hay fever)
*Living in a large urban area with increased exposure to air pollution
*A family history of asthma, allergic rhinitis, hives or eczema
*Low birth weight
*Obesity
*Complications

Asthma may cause a number of complications, including:
*Severe asthma attacks that require emergency room visits or even hospitalization
*Permanent narrowing of the bronchial tubes (airway remodeling)
*Side effects from long-term use of some medications used to stabilize severe asthma (oral corticosteroids)
*Slightly slowed growth in children caused by long-term use of inhaled corticosteroids

Preparing For Your Appointment
A big part of diagnosing childhood asthma depends on accurately reporting your child's symptoms. Be prepared to talk to the doctor about:
Exactly what symptoms your child has
Whether symptoms occur at certain times of day
Whether symptoms get worse or improve at certain times of the year
What, if any, triggers seem to set off asthma flare-ups
Whether your child has allergies, and whether he or she has a family history of allergies or asthma

Tests and Diagnosis
Asthma is a very individual condition. Your child's doctor will consider the nature and frequency of symptoms along with results from tests to rule out other diseases before diagnosing asthma.
First, the doctor will ask for a detailed description of your child's symptoms and ask about your family history of asthma or allergic diseases such as eczema, hives or allergic rhinitis (hay fever).
In children 6 years of age and older, doctors diagnose asthma with the same tests used to identify the disease in adults. Lung function tests (spirometry) measure how quickly and how much air your child can exhale. Your child may have pulmonary function tests at rest, after exercising and after taking asthma medication. Allergy tests also may be part of the evaluation.
In younger children, diagnosis can be difficult because lung function tests aren't accurate before 6 years of age. Some children also simply outgrow asthma-like symptoms over time. Your doctor will rely on detailed information about symptom type and frequency when considering an asthma diagnosis in a young child. Sometimes a diagnosis is not made until later, after months or years of observing symptoms.

If you suspect your child has asthma, it's important to start the testing process early. Early diagnosis and proper treatment can prevent disruptions from daily activities such as sleep, play, sports and school. It may also prevent dangerous or even life-threatening asthma attacks.
For children younger than age 3 who have symptoms of asthma, many times doctors will use a "wait-and-see" approach. This is because the long-term effects of asthma medication on infants and young children aren't clear. If an infant or toddler has frequent or severe wheezing episodes, a course of medication may be prescribed to see if the wheezing improves symptoms.

Treatments and Drugs
The goal of asthma treatment is to get the asthma under control.
Well-controlled asthma means that your child has:
*Minimal or no symptoms
*Few or no asthma flare-ups
*No limitations on physical activities or exercise
*Minimal use of fast-acting "rescue" inhalers
*Few or no side effects from medications

Treating asthma involves both preventing asthma symptoms and treating an asthma attack in progress. Preventive medications reduce the inflammation in your child's airways that can lead to symptoms. Quick-relief (rescue) medications quickly open airways that are swollen and limiting breathing.

While quick-relief medications work quickly, they can't keep your child's symptoms from coming back. If your child has frequent or severe symptoms, he or she will need to take a long-term control medication as well. Your child's symptoms and triggers are likely to change over time. You and your child will need to carefully monitor asthma symptoms and work with your doctor to adjust medications as needed.

Long-term control medications These preventive anti-inflammatory medications are generally taken every day on a long-term basis to control persistent asthma. In some cases, these medications are taken seasonally if asthma symptoms get worse at certain times of the year. These medications include:
*Inhaled corticosteroids, used to treat persistent asthma. These medications reduce chronic inflammation in the airways and reduce the need for other medications. Examples include fluticasone (Flovent), budesonide (Pulmicort), mometasone (Asmanex), triamcinolone (Azmacort), flunisolide (Aerobid) and beclomethasone (Qvar). Continuous inhaled corticosteroids have been associated with slightly slowed growth in children, but research has shown that the effect is minor. In most cases, the benefits of good asthma control outweigh the risks of possible side effects.
*Combination inhalers, which contain inhaled corticosteroids plus a long-acting bronchodilator. Advair combines the corticosteroid fluticasone and the bronchodilator salmeterol. Symbicort contains the corticosteroid budesonide plus the bronchodilator formoterol.
Leukotriene modifiers, which include montelukast (Singulair) and zafirlukast (Accolate) and zileuton (Zyflo).
*Cromolyn, which may help prevent mild to moderate asthma attacks. Cromolyn needs to be taken two to four times a day and is usually taken along with an inhaled corticosteroid.
Theophylline, a daily pill that opens the airways (bronchodilator). It relaxes the muscles around the airways to make breathing easier.
*Quick-relief (rescue) medications These medications — called short-acting bronchodilators — provide immediate relief of asthma attack signs and symptoms such as coughing, wheezing, chest tightness or shortness of breath. These inhaled medications are delivered using a small, hand-held device called a metered dose inhaler. Albuterol is the most commonly used short-acting bronchodilator. Others include pirbuterol and levalbuterol. These bronchodilators begin working within minutes and last four to six hours.
*Allergy-desensitization shots (immunotherapy) Immunotherapy may help if your child has allergic asthma that can't be controlled by avoiding triggers. With immunotherapy, your child will probably need injections once a week for a few months, then once a month for a period of three to five years. Your child's allergic reactions will gradually diminish, lessening the immune system response that triggers asthma symptoms.
*Inhaled medication devices Inhaled short- and long-term control medications are used by inhaling a measured dose of medication.

Older children and teens may use a small, hand-held device called a pressurized metered dose inhaler or an inhaler that releases a fine powder.
Infants and toddlers need to use a face mask attached to a metered dose inhaler or a nebulizer to get the correct amount of medication.
Babies need to a use a device called a nebulizer, a machine that turns liquid medication into fine droplets. Your baby wears a face mask and breathes normally while the nebulizer delivers the correct dose of medication.
*HFA inhalers: A recent change The chlorofluorocarbon (CFC) propellant in quick-relief asthma inhalers has been replaced with a propellant called hydrofluoroalkane (HFA). Unlike CFC inhalers, HFA inhalers don't harm the environment. The spray from the new inhalers may taste different. Although the spray from an HFA inhaler may not seem as strong, your child is still getting the full dose of medication.

Lifestyle and Home Remedies
Taking steps to reduce your child's exposure to things that trigger asthma symptoms will help your child stay healthy and lessen the possibility of asthma attacks. Here are some things you can do:
*Use your air conditioner. Air conditioning helps reduce the amount of airborne pollen from trees, grasses and weeds that finds its way indoors. Air conditioning also lowers indoor humidity and can reduce your exposure to dust mites. If you don't have air conditioning, try to keep your windows closed during pollen season.
*Make your home more asthma friendly. Minimize dust that may aggravate nighttime symptoms by replacing certain items in your bedroom. For example, encase pillows, mattresses and box springs in dust-proof covers. Remove carpeting and install hardwood or linoleum flooring. Use washable curtains and blinds.
*Maintain low humidity. If you live in a damp climate, talk to your doctor about using a dehumidifier.
*Keep indoor air clean. Have a utility company check your air conditioner and furnace once a year. Change the filters in your furnace and air conditioner according to the manufacturer's instructions. Also consider installing a small-particle filter in your ventilation system.
*Reduce pet dander. If your child is allergic to dander, it's best to avoid pets with fur or feathers. *Regular bathing or grooming also may reduce the amount of dander in your surroundings.
*Clean regularly. Clean your home at least once a week.
*Reduce exposure to cold air. If your child's asthma is worsened by cold, dry air, a face mask can help.
*Help your child stay healthy Staying active and treating other conditions linked to asthma will help keep your child's asthma under control.

Make sure your child:
*Gets regular exercise. Asthma symptoms can interfere with active play or sports. But don't let asthma sideline your child. Exercise is proved to reduce asthma symptoms and is a critical part of your child's cardiovascular health. With asthma under control, there usually is no limit to your child's physical activity level.
*Maintains a healthy weight. Being overweight can worsen asthma symptoms, and it puts your child at higher risk of other health problems.
*Controls heartburn and gastroesophageal reflux disease (GERD). It's possible that the acid reflux that causes heartburn may damage lung airways and worsen asthma symptoms.

Alternative medicine
*While some alternative remedies are used for asthma, in most cases more research is needed to see how well they work and to measure the extent of possible side effects.

(Information derived from: MayoClinic.com)

Hypoplastic Left Heart Syndrome (HLHS)

What is HLHS?

Hypoplastic means ‘not developed’. Left Heart – the structures on the left side of the heart.Syndrome – a number of anomalies together. So HLHS means that the left side of the heart has not developed properly – the left ventricle, which should pump red (oxygenated) blood to the body, is very small, and there is a complete blockage between it and the aorta. The aorta, which should carry red blood to the body, is much too small.

Diagnosis

Your baby may have been diagnosed as having a heart condition before birth. HLHS can be seen on a scan of the foetal heart from about 16 weeks. HLHS can develop if there is a blocked or narrow valve, when the left side of the heart does not grow as it should during the later stages of pregnancy.

After birth, your baby can survive before the foetal circulation system has closed down. This is because red blood will still be crossing from the left atrium to the right. From there it will be pumped, with blue blood, into the pulmonary artery. While the ductus arteriosus is still open, blood will flow through it into the aorta, and thus round the body.

Often your baby will only be diagnosed because, as the foetal circulation closes down, less and less oxygen reached organs and he or she became extremely ill.

When a heart problem is detected the tests used can be:

1. pulse, blood pressure, temperature, and number of breaths a baby takes a minute


2. listening with a stethoscope for changes in the heart sounds


3. an oxygen saturation monitor to see how much oxygen is getting into the blood


4. a chest x-ray to see the size and position of the heart


5. an ECG (electrocardiogram) to check the electrical activity


6. an ultrasound scan (echocardiogram) to see how the blood moves through the heart


7. checks for chemical balance in blood and urine


8. a catheter or Magnetic Resonance Imaging test may be needed.

Treatment

This is a very difficult problem to treat: The treatment for HLHS is palliative. Your child’s heart cannot be corrected – that is, made to work like a normal heart – but in some cases it can be improved with a Norwood operation (palliated). The aim of the treatment is to use the pumping power of the right ventricle to get blood to the body and the lungs. This means that your child will have one working ventricle.

There is a risk to your child in all the procedures, but how great that risk is depends on the shape of the individual heart, and how well your child is otherwise. The doctors will discuss risks with you in detail before asking you to consent to any of the operations.

If you have had the condition diagnosed during pregnancy, there is time to think about the treatment options, but time is often very short to take decisions on behalf of a newborn.

Norwood Procedure: This is a high risk procedure. It is a series of three surgical operations which would eventually allow the right side of your child’s heart to take over the work of the left. The aim of the three operations is for the right ventricle to pump red blood to the body, while the blue blood is allowed to flow directly to the lungs.

Stage One – in the first few days of life, the wall between the left and right atrium is removed so that red blood coming back from the lungs will pass into the right atrium, and from there to the right ventricle. The pulmonary artery is attached to the aorta. A shunt (passage) is created between the aorta and the pulmonary artery branches to the lungs. Mixed red and blue blood will now be pumped through the pulmonary artery to the aorta, to both lungs and to the body.

Stage Two – between the ages of four to nine months the blood flow to the lungs is increased. The SVC (superior vena cava), which carries blue blood from the top of the body to the right atrium, is joined directly to the pulmonary arteries. The shunt between the aorta and the branch arteries created at stage one is closed.

Stage Three – the IVC (Inferior vena cava), which carries blue blood from the lower part of the body to the right atrium, is joined directly to the pulmonary arteries (Fontan operation).

Other forms of treatment:

Transplantation: This is very rarely available in the UK. It will involve trying to keep your baby’s foetal circulation open, using medicines or a stent in the ductus arteriosus, while waiting for a heart to become available. Transplants into very young babies are often more successful than older children or adults, but a majority of babies die waiting for a heart to become available.Other forms of treatment are being used in some Paediatric Cardiology Units and these are developing all the time.

Hypoplastic Right Heart Syndrome

Hypoplastic right heart syndrome (HRHS) refers to underdevelopment of the right sided structures of the heart. These defects cause inadequate blood flow to the lungs and thus, a blue or cyanotic infant. The major problem is pulmonary valve atresia (absence). This valve normally opens and closes to let blood flow to the pulmonary artery. Secondary problems include a very small (hypoplastic) right ventricle (lower chamber which normally pumps blood to the lungs); a small tricuspid valve (this valve allows blood to flow into the right ventricle) and a small (hypoplastic) pulmonary artery. Also, the blood flow into the coronary arteries may be abnormal causing damage to the heart muscle.

The infant is born with two connections that help blood flow. These are a foramen ovale (hole between the atria) and patent ductus arteriosus (or PDA, a blood vessel between the aorta and pulmonary artery). As these connections begin to close, the infant becomes critically ill.
Because the blue blood cannot pass through the right side of the heart to get to the lungs, it crosses into the left atrium and mixes with red blood returning from the lungs. This mixed blood is pumped out of the aorta. The only way in which blood gets to the lungs is through the PDA. The PDA must be maintained open with medicine (PGE1). Surgery is usually performed shortly after starting PGE1 to create an artificial connection (shunt) between the aorta and the pulmonary artery to deliver blood to the lungs.