INTRODUCTION
Obstructive
sleep apnea (OSA) is a syndrome that mostly affects adult males of over forty
years of age. It is thought to occur as a result of soft tissue laxity in the
buccal and pharyngeal musculature.1 Adenotonsillar enlargement is
the most common cause of pharyngeal airway obstruction in infants and children.
Often this is mild and has no sequalae. However when constant and severe
obstruction is present, a condition of OSA develops which leads to disturbed
sleep, snoring, behavioral abnormalities, and sometimes growth failure. Long
standing OSA is known to cause hypoxia, polycythemia and cor pulmonale.2
We report a case of severe tonsillar hypertrophy causing OSA and right heart
failure, who improved dramatically after tonsillectomy.
CASE REPORT
Four
years old AH had increasing breathlessness and abdominal distention for one
year. He was also frequently ill with fever and cough for the same duration. He
did not have jaundice, anorexia or contact with tuberculosis. He was an Afghan
refugee and had previously been healthy.
On examination he had puffy cheeks
with malar flush, central cyanosis, mild clubbing, raised jugular venous
pulsations and pedal edema. He also had grossly enlarged hyperemic tonsils and
no lymphadenopathy. Precordium was hyperactive with tachycardia, gallop rhythm,
loud pulmonary component of 2nd heart sound and a pansystolic murmur of grade
3/6 intensity, best audible at lower left sternal edge. The abdomen was grossly
distended with visible veins, moderate hepatosplenomegaly (each measuring 5 cms
below costal margin) and ascites. Fine basal crepitations were audible in the
chest. The initial diagnosis was congestive cardiac failure and chronic liver
disease.
Laboratory investigations revealed a
high hematocrit (53%), normal white cell and platelet count, normal serum
electrolytes and renal functions. Liver functions were normal except a low
serum albumin (total serum proteins = 5.8 gm/dl, albumin = 2.9 gm/dl, globulin
= 2.9 gm/dl, A: G ratio = 1). Erythrocyte sedimentation rate was 02 mm after
1st hour and the Mantoux test was negative.
Chronic liver disease was evaluated
and the results were normal for hepatitis B, collagen vascular disease, a1-antitrypsin deficiency and cystic fibrosis
(sweat chloride and delta 508). Ultrasound of abdomen showed hepatospleno-megaly
and ascites. Liver biopsy did not show significant histological abnormality.
Chest X-ray revealed moderate
cardio-megaly. Electrocardiogram showed right axis deviation (QRS = 120o),
right atrial enlargement with “P pulmonale” in lead II and severe right
ventricular hypertrophy (Figure 1).
Figure-1: Electrocardiogram showing evidence of right ventricular
pressure overload
Echocardiography confirmed the right
atrial & right ventricular dilatation, moderate right ventricular hypertrophy,
severe tricuspid regurgitation (systolic pressure gradient being 60 mm Hg) and
pulmonary hypertension.
Cardiac catheterization (Table-1)
and pulmonary angiogram were done which confirmed severe pulmonary arterial
hypertension and moderate degree of systemic desaturation.
During the hospital stay, AH was
observed to snore very loudly and sweat significantly during sleep. The
possibility of OSA was considered and an overnight oximetry was performed. It
revealed moderate degree of sleep hypoxia with a lowest oxygen saturation of
48% and a mean low saturation being 78% (Figure 2), thus confirming the
diagnosis of OSA.
Table – 1: Cardiac
Catheterization Data
|
Catheterization Data |
Pressures
(mmHg) |
Oxygen Saturation
on room air (%) |
Preoperative
Right
atrium Right
ventricle Pulmonary artery
Left
Ventricle Aorta |
a = 38, v = 26, m = 25 s = 118, ed = 18 130 / 62, m = 90 s = 118, ed = 8 116 / 76, m = 95 |
30 22 27 56 45 |
|
Postoperative Right atrium
Right
ventricle Pulmonary
artery Left
ventricle Aorta |
a = 6, v = 3, m = 2 s = 48, ed = 6 47 / 12, m = 28 s = 112, ed = 8 102 / 50, m = 71 |
72 69 71 95 95 |
The child underwent tonsillectomy
with an uneventful post operative recovery. Follow up three months later revealed
a barely audible cardiac murmur and regression of the hepatosplenomegaly.
Repeat echocardiogram showed significant reduction in estimated pulmonary
arterial pressures, measuring 25 mmHg. Sleep oximetry was repeated and there
were no episodes of desaturation (Figure-3). A follow up cardiac
catheterization was also done and the results are given in table-1. The
pulmonary arterial hypertension had reduced to a significant degree with
normalization of systemic hypoxemia.
Figure-2: Pre-operative Sleep Oximetry Graph
DISCUSSION
OSA
is not an uncommon entity in children but its pathophysiology is poorly
understood.3 Obstruction to upper airways in children is caused by a
variety of diseases, more common being adenotonsillar hypertrophy. The others
include macroglossia, micrognathia, choanal atresia, Down’s syndrome,
mucopolysaccharidosis, craniofacial abnormalities, cleft palate repair and
obesity.4-6
It is well known that chronic
hypoxia occurring at high altitudes increases hematocrit and causes pulmonary
hypertension and right ventricular hypertrophy. In OSA, the exposure to hypoxia
is intermittent rather than continuous. Experimental animals like Winstar rats,
when exposed to alternating periods of hypoxia and normoxia twice per minute
for eight hours per day for 5 weeks, to mimic the OSA in humans, showed rising
hematocrit from day 7 onwards. There was also a significant increase in the
right ventricular mass.7 Thus intermittent nocturnal hypoxemia due
to obstructive sleep apnea causes pulmonary arterial hypertension and
polycythemia. The triad of loud snoring, difficulty in breathing during sleep
and sleep related breathing pauses is characteristic of OSA in most children.
During wakefulness such children may appear either normal or have adenoid
facies with mouth breathing. The spectrum of severity has been graded over a
scale of 5 by Brouillette and Waters.8 The grade 5 severity
represents cor-pulmonale, cardiomegaly and congestive cardiac failure. Our
patient had grade 5 severity of OSA.
Figure-3:
Post-operative Sleep Oximetry Graph
The hepatomegaly, splenomegaly, ascites and pedal edema seen in our
patient were due to the long standing right heart failure. In adults,
potentially lethal complications like cardiac arrhythmias, ischemic heart
disease and stroke can also occur with OSA.9
Gorur
et al found children with OSA to have right ventricular hypertrophy when
compared to controls.10 Sanner et al11 have shown that
right heart failure can occur in OSA independent of lung disease and is thought
to be due to reduced right ventricular ejection fraction and systolic
dysfunction. In our patient the right ventricular dysfunction was mild (end
diastolic pressure (edp) = 18 mmHg) and pulmonary arterial pressures were
grossly elevated (Table-1). The right ventricular function returned to normal
(edp = 6 mmHg) and drastic reduction in pulmonary arterial pressures were seen
(Table -1) after tonsillectomy.
The massive tonsillar enlargement in
our patient led to OSA with its attending repetitive hypoxia, secondary
pulmonary hypertension and cardiac failure. Tonsillectomy removed the upper
airway obstruction and led to complete reversal of these complications in 3
months time.
In summary, this case highlights the
need for increased awareness among pediatricians and general practitioners of
the possibility of OSA in children. A common pediatric problem like
adenotonsillar hypertrophy could possibly lead to serious complications like
severe pulmonary hypertension, cardiac failure and neurobehavioral problems.12
Emergency management would consist of tracheotomy which is certainly not a
benign procedure. However definitive treatment would be of the underlying
disease making tonsillectomy and adenoidectomy the mainstays of therapy in such
cases.
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