Complications of local anesthesia

1. -Danveera Raut Dessai

2. An anesthetic complication may be defined as any
deviation from the normally expected pattern
during or after the securing of regional anesthesia.
These complications may be classified as:
1. Primary or secondary
2. Mild or severe
3. Transient or permanent

3.  A primary complication
is the one that is caused
and manifested at the
time of anesthesia.
 A mild complication is
the one that exhibits a
slight change from the
normally accepted
pattern and reverses
itself without any
specific treatment.
 A transient
complication is one
that, although severe at
the time of occurrence,
leaves no residual
effects.
 A secondary
complication is one
that is manifested later,
even though it may be
caused at the time of
insertion of the needle.
 A severe complication
manifests itself by a
pronounced deviation
from the normally
expected pattern and
requires a definite plan
of treatment.
 A permanent
complication would
leave a residual effects,
even though mild in
nature.

4. Those that result from the
absorption of LA
1. Toxicity
2. Idiosyncrasy
3. Allergy
4. Anaphylactoid reactions
5. Infections caused by
contaminated solutions
6. Local irritations or
tissue reactions
Those complications
attributed to the
insertion
of the needle
1. Syncope
2. Muscle trismus
3. Pain
4. Edema
5. Infections
6. Broken needles
7. Hematoma
8. Bizarre neurological
symptoms
9. Sloughing of tissues
10. Post anesthetic intra
oral lesions
local
systemic

5. Cause:
 Intravascular injection usually coupled with too rapid deposition of solution
 Too large a volume
 Too great a percentage stregth
 Rapid absorption into bloodstream
Symptoms:
Talkativeness, restlessness, apprehension, excitement, convulsions, lethargy,
sleepiness, unconsciousness
Increase or decrease in BP, pulse rate and respiration, nausea and vomiting is
also seen.
Prevention:
 Aspiration must be performed before injecting
 Smallest possible volume of drugs should be used
 A vasoconstrictor should be employed with the local anesthetic

6. The term idiosyncrasy is defined as any reaction to a
local anesthetic or drug that cannot be classified as
toxic or allergic.
Idiosyncrasy have no relation to the pharmacology of the
drug and may vary in degree from day, to day even in
the same patient.
The treatment for idiosyncrasy type of emergency:
 The patients airway must be maintained and adequate
oxygenation assured.
 Steps should be taken to evaluate the circulation and
support it by positional changes, drugs, or parenteral
fluids.
Precautions may also be exercised to protect the patient
from injury to himself as a result of convulsive seizures,
loss of consciousness or similar reactions.

7. Cause:
The primary cause of allergic reactions is a specific antigen-
antibody reaction in a patient who has previously been
sensitizing to a particular drug or chemical derivative
thereof.
Symptoms:
1.Rashes
2.Urticaria
3.Angioneurotic edema
4.Mucous membrane congestion
a. Rhinitis
b. Asthmatic symptoms
Prevention:
1. Adequate preanesthetic evaluation must be done.
2. No drug or drugs should be used if the patient gives a
history of previous allergic reactions to them.

9. Infections caused by contaminated solutions are rare at the present
time as high standards of asepsis practiced by the manufacturers of
LA.
The cartridges should be stored as aseptically as possible.
Injections of alcohol contaminated anesthetic may result in prolonged
anesthesia or local irritation.
There should be o burning or irritation caused by the isotonic sterile
solutions used in dentistry.
If the local aesthetic solution is injected too rapidly, particularly In
confined areas such as palate, local tissue damage can occur. To
avoid this, the LA is injected slowly without undue pressure.

10.  Syncope:-
Syncope is the most frequent complication associated with LA in
dental office. This is a form of neurogenic shock and is
caused by cerebral ischemia, with a corresponding drop in BP.
If the patient is conscious, he should be instructed to take a few
deep breaths. This assists venous return while providing
adequate oxygenation.
However if the patient is unconscious, the pulse, respiration,
and color should be checked to determine severity of the
condition.
Such a patient should be placed in a semi reclining position with
legs ad thorax slightly elevated.

11.  Muscle trismus:-
Fairly common complication of regional
anesthesia particularly after blocks to the
inferior alveolar nerve. Any muscle soreness or
limitation of motion is referred as trismus.
The most common cause of trismus is trauma to
muscle during the insertion of needle. irritating
solutions, hemorrhage or low degree infections
within muscle may also cause trismus.
Trismus may be prevented by use of sharp, sterile
needle so that the trauma of insertion ad low
grade infections are prevented. The area of
insertion should be cleaned and painted with
suitable antiseptic.

12. Pain
Pain during or after the administration of a regional anesthetic
is very common.
Only sharp needles are to be used, and the area of penetration
should be anesthetized with tropical anesthetic.
The insertion if needle should be slow and atraumatic.
Infections, low grade or otherwise, are common cause of pain
after regional anesthesia . Aseptic conditions should be
maintained.
Injected solutions that are too hot seem to cause greater tissue
damage than that of too cold.

13.  Edema
Edema or swelling of tissue, is usually symptom ad rarely
an entity itself.
• Trauma, infection, allergy, hemorrhage, and other
factors ca produce edema.
• Each cause of edema should be considered under its
own classification in regards to prevention and
treatment.

14. Infection
• Dentists should constantly apply all means of their
command to prevent infection.
• All area, instruments, needles, and solutions
should be aseptic as possible.
• The operators hands should be scrupulously
cleaned before working on each patient.

15. Broken needles
Breakage of needle is one of the most depressing and annoying
complication of regional anesthesia.
Principles to be observed to prevent needle breakage:
1. Do not force the needle against resistance.
2. Do not change the direction of needle while it is embedded
in in the tissue.
3. Do not use too fine needle.
4. Use disposable needles only.
5. Do not insert needle so far as it is out of sight in tissue.

16. Bizarre neurological symptoms
On rare occasions unexplained neurological symptoms may
occur following the insertion of needle.
Patients may exhibit facial paralysis, crossed eyes, muscular
weakness, temporary blindness and many other
complications.

17. Hematoma(Common complication of
intraoral regional anesthesia.)
Most commonly associated with posterior superior
alveolar and infraorbital nerve block.
o Hematoma is an effusion of blood into the
surrounding tissue and a result of torn blood
vessels.
o The traumatic puncture of vein does not cause
hematoma.

18. Sloughing of tissues
Due to epithelial desquamation and sterile abscess
Epithelial desquamation
1. Application of topical anesthetic to the gingival tissues for a
prolonged period
2. Heightened sensitivity of the tissues to a local anesthetic
3. Reaction in a area where topical anesthesia has been applied
 Sterile abscess
1. Secondary to prolonged ischemia resulting from the use of local
anesthetic with vasoconstrictor
2. Usually develops on the hard palate
Symptoms
1. Severe pain & infection

19. Post anesthetic intraoral lesion
Ulcers are developed in the mouth after 2 days of intraoral LA
Cause
Trauma to the tissue by the needle, local aesthetic solutions
cotton swab or ay other instruments may activate the latent
form of the disease like herpes simplex, recurrent apthous
stomatitis that was present in the tissues before injection
Problems
Acute sensitivity in the ulcerated area

20.  Local Anesthesia- Stanley Malamed.
 Monheim’s Local Anesthesia And Pain Control
In Dental Practice.