Tetraology of Fallot What is it?

Definition  Tetralogy of Fallot is the result of unequal division of the conus. Four alterations result: Narrower right ventricle outflow region Defect in the interventricular septum An aorta that overrides directly above the septal defect The right ventricular wall hypertrophies.

Brief overview  The frequency of this disorder in humans is approximately 1 in  This problem is not necessarily fatal.  If not treated, the mortality rate is 95% by age 40.  Treatment is typically done at age 6-12 months.

Disease history  Cyanosis (which is also characteristic in a blue baby or any person not getting sufficient oxygen) develops in early life.  Surgery must be done to correct this. If not: Growth can be retarded (because birth weight is already low).

TOF causes (developmental)  Not clear at this time, but it is believed to be ablation of cells at the neural crest.  The same problem can also lead to DiGeorge syndrome.  Children born to mothers with PKU are highly susceptible, as are mothers who drink during birth.

What else can happen?  Scoliosis  Retinal engorgement  Systolic murmur

Some pictures of Tetralogy of Fallot

Drugs that can treat TOF  Drugs that are used must be used with corrective surgery (mentioned previously)  Morphine sulfate, usually administered IV Pediatric dosage Can cause hypersensitivity, hypotension, respiratory depression, nausea, emesis, constipation, urinary retention. Do not use with depressants such as TCAs and MAOIs, or in patients who have experienced the above when treated with morphine sulfate

Drugs that can treat TOF  Phenylephrine, administered by IV  Pediatric dosage shown here Pediatric dosage shown here  IF NOT TREATED: the prognosis is poor. Usually lethal.

BIBLIOGRAPHY  eMedicine—Tetralohy of Fallot. Article by Kurt Pflieger, MD.  HeartPoint: Teratology of Fallot.  Sadler, T. W. Langman’s Medical Embryology. Philadelphia: Lippincott Williams and Wilkins, 2000.