The primary objective of our study was to
determine the predictive factors for the development
of hypoglycemia in cases with BB intoxication. We
found a correlation between decreased HR and
decreased BGL. In addition, younger age, female sex,
and a higher dose of the drug taken facilitated the
development of hypoglycemia. However, bradycardia
and hypotension were not seen more frequently in
cases with hypoglycemia.
The secondary objective of our study was to
determine how HR and SBP were affected in cases
with BB intoxication. In male cases, while the mean
HR was lower, the mean SBP was higher than the
female cases. Additionally, the mean HR was lower
in those older than six years, while the mean SBP was
higher. As the amount of medication taken increased,
the mean HR and SBP decreased.
Among the consequences that occur in cases of BB
intoxication, those related to the CVS are the most
important. Morbidity is dependent on bradycardia and/or hypotension. One of the studies on this subject
was conducted by Love et al.[10] In this study, 280 BB
poisoning cases were examined, and cardiotoxicity
was found in 41 (15%) cases. Four (1.4%) of these 41
cases died, and these cases were additionally exposed
to a different drug. In our study, no exitus cases were
detected. The reason for this may be that those who
used another drug were excluded from our study.
Similarly, in a study conducted by Belson et al.,[18]
BB-linked cardiotoxicity was found in 1.6% of the
cases. This low rate of cardiotoxicity can be explained
by how, in this study, 83% of the cases came from
exposure to only a single tablet. In this study group,
272 of 280 patients were discharged without any
problems, four were reported to have minor and four
to have moderate effects. In childhood, BB agents are
considered toxic, even for those taking a single tablet. It
is undeniable that the toxicity potential increases if the
number of drugs increases. In a study by Langemeijer et
al.,[19] myocardial depression increased as the dose of BB
increased. In our study, the term PTD was developed
to calculate how much the drug taken exceeds the
determined dose, how much the HR increases, and
how much the SBP decreases at that rate.
In our previous study, our team compared the
BGLs of patients who received BB with those of
patients who took a selective serotonin receptor
inhibitor (SSRI).[20] The purpose of using SSRIs was
that these drugs usually do not cause hypoglycemia.
It was shown that BB intoxication decreased BGLs
compared to other poisoning instances, but these
values were not serious hypoglycemic events. Based
on this result, in the current study, we attempted to
examine which characteristics of patients with BB
poisoning might be risk factors for the development
of hypoglycemia. We found a correlation between
the decrease in HR and BGL. In addition, we
found that younger age, female sex, and a high
dose of the drug used facilitated the development of
hypoglycemia. However, since there is no similar study
in the literature, we could not find an opportunity to
compare our results.
According to BB poisoning cases in terms of age
and sex, in a study conducted by Love et al.,[4] 208
children with BB poisoning were examined and they
found that 57% of the cases were under four years old
and 57% of them were males.
In many studies about poisoning, boys are exposed
to toxic agents at a younger age and girls in the adolescent ages.[21] According to a study conducted
by Lauterbach et al.,[22] 59% of 2,967 cases with BB
poisoning were found to be female in the adult age
group. In our study, 64.7% of the cases were over six
years old and 61% of them were females. We believe
that the reason for identifying such a high number
of female cases is that we included adolescents in our
study group.
According to the relationship between age and
cardiac function, at younger ages, toxins are more
destructive to cardiac functions.[23] In our study,
although the mean HR value was higher in patients
younger than six years old, the rate of bradycardia was
higher. This may be due to the increased sensitivity to
bradycardia when the age gets younger. This is also
why SBP is lower in those younger than six years old.
However, the fact that the number of cases exceeding
the hypotension limit is higher in those over six years
of age can be explained by the higher amount of drugs
taken in the older age group (where the percentage
of the toxic dose is higher than in the younger ones).
Besides, BB agents show their cardiac effects through
ß1-receptors first and they show vascular effects
later.[24]
When we investigated which BBs were seen most
frequently in cases of BB poisoning, the most common
three BBs were atenolol, metoprolol, and propranolol
in Love et al.’s studies.[4,6] Similarly, in our study, the
most common poisoning agents were propranolol and
metoprolol. Even in Love et al.’s[10] study conducted in
2000, propranolol (43.2%) was found to be the most
common BB, as in this study.
When we examine the pathological conditions
that occur in cases poisoned with BB, Love et al.[4]
found that bradycardia was detected only in a twoyear-
old patient who received 50 mg of atenolol out
of 208 children who were followed in their study, and
this case was resolved without any treatment. In the
same study, in one case, BGL was determined to be
55 mg/dL, and in other cases, hypoglycemia was not
observed. In a study by Litovitz et al.,[25] a seven-yearold
girl presented with hypotension, hypoglycemia,
aspiration, and asystole after propranolol intake.
In a study conducted by Eibs et al.,[26] out of
49 children who received BBs, 30 (61.2%) had
bradycardia and/or hypotension as CVS effects.
In addition to CVS effects, hypoglycemia was
observed in 12 children. Most of the cases that
developed hypoglycemia received propranolol. Similarly, 90 (66.1%) patients had cardiovascular
effects (hypotension and/or bradycardia) in our study.
There are publications in the literature showing
that children who develop hypoglycemia are mostly
exposed to agents with high lipophilicity, such as
propranolol, or high membrane-stabilizing activity
(MSA), such as acebutolol.[9,10] In our study, cases
who developed hypoglycemia were exposed to either
high-MSA or high-liposolubility drugs, such as
acebutolol, metoprolol, and propranolol.
In the literature, hypoglycemia associated with BB
intoxication has been linked to prolonged fasting in
non-diabetic cases.[21] In our previous study, our team
compared the BGLs of 40 cases who received BBs and
40 cases who received SSRIs. There was no low BGL
at the time of the first admission in the BB group, but
BGL was significantly lower at 1 and 24 h of followup
than in the SSRI group.[20] However, based on the
cases that exceeded the hypoglycemia limit, there was
no significant difference. These data suggest that, as
in the literature, the low BGL might have been due to
prolonged fasting, not drugs.
Based on the mortality of BB intoxication, Love et
al.[6] examined 10-year poison control service reports
and did not see any deaths under the age of six in
19,388 cases of BB intoxication. In Langemeijer et
al.’s[20] study, they did not observe any exitus in the
same age group. Similarly, there was no mortality in
our study.
The limitation of our study is that the number
of cases, particularly the number of cases developing
hypoglycemia, is low. If there were more cases of
hypoglycemia, it would be easier to evaluate risk
factors. Our study was established with a retrospective
design, as it aimed to investigate the risk factors of a
result. However, in light of these data, in a prospective
study in which patients with BB poisoning may have
been monitored for a longer period, the late effects of
BB may have been detected. Moreover, knowing the
nutritional status of the cases and body mass indexes
would contribute to eliminating the confounding
factors that may cause hypoglycemia. However, our
study would still contribute to the literature, since it is
the first study of this subject focusing on childhood.
In conclusion, in our study, patients who were
younger, who took a large amount of drugs, and whose
HRs were lower were at a greater risk of developing
hypoglycemia. Therefore, cases of BB poisoning with
these characteristics should be monitored more closely
for BGL.
Declaration of conflicting interests
The authors declared no conflicts of interest with respect
to the authorship and/or publication of this article.
Funding
The authors received no financial support for the research
and/or authorship of this article.
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