in Pets with Diabetes Mellitus.
There was a very good article that was found at this
which seems to not be working at this time so here
is the page
that was originally found there.
Below is a blood glucose curve depicting the Somogyi phenomenon. In
the positive urine glucoses prompted continued escalation in the insulin
The subsequent insulin toxicity (and concomitant hypoglycemia –or low
blood glucose) resulted in
initiation of protective compensatory mechanisms which caused massive
transient rises in blood sugar.
In this case, urine dipsticks for glucose were checked twice daily
and were always positive, prompting
the owners to incrementally increase the insulin dose. This graph depicts
in days what usually happens
over weeks when well-meaning concerned pet owners try to use urine
dipsticks to determine insulin
dosing. Fortunately, the body is able to release several hormones which
increase the amount of
circulating glucose and which “shield” the tissues from the effects
of insulin. Over time, even as the body
is experiencing dramatic fluctuations in blood sugar levels, the tissues
develop a resistance to insulin which
may require weeks of insulin withdrawal to resolve. The best way to
avoid Somogyi is to base insulin dose
adjustments on blood, not urine glucose levels. Your veterinarian can
do this by using a glucometer with just
a drop of blood acquired every 2-3 hours for 12-24 hours, depending
on how often insulin is administered.
From the Pet Diabetes
Somogyi effect: A condition in which the blood glucose level increases
if too much insulin is given.
It occurs when insulin causes the blood glucose level to go so low
it stimulates the production of
other hormones in the body such as epinephrine which promote the breakdown
of glycogen (
the chemical compound which the body uses to store glucose) and increases
the blood glucose
level above normal. It is also called rebound hyperglycemia or insulin-induced
Caninsulin Book Definition
In case the insulin dose is slightly too high, the Somogyi - effect
occur. This is a chain reaction of the body to a sluggish decline
blood glucose leve. If after insulin injection the glucose level
decreased to approx. 3 mmol/l, the patient will become hungry and restless
or lethargic. Due to a decling glucose level in the CNS, adrenaline
subsequently cortisol, glucagon and growth hormone will be released.
hormones will induce an increase of the blood glucose level(through
gluconeogenesis, release of glucose from hepatic glycogen and increase
the peripheral resistance to insulin). This results in a rapid
rise of the
glucose level shortly after the second meal. During the rest
of the 24
hour period, the blood glucose level further increases to 15-18 mmol/l
even higher. The urine glucose level is negative during the day,
in the evening and night and will become strongly positive in the morning.
Symptoms of polyuria and polydipsia will occur. This condition
risk that if guided only by the results of urine tests, the insulin
will be increased. This is absolutely contraindicated since in
this way a
severe hypoglycemia will be induced. In contrast, the insulin
dose must be
decreased by 20%!
Detecting and avoiding chronic somogyi rebound
Oddly, too little insulin means pre-shots are too high and too much
insulin often also means pre-shots are too high. This effect is often noted
by those who test their pets' blood glucose at home.
The reason: Anytime the glucose level drops too far or too fast, the
cat or dog may defensively dump glucose (converted from glycogen in the
liver), as well as hormones epinephrine and cortisol, into the bloodstream.
(If these are insufficient, hypoglycemia ensues!) The glycogen raises the
blood glucose, the other two may make the pet insulin-resistant for a time.
This phenomenon was first documented by a Dr. Somogyi. .
Even when raising the insulin dose slowly and carefully, it's possible
to pass the correct dose and go on to an overdose. (A typical case is increasing
bidaily dosage from 1 unit to 2, passing a correct dose of 1.5 units.)
This may produce a rebound -- a swift jump in blood glucose up from a dangerously
low reading, to beyond the previous pre-shot level. The pet may be a bit
less responsive to the same dose the next shot, from those other hormones.
Repeating the overdose on subsequent days, and checking only pre-shot readings
or urine glucose, can give the dangerously wrong impression that more insulin
is needed! Remember to check occasionally at the expected nadir (low point)
It's unusual to be monitoring glucose right when this happens, and typical
to just continue the overdose, leading to a repeated rebound situation.
So it's good to learn to recognize the patterns of repeated rebound.
A typical rebound pattern, most often seen with long-acting insulins,
is a high, flat, unresponsive blood sugar over a period of days. Sometimes,
often when raising dosage, this high flat curve will be punctuated by sudden
drops to very low values, (with possible hypoglycemic events) followed
by a fast return to high unresponsive numbers. (It's the sudden dip that
distinguishes this pattern from inadequate insulin!)
When using shorter-acting insulins, repeated Somogyi rebound may manifest
instead as rapidly alternating high and low blood sugar numbers with no
apparent logic. The highs and lows will both be exaggerated compared to
what you'd see on a smaller dose.
It's not always easy to tell a rebound from a regular curve showing
insulin action ending normally. One way to tell the difference is to take
a "curve" (repeated tests every 2 hours starting with the insulin shot)
on a weekend and look for the shape of the curve. If the curve is valley-shaped,
and gradual, then you are not seeing Somogyi rebound. Other shapes should
arouse suspicion. In particular, if the rise after peak action is faster
and rises higher than the original pre-insulin level and the original fall
in blood sugar, you have good cause to consider rebound. The only sure
way to check is to reduce dosage and look for a better-shaped curve.
A fairly sure sign: Anytime blood glucose numbers seem higher after
dosage is raised, consider the possibility of a somogyi rebound. But other
things can cause unexpectedly high blood glucose too, so look for a clear
correlation with dosage changes.
This article is from Wikipedia.
All text is available under the terms of the GNU
Free Documentation License.
www.petdiabetes.org has a very good page on somogyi phenomenon
This page was updated on July 5, 2006