Download Diabetes mellitus - Acute complications

Con Ed
Diabetes/PG/AM
26/09/2007
MODULE 15:
12:31
Page 1
Diabetes mellitus
GLOBALLY the incidence of diabetes is likely to exceed 250
million people by 2025 – that is a measure of the scale of the
problem this condition is likely to present in the future. It is
evidence of how diabetes will be one of the foremost public
PART 9
Acute
complications
by Rita Forde
THE complications of diabetes can be broadly categorised as
acute or chronic, with the latter resulting in the debilitating
macrovascular and microvascular conditions. It is these chronic
complications that present the greatest cost both in human and
fiscal terms. A significant proportion of diabetes care is aimed at
preventing these conditions, namely retinopathy, nephropathy,
neuropathy and cardiovascular disease. However the acute complications of diabetes can also lead to serious morbidity and
mortality. Hypoglycaemia and hyperglycaemic states provide a
challenge for the person living with diabetes and the healthcare
professionals alike.
Hypoglycaemia
Clinically hypoglycaemia is defined as a blood glucose level of
less than 4mmols/l. For people requiring insulin and sulphonylureas hypoglycaemia is a significant limitation in the
management of their diabetes as without it all people with diabetes could have normal glycaemic control over a lifetime of
diabetes.2
Hypoglycaemia is the most common acute complication of diabetes, with its onset usually being rapid and the symptoms
ranging from very mild to severe enough to cause brain damage
or death.3
Falling levels of blood glucose concentration cause an array of
signs and symptoms that are triggered by the central nervous
system and the sympatho-adrenal system.2 The symptoms of
hypoglycaemia are subjective and idiosyncratic but have a fundamental protective role by providing early warning of a fall in
blood glucose. The symptoms of hypoglycaemia can be considered as neurogenic (autonomic), neuroglycopenic or non-specific.
The neurogenic symptoms are the result of the perception of the
physiological changes caused by activation of the central nervous
system due to the falling blood glucose level. The neurogenic
symptoms are either adrenergic or cholinergic mediated and
include tremor, feelings of anxiety and or hunger and sweating.
health challenges facing the world in the decades ahead.
This month Rita Forde discusses the range of complications that
can arise from diabetes and emphasises the importance of not
underestimating the psychological implications for patients.
Neuroglycopenic symptoms are the result of brain neuronal
glucose deprivation. Symptoms range from feelings of warmth
and confusion to include seizure activity, loss of consciousness
and, if severe and prolonged, brain damage or death may occur.
The non-specific symptoms include feelings of nausea and
headache.4
The physical signs resulting from the activation of the sympatho-adrenal system include pallor and diaphoresis. These signs
are often prominent compared to the more subtle increase in
heart rate and blood pressure.
Awareness of hypoglycaemia is largely the result of the perceptions of the neurogenic symptoms and the recognition that they
are indicative of hypoglycaemia. However the neuroglycopenic
symptoms are often the clues recognised by the family and
friends of the person with diabetes.2 During a hypoglycaemic
episode the intensity of an individual symptom is of greater
importance than either the nature or the total number of symptoms in the perception of the low blood glucose level.5
Diagnosis
While the clinical presentation of hypoglycaemia can be characteristic the signs and symptoms are often non-specific. It is for
this reason that it is recommended to test and record the blood
glucose level when hypoglycaemia is suspected.2 A blood glucose
reading of less than 4mmols/l is considered a hypoglycaemia
event and should be treated accordingly. While there is no grading system for hypoglycaemia it is generally categorised as mild,
moderate or severe. Mild hypoglycaemia is one that is easily
treated by the individual by the intake of some refined carbohydrate. Moderate hypoglycaemia is when the intervention of
someone else is necessary to provide carbohydrate (food or
drink) to the person with diabetes as they may display some cognitive impairment. A severe hypoglycaemia means that the
individual has altered consciousness or maybe unconscious and
requires assistance with treating the episode.6
Treatment
Treatment of hypoglycaemia should be initiated immediately
once diagnosed. When the person is conscious 15gm of a refined
carbohydrate should be taken orally. This can be taken in many
forms such as 80ml of regular lucozade, 200ml of orange juice or
five dextrose sweets. The blood sugar should be rechecked after
15 minutes and if it remains less than 4mmols/l the above treatment repeated. Oral carbohydrate should only be administered if
the person is conscious and coherent. In the event that it is not
safe to take carbohydrate orally, 1mg glycogen should be administered subcutaneously or intramuscularly. This treatment can be
repeated after ten minutes if the blood glucose level has not risen
WIN October 2007 Vol 15 Iss 9
47
Con Ed
Diabetes/PG/AM
26/09/2007
12:33
Page 2
Continuing Education
Table
Counter regulatory hormonal response
to at least 4mmols/l. If the hypoglycaemic episode does not
resolve following the second glycogen then intravenous glucose
is necessary, therefore the person will need to be brought to their
local emergency department.6
In the event that a mild to moderate hypoglycaemic episode
occurs while the person is hospitalised 15gm of a refined carbohydrate should be administered as described previously.
However, if the person is unconscious or not capable of safely taking fluids orally then intravenous dextrose (usually 20ml of
dextrose 50%) should be the first line treatment. In the event that
this is not possible then glycogen should be administered.
The brain is dependent on adequate levels of circulating blood
glucose as it requires 120gm-140gm per day to function normally.
When the blood glucose level falls below normal the body
releases hormones to counteract the effects of hypoglycaemia,
known as the counter regulatory response.7
Prevention
Hypoglycaemia is a classic example of prevention being better
than cure and patient education is fundamental to the avoidance
of this potentially life threatening complication of diabetes.5 It is
important to appreciate that hypoglycaemia is not caused by diabetes but by the treatment of diabetes. All people requiring
insulin and sulphonylureas should receive education in relation to
hypoglycaemia. This should include information about the signs
and symptoms and also how to treat hypoglycaemia. However
strategies to prevent its occurrence are a fundamental component of this education. An awareness of the several risk factors
involved should be outlined and the methods to avoid hypoglycaemia explained to all people with diabetes.
Risk factors
There are many risk factors for hypoglycaemia including5:
Insulin excess
Too much insulin taken for the carbohydrate being consumed,
or insulin taken at the wrong time or the incorrect type of insulin
administered.
Decreased exogenous glucose
Missed meals or snacks or not enough food taken at a meal.
Prolonged fasting can also lead to hypoglycaemia.
Decreased endogenous glucose production
Alcohol can inhibit glycogenolysis
Increased glucose utilisation
Excessive exercise or activity for the food consumed.
Increased insulin sensitivity
This can occur after exercise or if the person increases their fitness level or loses weight. It can also be induced by some
medications and also by increased temperatures such as very
warm weather or following a hot bath or shower.
Decreased insulin clearance
Occurs as a result of diminished renal function or renal failure.
Compromised glucose counter regulation
An insulin deficiency or a history of severe or frequent hypoglycaemic episodes can lead to this. In addition intensive diabetes
management with a very low glycaemic control can result in a
compromised glucose counter regulation system.
Hypoglycaemia unawareness
This is defined as the reduced ability or failure to recognise
hypoglycaemia at the physiological plasma glucose concentration at which warning symptoms would normally occur.8 People
with hypoglycaemia unawareness either do not realise that their
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WIN October 2007 Vol 15 Iss 9
Hormone
Glucagon
Action
Increased glucose output from the
liver and muscle (glycogenolysis)
Adrenaline and
nor adrenaline
Enhanced glycogenolysis in liver and
muscles
Enhanced gluconeogenesis
Decreased insulin secretion
Causes many of the signs and
symptoms of hypoglycaemia
Cortisol
Mobilises the substrate for
gluconeogenesis
Growth hormone
Acts with glucose and adrenaline to
inhibit peripheral glucose utilisation
blood glucose level has fallen below normal or they ultimately
feel the warning symptoms but at a much lower than normal
plasma glucose level.8 Unawareness is thought to be due to
reduced sympathoadrenal responses and the resultant reduced
neurogenic symptoms to a given level of glucose concentration.2
It is associated with the frequency of hypoglycaemia episodes
and their severity. The more episodes experienced by the person
or the more severe the episode the greater the risk of hypoglycaemia unawareness in the future.This can be reversed with strict
avoidance of hypoglycaemia and early treatment of falling blood
glucose levels. However a chronic complication of diabetes, autonomic neuropathy can lead to hypoglycaemia unawareness that
is not reversible.
Once hypoglycaemic unawareness is suspected the person
should receive further education on the avoidance of a low blood
sugar level and its treatment. It is imperative that the frequency of
home blood glucose monitoring is adequate. More frequent testing will be required especially before driving. If driving for a long
distance the blood sugar level should be re-tested periodically.
Psychological implications
Hypoglycaemia is feared by a significant proportion of people
with diabetes as it has a profound effect on quality of life. This is
evident in relation to having a hypoglycaemic event while driving, while at work or at any social event. There is also the fear of
brain damage or death to be considered. Therefore it is not
unusual for people to deliberately have their blood glucose level
higher than recommended in an attempt to avoid hypoglycaemia
and a potentially embarrassing or unsafe situation. However this
compromise in glycaemic control increases the risk of the chronic
debilitating complications of diabetes.The psychological implications of diabetes and its management should be considered at all
stages of care and education.
Hypoglycaemia is an acute complication of the management of
diabetes and is defined as a blood glucose level less than
4mmols/l. The symptoms of hypoglycaemia can be considered as
neurogenic (autonomic), neuroglycopenic or non-specific and are
resultant of a cascade of events triggered by the falling glucose
level. All patient education programmes should include strategies
to prevent hypoglycaemia in addition to the correct management of it. Loss of awareness of a falling blood glucose level can
occur as a result of frequent or severe episodes of hypoglycaemia.
The psychological implications of this acute complication of diabetes should not be under estimated.
Rita Forde is an advanced nurse practitioner in diabetes at the Mater University
Hospital, Dublin
References on request from [email protected] (quote: R.Forde WIN 2007; 15(9): 47-48)