Thrombocytopenia & Thrombocytosis

Thrombocytopenia

Differentials

1. Platelet disorder

• ITP (Immune Thrombocytopenic Purpura) 

• TTP (Thrombotic thrombocytopenic purpura) 

• Haemolytic Uraemic Syndrome (Ecoli)

• Heparin induced thrombocytopenia (HIT)

• DIC

  • AML

• PNH (paroxysmal nocturnal haemoglobinuria) 

• Antiphospholipid Syndrome (APS) 

2. Non-haematologic

   • Bone marrow failure

     1. 1. Medication: carbimazole, clozapine, sulphonamides, NSAIDs, paracetamol, quinine

        2. Infective

           1. Sepsis

           2. HIV, HCV, EBV, parvovirus, Mumps, VZV, Rubella

           3. H. Pylori

           4. Leptospirosis

           5. Malaria

        3. Malignant infiltration

           1. Metastatic

           2. Haematological: leukaemia, lymphoma, myelofibrosis

   • Liver Cirrhosis (splenomegaly), chronic alcoholic abuse

   • Nutritional deficiency: B12

Platelet Aims:

> 20: avoid spontaneous bleeding

> 50: ascitic tap, SBP, major haemorrhage protocol

> 80: epidural 

Management

1. Treat underlying cause

2. Pool of platelets

Thrombocytosis

Presentation

• Asymptomatic

• Venous or arterial clots- e.g. petechia or purpura

Differentials

1. Essential Thrombocytosis (ET)

2. Reactive (inflammatory response)

   • Cancer

   • Infection

   • Inflammation

Assessment

• History & Examination

• Baseline bloods: FBC, EUC, LFTs, CRP

• JAK-2 if considering ET if platelets >> 400

Management

Treat underlying cause. 

Resources and References

1. https://bestpractice.bmj.com/topics/en-gb/795

2. Jinna S, Khandhar PB. Thrombocytopenia. [Updated 2023 Jul 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK542208/

Written in 2025