complications of local anesthesia and its management

1. COMPLICATIONS OF LOCAL
ANAESTHESIA
AND THEIR MANAGEMENT
Dr.Geetika Gupta
JR III
Department of paediatric and
preventive dentistry

2. Anaesthesia
AN AISTHETOS
WITHOUT
GREEK WORD - MEANING
SENSATION
LOCAL – PERTAINING TO PARTICULAR PLACE OR LIMITED
PORTION OF SPACE

3. A loss of sensation in a circumscribed area of the
body caused by a depression of excitation in nerve
endings or an inhibition of the conduction process in
peripheral nerves.
STANLEYF.MALAMED
Local anesthesia is defined as a reversible,
temporary cessation of painful impulses from a
particular region of the body
KOCH
What is Local Anesthesia:-

4. History
 COCAINE -first local anesthetic agent-isolated by Nieman
- 1860 -from the leaves of the coca tree.
 Its anesthetic action was demonstrated by Carl Koller in
1884.
 First effective & widely used synthetic local anesthetic -
PROCAINE -produced by Einhorn in 1905 from benzoic
acid & diethyl amino ethanol.
 It anesthetic properties were identified by Biberfield
and the agent was introduced into clinical practice by
Braun.

5. PROPERTIES OF LA:-
1.It should not be irritating to the tissue.
2.It should not cause any permanent alteration to the tissues.
3.Its systemic toxicity should be low.
4.It should be effective regardless of whether it is injected into the tissues or
applied locally to mucous membrane.
5.The time of onset of LA should be as short as possible.

6. 6.The duration of action must be long enough to complete procedure yet not so
long as to require an extended recovery.
7.It should have potency sufficient to give complete anesthesia without the use
of harmful concentrated solutions.
8.It should be relatively free from producing allergic reactions.
9.It should be stable in solution & readily undergo biotransformation in the body.
10.It should be sterile or capable of being sterilized by heat without
deterioration.

7. 1.Displacement of Ca ions from the Na channel receptor site which
permits..
2.Binding of LA molecule to this receptor site which thus produces…
3.Blockade of the Na channel & a
4.Decrease in the Na conductance which leads to
5.Depression of the rate of electrical depolarization & a
6.Failure to achieve the threshold potential level along with a
7.Lack of development of propagated action potentials,which is
called
8.Conduction blockade.

8. FACTORS AFFECT THE REACTION OF
LOCAL ANESTHETICS
pKa:
 Local anesthetics have two forms, ionized and nonionized. The nonionized
form can cross the nerve membranes and block the sodium channels.
pH influence:
 Usually at range 7.6 – 8.9
 Decrease in pH shifts equilibrium toward the ionized form, delaying the onset
action.
Lipid solubility:
 All local anesthetics have weak bases. Increasing the lipid solubility leads to
faster nerve penetration, block sodium channels, and speed up the onset of
action.

9. Protein binding:
 The more tightly local anesthetics bind to the protein, the longer the duration
of onset action.
Vasodilation:
 Vasodilator activity of a local anesthetic leads to a faster absorption and
slower duration of action
 Vasoconstrictor is used to keep the anesthetic solution in place at a longer
period and prolongs the action of the drug

10. Composition :
Local anesthetic drug – 24.64 mg
Vasoconstrictor – adrenaline 0.0125 mg
Antioxidant – sodium bisulfite or sodium metabisulfite
Sodium chloride or ringer’s solution 0.29 ml
Distilled water 1 ml
General preservatives
(a) methylparaben 1 mg
(b) thymol 0.4 mg
(c) chlorbutol 5 mg

11. CLASSIFICATION OF
LOCALANESTHETICS

12. BASED ON CHEMICAL STRUCTURE
ESTERS:
Benzoic acid esters:
• Benzocaine
• Cocaine
• Tetracaine
Para-amino benzoic esters:
• Chlorprocaine
• Procaine
• Propoxycaine
AMIDES:
• Articaine
• Bupivacaine
• Etidocaine
• Lidocaine
• Mepivacaine
• Prilocaine
QUINOLINE:
• Centbucridine

13. Based on
duration of
action
Ultra short Short Medium Long
Less than 30mins
Chlorprocaine
procaine
45 to 75 mins
Lidocaine
Prilocaine
90 to 150 mins
Mepivacaine
Artricaine
180 mins or longer
Bupivacaine
Etidocaine

14. Based on
mode of
application
Topical
Soluble Insoluble
Injectable
Cocaine
Lidocaine
Tetracaine
Benzocaine
Butylamino-
benzoate
Lidocaine
Mepivacaine
Tetracaine
Bupivacaine
Dibucaine

15. Based on
potency
LOW Intermediate HIGH
Procaine
chlorprocaine
Lidocaine
mepivacaine
Tetracaine
Bupivacaine
Dibucaine

16.  Local complications
 Systemic complications

17. NEEDLE BREAKAGE
PAIN ON INJECTION
BURNING ON INJECTION
TRISMUS
LOCAL COMPLICATIONS

18. HEMATOMA
INFECTION
EDEMA
SLOUGHING OF TISSUE

19. FACIAL NERVE PARALYSIS SOFT TISSUE INJURY

20. Needle breakage
 Rare complication in dental LA
injection.
CAUSES:
 Sudden unexpected movement
of the patient
 Small needle size
 Bent needles
 Defective needles
 Forceful contact with bone.

21. Prevention
 Use long needles for deep injection (>18mm), i.e for inferior alveolar nerve
block in adults or older children.
 Avoid using 30-gauge needles for IAN block in adults or children.
 Do not bend needles when inserting them into soft tissue .
 Do not insert the needles till its hub.
 Redirect only when adequately withdrawn.

22. Management
 Remain calm
 Don't explore
 Have the patient keep opening wide
 Remove needle if it is visible with help of a
small haemostat or Magill forceps.
 If not visible take radiographs of the region .
 If needle is lost into the tissue spaces ,e.g.
pterygomandibular space, infratemporal space,
assure the patient and review regularly.
 3D CT scanning recommended.
 Refer to an Oral Surgeon

23. Prolong anesthesia or paresthesia
 Persistent anesthesia or altered sensation well beyond the expected duration of
anesthesia .
 In addition it includes hyperesthesia, dysesthesia in which patient experiences
both pain and numbness.
 The patient reports feeling NUMB [frozen] many hours or days after LA injection.
 Clinical response: sensation , swelling, tingling, itching, oral dysfunction, tongue
biting ,drooling, loss of taste ,speech impediment.

24. Causes
 Trauma to any nerve
 Neurolytic agents: Injection of LA solution with
alcohol or cold sterilizing solution near a nerve
produces irritation and edema of the tissue and
subsequent pressure on the nerve.
 Intraneural injection
 Hematoma : Hemorrhage around the neural
sheath also causes pressure on the nerve,
leading to paresthesia.
 Articaine and prilocaine are more likely than
other anesthetics to be associated with
paresthesia and have most commonly affected
the lingual nerve.

25. Management
 Most case resolve within 8 weeks
 Reassurance to the patient
 Reschedule the patient for examination every 2 months
for as long as the sensory deficit persist.
 Dental treatment may continue,but avoid re-administering
LA into region of the previously traumatized nerve. Use
alternate LA techniques if possible.
PREVENTION
 Strict adherence to injection protocol and
 proper care and handling of dental cartridges

26. Pain on injection
CAUSES:
 Careless injection technique and a callous attitude
 Dull needles
 Rapid deposition of LA solution (may cause tissue damage)
 Needle with barbs produce pain during withdrawal

27. Problem
 It increases patient anxiety and may lead to sudden
unexpected movement, increases risk of needle breakage,
traumatic soft tissue injury to the patient or needle stick
injury to the administrator.

28. Prevention
 Use the correct technique and equipment
 Stretch the mucosa with finger
 Distract the patient at the moment when the
mucosa is pierced
 Position the needle supraperiosteally
 Direct the bevel toward the bone

29.  Use sharp and small gauge needles.
 Use topical anesthetics properly.
 Room temperature solutions
 Rate of injection: faster injection is painful
…Inject LA slowly
 Slow removal of the needle

30. Burning on injection
 A burning sensation on injection may occur for two
reasons.:
 First, local anaesthetics with a vasoconstrictor are
acidic(pH approx. 3.5) because of the preservative
required for the vasoconstrictor.
 This acidity can cause the anaesthetic to burn when it is
injected into tissues.
 As the cartridge ages and approaches the expiry date, the
vasoconstrictor begins to break down, resulting in even a
lower pH and therefore even more burning on injection.

31.  Second, if cartridges are immersed in sterilizing solution
and the solution seeps into the cartridge, the sterilizing
solution can cause a burning sensation upon injection.
CAUSES:
 pH of solution
 Rapid injection
 Contamination
 Warmed solutions

32. Prevention
By using fresh anaesthetics with little or no
vasoconstrictor .
By buffering the LA solution to a pH of 7.4
immediately before injection(using sodium
bicarbonate)…dilution factor 10:1
By injecting slowly (ideal rate 1ml/min) and not
exceeding the recommended rate of 1.8ml/min.
Storing at room temperature.

33. Soft tissue injury
 Self-inflicted trauma to the lips
and tongue is frequently caused
by the patient inadvertently
biting or chewing this tissue while
still anesthetized.
 Can lead to swelling and
significant pain.

34. CAUSES
 Most frequently in younger children, in mentally or physically disabled
children or adults.
 The primary reason is the fact that soft tissue anesthesia lasts significantly
longer than does pulpal anesthesia.
Problem:
 A younger child or a handicapped individual may have difficulty coping with
the situation and may lead to behavioral problems

35. Prevention
 A cotton roll can be placed between the lip and the teeth if they are still
anesthetized at the time of discharge.
 Telling the patient and the guardian against eating, drinking hot fluids, and
biting on the lips or tongue to test for anesthesia.
 A self-adherent warning sticker may be used on children.

36. Management
 Analgesics for pain, as necessary.
 Antibiotics, as necessary, in the unlikely situation that infections results .
 Lukewarm saline rinses to aid in decreasing any swelling that may be present.
 Petroleum jelly or other lubricant to cover a lip lesion and minimize
irritation.

37. Oedema
Swelling of the tissue is not a
syndrome but a clinical sign of
the presence of some disorder.
Causes:
Trauma during injection
Infection
Allergy
Hemorrhage
Injection of irritating
solution

38. Problem
 Edema result in pain and dysfunction of the region and embarrassment for the
patient.
 Angioneuroticedema produced by topical anesthetic in the allergic individual
although exceedingly rare can compromise the airway.
 Edema of the tongue, Pharynx or Larynx may develop and represents life
threatening situation that requires vigorous management.

39. Management
 Traumatic oedema resulting from inflammation resolves in one to three days
with antiinflammatory drugs.
 Allergic oedema: requires immediate assessment to avoid the risk of
anaphylaxis : treated with epinephrine ,antihistaminics and steroidal
antiinflammatory drugs [systemic complication]

40. Prevention
 Proper care for handling the local anesthetic armamentarium.
 Use atraumatic injection technique.
 Complete an adequate medical evaluation of the patient before drug
administration(allergy)

41. Sloughing of
tissues
 Prolonged irritation or ischemia of
the gingival soft tissues may lead
to a number of unpleasant
complications,including epithelial
desquamation and sterile abscess.
Causes
 Application of topical anesthesia
for prolonged period
 Heightened sensitivity to topical
or injectable LA
 Secondary to prolonged ischemia
;use of LA with vasoconstrictor
(mostly on hard palate)

42. Prevention
 Apply topical anesthesia for 1-2 min to minimize toxicity
 Avoid using overly concentrated LA solutions when using vasoconstrictors for
hemostasis
Management
 Reassure the patient
 Symptomatic treatment of pain using NSAIDS and topically applied ointment is
recommended
 Epithelial desquamation resolves within 7-10 days

43. Trismus
 Defined as a prolonged tetanic spasm of the jaw muscle
by which the normal opening of the mouth is restricted
 A motor disturbance of the trigeminal nerve
precipitating or resulting in spasm of the muscles of
mastication
CAUSES :
 Trauma to muscles or blood vessels : caused by
repeated needle insertion especially into medial
pterygoid in inferior alveolar nerve block.
 Contaminated anesthetic solutions
 Hemorrhage
 Infection
 Excessive anesthetic volume

44.  Injection of local anesthetic directly into
muscle may cause a mild myotoxic
response, which can lead to necrosis. The
symptoms of trismus, often associated with
pain, arise anywhere from 1 to 6 days
following an injection.
 Infection may produce hypomobility
through increase pain, increase tissue
reaction and scarring

45. Prevention
 Sharp and disposable needles
 Proper care and handling of cartridges
 Septic technique and clean injection site
 Atraumatic insertion
 Avoid repeated insertion
 Minimal injections and volume
[Follow basic principles of atraumatic injection technique]

46. Management
 Conservative therapy
 Physiotherapy: passive ROM (range of motion) therapy ; advise the patient to
gradually open and close the mouth
 Analgesics
 Heat (warm saline rinses):Apply hot moist towels to the site for approximately
20 minutes every hour...
 Muscle relaxants (to manage initial phase of muscle spasm)

47. Facial nerve
paralysis
 Usually occurs in inferior alveolar
nerve block
 Loss of the motor action of the
muscle of facial expression
produced by LA lasts for one to
seven hours.
 The patient suffers unilateral
paralysis of the facial muscles

48. Cause
 Caused by the induction of local anesthetic into the capsule of the parotid
gland which is located at the posterior border of mandibular ramus clothed by
medial pterygoid and masseter muscles.
 Needle positioned inadvertently in the posterior direction

49. Problem
 Lasts no longer than several hours depending on the LA formulation used
 Primary problem is cosmetic.
 Second problem is patient is unable to voluntarily close one eye.
 Corneal reflex is intact and tears lubricate the eye.

50. Prevention
 BONE CONTACT when injecting
 Avoid over penetration
 Avoid arbitrary injection

51. Management
 Defer dental treatment
 Reassure patient( transient; no residual
effect)
 Cornea care(an eye patch should be applied
until muscle tone return)

52. Infection
CAUSES:
 Needle contamination
 Improper handling of armamentarium
 Infection at injection site
 Improper handling of tissue

53. Prevention
 Disposable needles
 Aseptic technique
 Proper care of equipment
MANAGEMENT
 Usual sign is trismus (1-3 days resolution)
 Antibiotics

54. Hematoma
 Defined as effusion into the extravascular
space by inadvertent nicking of blood vessels
during administration o f LA.
 Rare in palatal region due to close
adherence of mucoperiosteum to the bone
CAUSE:
 Damage to blood vessels by the needle
during penetration into soft tissue
 Most commonly involved vessels are
pterygoid plexus of veins ,PSA vessels.
 Inferior alveolar nerve hematomas are visible
intraorally whereas PSA hematomas are
visible extra orally.

55. Problem
 Causes inconvenience to the
patient.
 Possible complication include
trismus and pain.
 Swelling and discoloration of the
region subside gradually over 7-
14 days

56. Prevention
 Follow basic principles of atraumatic injection technique.
 Use a short needle for the posterior superior alveolar nerve block.
 Number of needle penetration should be as low as possible

57. Management:
 If hematoma is visible immediately following the
injection, apply direct pressure, if possible. Once
bleeding has stopped, discharge patient with
instructions to :
 Apply ice intermittently to the site for the first 6
hours.
 Do not apply heat for at least 6 hours.
 Use analgesics as required.
 Expect discolouration.
 If difficulty in opening occurs, treat as with
trismus, described above

58. SYSTEMIC
COMPLICATIONS

59. Systemic complications
Toxicity
Adverse drug reactions
-Allergies
-Idiosyncrasy
Fainting /syncope
Methemoglobenemia

60. Toxicity
 Occurs due to systemic absorption of an excessive amount of the drug.
 Because local anesthetics block conduction in many tissues in addition to the
peripheral nerve, toxicity could result if sufficient amounts of the anaesthetic reach
these other tissues, such as the heart or brain.
 High blood levels of the drug may be secondary to repeated injections or could be a
result of a single intravascular administration.
 This risk is one reason why aspiration prior to every injection is so important.

62. Anesthetic overdose

63. Manifestations and management of LA
toxicity
Manifestations
 Mild to moderate toxicity:
Restlessness, anxiety, slurred
speech, nystagmus, tremors,
headache, dizziness, blurred
vision, drowsiness, metallic taste
 Elevated BP ,Elevated heart rate
 Elevated resp. rate
 Disorientation: Failure to follow
commands / reason
Management
 Stop administration of LA
 Monitor vital signs
 Place in supine position
 Observe in office for 1hr

64. Severe toxicity: seizure, cardiac dysrhythmia or arrest.
 MANAGEMENT
• Place in supine position
• If seizure, protect from nearby objects and suction oral cavity if vomiting
occurs
• Have someone summon medical assistance
• Monitor vital signs
• Establish airway , administer oxygen
• Start IV
• Administer diazepam 5-10 mg slowly or midazolam 2-5 mg slowly
• Institute BLS if necessary
• Transport to emergency care facility

65. Pathophysiology
 Local anesthetics cross the blood-brain barrier, producing CNS depression as
the blood level rises eg. LIDOCAINE
Blood Level Action Produced
 < .5 ug/ml - no adverse CNS effects
 0.5-4 ug/ml – anticonvulsant
 4.5-7.5 ug/ml - agitation, irritability
 > 7.5 ug/ml - tonic-clonic seizures

66.  Local anesthetics exert a lesser
effect on the cardiovascular
system e.g. LIDOCAINE
Blood Level Action Produced
 1.8-5 ug/ml – treat tachycardia
 5-10 ug/ml - cardiac depression
 >10 ug/ml - severe depression,
bradycardia, vasodilatation, arrest

67. Prevention of toxicity
Aided by:
 Aspiration before injection
 Slow injection
 Dose limitation

69. Allergy
 Reports of allergic reactions to local anesthetics are somewhat common, but
investigation finds most of these reactions to be of psychogenic origin.
 A confirmed allergy to an amide is rare; the ester procaine is somewhat more
allergenic.
 An allergy to one ester rules out using another ester, as the allergenic component
is the breakdown product para-aminobenzoic acid (PABA), and all esters are
metabolized to this product.
 Conversely, an allergy to one amide does not rule out using another amide.
 Epinephrine has not been shown to have any allergenic potential.

70.  Methylparabens are preservatives used for multi-dose vials. In the past,
methylparabens were often found to be the source of allergy.
 Today they are no longer included in dental cartridges.
Alternative to methylparaben: CAPRYL HYDRO-CUPRIENOTOXIN
If patient is allergic to esters LA  AMIDES
If patient is allergic to both amide and esters then either CENTBUCRIDINE or
DIPHENHYDRAMINE

71. Testing for LA
allergy
 The local anesthesia to be tested should be
free of all additives (plain LA)
 Intradermal injection is performed by inserting
the needle tip,bevel up, just underneath the
surface of the skin and injecting 0.1 ml of the
agent.
 A “bleb” should be formed if injection is
properly performed.

74. Allergy –signs and symptoms
Respiratory:
 Laryngeal edema
 Bronchospasm, wheezing
 Use of accessory muscles
 Distress
 Dyspnea
 Anxiety
 Cyanosis or flushing
 Tachycardia
Dermatologic:
 Urticaria - wheals, pruritis
 Angioedema
 Minor rash

75. Management of allergy
Delayed skin reaction
• Benadryl(Diphenhydramine) - 50 mg stat & Q6H X 3-4 days
•
Immediate skin reaction
• Epinephrine 0.3 mg IM , Benadryl - 50 mg IM
• Observation, medical consultation
• Benadryl - 50 mg Q6H X 3-4 days
Bronchial constriction
• Semi-erect position, O2 - 6 L/min
• Epinephrine 0.3 mg IM
• Benadryl - 50 mg IM
• Observation, medical consultation
• Benadryl - 50 mg Q6H X 3-4 days

76. Laryngeal edema
• Place supine, O2 - 6 L/min
• Epinephrine 0.3 mg IM
• Maintain airway
• Benadryl - 50 mg IV or IM
• Hydrocortisone - 100 mg IV or IM
• Perform Cricothyrotomy

77. Anaphylaxis (type I reactions)
 Mediated by antibodies derived from immunoglobulin IgE.
 Typical progression * (may occur rapidly, with considerable overlap)
Skin reactions
Smooth muscle spasms (GI,respiratory)
Respiratory distress
Cardiovascular collapse

78. • Place supine, on flat surface
• ABCs of CPR, call for medical help
• Epinephrine 0.3-0.5 mg IM (every
5 mins)
• O2 - 6 L/min, monitor vital signs
• After clinical improvement,
• Benadryl and Hydrocortisone
Anaphylaxis

79. Fainting / Psychogenic reactions
 Anxiety-induced reactions are by far the most common adverse event
associated with local anaesthetics.
 Most common manifestation of fear of the injection.
 Other common reactions include hyperventilation, nausea, vomiting and
changes in heart rate or blood pressure.
 Because psychogenic reactions can mimic allergic reactions, such as urticaria
(rash), edema (swelling) and bronchospasm (wheezing), they are often
misdiagnosed.
MANAGEMENT :
 Sympathetic management and supine position with legs slightly elevated

80. IDIOSYNCRASY
 The term idiosyncrasy is often assigned to a bizarre type of reaction
that cannot be classified as toxic or allergic.
 Unexplained by any known mechanism of the drug’s action
 Neither overdose nor allergic reaction
 Unpredictable; treat symptoms

81. Methemoglobinemia
 Pathophysiology: The oxidation of heme groups within
deoxyhemoglobin (Fe2+) results in methemoglobinemia
(Fe3+), which cannot transport oxygen and thus
produces a functional anemia and cyanosis.
 Common local anesthetics that cause
methemoglobinemia include prilocaine (an ingredient
of EMLA cream), which is metabolized to o-toluidine in
the liver and oxidizes hemoglobin to methemoglobin,
and benzocaine, which is found in topical sprays.
 Treatment is with methylene blue (1 to 2 mg/kg
intravenously over 5 minutes), which converts
methemoglobin back to reduced hemoglobin.

82. PEDIATRIC CONSIDERATIONS…..
Structural make-up of bone
Anatomy (Maxillary & Mandibular considerations)
Emotional aspect

83. Maxillary Consideration
• From birth through adolescence, bone of maxilla remains
porous, that permits the use of local infiltration to secure
anesthesia
Anesthesia for first permanent molars:
• local infiltration cannot suffice; as in children, zygomatic
process of maxilla covers alveolar process in region of
permanent first molar

84. Mandibular Consideration
 Ramus of mandible: coronoid notch,
deepest cavity on anterior border is absent
at birth
 It indicates height at which needle is to be
inserted while performing inferior nerve
block
 Mandibular foramen: Benham
demonstrated that mandibular foramen
was even with occlusal plane in 75%
children, increases with age to average of
7mm above occlusal plane in adults

86. Rule of 10
A method of providing a guide as to whether an infiltration or a block
injection of local analgesic is appropriate for a child requiring
treatment to a mandibular tooth.
The primary tooth to be anaesthetized is assigned a number from
1 to 5 according to its location in the dental arch (central incisor
= 1, second molar = 5).
This number is added to the age of the child (in years),
If the number = <10 infiltration analgesic
>10 an inferior dental nerve block

88. Dentistry for the child & adolescent:- McDONALD
& AVERY
Pediatric dentistry- Infancy through adolescence:-
PINKHAM
Textbook of Pedodontics:- SHOBHA TANDON
Handbook of Local Anesthesia:- MALAMED
Local Anesthesia & Pain control in Dental
Practice:- MONHEIM
Local Analgesia in Dentistry:- D. H. ROBERTS

89. MCQ’S
Q1 While giving a PSA nerve block ,you forgot to aspirate before injecting and
soon after administering LA, a swelling developed in the posterior maxilla which
is visible extraorally with no other signs and symptoms. The swelling is probably
due to:
 A. Allergy
 B. Infection
 C. Overdose
 D. Hematoma (pterygoid plexus)

90. Q2 What would be the max recommended dose of 2% lidocaine for a 30 kg boy;
how many cartridges?
 A 88mg; 2.4 cartridges
 B 132mg;3.6 cartridges
 C 100mg; 3 cartridges
 D 154mg; 5 cartridges

91.  Q3 A 5 years old child comes to your clinic with pain in upper right first
deciduous molar ;which type of LA injection should be given:
 A Nerve block
 B Intraligamentary injection
 C Field block
 D Local infiltration
Rule of 10

92. Q3 Common local anesthetic that cause methemoglobinemia is _____; treated
using _____?
 A. Lidocaine ,methylene blue
 B. Prilocaine ,epinephrine i.m
 C. Prilocaine ,methylene blue
 D. Articaine , epinephrine i.v

93. Q5 The ideal rate for administering LA solution is :
 A)1.8ml/min
 B)1.0ml/min
 C)2ml/min
 D)1.1ml/min