Purpura

Question 1

Definition

Answer 1

Bleeding into skin. Characteristically the lesion is flat, non blanchable by pressure and changes colour from red to purple to greenish-yellow.
•Petechiae are lesions less than 2 mm;
•Purpura are lesions between 2 – 5 mm
•Ecchymosis are above 5mm in diameter

Age of skin bleeding:
•red – day 1
•purple – day 1-3
•green-yellow – day 7-10
•yellow brown – day 8 or more
•pink > 2 weeks

Question 2

Causes of bleeding into skin

Answer 2

1. Vascular causes:
•Syndromes: Ehler Danlo’s, Marfan’s
•Strangulation
•Metabolic: Steroid, scurvy, uraemia
•Vasculitis: SLE, HSP
•Septicaemia- viral, meningococcal
   •Drugs 

2. Thrombocytopenia
   • Decrease production
   ••Leukaemia
   ••Aplastic anaemia – primary and secondary
   ••Marrow infiltration – Lymphoma, Histiocytosis
   ••Osteropetrosis
   ••Megaloblastic anaemia

• Increased destruction
  
  • •Immune-mediated: ITP, Autoimmune diseases
  • •Non-immune related –
    
    • ••Infection – viral
    • ••Drug – Sulphonamide, carbimazole, rifampicin
    • ••Hypersplenism
    • ••DIC, HUS
    • ••Kassabach- Meritt’s syndrome

3. Platelet dysfunction
   Primary
   • Von Willibrand’s disease : No ristocetin Rx
   • Thrombasthenia: positiveristocetin Rx

Secondary
• Drugs: Aspirin, penicillin, S-drugs and herbs
• Liver or Renal failure
• Scurvy

4. Coagulation defect
Hereditary:
1. Vascular causes:
•  Syndromes: Ehler Danlo’s, Marfan’s
•  Strangulation
•  Metabolic: Steroid, scurvy, uraemia
•  Vasculitis: SLE, HSP
•  Septicaemia- viral, meningococcal
•  Drugs 

2. Thrombocytopenia
   • Decrease production
   •• Leukaemia
   •• Aplastic anaemia – primary and secondary
   •• Marrow infiltration – Lymphoma, Histiocytosis
   •• Osteropetrosis
   •• Megaloblastic anaemia

• Increased destruction
• • Immune-mediated: ITP, Autoimmune diseases
• • Non-immune related –
• •• Infection – viral
• •• Drug – Sulphonamide, carbimazole, rifampicin
• •• Hypersplenism
• •• DIC, HUS
• •• Kassabach- Meritt’s syndrome

3. Platelet dysfunction
   Primary
   • Von Willibrand’s disease : No ristocetin Rx
   • Thrombasthenia: positiveristocetin Rx

Secondary
• Drugs: Aspirin, penicillin, S-drugs and herbs
• Liver or Renal failure
• Scurvy

4. Coagulation defect
   Hereditary:
   • Haemophilia, Christmas/ VWD
   • Other hereditary clotting factor defect; either quantitative or qualitative

Acquired:
• Liver failure
• Vit K deficiency
• Massive transfusion
• DIC

Question 3

Steps in examination of bleeding into skin

Answer 3

1. Confirm purpura by its character
2. Note the extent of distribution:
   • Generalised vs local bleeding, esp bleeding into joint = coagulation defect
   • Mucosal bleeding

3. Look for pallor, fever
• Sore throat, mucosal ulcer (infection)
• LN enlargements (leukaemia etc)
• Sternal tenderness
• Pseudoparalysis of limbs

4. Abdo examination

NB.
• Raised purpuric rash of LL & buttock distribution = HSP
• Factor XII deficiency - abn aPTT but no clinical disease
• Factor XIII deficiency - normal blood tests but with clinical bleeding