Abnormal bleeding Flashcards
What are the two main types of bleeding encountered in dentistry?
Post-operative bleeding – occurs after procedures such as extractions, surgeries, biopsies, trauma, or periodontal therapy 🛠️🦷
Spontaneous bleeding – occurs without dental intervention, often due to local or systemic pathology ⚠️
Give 4 examples of dental procedures that may result in post-operative bleeding 🧾🔪
Tooth extractions 🦷
Oral surgery or trauma 🛠️
Periodontal therapy (scaling/root planing) 🧼
Vital pulp exposure during caries management 🧪
Name 3 local causes and 3 systemic causes of spontaneous oral bleeding 🔍🧠
Local:
Gingivitis 🪥
Trauma 🩹
Ulcers/infections 🦠
Systemic:
Liver disease 🧬
Coagulopathies (e.g., hemophilia) 🩸
Thrombocytopenia 🧪
List 6 physiological or clinical consequences of significant blood loss 🏥
Patient distress 😰
Inflammation and infection from blood in tissues 🦠
Nausea and vomiting if swallowed 🤢
Aspiration/airway obstruction 😮💨
Hypovolemic shock 💔
Reduced oxygen-carrying capacity 🫁
What is the effect of blood loss on platelet count and protein levels? 📉🧫
Decreased platelet count, impairing clot formation 🩸
Loss of plasma proteins, affecting osmotic balance and clotting factor availability ⚖️
What are the 4 key pillars of managing bleeding in dental practice? 🦷🛠️🧠
History-taking and preparation 📋
Atraumatic surgical technique ✂️
Local haemostatic measures 🧽
Clear post-op instructions and follow-up 📞
List at least 3 local haemostatic methods used in dentistry 🛑
Direct pressure with gauze 🩹
Suturing 🧵
Haemostatic agents (Surgicel, Gelfoam, oxidised cellulose) 🧽
Tranexamic acid mouthwash 🧪
What are the essential post-operative instructions to prevent bleeding? 📝🚫
Avoid rinsing, hot food, alcohol, and smoking 🚬🥵
Rest and elevate the head 🛏️
Apply pressure if bleeding restarts ⏱️
Provide emergency contact info ☎️
What are the three components of Virchow’s Triad? 🔺
Vessel wall injury 💥
Altered blood flow 🌊
Changes in coagulation factors 🧬
What are the 4 steps of haemostasis? ⛔🧪
Vascular spasm 💢
Platelet plug formation 🧷
Coagulation 🩸
Fibrous tissue repair 🧶
Describe the three steps in platelet plug formation 🧲🧪
Adhesion to collagen 🧬
Activation (release of ADP and thromboxane A2) 💥
Aggregation of more platelets to form plug 🧲
How does aspirin affect platelet function? 💊🧠
It irreversibly inhibits cyclooxygenase (COX), preventing thromboxane A2 synthesis, which is necessary for platelet aggregation ❌🩸
How long does aspirin’s effect last and why? 🕒
~10 days, because platelets have no nucleus and cannot regenerate COX enzymes 🧬❌
What is the mechanism of clopidogrel? 🧬💥
Clopidogrel blocks the P2Y12 receptor on platelets, inhibiting ADP-induced platelet aggregation 🚫🩸
Should aspirin or clopidogrel be stopped prior to a dental procedure? Why or why not? 🤔🦷
No – stopping increases thrombotic risk 🧠💥 and bleeding can usually be managed with local measures 🩹
What does warfarin inhibit in the liver? 🍷🧠
It inhibits vitamin K epoxide reductase, blocking synthesis of clotting factors II, VII, IX, X 🔒🧬
What is INR and what should it be before dental extraction? 🔢🩺
INR = International Normalised Ratio 🌍🧪
Should be <4.0 for extractions ✅
Check INR within 72 hrs if stable, 24 hrs if unstable ⏱️📋
. Name 4 commonly used NOACs 🚫🩸
Apixaban
Rivaroxaban
Edoxaban
Dabigatran
How do we manage bleeding in dentistry?
Be prepared ✅
Manage patient expectations 🧍♂️
Check bleeding/clotting history 📋
Use careful surgical technique ✂️
Apply local measures: pressure, sutures, etc 🩹
Be patient
Provide good post-op care and follow-up 👩⚕️
What happens during vascular spasm?
Smooth muscle in the vessel wall contracts
Reduces blood flow to the injury
More effective in arteries due to higher pressure
What enhances Factor X and prothrombin activation during platelet plug formation?
Tissue damage
Collagen exposure
Platelet activation
Enhanced adhesion & aggregation
How long does it take for a tooth socket to clot in a patient on aspirin?
It may take longer
But it will clot eventually
Use pressure, gauze, and patience
How does warfarin work?
Inhibits vitamin K action in the liver
Reduces production of factors II, VII, IX, X
Full effect: 7 days
Stopping takes days
Interacts with metronidazole, fluconazole, etc, St Johns WORT , cranberry juice , carbamazepine ,miconazole
What is the safe INR level for dental extractions?
<4.0 is generally safe
Stable INR (e.g. 3.4, 3.5, 3.6): check within 72 hours
Unstable INR: check within 24 hours
What’s the extraction protocol based on INR values?
INR 2–3: extract one side only
INR 3–4: extract one quadrant at a time
Avoid IDB unless necessary
Always suture and give post-op advice
Why are NOACs becoming more common than warfarin?
Predictable effect
No INR monitoring
Fewer food/drug interactions
Once/twice daily dosing
What are some disadvantages of NOACs?
No reversal agent (in most cases)
Half-life up to 17 hours
Risk of bleeding if not timed carefully
Management of patients on NOACs for dental surgery?
Do not stop medication routinely
Use local measures
Consider omitting morning dose if taken twice daily
Liaise with medical team for complex cases
What lab tests assess bleeding risk?
INR – warfarin effect
Platelet count – normal: 150–450 x 10⁹/L
APTT – intrinsic pathway/heparin
Bleeding time – platelet function
PT – extrinsic pathway
What are signs a patient may have a coagulopathy?
asy bruising
Prolonged bleeding
History of heavy periods or joint bleeds
Family history
Liver disease or medications (e.g. warfarin)
: How do you manage a patient with coagulopathy pre-op?
Get haematology advice
Check clotting status (INR, APTT, platelets)
Plan atraumatic procedure
Use local haemostasis
Suture, Curacel, Tranexamic acid
What is tranexamic acid and how does it work?
Antifibrinolytic
Inhibits plasminogen activation
Prevents breakdown of fibrin clot
Used as a mouthwash post-extraction to stabilise clot
: What is Virchow’s Triad?
Virchow’s Triad describes the three main contributors to thrombosis:
Vessel wall damage
Abnormal blood flow
Altered coagulation (hypercoagulability)
How can each point of Virchow’s Triad be affected by disease?
Vessel damage – Trauma, surgery, inflammation
Abnormal blood flow – Stasis (immobility, atrial fibrillation), turbulence (atherosclerosis)
Hypercoagulability – Genetic disorders (e.g. Factor V Leiden), cancer, pregnancy, dehydration, medications
ow can local measures in a dental socket affect each point of Virchow’s Triad to promote clotting?
Vessel damage – Pressure & trauma help initiate vascular spasm & platelet plug
Abnormal flow – Gauze pressure reduces blood flow = encourages clot formation
Altered coagulation – Local agents (e.g. oxidised cellulose, tranexamic acid) enhance clot stability
What are the differences between antiplatelets, warfarin, and NOACs?
Antiplatelets (e.g. aspirin, clopidogrel): Inhibit platelet aggregation
Warfarin: Vitamin K antagonist – reduces synthesis of clotting factors II, VII, IX, X
NOACs (e.g. Rivaroxaban, Apixaban): Directly inhibit specific clotting factors (Xa or thrombin)
A patient is on warfarin with INR 2.5. What does this mean?
Their blood takes 2.5 times longer than normal to clot. This is within the safe range (2.0–4.0) for most dental procedures.
A patient not on medication has INR 0.5. Should they see their doctor?
Yes — this is abnormally low, meaning blood is clotting too quickly. Could suggest a lab error or hypercoagulable state. Needs medical assessment.
A patient on Rivaroxaban has INR 1.0. Should they see their doctor?
No — INR is not a reliable marker for NOACs like Rivaroxaban. Instead, assess bleeding risk based on last dose timing, renal function, and liaise with their GP if needed.
Patient returns 3 hours post-extraction with socket bleeding. What is the most likely cause?
Local clot dislodgement — due to trauma, rinsing, or inadequate pressure after extraction.
How would you manage this patient? LOCAL CLOT DISLODGEMENT
Calm the patient
Clean the socket gently
Apply gauze with firm pressure for 10–15 minutes
If bleeding persists:
Suture
Use oxidised cellulose or haemostatic agents
Consider tranexamic acid mouthwash
Give post-op advice and review instructions
A patient with thrombocytopaenia has a platelet count of 150 x 10⁹/L. Can they proceed with extraction?
Yes — this is within the normal range (150–450 x 10⁹/L). Proceed with care and use local haemostatic measures
What is the relationship between platelet activation and the clotting cascade?
Platelets form the initial plug
Their granules release substances (e.g. thromboxane A2, ADP)
These activate clotting factors → leads to fibrin mesh that stabilises the clot
Platelets + clotting cascade = complete haemostasis
What are the advantages of NOACs over warfarin?
No routine monitoring (INR)
Rapid onset/offset
Fewer food & drug interactions
Fixed dosing
Lower risk of intracranial bleeding
What are the disadvantages of NOACs?
Shorter half-life → missed doses = risk
No routine lab monitoring = harder to assess effect
Limited reversal agents (but improving)
Expensive
Caution needed in renal impairment
What information is in the Orange Book (anticoagulant therapy booklet)?
INR values
Dosing information
Warfarin strength (mg)
Indication for therapy
Doctor or anticoag clinic details
How can you tell if a patient has a “stable INR”?
INR remains within target range (e.g. 2.0–3.0)
No major fluctuations over time
INR checked regularly (e.g. every 4–12 weeks)
No recent dose changes
How does oxidised cellulose promote blood clotting?
Forms a physical matrix for clotting
Swells and becomes gel-like in the socket
Promotes platelet adhesion and activation
Aids in fibrin formation
How does tranexamic acid mouthwash promote clotting?
Inhibits plasminogen activation → reduces fibrinolysis
Prevents clot breakdown
Stabilises the clot within the socket
Used post-op (10 mL, 2–4 times/day)
