Cardiovascular Disorders

30 Cardiovascular Disorders



Most cardiovascular problems in the pediatric population are due to congenital heart disease (CHD), which occurs in 0.4% to 5% of all live births, 3% to 4% of stillborns, 10% to 25% of abortuses, and 2% of premature infants (patent ductus arteriosus [PDA] excluded) (Botto et al, 2008). Incidence rates vary depending on diagnostic techniques used and the inclusion and exclusion criteria of studies. By 1 week of age, 40% to 50% of infants with CHD have been detected. Some defects, such as small ventricular septal defects (VSDs) or bicuspid aortic valves, may cause no disability to a child; however, they pose a risk for bacterial endocarditis and may cause great concern for parents and caregivers.


The primary care provider (PCP) must maintain a high index of suspicion regarding any signs or symptoms of cardiovascular disease. This facilitates early identification and referral of infants and children with potential cardiovascular problems. PCPs also assist in the management of patients with CHD before and after heart surgery or procedures. Providers need to be attentive to the needs of the whole child because the focus of subspecialists and the family is on the heart disease. They also support families and children once a diagnosis is made and educate families about prevention of acquired heart disease.



image Anatomy and Physiology



Fetal Circulation


Knowledge of the fetal circulation is essential for understanding the circulatory changes that occur in the newborn at delivery (Fig. 30-1). Fetal circulation has four unique features that differ from postnatal circulation:




Oxygen is diffused into the fetal circulation from the maternal uterine arteries in the placenta. From the placenta oxygenated blood flows through the umbilical vein and is diverted through the liver to the inferior vena cava (IVC) by the ductus venosus. When this well-oxygenated blood reaches the right atrium, it flows preferentially toward the atrial septum, through the foramen ovale, and into the left atrium. Oxygenated blood then flows into the left ventricle and out the aorta. Approximately two thirds of the blood from the aorta flows toward the head and neck to ensure that the fetal brain constantly receives well-oxygenated blood.


Venous blood returns from the head and upper extremities through the superior vena cava (SVC) to the right atrium. This blood preferentially flows toward the tricuspid valve into the right ventricle. From the right ventricle the blood enters the pulmonary artery. Because pulmonary vascular resistance is high and systemic resistance is low, most blood in the pulmonary artery flows through the ductus arteriosus into the descending aorta to supply oxygen and nutrients to the trunk and lower extremities. Only a small amount of blood flows into the pulmonary circuit to perfuse the lungs.


The fetal circulation is best described as two parallel circuits, with the left ventricle supplying blood to the upper extremities and the right ventricle serving the lower extremities and the placenta. At the time of transition to extrauterine life, these separate blood flows become a serial circuit.



Neonatal Circulation


A number of complex events occur at birth that rapidly shift the fetal circulation toward a neonatal circulation pattern. Clamping the umbilical cord, with subsequent removal of the placenta as the oxygenating organ, causes an immediate circulatory change in which the lungs become the new source of oxygenation. This change causes an increase in systemic vascular resistance (systemic blood pressure [BP]). With the first breath, mechanical inflation of the lungs and an increase in oxygen saturation bring about a dramatic fall in pulmonary vascular resistance and, consequently, increased pulmonary blood flow. This begins constricting the ductus arteriosus. As the pressures within the heart become relatively higher on the left side and lower on the right, the foramen ovale closes. Functional closure of the ductus arteriosus and foramen ovale usually occurs within the first hours to days of life, and a serial circuit forms out of the once-parallel pulmonary and systemic circulation.


The transition toward complete anatomic closure, or obliteration of fetal structures by tissue growth or constriction, is more gradual. Pulmonary vascular resistance drops gradually over the first 6 to 8 weeks of life, which may protect the pulmonary circulation against volume overload in some congenital heart anomalies. If not noted earlier, shunt murmurs or symptoms of congestive heart failure (CHF) gradually become apparent as the infant approaches 8 weeks of age. At this time, resistance to flow is less, and shunting to the pulmonary bed increases.


Conditions that cause persistence of fetal shunts allow unoxygenated blood to flow from the right side of the heart to the left. Any murmur or cyanosis in a newborn should be carefully monitored and evaluated to detect cardiac abnormalities.



Normal Cardiac Structure and Function


The heart is a muscular four-chambered organ located in the mediastinum, the space in the chest between the lungs. The four chambers are divided into two larger muscular pumping chambers, the ventricles, and two smaller receiving chambers, the atria. Desaturated systemic blood returns to the right atrium by way of the inferior and superior venae cavae. The blood passes from the right atrium through the tricuspid valve to the right ventricle. The right ventricle pumps the blood through the pulmonic valve into the pulmonary artery and the lungs, where it is oxygenated. Blood returning from the lungs enters the left atrium by way of the pulmonary veins and then passes through the mitral valve into the left ventricle. The left ventricle pumps the blood through the aortic valve into the aorta to provide oxygenated blood for the systemic circulation.


The heart valves are one-way valves that open and close because of pressure changes within the heart, controlling the flow of blood from chamber to chamber. The tricuspid valve has three cusps held in place by the chordae tendineae. The pulmonary valve directs blood flow from the right ventricle into the pulmonary artery, which bifurcates into right and left arteries to allow flow into both lungs. The pulmonary veins entering the left atrium contain no valves, so blood can flow freely from the lungs into the atrium. The mitral valve controls flow from the left atrium into the left ventricle. The aortic valve controls flow from the high-pressure left ventricle out to the body.





image Pathophysiology


The term congenital heart disease implies only that a cardiovascular malformation is present at birth. It does not indicate the etiology or the cause of the malformation. When CHD is diagnosed in an infant or child, parents may incorrectly assume that they are somehow responsible for the child’s defect. Health care professionals must be clear about what is and what is not known about CHD to spare parents needless worry and guilt.


It is assumed most CHD is due to a complex interaction of genetic (including gender) and environmental or intrauterine factors, although currently about 75% of CHDs have no identified cause. However, as more genetic testing becomes available and further research is done, it is becoming clearer that the genetic contribution to CHD is greater than previously thought (Pierpont et al, 2007).


The heart is essentially formed by 6 weeks of fetal life, a time when the fetus is most susceptible to infectious or teratogenic exposure or to predisposing genetic or chromosomal factors. Up to 25% of children with CHD also have noncardiac abnormalities (Goldmuntz and Lin, 2008).


Table 30-1 lists the most common known chromosomal abnormalities associated with heart disease. Information about ordering genetic tests and resources for families is available from the National Institutes of Health (NIH) website (http://www.nih.gov/) and in-depth information about specific genetic defects or syndromes is available from Online Mendelian Inheritance in Man (OMIM) website (http://www.ncbi.nlm.nih.gov/omim). Genetic testing should also be done in children who have, in addition to CHD, other congenital anomalies, dysmorphic features, neurocognitive deficits, growth retardation, mothers with multiple miscarriages, or siblings with congenital defects (Goldmuntz and Lin, 2008).


TABLE 30-1 Congenital Malformation Syndromes Associated With Selected Congenital Heart Disease





























































































Disorders Resultant Heart Defect(s)/Occurrence
Syndromes With Chromosomal/Gene Disorders
Trisomy 21 (Down syndrome) Atrioventricular septal defect, VSD, ASD, PDA, TOF (50%)
Trisomy 18 (Edwards syndrome) VSD, ASD, PDA, COA, bicuspid aortic or pulmonary valve (99%)
Trisomy 13 (Patau syndrome) VSD, PDA, dextrocardia (90%)
Turner syndrome (XO) Bicuspid aortic valve, COA (35%), pulmonic stenosis
Marfan syndrome (FBN1 gene) Mitral valve prolapse, aortic root dilation
22q11.2 deletion syndrome Interrupted aortic arch, truncus arteriosus, TOF, perimembranous VSD, aortic arch anomalies
Klinefelter variant (XXXXY) PDA, ASD (15%)
Williams syndrome PS, supravalvular AS
Noonan syndrome (PTPN11) Valvular pulmonic stenosis, hypertrophic cardiomyopathy
CHARGE (gene CHD7) Truncus arteriosus, interrupted aortic arch type B
Jacobsen (11q23 deletion) Hypoplastic left heart syndrome, COA
Long QT syndrome Palpitations, syncope, sudden death
Holt-Oram syndrome (TBX5) ASD, VSD
Cri du chat syndrome (5p) VSD, PDA, ASD (25%)
Neurofibromatosis PS, COA
Nonhereditary Syndromes
Fetal alcohol syndrome VSD, PDA, ASD, TOF (25%-30%)
Fetal hydantoin syndrome PS, AS, COA, PDA, VSD, ASD (<5%)
Fetal trimethadione syndrome TGA, VSD, TOF (15%-30%)
Infant of diabetic mother TGA, VSD, COA (3%-5%); cardiomyopathy (10%-20%)
Pierre Robin syndrome VSD, PDA (29%); ASD, COA, TOF (less commonly)
VATERL association VSD, other defects (>50%)
Congenital diaphragmatic hernia VSD, TOF (25%)
Cornelia de Lange (de Lange) syndrome VSD (30%)
Other System Malformations
Hydrocephalus VSD, ECD, TOF (6%)
Dandy-Walker syndrome VSD (3%)
Tracheoesophageal fistula and/or esophageal atresia VSD, ASD, TOF (21%)
Imperforate anus TOF, VSD (12%)

AS, Aortic stenosis; ASD, atrial septal defect; COA, coarctation of the aorta; ECD, endocardial cushion defect; PDA, patent ductus arteriosus; PS, pulmonary stenosis; TGA, transposition of the great arteries; TOF, tetralogy of Fallot; VATERL, vertebral anomalies, anal atresia, cardiovascular anomalies, tracheoesophageal fistula, esophageal atresia, renal and/or radial anomalies, limb defects; VSD, ventricular septal defect.


Data from Goldmuntz E: The genetic contribution to congenital heart disease, Pediatr Clin North Am 51:1721-1737, 2004; Lin A, Belmont J, Malik S: Heart. In Stevenson R, Hall J, editors: Human malformations and related anomalies, ed 2, Oxford, 2006, Oxford University Press; Park MK, Troxler RG: Pediatric cardiology for practitioners, ed 4, St Louis, 2002, Mosby.


Two percent to 4% of CHD is caused by well-documented teratogens and maternal conditions or environmental influences. Teratogens known to affect the heart include maternal use of thalidomide, cocaine, lithium, fluconazole, phenothiazine, alcohol, anticonvulsants, and retinoic acid. Maternal exposure to pesticides and solvents has also been associated with CHD. Infection, especially cytomegalovirus, mumps, or rubella, contracted in the first 8 weeks of gestation can cause CHD. Infants born to mothers with insulin-dependent diabetes, systemic lupus erythematosus (SLE), and phenylketonuria also have increased risk for various cardiac defects (Goldmuntz and Lin, 2008) (Box 30-1 and Table 30-1).



BOX 30-1 Risk Factors Suggestive of Congenital Heart Disease








image Assessment of the Cardiovascular System


Cardiac assessment includes a comprehensive history, a thorough physical assessment, and a variety of diagnostic tests.




Physical Examination


Physical assessment in a child with suspected CHD should be adapted to the age of the child (Box 30-2). Be flexible, yet thorough, in any evaluation and include all aspects of the physical examination in an order that best suits the comfort and needs of the infant, child, or adolescent.



BOX 30-2 Developmental Approach to Cardiac Assessment







Vital Signs


Heart rate, respiratory rate, and BP vary considerably throughout childhood. Measurements of vital signs must be obtained on each visit with the child at rest because crying and exercise affect results. Refer to charts for normal ranges for various age groups, gender, and height for comparison.



Heart rate (Table 30-2). Heart rates should always be obtained by auscultation of the heart in children younger than 10 years old. Assessment should include rate and rhythm variations. An increased heart rate can be caused by excitement, anxiety, hyperthyroidism, heart disease, anemia, or fever. Assess the rhythm for regularity.


Pulses. Pulses should be checked in the upper and lower extremities and evaluated for character (strength) and variation between the different sites. A bounding pulse may indicate a PDA or aortic insufficiency. Weak or “thready” pulses may indicate CHF or an obstructive lesion, such as severe AS. Good brachial pulses in conjunction with weak or absent femoral pulses may indicate coarctation of the aorta (COA).


BP. The National Institutes of Health National High Blood Pressure Education Program (NIH-NHBPEP) (2004) on BP control in children and adolescents recommends measuring BP annually beginning at 3 years of age. Providers should auscultate BP on children 3 years or older. In selected cases, in which the index of suspicion of heart disease is high, providers should check BPs in younger children. It is important to always use a BP cuff that is appropriate for the child’s size. For arm pressure, the width of the cuff should be two thirds the length of the upper arm measured from the axilla to the antecubital space. A cuff that is too narrow or does not fit around a chubby arm may cause an erroneously high reading. Cuff sizes of 3, 5, 7, 12, and 18 cm should be on hand in order to accommodate the array of pediatric patient sizes. Initial evaluation should compare the pressure in all four extremities. Pressure in all extremities should be equal, with pressure in the legs being slightly higher (10 to 20 mm Hg) in a child who walks. Lower extremity pressure is measured with the stethoscope placed over the popliteal artery. The NIH periodically publishes norms for BP by gender, age, and height; they are found in Tables 30-3 and 30-4 (NIH-NHBPEP, 2004).


The pulse pressure (difference between systolic and diastolic pressure) is normally 20 to 50 mm Hg throughout childhood. A wide pulse pressure caused by an abnormally low diastolic pressure may be an indication of PDA, aortic regurgitation, or other cardiac pathologic conditions.


Respiratory rate. Evaluation of the respiratory system includes the respiratory rate, assessment of effort, and breath sounds in all five lobes of the lungs. It is important to evaluate the respiratory rate in a quiet infant or child. A respiratory rate greater than 40 in a young child or 60 in a newborn who is quiet, resting, and afebrile warrants further evaluation. An infant with CHD may be happily tachypneic and not show significant signs of grunting, intercostal retractions, nasal flaring, or tracheal tug (up and down movement of the trachea with each inspiration).


Oxygen saturation. Oxygen saturation is considered to be an essential vital sign in many settings. It is important to obtain oxygen saturations in new babies or new patients because cyanosis is often subtle and not always readily perceptible to all examiners. Pulse oximetry alone may detect cyanotic heart disease in asymptomatic newborns, preventing possible mortality and morbidity from delayed diagnosis (Mahle et al, 2009).






General Appearance


The provider should observe an infant while obtaining a history and before performing any other part of the physical examination. General nutritional state, respiratory effort, color, physical abnormalities, and distress or discomfort level should be observed.



During this observation period note the presence of unusual facial characteristics (e.g., malformed ears, wide-spaced eyes, noticeable anomalies) or extracardiac anomalies (e.g., cleft lip or palate, polydactyly, microcephaly) that may be associated with a syndrome or chromosomal abnormalities. Children may have obvious stigmata, such as those seen with Down syndrome, Marfan syndrome (unusually tall with an arm span wider than the head-to-toe height), Turner syndrome (webbed neck, prominent ears), or fetal alcohol syndrome (microcephaly and pinched facies), all of which are associated with CHD.


Overall skin color should be assessed for signs of mottling or central cyanosis while the infant is at rest. Cyanosis caused by heart disease is recognized as a pale blue or ruddy red color of the mucous membranes (lips, tongue, nailbeds). The tongue is the best indicator because it lacks pigmentation and is abundantly served by the vascular system. Peripheral cyanosis or acrocyanosis, a blueness or pallor noted around the mouth and on the hands or feet, can be a normal variant, especially if it intensifies when the infant is cold. Clubbing of the fingers and toes may be seen in children with long-standing cyanosis.


Note any wheezing, nasal flaring, retractions, prominent neck veins, or head bobbing with respirations.


Note also signs of peripheral or periorbital edema. Edema or puffiness around the eyes may be evident in an infant with CHF even in the absence of peripheral edema of the hands or feet. True pitting edema of the feet is an unusual finding in an infant with CHF.


Measure and plot height and weight on standardized charts, including Down and Turner syndrome charts, at each assessment. Although many children with CHD fall within the normal ranges of height, weight, and development, a large number of infants and children with heart disease experience poor weight gain, less than normal linear growth, and delays in achieving developmental milestones.



Palpation


Palpate all five areas of the chest: the aortic, pulmonic, tricuspid, and mitral areas, and Erb’s point (Fig. 30-2). Chest palpation is best accomplished by using the open palm of the hand near the base of the fingers. The hand should be gently moved across the chest to assess abnormal precordial activity, including pulsations, lifts, heaves, or thrills, and to determine the location of the apical impulse. The apical impulse is used to determine the size of the heart and is the most lateral point at which cardiac activity can be palpated. In infants and children, the impulse is normally palpated at the apex of the heart in the fourth intercostal space just to the left of the midclavicular line. At approximately 7 years old, the point shifts to the fifth intercostal space. In the presence of cardiomegaly, the apical impulse is shifted laterally or downward.





Auscultation of Heart Sounds




The examiner should approach auscultation of the heart in the same manner for every child either beginning at the base or apex of the heart. Ideally, assess heart sounds in a quiet environment when the child is cooperative.


Four individual heart sounds can be heard: S1, S2, S3, and S4. S1 and S2 represent normal heart sounds, whereas the presence of S3 or S4 may indicate cardiac enlargement or volume overload.


At each area of examination, the provider should accurately identify the first (S1) and second (S2) heart sounds.


S1 has the following characteristics:





S2 has the following characteristics:








S3 and S4 have the following characteristics:







Clicks: Ejection clicks are heard early in systole, immediately after S1, and may sound like a split first heart sound. Pulmonic ejection clicks are high in frequency, vary with respiration, and disappear with inspiration. An aortic ejection click, heard best at Erb’s point, is constant in intensity with a sound of a “snap” or a “click.” Nonejection clicks are heard best in midsystole, or midway between S1 and S2 in the cardiac cycle at the apex. These clicks are best heard in patients who are leaning forward or standing, may disappear with inspiration, and are due to mitral valve prolapse (Park, 2008). Figure 30-2 describes cardiac conditions associated with each of these clicks.



Murmurs


Up to 80% of children may have a murmur, especially beginning at 3 to 4 years old (Park, 2008). It may be caused by normal blood flow through normal cardiac structures (innocent or physiologic murmur) or by turbulent blood flow caused by a defect or abnormal cardiac structures. Murmurs may be intensified by anything that increases cardiac output (e.g., anemia, fever, exercise).



Innocent or Functional Murmurs


Functional or innocent cardiac murmurs are common in children and can be evident in newborns. Table 30-5 describes common types of innocent murmurs; Box 30-3 describes the characteristics of an innocent murmur. Families and older children with innocent murmurs should be reassured that there is no cardiac pathology. They should be informed that this murmur may come and go and may be louder at times of fever, anxiety, pain, or exercise, and that activities do not need to be limited or any special precautions taken.





Criteria for Describing a Heart Murmur


Every murmur is assessed according to the criteria listed in Table 30-6. These are further illustrated and discussed in Figure 30-3. Characteristics of pathologic murmurs needing referral are listed in Box 30-3. The presence of a murmur causes great anxiety for a family awaiting a diagnosis. All murmurs should have a second opinion from a pediatric colleague or pediatric cardiologist if the diagnosis is uncertain or there is a suspicion of heart disease (Allen et al, 2008).


TABLE 30-6 Describing a Heart Murmur
























Grade or intensity:
Grade I: Barely audible; heard faintly after a period of attentive listening
Grade II: Soft but easily audible
Grade III: Moderately loud, no thrill
Grade IV: Loud, present
Grade V: Loud, audible with stethoscope barely on the chest
Grade VI: Heard without stethoscope (rare)
Timing with cardiac cycle Systolic
Diastolic
Continuous
Location on chest where murmur is loudest Aortic
or pulmonic listening areas, URSB, ULSB, Erbs point, LLSB, apex
Radiations or transmission to other locations To back
To apex
To carotids
Quality Musical
Harsh blowing
Duration Point of onset and length of time systole and diastole murmurs last (e.g., “early systole, heard throughout cardiac cycle”)
Pitch Low
Middle
High

LLSB, Left lower sternal border; ULSB, upper left sternal border; URSB, upper right sternal border.




Common Diagnostic Studies


If the provider intends to refer for a cardiology consult, performing any of the following routine diagnostic studies is not cost-effective. The cardiology consultant will be able to determine with greater discrimination which, if any, tests should be ordered (Allen et al, 2008).





Other diagnostic tests may include the following:




image Management Strategies





Primary Health Care for Children with Cardiovascular Diseases


The goals of primary health care for a child with cardiovascular disease include the following:



Adequate nutritional intake and optimal growth. Depending on the child’s condition, the family may need help in modifying the diet to provide maximum calories or limit various types of foods. The young infant with CHF may need 24, 27, or 30 kilocalories per ounce of formula or fortified breast milk. The child may also need a nasogastric or gastric tube to obtain adequate calories because he or she may be unable to suck adequately. Children with cyanotic conditions may initially have adequate weight gain. The provider should refer to a nutritionist if available for assistance with complex diets (see Chapter 10 for more detailed information).


Optimal psychosocial development and functioning. Discuss with the family the need to treat the child as normally as possible. Direct parents to support groups that provide informational and emotional support for families. Provide support to siblings of the affected child as well. Poor sibling bonding and unexpressed fears and anger in young siblings toward an infant with a severe or chronic disease can affect their relationships and family dynamics for many years. A retrospective review of studies that pertained to the long-term psychological adjustment of children and adolescents following open heart surgery for CHD concluded that these survivors are at risk for psychological maladjustment and impaired health-related quality of life (Latal et al, 2009).


Optimal preventive and primary health care. Live virus vaccines should be delayed until 6 to 7 months after cardiopulmonary bypass (and exposure to red blood cells and plasma) or immune globulin exposure (AAP, 2009). This most often affects 1-year-old infants who are due for varicella and measles, mumps, and rubella vaccines. Other vaccines can be given on a regular schedule. The AAP recommends provision of respiratory syncytial virus (RSV) prophylaxis for infants less than 2 years old who have cyanotic or complicated CHD. (Refer to the current AAP Red Book or Centers for Disease Control and Prevention [CDC] website for immunization schedule.)


Prevention of avoidable complications. Prevention of respiratory infections through good handwashing and avoiding contact (if possible) with others with upper respiratory infection (URI) symptoms, should be emphasized. Vaccination against seasonal influenza is prudent.


Prevention of infective endocarditis (IE). Although uncommon in children, IE (also called subacute bacterial endocarditis [SBE]) is associated with a high morbidity and mortality rate (discussed later in this chapter) and warrants primary prevention whenever indicated. Standards for prophylaxis against SBE are available in Box 30-4, and Tables 30-7 and 30-8). A high index of suspicion for IE should be maintained if any unusual clinical findings (e.g., petechiae, fever) are present after any procedure. Children with CHD appear to have more severe gingival inflammatory conditions, with a concomitant increase in Haemophilus species, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella species (HACEK) and other microbes known to cause endocarditis compared with other children (Steelman et al, 2003). The reason for this is not clear. Good dental hygiene is extremely important for these patients.


Optimal fitness. Reassure the parents that the child generally “self-limits” activity according to ability. The cardiology provider should be consulted regarding exercise limitations before entrance into sports or any activities that require strenuous physical exertion. Parameters for sports participation for children with various forms of cardiac diseases or conditions can be found in Chapter 13, Table 13-5.


Optimal neurodevelopmental adaptation to school and life tasks. Several studies have shown relatively high incidences (up to 50%) of neurodevelopmental impairments in school-age children who had open heart surgery in infancy (Majnemer et al, 2008). Although mean intelligence scores are generally within the average range, many of these children have difficulties with visuospatial tasks, fine motor functions, higher order language skills, memory and attention. They may be impaired in their ability to coordinate lower-order skills to perform higher-order tasks. In one study, 25% of children who had neonatal heart surgery had developmental disabilities. A few studies show that there is brain injury and immature brain development in infants with CHD prior to heart surgery, presumably due to disordered fetal circulation (Miller el al, 2007).



TABLE 30-7 Procedures for Which Endocarditis Prophylaxis Is or Is Not Recommended in High-Risk Individuals



































  Prophylaxis Recommended Prophylaxis Not Recommended
Dental Dental extractions
Periodontal procedures
Dental implant placement and reimplantation of avulsed teeth
Root canal instrumentation
Initial placement of orthodontic braces but not brackets
Teeth or implant cleaning where bleeding is expected
Postoperative suture removal
Restorative dentistry
Routine anesthetic injections through noninfected tissue
Intracanal endodontic treatment; postplacement and buildup
Rubber dam placement
Placement of removable prosthodontic or orthodontic appliances
Bleeding from trauma of lips or oral mucosa
Taking oral impressions
Fluoride treatments
Taking oral radiographs
Orthodontic appliance adjustment or placement of brackets
Shedding of primary teeth
Respiratory tract Tonsillectomy or adenoidectomy
Surgery involving respiratory mucosa
Endotracheal intubation
Flexible bronchoscopy without biopsy
Pressure tympanostomy tube insertion/removal
Rigid bronchoscopy
Skin Procedures involving infected skin or skin structures Uncomplicated skin biopsy
Tattooing (but this is highly discouraged in high-risk individuals)
Musculoskeletal tissue Procedures involving infected
musculoskeletal tissue
 
Genitourinary tract Cystoscopy or urinary tract manipulation in patients with enterococcal infection
Vaginal delivery
Cesarean section
Urethral catheterization without infection
Therapeutic abortion
Circumcision
Hysterectomy
Gastrointestinal tract   GI tract procedures including esophagogastroduodenoscopy or colonoscopy
Other procedures   Cardiac catheterization, including device placement and pacemakers

Data from Nishimura RA, Carabello BA, Faxon DP et al: ACC/AHA 2008 guideline update on valvular heart disease: focused update on infective endocarditis. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines: endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons, Circulation 118:887-896, 2008.


TABLE 30-8 Prophylactic Regimens for Dental Procedures*



































Route Agent Regimen
Able to take oral medication Amoxicillin Adults: 2 g PO; children: 50 mg/kg PO (max 2 g)
Unable to take oral medication Ampicillin
or
Adults: 2 g IM or IV; children: 50 mg/kg IM or IV (max 2 g)
Cefazolin or ceftriaxone Adults: 1 g IM or IV; children: 50 mg/kg IM or IV (max 1 g)
If penicillin allergic, oral Clindamycin
or
Adults: 600 mg PO; children: 20 mg/kg PO (max 600 mg)
Cephalexin or cefadroxil
or
Adults: 2 g PO; children: 50 mg/kg PO (max 2 g)
Azithromycin or clarithromycin Adults: 500 mg PO; children: 15 mg/kg PO (max 500 mg)
Penicillin allergic and unable to take oral medication Clindamycin
or
Adults: 600 mg IM or IV; children: 20 mg/kg IM or IV (max 600 mg)
Cefazolin or ceftriaxone Adults: 1 g IM or IV; children: 50 mg/kg IM or IV (max 1 g)

IM, Intramuscular; IV, intravenous; max, maximum, PO, orally.


* Antibiotic regimens are procedure specific; refer to the American Heart Association reference for nondental prophylaxis recommendations.


Take 30-60 minutes prior to the procedure.


Or other first- or second-generation oral cephalosporin in equivalent adult or pediatric dosage. Cephalosporins should not be used if there is a history of anaphylaxis, angioedema, or urticaria with penicillins.


Data from Nishimura RA, Carabello BA, Faxon DP et al: ACC 2008 guideline update on valvular heart disease: focused update on infective endocarditis. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines: endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons, Circulation 118:887-896, 2008.



image Congenital Heart Diseases



Congestive Heart Failure


CHF refers to a progressive clinical and pathophysiologic syndrome found in many children with heart problems. The symptoms vary with age of the child and the root cardiac problem. Box 30-5 provides information on age specific signs and symptoms of CHF. Besides functional changes, CHF is marked by changes in neurohormonal and molecular changes within the heart (Hsu and Pearson, 2009a).



CHF in children can be caused by congenital malformations leading to volume overload (such as a large VSD) or pressure overload (such as AS) or more complex heart disease. CHF can also occur in children with structurally normal hearts due to cardiomyopathy or secondary to dysrhythmias, ischemia, toxins, or infections (Table 30-9). These conditions are discussed in more detail later in this chapter. One set of authors estimate CHF affects 12,000 to 35,000 children each year (Hsu and Pearson, 2009a).


TABLE 30-9 Conditions That Can Lead to Congestive Heart Failure in Children


































































Age Condition
Premature infant Patent ductus arteriosus
Birth to 1 week Hypoplastic left heart syndrome
  Coarctation of the aorta
  Critical aortic stenosis
  Interrupted aortic arch
  Arteriovenous malformations
  Tachycardia
  Cardiomyopathy
1 week to 3 months Ventricular septal defect
  Truncus arteriosus
  Atrioventricular canal (endocardial cushion defect)
  Total anomalous pulmonary venous return
  Coarctation
  Tachycardia
  Patent ductus arteriosus
  Aortic stenosis
  Tricuspid atresia
Older than 1 year Bacterial endocarditis
  Rheumatic fever
  Myocarditis

The largest group of infants and children with CHF are those with excessive left to right shunting through unrepaired congenital defects. CHF is somewhat of a misnomer in these cases, as the myocardium generally responds quite well to the challenge of excessive blood volume for a long time and cardiac output remains adequate. However, the compensatory response to this excessive workload does provoke electrolyte and fluid imbalances as well as a host of other neurohormonal changes. Children with heart failure from systolic or diastolic cardiac dysfunction from infections, obstruction, or dysrhythmia need treatment to ameliorate fluid and electrolyte imbalances, increase contractility, and decrease cardiac afterload.


A greater understanding of the underlying neurohormonal mechanisms of CHF has been detailed and aided by therapies in the adult population. Depending on the underlying pathophysiology, the same patterns of elevated neurohormonal and inflammatory mediators (aldosterone, norepinephrine, natriuretic peptides, tumor necrosis factor, and renin) occur in children. In adult populations large-scale studies have shown the value of blocking some of the chronic neurohormonal changes to CHF with agents such as aldosterone inhibitors, angiotensin inhibitors, and sympathetic inhibitors (beta-blockers). To date, however, no large-scale pediatric study has been able to show positive effects with this change in CHF therapeutic focus. However, based on adult evidence and some small pediatric studies, the International Society of Heart and Lung Transplantation recommended angiotensin-converting enzyme (ACE) inhibitors for moderate to severe left ventricular dysfunction (Hsu and Pearson, 2009b). The traditional armamentarium of heart failure therapies (i.e., diuretics, inotropes, and afterload reducers) is likely to be added in the future after further elucidation of the neurohormonal responses in children with the different conditions listed in Table 30-9. The role of monitoring B natriuretic peptides (amino acid polypeptides secreted by the ventricles in response to stretching) in managing CHF is also evolving.




Atrial Septal Defect



Description and Epidemiology


An ASD is a defect or hole in the atrial septum. Of the four types of ASD, the most common involves the midseptum in the area of the foramen ovale and is called an ostium secundum–type defect (Fig. 30-7). Defects of the sinus venosus type are high in the atrial septum, near the entry of the SVC, and are frequently associated with anomalous pulmonary venous return. A primum ASD is in the lower portion of the septum and is most often seen in children with Down syndrome. The rarest form of ASD is an unroofed coronary sinus (see Table 30-10 for incidence figures). Usually ASDs occur spontaneously; however, there are a few identified genetic mutations which cause familial ASDs (Porter and Edwards, 2008).



Jul 24, 2016 | Posted by in PEDIATRICS | Comments Off on Cardiovascular Disorders

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