Heart failure in children - Pediatrics

Question 1

Etiology of Heart failure (A++)

Answer 1

1.Cardiac causes
A. Congenital heart disease
➢ Volume overload:
- Left to right shunt (VSD, PDA,CAVC)
- Atrioventricular or semilunar valve insufficiency( aortic regurge (AR), pulmonary regurge (PR)
➢ Pressure overload
- Left sided obstruction :( severe aortic stenosis (AS), aortic coarctation)
- Right sided obstruction( severe pulmonary stenosis( PS))
- Complex congenital heart disease:
a) (Single ventricle, hypoplastic left heart syndrome, unbalanced AV canal)
b) Systemic RV in L-transposition of great arteries

B. Myocardial dysfunction: Cardiomyopathies may be (hereditary or acquired)
➢ Cardiomyopathies with systolic dysfunction or failure: ↓ ventricular contractility → low c.o.p:
- Dilated cardiomyopathy→ is hereditary in up to 50% of cases
- Infectious myocarditis: Viral or bacterial,
- Malnutrition
- Anthracycline (Doxorubicin chemotherapy) induced cariomyopathy
- Cardiomyopathies associated with muscular dystrophy and Friedreich’s ataxia
- Myocarditis in Kawasaki’s disease
- Endocardial fibroelastosis,
➢ Cardiomyopathies with Diastolic dysfunction or failure: ↓ventricular compliance, →↑venous pressure to maintain adequate ventricular filling.
❖ Hypertrophic cardiomyopathy
❖ Restrictive cardiomyopathy

C.Acquired HD:
➢ Rheumatic valvular heart diseases, usually volume overload lesions such as mitral regurgitation (MR) or aortic regurgitation(AR).
➢ Post-op repaired cyanotic CHD
➢ Ischemia: Coronary anomalies, Kawasaki’s disease

D.Arrhythmias; e.g. Tachycardias (e.g. supraventricular tachycardia)
Bradycardias (e.g. complete AV block)

2.Non cardiac:
* Hypertension, anemia, sepsis, thyrotoxicosis, carnitine deficiency
* Bronchoplumonary dysplasia in premature
* Acute corpulmonle due to airway obstruction
* Hypertensive heart failure in PSGN

Question 2

Timing of onset of heart failure (A++)

Answer 2

❖ Causes of congestive heart failure in infancy and children:
A- Congenital HD:
- Volume overload:
- Pressure overload:
B- Acquired HD:
C- Other causes:
* Neonates → obstructed systemic circulation (duct dependent)
o Hypoplastic left heart syndrome
o Critical aortic valve stenosis
o Severe coarctation of the aorta or interruption of the aortic arch
* Infants (high pulmonary blood flow)
o Ventricular septal defect
o Large persistent ductus arteriosus
* Older children and adolescents (right or left heart failure)
o Eisenmenger syndrome (right heart failure only)
o Rheumatic heart disease especially regurgitant lesions as rheumatic MR or AR
o Cardiomyopathy.
* Other causes in infancy and children
o Storage diseases: Fabry, Gaucher, Glycogen storage disease ….
o Infectious myocardial disease as viral or bacterial myocarditis
o Myocardial ischemia/infarction as in Kawasaki disease….
o Metabolic/endocrine conditions: as in hyperthyroidism, severe acidosis….
o Nutritional: in thiamine or selenium deficiency, kwashiorkor, severe anemia.
o Volume overload as in renal failure, aggressive blood transfusion, overhydration
o Arrhythmias supraventricular tachycardia or atrial fibrillation

Question 3

Clinical picture of Heart failure (B)

Answer 3

• Symptoms either:
  o Low COP symptoms: easy fatigue, anginal pain, dizziness, or syncopal attack.
  o Systemic congestion symptoms: dyspepsia, generalized oedema, tender liver.
  o Pulmonary venous congestion symptoms:
  ▪ In infancy: poor feeding, growth retardation, recurrent chest infections
  ▪ In older children: Cough, dyspnoea on exertion, or haemoptysis.
• Physical exam findings:
  o Cardiomegaly with tachycardia, gallop, weak pulses, and cold extremities
  o Enlarged tender liver (may be absent in early left sided failure).
  o Congested neck veins; hard to detect in infants due to short neck.
  o Oedema → generalized start in ankles (sacral in bed ridden). Oedema in infants usually involve eye lids and sacrum

Question 4

Investigations in Heart failure (B)

Answer 4

• Laboratory findings: no single test is specific for CHF. Increased levels of B- type natriuretic peptide (BNP) is helpful.
• Chest X- ray: shows cardiomegaly, pulmonary oedema/congestion
• ECG: may have left axis deviation, left atrial enlargement, LVH with strain pattern, and left bundle branch block.
• Echo can detect
  o Enlarged ventricular chambers
  o Impaired LV systolic function
  o Impaired diastolic function
  o Decreased fractional shortening or ejection fraction
• Cardiac catheterization
  o May be needed for biopsy to identify underlying cause
  o Allows accurate assessment of pressures in various chamber

Question 5

Treatment of Heart failure (b)

Answer 5

❖ General measure:
* Hospitalization
* Bed rest in semi sitting position
* O2 inhalation and sedation (the best with morphine)
* Low salt diet (to avoid further salt & water retention).
* Specific treatment:
* Preload reduction Diuretics (first line)
o Loop diuretics preferred (furosemide): 1-2 mg /kg/dose but can cause hypokalaemia.
o Spironolactone (K sparing diuretic): 2 mg/ kg / day oral may be added.
* Afterload reduction
o Preferred: mixed vasodilators (ACE inhibitors)
o Arteriolar vasodilators (hydralazine)
o Vasodilators (nitro-glycerine, isosorbide dinitrate)
* Inotropic agents
o Digoxin that increases the myocardial contractility (commonest one)
o Dopamine, dobutamine, epinephrine if severely ill
❖ Digoxin is given as follow:
* Loading dose (0.03- 0.05 mg/ kg according to the age of the child) is given within 24
hours: ½ of the total digitalizing dose (TDD) immediate followed by ¼ after 8 hours and
¼ after another 8 hours.
* Maintenance dose ¼ TDD is given in two divided doses after 12 hours.

Question 6

Digitalis toxicity short note (A++)

Answer 6

occurs when serum digitalis level is > 2 mg/ml.

o Etiology: usually caused by digitalis over dose, renal impairment, or secondary to increased myocardial sensitivity to digitoxin (hypokalemia)
o Manifestations:
▪ Anorexia and vomiting,
▪ Bradycardia
▪ Worsening of heart failure.
▪ Arrythmias (supraventricular arrythmia & heart block).
o Treatment:
▪ Stop digitalis and continuous ECG monitoring.
▪ Correct hypokalemia
▪ Correct arrythmias by atropine for heart block and lidocaine for ventricular arrythmia
▪ Increase excretion of digoxin by Digoxin immune Fab.