Hypoglycemia
Hypoglycemia
or hypoglycæmia is the medical term for a state produced by a lower than normal
level of blood glucose. The term literally means "under-sweet blood"
(Gr. hypo-, glykys, haima).
Hypoglycemia
can produce a variety of symptoms and effects but the principal problems arise
from an inadequate supply of glucose as fuel to the brain, resulting in
impairment of function (neuroglycopenia). Effects can range from vaguely
"feeling bad" to seizures, unconsciousness, and (rarely) permanent
brain damage or death.
The
most common forms of moderate and severe hypoglycemia occur as a complication
of treatment of diabetes mellitus with insulin or oral medications.
Hypoglycemia is less common in non-diabetic persons, but can occur at any age,
from many causes. Among the causes are excessive insulin produced in the body,
inborn errors of carbohydrate, fat, amino acid or organic acid metabolism,
medications and poisons, alcohol, hormone deficiencies, certain tumors,
prolonged starvation, and alterations of metabolism associated with infection
or failures of various organ systems.
Hypoglycemia
is treated rapidly by restoring the blood glucose level to normal by the
ingestion or administration of dextrose or carbohydrate foods quickly
digestible to glucose. In some circumstances it is treated by injection or
infusion of glucagon. Prolonged or recurrent hypoglycemia may be prevented by
reversing or removing the underlying cause, by increasing the frequency of
meals, with medications like diazoxide, octreotide, or glucocorticoids, or even
by surgical removal of much of the pancreas.
The
level of blood glucose low enough to define hypoglycemia may be different for
different people, in different circumstances, and for different purposes, and
occasionally has been a matter of controversy. Most healthy adults maintain
fasting glucose levels above 70 mg/dL (3.9 mmol/L), and develop symptoms of
hypoglycemia when the glucose falls below 55 mg/dL (3 mmol/L).
It
can sometimes be difficult to determine whether a person's symptoms are due to
hypoglycemia. Endocrinologists (physicians with expertise in disorders of
glucose metabolism) typically consider the criteria referred to as Whipple's
triad as conclusive evidence that an individual's symptoms can be attributed to
hypoglycemia instead of to some other cause:
1. Symptoms known to be caused by
hypoglycemia
2. Low glucose at the time the symptoms
occur
3. Reversal or improvement of symptoms or
problems when the glucose is restored to normal
Hypoglycemia
(common usage) is also a term in popular culture and alternative medicine for a
common, often self-diagnosed, condition characterized by shakiness and altered
mood and thinking, but without measured low glucose or risk of severe harm. It
is treated by changing eating patterns.
·
Contents
- 1 Defining hypoglycemia
1.1 Method of measurement
1.2 Age differences
1.3 Presence or absence of effects
1.4 Purpose of definition
- 2 Pathophysiology
- 3 Signs and symptoms
3.1 Adrenergic manifestations
3.2 Glucagon manifestations
3.3 Neuroglycopenic
manifestations
- 4 Determining the cause
4.1 Further diagnostic steps
- 5 Causes
5.1 Hypoglycemia in newborn infants
5.2 Hypoglycemia in young children
5.3 Hypoglycemia in older children and young
adults
5.4 Hypoglycemia in older adults
- 6 Treatment and prevention
6.1 Reversing acute hypoglycemia
6.2 Prevention
- 7 Hypoglycemia as holistic medicine
1. Defining hypoglycemia
No
single glucose value alone serves to define the medical condition termed
hypoglycemia for all people and purposes. Throughout the 24 hour cycles of
eating, digestion, and fasting, blood plasma glucose levels of healthy people
past infancy are generally maintained between 72 and 144 mg/dL (4-8 mmol/L) throughout
a 24 hour period. Although 60 or 70 mg/dL (3.3 or 3.9 mmol/L) is commonly cited
as the lower limit of normal glucose, different values (typically below 40, 50,
60, or 70 mg/dL) have been defined as low for different populations, clinical
purposes, or circumstances. In other words, many healthy people can
occasionally have glucose levels in the hypoglycemic range without symptoms or
disease.
The
precise level of glucose considered low enough to define hypoglycemia is
dependent on (1) the measurement method, (2) the age of the person, (3)
presence or absence of effects, and (4) the purpose of the definition. While
there is no disagreement as to the normal range of blood sugar, debate
continues as to what degree of hypoglycemia warrants medical evaluation or
treatment, or can cause harm.
Glucose
concentrations are expressed as milligrams per deciliter (mg/dL or mg/100 mL)
in the United States, Japan,Spain, France, Egypt, and Columbia, while
millimoles per liter (mmol/L or mM) are the units used in most of the rest of
the world. Glucose concentrations expressed as mg/dL can be converted to mmol/L
by dividing by 18.0 g/dmol (the molar mass of glucose). For example, a glucose
concentration of 90 mg/dL is 5.0 mmol/L or 5.0 mM.
·
Method
of measurement
Blood
glucose levels discussed in this article are venous plasma or serum levels
measured by standard, automated glucose oxidase methods used in medical
laboratories. For clinical purposes, plasma and serum levels are similar enough
to be interchangeable. Arterial plasma or serum levels are slightly higher than
venous levels, and capillary levels are typically in between. This difference
between arterial and venous levels is small in the fasting state but is
amplified and can be greater than 10% in the postprandial state. On the other
hand, whole blood glucose levels (e.g., by fingerprick meters) are about
10%-15% lower than venous plasma levels. Furthermore, available fingerstick
glucose meters are only warranted to be accurate to within 15% of a
simultaneous laboratory value under optimal conditions, and home use in the
investigation of hypoglycemia is fraught with misleading low numbers. In other
words, a meter glucose reading of 39 mg/dL could be properly obtained from a person
whose laboratory serum glucose was 53 mg/dL; even wider variations can occur
with "real world" home use.
Two
other factors significantly affect glucose measurement: hematocrit and delay
after blood drawing. The disparity between venous and whole blood
concentrations is greater when the hematocrit is high, as in newborn infants,
or adults with polycythemia. High neonatal hematocrits are particularly likely
to confound glucose measurement by meter. Second, unless the specimen is drawn
into a fluoride tube or processed immediately to separate the serum or plasma
from the cells, the measurable glucose will be gradually lowered by in vitro
metabolism of the glucose at a rate of approximately 7 mg/dL/hr, or even more
in the presence of leukocytosis. The delay that occurs when blood is drawn at a
satellite site and transported to a central laboratory hours later for routine
processing is a common cause of mildly low glucose levels in general chemistry
panels.
·
Age
differences
Children's
blood sugar levels are often slightly lower than adults'. Overnight fasting
glucose levels are below 70 mg/dL (3.9 mM) in 5% of healthy adults, but up to
5% of children can be below 60 mg/dL (3.3 mM) in the morning fasting state. As
the duration of fasting is extended, a higher percentage of infants and
children will have mildly low plasma glucose levels, usually without symptoms.
The normal range of newborn blood sugars continues to be debated. It has been
proposed that newborn brains are able to use alternate fuels when glucose
levels are low more readily than adults. Experts continue to debate the
significance and risk of such levels, though the trend has been to recommend
maintenance of glucose levels above 60–70 mg/dL after the first day after
birth.
·
Presence
or absence of effects
Research
in healthy adults shows that mental efficiency declines slightly but measurably
as blood glucose falls below 65 mg/dL (3.6 mM) in many people. Hormonal defense
mechanisms (adrenaline and glucagon) are normally activated as it drops below a
threshold level (about 55 mg/dL (3.0 mM) for most people), producing the
typical hypoglycemic symptoms of shakiness and dysphoria.[15]:1589 Obvious
impairment may not occur until the glucose falls below 40 mg/dL (2.2 mM), and
many healthy people may occasionally have glucose levels below 65 in the
morning without apparent effects. Since the brain effects of hypoglycemia,
termed neuroglycopenia, determine whether a given low glucose is a
"problem" for that person, most doctors use the term hypoglycemia
only when a moderately low glucose level is accompanied by symptoms or brain
effects.
Determining
the presence of both parts of this definition is not always straightforward, as
hypoglycemic symptoms and effects are vague and can be produced by other
conditions; people with recurrently low glucose levels can lose their threshold
symptoms so that severe neuroglycopenic impairment can occur without much
warning, and many measurement methods (especially glucose meters) are imprecise
at low levels.
Diabetic
hypoglycemia represents a special case with respect to the relationship of
measured glucose and hypoglycemic symptoms for several reasons. First, although
home glucose meter readings are often misleading, the probability that a low
reading, whether accompanied by symptoms or not, represents real hypoglycemia
is much higher in a person who takes insulin than in someone who does not.
Second, because injected insulin cannot be "turned off", diabetic
hypoglycemia has a greater chance of progressing to serious impairment if not
treated, compared to most other forms of hypoglycemia. Third, because glucose
levels are often above normal for long periods of time (hours, days, or months)
in persons with diabetes, hypoglycemic symptoms may sometimes occur at higher
thresholds than in people whose blood sugar is usually normal. For all of these
reasons, higher meter glucose thresholds are often considered
"hypoglycemic" in people with diabetes.
·
Purpose
of definition
For
all of the reasons explained in the above paragraphs, deciding whether a blood
glucose in the borderline range of 45–75 mg/dL (2.5-4.2 mM) represents
clinically problematic hypoglycemia is not always simple. This leads people to
use different "cutoff levels" of glucose in different contexts and
for different purposes. Because of all of the statistical and measurement
variations listed above, the Endocrine Society recommends that a diagnosis of
hypoglycemia as problem for an individual person be based on the combination of
a low glucose level and evidence of adverse effects.
2. Pathophysiology
Like
most animal tissues, brain metabolism depends primarily on glucose for fuel in
most circumstances. A limited amount of glucose can be derived from glycogen
stored in astrocytes, but it is consumed within minutes. For most practical
purposes, the brain is dependent on a continual supply of glucose diffusing
from the blood into the interstitial tissue within the central nervous system
and into the neurons themselves.
Therefore,
if the amount of glucose supplied by the blood falls, the brain is one of the
first organs affected. In most people, subtle reduction of mental efficiency
can be observed when the glucose falls below 65 mg/dl (3.6 mM). Impairment of
action and judgment usually becomes obvious below 40 mg/dl (2.2 mM). Seizures
may occur as the glucose falls further. As blood glucose levels fall below 10
mg/dl (0.55 mM), most neurons become electrically silent and nonfunctional,
resulting in coma. These brain effects are collectively referred to as
neuroglycopenia.
The
importance of an adequate supply of glucose to the brain is apparent from the
number of nervous, hormonal and metabolic responses to a falling glucose level.
Most of these are defensive or adaptive, tending to raise the blood sugar via
glycogenolysis and gluconeogenesis or provide alternative fuels. If the blood
sugar level falls too low the liver converts a storage of glycogen into glucose
and releases it into the bloodstream, to prevent the person going into a
diabetic coma, for a short period of time.
Brief
or mild hypoglycemia produces no lasting effects on the brain, though it can
temporarily alter brain responses to additional hypoglycemia. Prolonged, severe
hypoglycemia can produce lasting damage of a wide range. This can include
impairment of cognitive function, motor control, or even consciousness. The
likelihood of permanent brain damage from any given instance of severe
hypoglycemia is difficult to estimate, and depends on a multitude of factors
such as age, recent blood and brain glucose experience, concurrent problems
such as hypoxia, and availability of alternative fuels. The vast majority of
symptomatic hypoglycemic episodes result in no detectable permanent harm.
3. Signs and symptoms
Hypoglycemic
symptoms and manifestations can be divided into those produced by the
counterregulatory hormones (epinephrine/adrenaline and glucagon) triggered by
the falling glucose, and the neuroglycopenic effects produced by the reduced
brain sugar.
·
Adrenergic
manifestations
- Shakiness,
anxiety, nervousness,
- Palpitations,
tachycardia
- Sweating,
feeling of warmth
- Pallor,
coldness, clamminess
- Dilated pupils
(mydriasis)
- Feeling of
numbness "pins and needles" (parasthaesia)
- Hypercapnia
(Fast respiration rate)
·
Glucagon
manifestations
- Hunger,
borborygmus
- Nausea,
vomiting, abdominal discomfort
- Headache
·
Neuroglycopenic
manifestations
- Abnormal
mentation, impaired judgment
- Nonspecific
dysphoria, anxiety, moodiness, depression, crying
- Negativism,
irritability, belligerence, combativeness, rage
- Personality
change, emotional lability
- Fatigue,
weakness, apathy, lethargy, daydreaming, sleep
- Confusion,
amnesia, dizziness, delirium
- Staring,
"glassy" look, blurred vision, double vision
- Automatic
behavior, also known as automatism
- Difficulty
speaking, slurred speech
- Ataxia,
incoordination, sometimes mistaken for "drunkenness"
- Focal or general
motor deficit, paralysis, hemiparesis
- Paresthesia,
headache
- Stupor, coma,
abnormal breathing
- Generalized or
focal seizures
Not
all of the above manifestations occur in every case of hypoglycemia. There is
no consistent order to the appearance of the symptoms, if symptoms even occur.
Specific manifestations may also vary by age, by severity of the hypoglycemia
and the speed of the decline. In young children, vomiting can sometimes
accompany morning hypoglycemia with ketosis. In older children and adults,
moderately severe hypoglycemia can resemble mania, mental illness, drug
intoxication, or drunkenness. In the elderly, hypoglycemia can produce focal
stroke-like effects or a hard-to-define malaise. The symptoms of a single
person may be similar from episode to episode, but are not necessarily so and
may be influenced by the speed at which glucose levels are dropping, as well as
previous incidence.
In
newborns, hypoglycemia can produce irritability, jitters, myoclonic jerks,
cyanosis, respiratory distress, apneic episodes, sweating, hypothermia,
somnolence, hypotonia, refusal to feed, and seizures or "spells".
Hypoglycemia can resemble asphyxia, hypocalcemia, sepsis, or heart failure.
In
both young and old patients, the brain may habituate to low glucose levels,
with a reduction of noticeable symptoms despite neuroglycopenic impairment. In
insulin-dependent diabetic patients this phenomenon is termed hypoglycemia
unawareness and is a significant clinical problem when improved glycemic
control is attempted. Another aspect of this phenomenon occurs in type I
glycogenosis, when chronic hypoglycemia before diagnosis may be better
tolerated than acute hypoglycemia after treatment is underway.
Nearly
always, hypoglycemia severe enough to cause seizures or unconsciousness can be
reversed without obvious harm to the brain. Cases of death or permanent
neurological damage occurring with a single episode have usually involved
prolonged, untreated unconsciousness, interference with breathing, severe
concurrent disease, or some other type of vulnerability. Nevertheless, brain
damage or death has occasionally resulted from severe hypoglycemia.
4. Determining the cause
The
circumstances of hypoglycemia provide most of the clues to diagnosis.
Circumstances include the age of the patient, time of day, time since last
meal, previous episodes, nutritional status, physical and mental development,
drugs or toxins (especially insulin or other diabetes drugs), diseases of other
organ systems, family history, and response to treatment. When hypoglycemia
occurs repeatedly, a record or "diary" of the spells over several
months, noting the circumstances of each spell (time of day, relation to last
meal, nature of last meal, response to carbohydrate, and so forth) may be
useful in recognizing the nature and cause of the hypoglycemia.
An
especially important aspect is whether the patient is seriously ill with
another problem. Severe disease of nearly all major organ systems can cause
hypoglycemia as a secondary problem. Hospitalized patients, especially in
intensive care units or those prevented from eating, can suffer hypoglycemia
from a variety of circumstances related to the care of their primary disease.
Hypoglycemia in these circumstances is often multifactorial or even iatrogenic.
Once identified, these types of hypoglycemia are readily reversed and
prevented, and the underlying disease becomes the primary problem.
Apart
from determining nutritional status and identifying whether there is likely to
be an underlying disease more serious than hypoglycemia, the physical
examination of the patient is only occasionally helpful. Macrosomia in infancy
usually indicates hyperinsulinism. A few syndromes and metabolic diseases may
be recognizable by clues such as hepatomegaly or micropenis.
It
may take longer to recover from severe hypoglycemia with unconsciousness or
seizure even after restoration of normal blood glucose. When a person has not
been unconscious, failure of carbohydrate to reverse the symptoms in 10–15
minutes increases the likelihood that hypoglycemia was not the cause of the
symptoms. When severe hypoglycemia has persisted in a hospitalized patient, the
amount of glucose required to maintain satisfactory blood glucose levels
becomes an important clue to the underlying etiology. Glucose requirements
above 10 mg/kg/minute in infants, or 6 mg/kg/minute in children and adults are
strong evidence for hyperinsulinism. In this context this is referred to as the
glucose infusion rate (GIR). Finally, the blood glucose response to glucagon
given when the glucose is low can also help distinguish among various types of
hypoglycemia. A rise of blood glucose by more than 30 mg/dl (1.70 mmol/l)
suggests insulin excess as the probable cause of the hypoglycemia.
In
less obvious cases, a "critical sample" may provide the diagnosis. In
the majority of children and adults with recurrent, unexplained hypoglycemia,
the diagnosis may be determined by obtaining a sample of blood during
hypoglycemia. If this critical sample is obtained at the time of hypoglycemia,
before it is reversed, it can provide information that would otherwise require
a hospital admission and unpleasant starvation testing. Perhaps the most common
inadequacy of emergency department care in cases of unexplained hypoglycemia is
the failure to obtain at least a basic sample before giving glucose to reverse
it.
Part
of the value of the critical sample may simply be the proof that the symptoms
are indeed due to hypoglycemia. More often, measurement of certain hormones and
metabolites at the time of hypoglycemia indicates which organs and body systems
are responding appropriately and which are functioning abnormally. For example,
when the blood glucose is low, hormones which raise the glucose should be
rising and insulin secretion should be completely suppressed.
The
following is a brief list of hormones and metabolites which may be measured in
a critical sample. Not all tests are checked on every patient. A "basic
version" would include insulin, cortisol, and electrolytes, with C-peptide
and drug screen for adults and growth hormone in children. The value of
additional specific tests depends on the most likely diagnoses for an
individual patient, based on the circumstances described above. Many of these
levels change within minutes, especially if glucose is given, and there is no
value in measuring them after the hypoglycemia is reversed. Others, especially
those lower in the list, remain abnormal even after hypoglycemia is reversed,
and can be usefully measured even if a critical specimen is missed. Although
interpretation in difficult cases is beyond the scope of this article, for most
of the tests, the primary significance is briefly noted.
- Glucose: needed
to document actual hypoglycemia
- Insulin: any
detectable amount is abnormal during hypoglycemia, but physician must know
assay characteristics
- Cortisol: should
be high during hypoglycemia if pituitary and adrenals are functioning
normally
- Growth hormone:
should rise after hypoglycemia if pituitary is functioning normally
- Electrolytes and
total carbon dioxide: electrolyte abnormalities may suggest renal or
adrenal disease; mild acidosis is normal with starvation hypoglycemia;
usually no acidosis with hyperinsulinism
- Liver enzymes:
elevation suggests liver disease
- Ketones: should
be high during fasting and hypoglycemia; low levels suggest
hyperinsulinism or fatty acid oxidation disorder
- Beta-hydroxybutyrate:
should be high during fasting and hypoglycemia; low levels suggest
hyperinsulinism or fatty acid oxidation disorder
- Free fatty
acids: should be high during fasting and hypoglycemia; low levels suggest
hyperinsulinism; high with low ketones suggests fatty acid oxidation
disorder
- Lactic acid:
high levels suggest sepsis or an inborn error of gluconeogenesis such as
glycogen storage disease
- Ammonia: if
elevated suggests hyperinsulinism due to glutamate dehydrogenase
deficiency, Reye syndrome, or certain types of liver failure
- C-peptide:
should be low or undetectable; if elevated suggests hyperinsulinism; low
c-peptide with high insulin suggests exogenous (injected) insulin
- Proinsulin:
detectable levels suggest hyperinsulinism; levels disproportionate to a
detectable insulin level suggest insulinoma
- Ethanol:
suggests alcohol intoxication
- Toxicology
screen: can detect many drugs causing hypoglycemia, especially for
sulfonylureas
- Insulin
antibodies: if positive suggests repeated insulin injection or
antibody-mediated hypoglycemia
- Urine organic
acids: elevated in various characteristic patterns in several types of
organic aciduria
- Carnitine, free
and total: low in certain disorders of fatty acid metabolism and certain
types of drug toxicity and pancreatic disease
- Thyroxine and
TSH: low T4 without elevated TSH suggests hypopituitarism or malnutrition
- Acylglycine:
elevation suggests a disorder of fatty acid oxidation
- Epinephrine:
should be elevated during hypoglycemia
- Glucagon: should
be elevated during hypoglycemia, except in the case of type 1 diabetes
mellitus where irreparable damage is done to the cells which produce this
counterregulatory hormone.
- IGF-1: low
levels suggest hypopituitarism or chronic malnutrition
- IGF-2: low
levels suggest hypopituitarism; high levels suggest non-pancreatic tumor
hypoglycemia
- ACTH: should be
elevated during hypoglycemia; unusually high ACTH with low cortisol
suggests Addison's disease
- Alanine or other
plasma amino acids: abnormal patterns may suggest certain inborn errors of
amino acid metabolism or gluconeogenesis
- Somatostatin
should be elevated during hypoglycemia as it acts to inhibit insulin
production and increase blood glucose level
·
Further
diagnostic steps
When
suspected hypoglycemia recurs and a critical specimen has not been obtained,
the diagnostic evaluation may take several paths. However good nutrition and
prompt intake is essential.
When
general health is good, the symptoms are not severe, and the person can fast
normally through the night, experimentation with diet (extra snacks with fat or
protein, reduced sugar) may be enough to solve the problem. If it is uncertain
whether "spells" are indeed due to hypoglycemia, some physicians will
recommend use of a home glucose meter to test at the time of the spells to
confirm that glucoses are low. This approach may be most useful when spells are
fairly frequent or the patient is confident that he or she can provoke a spell.
The principal drawback of this approach is the high rate of false positive or
equivocal levels due to the imprecision of the currently available meters: both
physician and patient need an accurate understanding of what a meter can and
cannot do to avoid frustrating and inconclusive results.
In
cases of recurrent hypoglycemia with severe symptoms, the best method of
excluding dangerous conditions is often a diagnostic fast. This is usually
conducted in the hospital, and the duration depends on the age of the patient
and response to the fast. A healthy adult can usually maintain a glucose level
above 50 mg/dl (2.8 mM) for 72 hours, a child for 36 hours, and an infant for
24 hours. The purpose of the fast is to determine whether the person can
maintain his or her blood glucose as long as normal, and can respond to fasting
with the appropriate metabolic changes. At the end of the fast the insulin
should be nearly undetectable and ketosis should be fully established. The
patient's blood glucose levels are monitored and a critical specimen is
obtained if the glucose falls. Despite its unpleasantness and expense, a
diagnostic fast may be the only effective way to confirm or refute a number of
serious forms of hypoglycemia, especially those involving excessive insulin.
A
traditional method for investigating suspected hypoglycemia is the oral glucose
tolerance test, especially when prolonged to 3, 4, or 5 hours. Although quite
popular in the United States in the 1960s, repeated research studies have
demonstrated that many healthy people will have glucose levels below 70 or 60
during a prolonged test, and that many types of significant hypoglycemia may go
undetected with it. This combination of poor sensitivity and specificity has
resulted in its abandonment for this purpose by physicians experienced in
disorders of glucose metabolism.
5. Causes
There
are several ways to classify hypoglycemia. The following is a list of the more
common causes and factors which may contribute to hypoglycemia grouped by age,
followed by some causes that are relatively age-independent. See causes of
hypoglycemia for a more complete list grouped by etiology.
·
Hypoglycemia
in newborn infants
Hypoglycemia
is a common problem in critically ill or extremely low birthweight infants. If
not due to maternal hyperglycemia, in most cases it is multifactorial,
transient and easily supported. In a minority of cases hypoglycemia turns out
to be due to significant hyperinsulinism, hypopituitarism or an inborn error of
metabolism and presents more of a management challenge.
- Transient
neonatal hypoglycemia
- Prematurity,
intrauterine growth retardation, perinatal asphyxia
- Maternal
hyperglycemia due to diabetes or iatrogenic glucose administration
- Sepsis
- Prolonged
fasting (e.g., due to inadequate breast milk or condition interfering with
feeding)
- Congenital
hypopituitarism
- Congenital
hyperinsulinism, several types, both transient and persistent
- Inborn errors of
carbohydrate metabolism such as glycogen storage disease
·
Hypoglycemia
in young children
Single
episodes of hypoglycemia may occur due to gastroenteritis or fasting, but
recurrent episodes nearly always indicate either an inborn error of metabolism,
congenital hypopituitarism, or congenital hyperinsulinism. A list of common
causes:
- Prolonged
fasting
- Diarrheal
illness in young children, especially rotavirus gastroenteritis
- Idiopathic
ketotic hypoglycemia
- Isolated growth
hormone deficiency, hypopituitarism
- Insulin excess
- Hyperinsulinism
due to several congenital disorders of insulin secretion
- Insulin injected
for type 1 diabetes
- Hyperinsulin
Hyperammonia syndrome (HIHA) due to Glutamate dehydrogenase 1 gene. Can
cause mental retardation and epilepsy in severe cases.[19]
- Gastric dumping
syndrome (after gastrointestinal surgery)
- Other congenital
metabolic diseases; some of the common include
- Maple syrup
urine disease and other organic acidurias
- Type 1 glycogen
storage disease
- Type III
glycogen storage disease. Can cause less severe hypoglycemia than type I
- Phosphoenolpyruvate
carboxykinase deficiency, causes metabolic acidosis and severe
- hypoglycemia.
- Disorders of
fatty acid oxidation
- Medium chain
acylCoA dehydrogenase deficiency (MCAD)
- Familial Leucine
sensitive hypoglycemia [20]
- Accidental
ingestions
- Sulfonylureas,
propranolol and others
- Ethanol
(mouthwash, "leftover morning-after-the-party drinks")
·
Hypoglycemia
in older children and young adults
By
far, the most common cause of severe hypoglycemia in this age range is insulin
injected for type 1 diabetes. Circumstances should provide clues fairly quickly
for the new diseases causing severe hypoglycemia. All of the congenital
metabolic defects, congenital forms of hyperinsulinism, and congenital
hypopituitarism are likely to have already been diagnosed or are unlikely to
start causing new hypoglycemia at this age. Body mass is large enough to make
starvation hypoglycemia and idiopathic ketotic hypoglycemia quite uncommon.
Recurrent mild hypoglycemia may fit a reactive hypoglycemia pattern, but this
is also the peak age for idiopathic postprandial syndrome, and recurrent
"spells" in this age group can be traced to orthostatic hypotension
or hyperventilation as often as demonstrable hypoglycemia.
- Insulin-induced
hypoglycemia
► Insulin injected for type 1 diabetes
► Factitious insulin injection (Munchausen
syndrome)
► Insulin-secreting pancreatic tumor
► Reactive hypoglycemia and
idiopathic postprandial syndrome
- Addison's disease
- Sepsis
·
Hypoglycemia
in older adults
The
incidence of hypoglycemia due to complex drug interactions, especially
involving oral hypoglycemic agents and insulin for diabetes rises with age.
Though much rarer, the incidence of insulin-producing tumors also rises with
advancing age. Most tumors causing hypoglycemia by mechanisms other than
insulin excess occur in adults.
- Insulin-induced
hypoglycemia
► Insulin injected for diabetes
► Factitious insulin injection
(Munchausen syndrome)
► Excessive effects of oral diabetes
drugs, beta-blockers, or drug interactions
► Insulin-secreting pancreatic tumor
► Alcohol induced hypoglycemia often
linked with ketoacidosis (depletion of NAD+ leads to a block of gluconeogenesis)
► Alimentary (rapid jejunal emptying
with exaggerated insulin response)
+ After gastrectomy dumping
syndrome or bowel bypass surgery or resection
► Reactive hypoglycemia and
idiopathic postprandial syndrome
- Tumor
hypoglycemia, Doege-Potter syndrome
- Acquired adrenal
insufficiency
- Acquired
hypopituitarism
- Immunopathologic
hypoglycemia
6. Treatment and
prevention
Management
of hypoglycemia involves immediately raising the blood sugar to normal,
determining the cause, and taking measures to hopefully prevent future
episodes.
·
Reversing
acute hypoglycemia
The
blood glucose can be raised to normal within minutes by taking (or receiving)
10-20 grams of carbohydrate. It can be taken as food or drink if the person is
conscious and able to swallow. This amount of carbohydrate is contained in
about 3-4 ounces (100-120 ml) of orange, apple, or grape juice although fruit
juices contain a higher proportion of fructose which is more slowly metabolized
than pure dextrose, alternatively, about 4-5 ounces (120-150 ml) of regular
(non-diet) soda may also work, as will about one slice of bread, about 4
crackers, or about 1 serving of most starchy foods. Starch is quickly digested
to glucose (unless the person is taking acarbose), but adding fat or protein
retards digestion. Symptoms should begin to improve within 5 minutes, though
full recovery may take 10–20 minutes. Overfeeding does not speed recovery and if
the person has diabetes will simply produce hyperglycemia afterwards.
If
a person is suffering such severe effects of hypoglycemia that they cannot (due
to combativeness) or should not (due to seizures or unconsciousness) be given
anything by mouth, medical personnel such as EMTs and Paramedics, or
in-hospital personnel can establish an IV and give intravenous Dextrose,
concentrations varying depending on age (Infants are given 2cc/kg Dextrose 10%,
Children Dextrose 25%, and Adults Dextrose 50%). Care must be taken in giving
these solutions because they can be very necrotic if the IV is infiltrated. If
an IV cannot be established, the patient can be given 1 to 2 milligrams of
Glucagon in an intramuscular injection. More treatment information can be found
in the article diabetic hypoglycemia.
One
situation where starch may be less effective than glucose or sucrose is when a
person is taking acarbose. Since acarbose and other alpha-glucosidase
inhibitors prevents starch and other sugars from being broken down into
monosaccharides that can be absorbed by the body, patients taking these
medications should consume monosaccharide-containing foods such as glucose
tablets, honey, or juice to reverse hypoglycemia.
·
Prevention
The
most effective means of preventing further episodes of hypoglycemia depends on
the cause.
The
risk of further episodes of diabetic hypoglycemia can often (but not always) be
reduced by lowering the dose of insulin or other medications, or by more meticulous
attention to blood sugar balance during unusual hours, higher levels of
exercise, or alcohol intake.
Many
of the inborn errors of metabolism require avoidance or shortening of fasting
intervals, or extra carbohydrates. For the more severe disorders, such as type
1 glycogen storage disease, this may be supplied in the form of cornstarch
every few hours or by continuous gastric infusion.
Several
treatments are used for hyperinsulinemic hypoglycemia, depending on the exact
form and severity. Some forms of congenital hyperinsulinism respond to
diazoxide or octreotide. Surgical removal of the overactive part of the
pancreas is curative with minimal risk when hyperinsulinism is focal or due to
a benign insulin-producing tumor of the pancreas. When congenital
hyperinsulinism is diffuse and refractory to medications, near-total
pancreatectomy may be the treatment of last resort, but in this condition is
less consistently effective and fraught with more complications.
Hypoglycemia
due to hormone deficiencies such as hypopituitarism or adrenal insufficiency
usually ceases when the appropriate hormone is replaced.
Hypoglycemia
due to dumping syndrome and other post-surgical conditions is best dealt with
by altering diet. Including fat and protein with carbohydrates may slow
digestion and reduce early insulin secretion. Some forms of this respond to
treatment with a glucosidase inhibitor, which slows starch digestion.
Reactive
hypoglycemia with demonstrably low blood glucose levels is most often a
predictable nuisance which can be avoided by consuming fat and protein with
carbohydrates, by adding morning or afternoon snacks, and reducing alcohol
intake.
Idiopathic
postprandial syndrome without demonstrably low glucose levels at the time of
symptoms can be more of a management challenge. Many people find improvement by
changing eating patterns (smaller meals, avoiding excessive sugar, mixed meals
rather than carbohydrates by themselves), reducing intake of stimulants such as
caffeine, or by making lifestyle changes to reduce stress. See the following
section of this article.
7. Hypoglycemia as
holistic medicine
Hypoglycemia
is also a term of contemporary Alternative medicine which refers to a recurrent
state of symptoms of altered mood and subjective cognitive efficiency,
sometimes accompanied by adrenergic symptoms, which may or may not be
associated with low blood glucose. Symptoms are primarily those of altered
mood, behavior, and mental efficiency. This condition is usually treated by
dietary changes which range from simple to elaborate. Advising people on
management of this condition has been a focus of alternative medicine.