As mentioned in the earlier post, I am going to continue the discussion regarding medically compromised patient and medical emergencies in a dental clinic.
We discussed about Vasovagal syncope in the previous post.
Vasovagal syncope is the most common cause of loss of consciousness in a dental clinic. Other causes of loss of consciousness in a dental clinic are Postural Hypotension, Adrenal Insufficiency, Hypoglycaemia etc.
Steroids have been used medically to manage multiple diseases.
Steroids reduce inflammation and supresses the activity of immune system.
These properties make them indispensable after surgery as it prevents inflammation, hence less tissue damage. Steroids are also used in autoimmune disorders such as Angioedema or Rheumatoid arthritis.
Today we will be discussing the possible medical problem that you may face if a patient is on long term steroid therapy and how to manage it.
Long term use of Steroid lead to disuse atrophy of Adrenal Glands (more on this later), leading to Adrenal insufficiency under stress.
Before diving into the details of the medical complication because of steroids, we should first know how HPA (Hypothalamus-Pituitary-Adrenal) axis works.
Physiology
We have already discussed how our body deals with stress (physical or psychological) by releasing epinephrine, norepinephrine and steroid (cortisol and aldosterone) from the adrenal glands.
Epinephrine and norepinephrine cause tachycardia, increased force of contraction, increase in blood pressure, peripheral vasoconstriction.
Cortisol increases blood glucose level to cope up with the stress.
Aldosterone causes sodium retention and excretion of potassium in the kidneys leading to increased retention of water. Increased water in the body leads to increased blood volume and blood pressure. Hence, we can say that aldosterone also helps in the regulation of blood pressure.
Right now, we are more concerned with how the release of cortisol is regulated.
AdrenoCorticoTrophic Hormone (ACTH) released by the pituitary gland is responsible for the regulation of Cortisol production by the adrenal glands.
In a normal individual, in a non-stressful environment, when the body has less than the required amount of cortisol in the body, the pituitary gland increases the release of ACTH into the blood.
The increased ACTH concentration in the blood stimulates the cortex of the Adrenal glands to secrete cortisol.
As soon as the cortisol levels in the blood reach the required level, ACTH production by the pituitary gland is reduced. This is called as Negative feedback mechanism.
Plasma half-life of ACTH is 10 minutes. So as soon as the release of ACTH in pituitary glands is reduced the plasma concentration of ACTH in blood drops rapidly.
Less ACTH plasma levels mean less stimulation of the Adrenal cortex leading to reduction in secretion of cortisol.
But this mechanism is not responsible for the sharp rise of cortisol in blood when under stress.
When the patient is under stress, the hypothalamus secretes Corticotrophin Releasing Hormone (CRH).
This CRH then stimulates the pituitary gland to increase the secretion of ACTH into the blood.
This ACTH then causes increased secretion of cortisol required to deal with the stress.
Even when there are increased plasma levels of cortisol, it will not lead to reduction in ACTH secretion as ACTH secretion here is caused by CRH.
This pathway is called as HPA axis (Hypothalamus-Pituitary-Adrenal) axis.
Pathophysiology
So now that you understand how normally HPA axis functions, let us talk about what happens when a patient is on long term steroid medications.
Usually, in a normal individual HPA axis regulates cortisol at a daily dosage of approximately 20mg/day. This 20mg/day dosage is achieved purely by the endogenous steroid (cortisol released by our own body) secreted by adrenal glands.
When an individual for some reason (Angioedema, asthma, arthritis, Bell’s palsy, Meningitis, etc.) starts taking Exogenous steroids (cortisol with origin outside the body, eg.- Tablets or Injection), the adrenal glands reduces the production of the steroids (cortisol) in order to maintain the normal blood levels of steroids.
If this continues for longer duration; the size of the adrenal glands is reduced as they are no longer used much. This is called as Disuse Atrophy.
If a patient with disuse atrophy of adrenal glands is subjected to stress, his body is not able to produce the required excess amount of steroid to cope up with the stress.
The patient's body cannot handle stress and shows symptoms such as severe Hypotension, mental confusion, pain in abdomen & lower back, etc.
As there is less than the required amount of steroid in the body to cope up with the stress, the blood glucose level is low as steroids are required to increase the blood glucose level in stress.
This leads to signs of hypoglycemia like tachycardia, perspiration, weakness, nausea, vomiting, headache, loss of consciousness and coma.
To sum it up, suddenly adrenal glands are not able to produce the required amount of steroid.
This condition is called as Acute Adrenal Insufficiency.
Acute means sudden. Adrenal insufficiency means the inability of adrenal glands to produce the required amount of steroid.
Multiple studies have shown that if a person receives Exogenous steroid (Cortisone : synthetic cortisol is cortisone) at a dosage of 20mg/day or more, for a period of more than 2 weeks, it leads to disuse atrophy of the adrenal glands.
So, if the exogenous steroid administration is to be ceased, it should not be done suddenly. Rather it should be done in a tapering fashion.
Given sufficient time, the adrenal glands can regain their original function.
Studies have shown that minimum time required for that is 9 months and maximum time required is 2 years.
Based on these findings we have something called as Rule of 2.
If a patient consumed 20mg/day or more Cortisone or its equivalent, for a duration of 2 weeks or more, within 2 years then the dosage of the steroid medication should be doubled preoperatively.
Doubling of the steroid dosage is to ensure that the body has sufficient blood levels of steroids in the body so as to deal with the physical and psychological stress.
Of course, doubling of the steroid dose is to be done in consultation with the physician of the patient.
Now the most common steroids prescribed are hydrocortisone, prednisolone, Methylprednisolone, Triamcinolone, Dexamethasone.
Below mentioned are their equivalent dose to that of a 20mg cortisone.
Cortisone 20mg = 16 mg Hydrocortisone
Cortisone 20mg = 5 mg Prednisolone
Cortisone 20mg = 4 mg Methylprednisolone
Cortisone 20mg = 4 mg Triamcinolone
Cortisone 20mg = 0.75 mg Dexamethasone
So, for example, if a patient is taking 0.75 mg/day dexamethasone for 2 weeks or more, within 2 years of the dental procedure then you will have to double the dosage of dexamethasone before the procedure.
Management
As mentioned in the previous post, any medical emergency that happens in a dental clinic should be managed by following the P-C-A-B-D protocol.
Of Course, it goes without saying, before that you need to stop the dental procedure being performed.
P – Position
C - Circulation
A - Airway
B - Breathing
D - Definitive
In positions, supine position with feet elevated is preferred.
In circulation, Check for carotid pulse.
In airway, perform a Head tilt - Chin lift maneuver.
In breathing, check if the patient is breathing using the Look-Listen-Feel technique. Also, administer oxygen through Nasal hood at a rate of 5-10 Litres/Minute.
I have already talked about P-C-A-B steps in details in my previous post.
Definitive treatment can only be given when a proper diagnosis of the complication has been done.
When a patient loses consciousness because of Acute Adrenal insufficiency, it may be difficult to separate the diagnosis from vasovagal syncope.
To determine if the loss of consciousness is because of vasovagal syncope or Acute Adrenal insufficiency, place a cotton soaked with aromatic ammonia near the nostrils of the patient.
If the patient responds to the aromatic ammonia and regains consciousness, then it is because of vasovagal syncope.
If the patient does not respond to the aromatic ammonia, then it is Acute Adrenal Insufficiency.
Also, a proper medical history (history of steroid intake) taken prior to the commencement of the procedure will help in further confirming the diagnosis.
While you do all that, ask your assistant to call for Emergency Medical Services.
Definitive
Once the diagnosis of Acute Adrenal insufficiency is confirmed, administer 100 mg Hydrocortisone IV (preferable) or IM. If IV administration is done, 100 mg should be administered over a duration of a minimum of 30 seconds. It should be repeated every 8 hours, if required.
Hydrocortisone is preferred as its onset of action is rapid.
As there is hypotension, IV infusion of 1 Litre of 5% Dextrose solution (preferable, to counter hypoglycemia) or Normal Saline should be administered over a duration of 1 hour. This step is usually done at the hospital.
Acute Adrenal insufficiency, although life-threatening, is rare to occur and easily manageable if diagnosed on time.
But as I have said before, A great doctor not only knows how to manage a complication but also knows how to avoid them.
So, let’s talk about how we can stop Acute Adrenal insufficiency from occurring at your dental clinic.
Prevention
If the medical history shows that the patient is on long term steroid, then double the dosage of the steroids preoperatively.
Follow the stress reduction protocol.
Talk to the patient. Make him feel at ease.
Let him know what to expect from the procedure (Injection & dental treatment).
Reassure him that you are not going to do anything unpleasant to him.
Make sure the injection technique is as painless as possible.
If possible, prescribe an anxiolytic drug to be taken a night before and at the morning of the surgery.
Conclusion
To conclude, I would like to say that properly taken patient history goes a long way in preventing such medical complications.
Also, it is always beneficial to use aromatic ammonia when a patient loses consciousness. Aromatic ammonia will either aid with the recovery of the patient or it will help in diagnosing the actual cause of the loss of consciousness.
As mentioned at the beginning of the article, steroids suppress the immune system of the body. So in a patient with long term steroid therapy, always prescribe antibiotics to prevent infection at the surgical site.
So, there you go. Now you know what Acute Adrenal insufficiency is and how to prevent it.