Coagulation Disorders

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Venous thromboembolism (VTE) is a common disorder that comprises deep vein thrombosis (DVT)  and pulmonary embolism (PE). In most cases, pulmonary embolism arises from proximal deep vein  thrombosis i.e. popliteal, femoral or iliac veins in at least 90%. 

Deep Vein Thrombosis (DVT)

Clinical presentation 

  • Leg pain, tenderness and swelling.
  • A palpable cord representing thrombosed vessels.
  • Discoloration, venous distention and prominence of superficial veins and cyanosis.
  • The clinical diagnosis of DVT is highly nonspecific.

Investigations 

  • D-dimer,
  • Doppler USS,
  • PT, INR, Aptt

Pharmacological Treatment 

Long  term  anticoagulation  is  required  to  prevent  a  frequency  of  symptomatic  extension  of  thrombosis  and/or  recurrent  venous  thromboembolic  events.  Warfarin  is  started  with  initial  unfractionated heparin or enoxaparine therapy and then overlapped for 5days. 

C:  warfarin  (PO)  5mg  24hourly  for  5days,  then  adjust  the  dose  according  to  INR  levels for 3-6 months. 

AND 

S: Low Molecular weight heparin (SC)1mg/kg 24hourly for 5days 

OR 

S: Unfractionated heparin (IV) by 75units/kg followed by continuous infusion of 

18units/kg/hrs. 

Adolescents  or  children:  loading  dose  75units/kg  then  15–25  Units  /kg/hr  by  IV  infusion  or  250units/kg 12hourly by SC injection. 

S: rivaroxaban (PO) 15mg 12hourly for 21days, then rivaroxaban (PO) 20mg 24hourly for  the remaining duration of treatment. 

Pregnant women 

Warfarin is teratogenic, therefore low molecular weight heparin is recommended during pregnancy.  D: Low Molecular weight heparin (SC) 1mg/kg 12hourly for the whole duration of treatment.

Pulmonary Embolism (PE)

It is a medical emergency.  

Clinical presentation 

  • Transient dyspnea and tachypnea in the absence of other clinical features
  • Pleuritic chest pain, cough, haemoptysis, pleural effusion, and pulmonary infiltrate
  • Severe dyspnea and tachypnea and right-side heart failure
  • Cardiovascular collapse with hypotension, syncope, and coma
  • Several  less  common  and  nonspecific  presentation  including  unexplained  tachycardia  or arrhythmia, resistant cardiac failure, wheezing, cough, fever, apprehension and confusion.

Investigations 

  • PT, INR, aPTT, D-dimer, CXR and CT angiography

Pharmacological Treatment

Treat as Deep Vein Thrombosis 

Note:

  • Warfarin  therapeutic  INR  ranges  from  2  to  3  for  VTE,  and  2.5  -3.5  for  patients  with mechanical heart valves
  • Warfarin therapy should be monitored by INR after 5–7 days of treatment, then as needed throughout the duration of treatment.
  • If the cause of VTE is acquired thromboembolism, treatment lasts for 3-6 months, BUT if the cause is inherited thrombophilia, treatment is lifelong.
  • Warfarin interacts with many drugs therefore precaution should be taken when administered with other drugs.
  • If warfarin overdose/toxicity occurs, stop warfarin and give FFP 10-15mls/kg and vitamin K 5mg IV stat. Reinitiate warfarin after bleeding has stopped and INR is within therapeutic range, using the lower dosage.
  • For  VTE  prophylaxis  in  bedridden  patients,  give  enoxaparin  40mg  SC  OR  Rivaroxaban 10mg orally once a day until ambulation resume.
  • Unfractionated heparin should be monitored by aPTT before and during treatment.