Pentalogy of Fallot

# Overview
Pentalogy of Fallot is defined as the occurrence of Tetralogy of Fallot plus an atrial septal defect.

# Historical Perspective
- Tetralogy of fallot  was first discovered by Niel Stenson, a Denish physician Anatomist, in 1671. 
- The association between right ventricular outflow tract obstruction and a large ventricular septal defect  and tetralogy of fallot was made in 1888 by Etinne-Louise.
- In 1924, Canadian, Maude Abbott was the first to discover the association between ventricular septal defect , pulmonary stenosis, overriding aorta and right ventricular hypertrophy and the development of tetralogy of Fallot.

# Classification
- There is no established system for the classification of the pentalogy of Fallot.

# Pathophysiology
It is thought that conotruncal  diseases like tetralogy of fallot and pentalogy of Fallot  occur as a result of:
- Neural crest migration defect.
- Underdevelopment of right ventricular infundibulum

# Causes
- The cause of the pentalogy of Fallot has not been identified.
- To review risk factors for the development of pentalogy of Fallot, click here.

# Differentiating pentalogy of Fallot from other Diseases
- Pentalogy of Fallot  must be differentiated from other diseases that cause:

## Right to left shunt
- Transposition of great arteries with Pulmonic stenosis
- Double outlet right ventricle including Taussig-Bing anomaly
- Tricuspid atresia
- Ebstein Anomaly
- Pulmonary atresia with intact ventricular septum
- Respiratory diseases
Bronchiolitis
Viral and bacterial Pneumonia
Pneumothorax because when they are in heart failure they present with signs of respiratory distress, cyanosis and failure to thrive.
- Bronchiolitis
- Viral and bacterial Pneumonia
- Pneumothorax because when they are in heart failure they present with signs of respiratory distress, cyanosis and failure to thrive.

## Bidirectional shunt  diseases
- Total anomalous pulmonary venous return
- Hypoplastic left heart syndrome
- Single ventricle
- Truncus arteriosus

# Epidemiology and Demographics
The epidemiology of the pentalogy of Fallot has not been well studied.

# Risk Factors
Common risk factors in the development of pentalogy of fallot include:
- Alcoholism in mother
- Maternal Diabetes
- Advanced maternal age i.e greater than 40 years
- Malnutrition in pregnancy
- Family history of tetralogy of fallot
- Viral illness during pregnancy like Rubella.
- Presence of Down syndrome or DiGeorge syndrome

# Screening
There is insufficient evidence to recommend routine screening for the pentalogy of Fallot.

# Natural History, Complications, and Prognosis
If left untreated,  patients with pentalogy of fallot  may progress to develop finger clubbing, stunted growth, cardiac arrhythmias, hypoplastic pulmonary artery, paradoxical emboli and polycythemia .
Prognosis is generally excellent provided the  VSD has been closed and the right ventricular outflow tract has been relieved.

# Diagnosis

## Diagnostic Study of Choice
There are no established criteria for the diagnosis of pentalogy Fallot.

## History and Symptoms
The hallmark of pentalogy of fallot  is cyanosis. A positive history of cyanosis and easy fatigability leading to squatting during exercise is suggestive of cyanotic congenital heart defect.
. The most common symptoms of pentalogy of fallot include cyanosis, easy fatigabillity , and hypercyanotic spells with crying , feeding and defecating.

# Physical Examination
Patients with pentalogy of Fallot appear cyanotic.
- Physical examination of patients with Pentalogy of Fallot is usually remarkable for:
Right ventricular heave
Elevated jugular venous pressure
Finger clubbing
Displaced apex beat
Normal S1 with single S2
Peripheral edema
Diastolic murmur at the left sternal border
Systolic murmur increasing with inspiration at the left sternal border
- Right ventricular heave
- Elevated jugular venous pressure
- Finger clubbing
- Displaced apex beat
- Normal S1 with single S2
- Peripheral edema
- Diastolic murmur at the left sternal border
- Systolic murmur increasing with inspiration at the left sternal border

## Laboratory Findings
Some patients with pentalogy of fallot may have polycythemia 
which is usually suggestive of worsening hypoxia and compensatory production of erythropoetin.

## Electrocardiogram
An ECG may be helpful in the diagnosis of pentalogy of Fallot, 
Findings on an ECG suggestive of pentalogy of fallot include right axis deviation and  right ventricular hypertrophy.

## X-ray
An x-ray may be helpful in the diagnosis of pentalogy of Fallot. Findings on an x-ray suggestive of pentalogy of fallot include boot shaped heart or coeur en sabot.

## Echocardiography or Ultrasound
Echocardiography  may be helpful in the diagnosis of pentalogy of fallot. Findings on an echocardiography diagnostic of pentalogy of fallot include.
- Ventricular septal defect.
- Atrial septal defect.
- Right ventricular outflow tract obstruction.
- overriding aorta Department of Biochemistry, University of Allahabad, Allahabad-211002, India./

## CT scan
Thoracic CT angiography  may be helpful in the diagnosis of pentalogy of fallot. Findings on CT scan diagnostic of pentalogy of fallot include. 
- ventricular septal defect.
- right ventricular hypertrophy,
- pulmonary atresia
- aortopulmonary collateral arteries.

## MRI
cardiac MRI may be helpful in the diagnosis of pentalogy of fallot. Findings on MRI diagnostic of pentalogy of fallot include RVOT stenosis, VSD,  ASD,Overriding aorta, right ventricular hypertrophy and hypoplastic pulmonary arteries.

## Other Imaging Findings
Other imaging findings for pentalogy of fallot include Right ventricular angiopraphy which demonstrates infundibular and pulmonary artery anatomy.  left ventricular angiography, which demonstrates. 
- VSD
- ASD,
- Overiding aorta

## Other Diagnostic Studies
There are no other diagnostic studies associated with pentalogy of Fallot

# Treatment

## Medical Therapy
The mainstay of treatment for pentalogy of fallot  is Surgery.
Pharmacologic medical therapy is recommended among patients with severe RVOTO and hypercyanotic spells.
Pharmacologic medical therapies for pentalogy of fallot include.
- prostaglandin E1 in neonates with ductal dependent pulmonary blood flow
- Morphine and ketamine  for sedation
- vasopressors like phenylephrine
- propanolol to decrease the need for palliative surgical intervention.
- iron treatment to decrease frequency of spells.
Patients with hypercyanotic spells are treated with,
- oxygen
- volume expansion
- morphine sedation.

## Surgery
Surgery is the mainstay of treatment for the pentalogy of Fallot. interventional procedures are used to relieve pulmonary obstructions and embolize collaterals. 
different surgical procedures can be done to treat pentalogy of fallot and it includes.
- Pulmonary valvotomy( for stenotic pulmonic valve)
- Pulmonary valvectomy( for small and thickened pulmonic valve)
- Closure of ASD/VSD
- Shunt surgery for severe cyanosis or in patients with frequent spells in the first year of life
- Blalock -Taussig Shunt- communication between the right or left pulmonary artery and the right or left subclavian artery.
- Waterson-Cooley Shunt- communication between the ascending aorta with the right pulmonary artery
- Potts shunt-communication between the descending aorta and left pulmonary artery
- Central shunt- Communication between the main pulmonary artery and ascending aorta.

## Primary Prevention
There are no established measures for the primary prevention of the pentalogy of Fallot.

## Secondary Prevention
There are no established measures for the secondary prevention of the pentalogy of Fallot.