Platelets

Low platelets

Causes
- Artefact – repeat with blood film
- Infection – EBV, HIV, Malaria, TB
- Medications – NSAIDs, Heparin, Digoxin, Quinine, Anti-Epileptics, Anti-Psychotics, PPIs
- Alcohol
- Malignancy
- Liver/Renal disease
- Aplastic anaemia
- B12/Folate deficiency
- Autoimmune/ITP/SLE
History:
- Travel
- Drugs
- Alcohol
- Bleeding (bruising, GI, nose, gums, periods, post dental, joints)
Assess severity
- 100-150 x 109/L
  - Repeat monthly
  - Refer
    - progressive decrease
    - Other FBC abnormalities
    - Unwell
- 50-100 x 109/L
  - Refer
    - persists > 4weeks
    - other cytopenias, splenomegaly, lymphadenopathy, pregnancy, upcoming surgery
- <50 x 109/L
  - Refer (urgent outpatient)
  - Refer (emergency – < 20 or any bleeding)

Raised platelets

Causes
- Primary
  - myeloproliferative disorder (likely if splenomegaly and > 1000)
- Secondary (more common)
  - Reactive – infection, inflammation, exercise, tissue damage, post surgery, haemolysis
  - Bleeding – periods
  - Malignancy – esp lung, endometrial, gastric, oesophageal, colorectal (LEGO-C)
  - Hyposplenism
  - Iron deficiency
History/Examination
- Neurological symptoms
- Lung – haemoptysis, SOB
- Endometrial – Vaginal discharge, macroscopic haematuria, PMB, low ferritin
- Gastro-oesophageal – dysphagia
- Colorectal – PR bleeding, weight loss

Management of high platelets

Investigations
- FBC/blood film, CRP, ferritin
- Weight diary
If asymptomatic, repeat after 4 weeks
- < 450 x 109/L
  - No further action
- >450 x 109/L
  - Refer
    - persistent
    - >600
    - associated with other abnormalities
    - consider urgent cancer of unknown origin clinic
    - consider urgent CXR
    - If > 55yo, consider upper endoscopy, pelvic USS
    - consider FIT
Urgent referral
- Bleeding
- Neurological symptoms
- >1000 x 109/L
- >600 x 10 with thrombosis or high risk of thrombosis/CVD
- Splenomegaly
- Other significantly abnormal FBC indices