Coagulation Cases Mike Webb Division of Clinical Hameatology
Coagulation Cases Mike Webb Division of Clinical Hameatology 1 March 2010
• So what does it take to make a healthy blood clot? – Platelets – The blood vessels themselves – Clotting factors
Good vs bad • • Healthy blood clot: – At the site of a broken blood vessel, the point of injury. – A healthy clot stays put and does not cause a runaway clotting episode. – A healthy clot knows when it's time to dissolve. Pathological clot: – It causes vascular narrowing or outright occlusion. – Often inappropriately forms – It may embolize.
Evaluation of haemostasis • History: • • Site Recent onset vs. life-long pattern. Alcohol consumption. Use of NSAIDs. Males and females equally affected? Grandparents? Does it skip a generation? Bad arthritis of the ankles or knees in a male grandparent may indicate a clotting factor problem (IX or VIII).
Plt vs factor
Laboratory Evaluation of Hemostasis
Laboratory Evaluation of Hemostasis • • • FBC and smear PT/PTT Plt function Specialized tests Quality of the blood specimen • Volume • Clot • Hemolyzed
Platelets number vs function
PT/PTT:
PTT = XII, XI, IX, VIII Simple!! PT = VII Common = I, II, V, X
• PTT = XII, XI, IX, VIII PT = VII Common = I, II, V, X
Prolonged PT or PTT • Not enough of a single or combination of factors. • Does NOT tell you why.
Why? 1. Deficency Congenital Factor VIII, IX Acquired Liver diease Warfarin 2. Inhibitor Lupus Heparin Acquired Ab vs VIII, IX
Defn vs Inhibitor: Mixing studies Pt (defn) Normal Plasma PT/PTT = normal Pt (inhibitor) Normal Plasma PT/PTT = abnormal
Which factor? PT = VII PTT = XII, XI, IX, VIII Common = I, II, V, X
Tommy active four-year old • Scalp wound that won't heal. • Bled more than expected from his circumcision. • The mother's father had terrible arthritis of his knees and ankles: – He was wheelchair-bound by the age of 45. – Died of a 'bleeding ulcer' at age 51. • Physical exam – normal except for scalp wound.
• • Lab results FBC - normal PT = 11 sec (ref = 10 - 15 sec) PTT = 54 sec (ref = 25 -36 sec) PT = VII PTT = XII, XI, IX, VIII Common = I, II, V, X
What do we know? • Diagnosis? • Special investigations?
Hemophilia • Congenital defn of either • VIII = A • IX = B • A usually more common and severe • Both VIII and IX deficiencies are sex-linked recessive traits.
Mode of inheritance:
Forty-eight year-old man with ease of bruising. • • • Mr. BA complains of ease of bruising He was fine until about 8 months ago. FBC normal with round macrocytes. PT is 18 sec (N=10 -15) a. PTT is 48 sec (N= 25 - 36)
PTT = XII, XI, IX, VIII PT/PTT prolonged PT = VII Common = I, II, V, X
Both PT and PTT prolonged? ? • Diagnosis • Special Investigations
Results
Tiffany is a 15 year-old girl with a rash Her mom says she had a cold about 2 weeks ago. – She was fairly sick with upper respiratory symptoms for about 3 days. – She improved quickly, and returned to school. • • • Now she has a 'rash' from navel down both legs. Today, she is otherwise healthy and is afebrile. Tiffany has a little sister who is well. No one else in the family is sick. Exam NAD but for rash
Rash on legs
• Lab tests – PT = 11 seconds (ref = 11. 4 seconds) – a. PTT = 29 seconds (ref = 23 - 32 seconds) • FBC • WCC – 8 • Hgb – 13 • Plt – 9 (N = 150 -450)
Viral exanthem vs. petechiae? • Tiffany's spots are regional, not all over her body. • In fact, they seem gravity dependent. • They vary slightly in color from red to blue-brown.
Mrs. KL 28 yr old teacher complains of ease of bruising • Bleeds excessively with dental procedures • She also has menorrhagia • She claims if she takes just one aspirin, she will bruise for a week. • Her family history is significant for bleeding problems. – Some of her relatives, both male and female, have a bleeding tendency. – She's very concerned because an aunt supposedly died in childbirth from a hemorrhage.
Lab results • • PT = 11. 2 seconds (ref = 10 -15) a. PTT = 42 seconds (ref = 25 -36) FBC - normal Factor VIII (enzymatic) – 45% (ref 50 -150%)
von Willebrand disease • • VWD - most common inherited bleeding disorder. (1% of population) Abnormality in quantity or quality of v. WF • • Binds platelets to endothelium Protects Factor VIII from degredation
v. WD • Symptoms are very mild or lack of recognition (heavy menstrual bleeding) • Bleeding symptoms: – Easy bruising – Skin bleeding – Prolonged bleeding from mucosal surfaces • May mimic hemophilia • Ingestion of aspirin or NSAIDS may precipitate bleeding
v. WD • • • Lab tests: Normal FBC Normal PT Normal or prolonged PTT Specialized tests • • von Willebrand factor v. WF Antigen: decreased Ristocetin cofactor activity Platelet aggregation to Ristocetin
50 yr old man for hip replacement • • • On heparin pre-op for DVT prophylaxis Malena stool and epigastic pain FBC – normal PT – 18 (N-10 -15 sec) PTT >180 (N- 25 -36 sec)
Treatment? • Stop heparin! • Antidote – protamine sulphate
Tommy Late bleeder • Known with haemophilia A • 28 yrs old presents with painful knee • No improvement to factor replacement
• • • Mixing studies PT 14 (10 -15 sec) PTT 105 to 104 (25 -36 sec) Factor VII = 2% NOW WHAT? ? ?
Late bleeder PT = VII PTT = XII, XI, IX, VIII Common = I, II, V, X
Normal FBC, PT/PTT • v. WD • Plt dysfunction • Vasculitis
Prolonged PTT (normal PT) • Intrinsic pathway abn: – Hemophilia – v. WD – Heparin – Lupus anticoag – Auired inhibitors
Prolonged PT (normal PTT) • Extrinsic pathway: – Vit K defn – Liver disease
Prolonged PT and PTT • • • Combined defn Warfarin Heparin DIC Liver disease Deficency / inhibitor of common pathway
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