Local and Systemic Complications

Question 1

1. In the unlikely event that an anesthetic needle breaks within the patient’s tissues, the following steps should be taken:
2. Keep the patient’s mouth open either by keeping your fingers in the patient’s mouth or by using a bite block
3. Have the patient close her mouth immediately to avoid having the needle migrate
4. If the broken needle is visible, try to remove it with a hemostat
5. If the broken needle is not visible, have the dentist incise the area to locate the needle for easy removal

a. 1, 3 and 4 only
b. 2, 3 and 4 only
c. 1 and 3 only
d. 2 and 4 only

Answer 1

c. 1 and 3 only

In the unlikely event that an anesthetic needle should break within the patient’s tissues, the following steps should be taken:

keep the patient’s mouth open either by leaving your fingers in the mouth or by using a bite block
if the broken needle is visible, try to remove it with a hemostat
if the broken needle is not visible, DO NOT have the dentist incise the area to locate the needle - in this instance, referral to an oral and maxillofacial surgeon for a consultation is recommended

Question 2

2. After 3 attempts, you achieved anesthesia with a left IAN block on your patient, and then spent 1 hour scaling and root planing that quadrant. As he got up to leave, he informed you that he couldn’t open his mouth very wide at this time without experiencing pain. What is this condition called:
   a. hematoma
   b. trismus
   c. paresthesia
   d. facial nerve paralysis

Answer 2

b. trismus

this condition is called trismus and may have been caused by the repeated attempts to administer this injection. Multiple insertions can cause this post-injection discomfort.
Factors that can cause trismus include:

trauma to muscles or blood vessels in the infratemporal fossa
using a local anesthetic agent which has been contaminated by alcohol or other disinfectant or sterilizing agents
using a barbed needle
an excessive amount of local anesthetic solution deposited into a restricted area

Question 3

3. For this same patient, what would you recommend as a treatment to alleviate his trismus:
4. Aspirin
5. Cold pack every 20 minutes for 2 hours on affected side
6. Hot, moist towels for 20 minutes every hour on affected side
7. Warm, salt water rinses on affected side
8. Opening and closing the mouth for 5 minutes every 3 - 4 hours, including lateral movements
9. Muscle relaxants if necessary

a. all of the above
b. 1 and 2 only
c. 1, 2, 3 and 5 only
d. 1, 3 and 5 only
e. 1, 3, 4, 5 and 6 only

Answer 3

e. 1, 3, 4, 5 and 6 only

The patient should be instructed to:

take aspirin for pain and its anti-inflammatory properties

use hot, moist towels for 20 minutes every hour on affected side
use warm, salt water rinses on the affected side
take muscle relaxants if necessary
open and close his mouth for 5 minutes every 3 - 4 hours, including lateral movements
Improvement will usually be noted within 48 - 72 hours.

Question 4

4. After administering a left PSA injection to a patient, swelling becomes evident on the left side of her face within a few minutes. What has most likely occurred to this patient:
   a. the nerve has been damaged during the injection
   b. contaminated anesthetic solution has been administered
   c. the anesthetic solutions were administered too quickly
   d. the needle inadvertently nicked the pterygoid plexus of veins

Answer 4

d. the needle inadvertently nicked the pterygoid plexus of veins

Yes, the needle inadvertently nicked the pterygoid plexus of veins, causing this hematoma. The maxillary artery is also at risk of being penetrated in this area.
Diffuse bruising may appear on her face, progressing downwards and forwards toward the lower portion of her cheek.

Question 5

5. For the preceding question, what was the most likely technique error that created this hematoma from the PSA injection:
   a. the needle was inserted too far mesially
   b. the needle was inserted too far distally
   c. the needle was inserted at the height of the mucobuccal fold above the maxillary second molar
   d. the bevel was turned toward bone

Answer 5

b. the needle was inserted too far distally

The needle was inserted too far distally. To correct this, insert the needle at the height of the mucobuccal fold above the maxillary second molar. It is recommended to use a 25-gauge short needle, although a 27-gauge short is also acceptable.

Question 6

6. For this same patient with the hematoma from the PSA injection, how would you recommend that she treat the area:
   a. apply ice immediately to the area
   b. hot, moist towels for 20 minutes every hour on affected side
   c. open and close her mouth for 5 minutes every hour for 6 hours
   d. warm salt water rinses on the affected side

Answer 6

a. apply ice immediately to the area

Ice should be applied to the area immediately. If possible, digital pressure can be applied to the affected soft tissues in the mucobuccal fold.

Heat should not be applied to the area for at least 4 - 6 hours as it produces vasodilation which can further exacerbate the region. After 4 – 6 hours, warm, moist towels may be applied to the area for 20 minutes every hour.

Additionally, advise your patient that the area will probably be sore and will have discoloration that will last for 1 - 2 weeks.

Question 7

7. Immediately after administering a left IAN to your patient, the left side of his face droops. In addition, the area did not become anesthetized. What most likely occurred:
   a. the needle was inserted too deep
   b. the needle was not inserted deep enough
   c. the needle traumatized the lingual nerve
   d. anesthetic solution was inadvertently deposited while the needle was advancing

Answer 7

a. the needle was inserted too deep

The answer is that the needle was inserted too deep. In this situation, solution was injected into the parotid gland where terminal portions of the facial nerve extend. This resulted in the facial nerve paralysis.

For an IAN injection, the appropriate depth of penetration is 2/3 to 3/4 the length of a long needle, which is approximately 20 - 25 mm. In this case, the clinician penetrated almost to the hub, thus creating this complication.

Question 8

8. In the previous question involving facial nerve paralysis, what technique modification needs to be made to avoid this problem in the future:
   a. when administering an IAN, be certain to contact bone prior to depositing any solution
   b. when administering an IAN, avoid contacting bone prior to depositing any solution
   c. use a short needle for an IAN injection to avoid going too deep with the needle

Answer 8

a. when administering an IAN, be certain to contact bone prior to depositing any solution

When administering an IAN, be certain to gently contact bone prior to depositing any solution. This will prevent over-insertion and assure that the needle is not in the parotid gland.

However, remember that the correct depth is 2/3 to 3/4 the length of a long dental needle. If the clinician hasn’t contacted bone and is advancing the needle deeper than this, the needle should be withdrawn until only approximately 1/4 its length remains in tissue. Then the syringe barrel should be repositioned more posteriorly so it is over the mandibular molars. The needle should be advanced until it gently contacts bone.

If, on the other hand, the clinician contacts bone prior to being at least 2/3 the length of the needle into the tissue, the needle should be withdrawn slightly, the syringe barrel should be repositioned more anteriorly (over cuspid or lateral incisor, but keeping the syringe on the same side of the mouth as it originally was), and then advancing until bone is contacted.

Question 9

9. After applying topical anesthetic to an injection site for 4 minutes, the clinician notices that the epithelium is sloughing in the area where the topical was applied. This can be due to:
   a. presence of vasoconstrictor in the topical anesthetic
   b. topical anesthetic was held too long in the area
   c. the high degree of water solubility of the topical anesthetic
   d. the low degree of water solubility of the topical anesthetic

Answer 9

b. topical anesthetic was held too long in the area

Applying topical anesthetic at an injection site for 4 minutes can cause sloughing of the epithelium. It is recommended that topical anesthetic contact the mucous membranes for only 1 - 2 minutes, and then the excess should be wiped off.

Other factors that may cause sloughing of tissues can be sensitivity of the tissues to the topical or a reaction to the topical anesthetic.

Remember that a vasoconstrictor is NOT found in topical anesthetic.

Question 10

10. A major difference between overdose and allergic reactions is that allergic reactions are not dose related.
    a. True
    b. False

Answer 10

a. True

Overdose reactions are dose related and allergic reactions are NOT dose related.

When overdose reactions develop, there is a large enough amount of the drug administered to the patient leading to excessive blood levels in the target organ or tissues. On the other hand, a patient with an allergy to a local anesthetic can have an allergic reaction with an extremely small amount of the drug.

Question 11

11. What are the most likely cause(s) of an overdose from a local anesthetic:
    patient positioned in a supine position during the injection
    solution was administered too rapidly
    solution was inadvertently injected intravascularly
    solution contained a vasoconstrictor
    a. all of the above
    b. 1 and 2 only
    c. 2 and 3 only
    d. 3 and 4 only

Answer 11

c. 2 and 3 only

An overdose from a local anesthetic is most likely due to the solution being administered too rapidly and also inadvertent injection intravascularly.

Some other factors that can lead to overdose include:

the concentration of the anesthetic: A 4% solution contains more drug than does a 2% solution. It is advised to use the lowest concentration of a local anesthetic that is clinically effective.

the dose of the drug: Use the recommended amounts of anesthetic solution to achieve pain control. The smallest dose that is clinically effective should be administered.

Question 12

12. You have begun providing therapy to your patient, and you notice that he is sweating profusely and appears pale. Additionally, his face feels cool to your touch and he isn’t responding to your questions about how he is feeling. What is the probable complication:
    a. an allergic reaction
    b. an overdose reaction
    c. syncope
    d. infection from the anesthetic

Answer 12

c. syncope

These are the symptoms of syncope, or fainting, which is the most common medical emergency seen either before, during or after administration of anesthesia. Other symptoms include light-headedness, dizziness, tachycardia and palpitations.

Question 13

13. How would you manage the patient described in the previous question who has fainted:
    a. seat the patient in an upright position and administer oxygen
    b. recline the patient in a supine position and administer oxygen
    c. administer CPR immediately
    d. Call 911 immediately

Answer 13

b. recline the patient in a supine position and administer oxygen

Yes. To manage a patient who has just fainted, you would recline the patient in a supine position and administer oxygen.
Additionally, you would monitor their vitals and administer ammonia smelling salts if necessary.

It is best to prevent this from occurring to begin with, however. To do so, when administering local anesthesia it is advisable to have the patient reclining so the head and heart are even and parallel to the floor with the feet slightly elevated. This position enhances the delivery of oxygenated blood to the brain.

Question 14

14. Ten minutes after administering 2% lidocaine with 1:100,000 epinephrine to a healthy female adult, she starts to become very talkative and agitated. You immediately take her vitals and note that her blood pressure and pulse have increased substantially. What is occurring to her:
    a. a mild overdose reaction
    b. a severe overdose reaction
    c. syncope
    d. an allergic reaction

Answer 14

a. a mild overdose reaction

This patient is experiencing a mild overdose reaction to the local anesthetic. The symptoms she experienced - talkativeness, agitation and an increase in vital signs - are indicative of this condition. It will usually occur between 5 and 10 minutes following completion of the injection.

Question 15

15. How would you treat the patient in the previous question who is experiencing a mild overdose reaction to a local anesthetic agent:
    a. immediate basic life support
    b. IM injection of epinephrine
    c. administer oxygen
    d. no treatment is necessary - the patient will recover in a few minutes

Answer 15

c. administer oxygen

To treat a mild overdose reaction to a local anesthetic agent, administer oxygen after reassuring the patient that everything will be OK. Monitor vital signs and allow the patient to recover for as long as necessary.

However if the patient experiences a slower onset of the same symptoms (occurs 15 minutes or more after completion of the injection), the situation may be due to abnormal biotransformation of the drug and/or renal dysfunction.

In this situation, reassure the patient, administer oxygen, monitor vital signs and administer an anti-convulsant such as Diazepam (valium). Medical assistance should be summoned. Do not allow the patient to leave the dental office unattended.

Question 16

16. Upon reviewing your patient’s medical history, you note that he has indicated he has “atypical pseudocholinesterase.” Would this affect your decision to use a local anesthetic agent on him:
    a. no, there would be no contraindications to using a local anesthetic
    b. yes, he would not be able to tolerate a vasoconstrictor
    c. yes, he would not be able to tolerate the amide classification of local anesthetics
    d. yes, he would not be able to tolerate the ester classification of local anesthetics

Answer 16

d. yes, he would not be able to tolerate the ester classification of local anesthetics

When a patient has atypical pseudocholinesterase, it represents a relative contraindication to the use of esters.

Plasma pseudocholinesterase is primarily responsible for the hydrolysis of esters to para-aminobenzoic acid (PABA). Patients who have atypical pseudocholinesterase may not be able to biotransform esters at the usual rate. This could lead to higher levels of the ester drug in their blood.

These patients should receive amides when administration of local anesthetics are necessary.

Question 17

17. Your patient indicates that he has congenital methemoglobinemia. Because of this, which anesthetic is relatively contraindicated in his case?:
    a. Prilocaine
    b. Lidocaine
    c. Mepivacaine
    d. Bupivacaine

Answer 17

a. Prilocaine

Prilocaine, commonly available as Citanest®, can produce methemoglobinemia when administered in large doses. This condition can be congenital or acquired*, and produces a cyanosis-like state where the oxygen-carrying capacity of the blood is reduced. Respiratory depression, syncope and even death can result when the condition is severe.

While methemoglobinemia should not develop in otherwise healthy patients who are given doses of prilocaine within the recommended limits, the condition is nevertheless a relative contraindication for the use of prilocaine.

*An example of acquired, drug-induced methemoglobunemia is seen in people who take frequent, large doses of acetaminophen.

Question 18

18. Which three injections have the highest rates of positive aspiration, which could lead to intravascular injection:
    a. PSA, MSA, IAN
    b. PSA, GP, IAN
    c. IAN, MSA, Mental/Incisive
    d. IAN, Mental/Incisive, PSA

Answer 18

d. IAN, Mental/Incisive, PSA

In descending order, the injections with the highest rate of positive aspiration are:

IAN
mental/incisive
PSA

While positive aspiration can occur with any injection, it is more likely with the above-listed injections. Therefore, it is recommended that with these injections, a 25-gauge needle be used since aspiration of blood will be easier and more reliable with the larger diameter (lumen).

Question 19

19. Your HIV positive patient presents with severe gingivitis on #18, 19, 20 and 21. These teeth bleed profusely upon gentle probing. You decide to administer an IAN using lidocaine 2% with epinephrine 1:50,000 for hemostasis.
    After administering the nerve block, your patient tells you he has a throbbing headache, he becomes dizzy and also perspires profusely. He also states that his heart is pounding.

What appears to have happened?

a. overdose of lidocaine
b. allergic reaction to the lidocaine
c. overdose of epinephrine
d. allergic reaction to the epinephrine
e. syncope

Answer 19

c. overdose of epinephrine

These symptoms indicate that this patient is experiencing an overdose reaction to the epinephrine which was probably delivered intravascularly.

Other symptoms of epinephrine overdose include tenseness, restlessness, respiratory difficulty and an elevated heart rate.

Question 20

20. What would be the course of treatment for the preceding patient experiencing an epinephrine overdose:
    a. recline the patient so his head and heart are parallel to the floor with his feet slightly inclined
    b. no treatment is necessary; this episode is transitory and will be over quickly
    c. administer CPR
    d. position the patient in a sitting position to minimize any cardiovascular effects

Answer 20

d. position the patient in a sitting position to minimize any cardiovascular effects

To treat a patient experiencing an epinephrine overdose, position them so that they are comfortable and in a sitting position to minimize any cardiovascular effects which could raise the blood pressure.

As with any medical emergency, monitor the patient’s vitals and administer oxygen if necessary, but not if the patient is hyperventilating. This emergency should pass shortly, however allow the patient to fully recover as long as necessary.

According to the Handbook of Local Anesthesia by Malamed, 1:50,000 epinephrine should only be used in very small volumes infiltrated directly into a surgical site for hemostasis. You will remember that is what was used for this patient. It was given as an IAN block, and most likely it was administered intravascularly.

Question 21

21. Immediately after applying a lidocaine topical anesthetic and administering 3% mepivacaine to your patient, he loses consciousness and begins to convulse. What is the most likely cause of this:
    a. epinephrine overdose
    b. local anesthetic overdose
    c. reaction to using two different types of anesthetic
    d. allergic reaction to the topical anesthetic
    e. allergic reaction to the local anesthetic

Answer 21

b. local anesthetic overdose

In this instance, the patient is experiencing a severe overdose to the local anesthetic, most likely from a rapid intravascular injection.

Question 22

22. In this instance where the patient is experiencing a severe overdose reaction to a local anesthetic and is experiencing convulsions, what is the recommended management of the situation:
    a. 911, basic life support, administer IV anti-convulsant if seizure lasts longer than 4 - 5 minutes with no signs of terminating
    b. position patient in sitting position, monitor vitals for 5 minutes, summon 911 if vitals remain at high levels over 5 minutes
    c. position patient in supine position, monitor vitals for 5 minutes, summon 911 if vitals remain at high levels over 5 minutes
    d. administer oxygen, administer epinephrine via aerosol inhaler

Answer 22

a. 911, basic life support, administer IV anti-convulsant if seizure lasts longer than 4 - 5 minutes with no signs of terminating

In this situation, protect the patient if he is having convulsions, call 911, administer basic life support and administer an anti-convulsant IV, such as diazapam, if the seizure lasts longer than 4 - 5 minutes with no signs of terminating.

It is essential that the patient have an adequate airway and oxygenation during a local anesthetic-induced seizure.

Question 23

23. Using the same patient experiencing an overdose reaction to a local anesthetic agent, what could be done to prevent this from occurring:
24. deposit the solution slowly
25. deposit the solution in a quick manner
26. use a vasoconstrictor to slow the absorption of the local anesthetic agent
    a. none of the above
    b. 2 and 3 only
    c. 1 and 3 only
    d. 2 only

Answer 23

c. 1 and 3 only

To prevent this situation from occurring, the anesthetic solution should always be deposited slowly and whenever possible, a vasoconstrictor should be used to slow the absorption of the local anesthetic agent.

Also, aspiration must always be done to assure that the solution is not being deposited intravascularly.

Question 24

24. Signs of anaphylaxis include:
25. intense itching
26. severe abdominal cramps
27. nausea and vomiting
28. substernal tightness or pain in the chest
29. hypotension
30. convulsion
    a. all of the above
    b. 1, 2, 3 and 4 only
    c. 2, 3, 4, 5 and 6 only
    d. 1, 2, 3, 4 and 5 only

Answer 24

d. 1, 2, 3, 4 and 5 only

Signs and symptoms of anaphylaxis include:

intense itching
severe abdominal cramps
nausea and vomiting
substernal tightness or pain in the chest
hypotension
Convulsions would not be a sign of anaphylaxis.

Question 25

25. Your patient, a 35-year old healthy female, indicates on her medical history that she is allergic to penicillin and is 4 months pregnant. Her chief complaint is that she is noticing blood on her toothbrush when she brushes her teeth and that her “gums hurt.”
    Upon clinical examination, you observe that she has a pyogenic granuloma between her maxillary central incisors and there is moderate to advanced gingival inflammation throughout her mouth, accompanied by large deposits of supra- and sub-gingival calculus.

Your treatment plan includes full-mouth root debridement, to be performed in quadrants in 4 subsequent appointments. Your plan is to use lidocaine 2% with epinephrine 1:100,000.

Is the use of this anesthetic contraindicated?

a. yes, epinephrine should not be used on pregnant women
b. yes, lidocaine should not be used on pregnant women
c. no, there are not any contraindications to the use of local anesthetic agents on pregnant women
d. no, however the clinician should be conservative in using any drugs on pregnant women

Answer 25

d. no, however the clinician should be conservative in using any drugs on pregnant women

Local anesthetics and vasoconstrictors are not contraindicated in the treatment of pregnant women. However, only conservative amounts of any drug should be administered to a pregnant woman.

It is wise to consult with the patient’s physician prior to performing dental/dental hygiene therapy on a pregnant woman to determine if there are any problems with this pregnancy or past pregnancies.