Thursday, 1 May 2014

Idiopathic Thrombocytopenic Purpura

ITP is more common in children, than in adults - but I've come across it in the adult syllabus first...so we'll cover kids and adults now.

Pathophysiology
Once again, go no-where else but the Calgary Guide!

- IgG mediated
- Platelets get prematurely destructed. Instead of lasting 8 - 10 days, they only last a few hours.
- Often after a recent cold or other infection
- May be associated with HIV and hepatitis
- May be related to immune disorders or pregnancy.

Epidemiology
- Peak age 2 - 10 years old
- Most cases <5 years
- Can occur in adults in the 3rd and 4th decade
- Acute is more likely to be younger children, and resolves in 1-2 months
- Chronic is >3months, more likely to have underlying disease, rarely remits spontaneously.

Diagnosis
- Platelet count of <100,000 /microLitres
- 40,000 – 90,000 are more concerning for undiagnosed marrow failure or leukemia.
- Normal Hgb and WBC with normal differential.
- The absence of signs of other identifiable causes of thrombocytopenia.

Clinical Features
Cutaneous Bleeding
                Petechiae + Purpura
Mucous Membrane
                Epistaxis
                Wet Purpura – Buccal mucosa, Gingiva, palate, tonsillar pillar purpura or petchiae
                Melena / GIB
                Hematuria
                Menorrhagia
Internal bleeding

Historic points favoring another diagnosis:    Bone/Joint Pain
    Family Hx of easy bruising or low platelets

Exam findings concerning for another diagnosis:    Soft tissue or skeletal morphologic abnormalities
    Nonpetechial rash
    Lymphadenopathy
    Hepatosplenomegaly

Management
Based on clinical findings, rather than absolute platelet count. 
IV 1g + steroids 1mg/kg
no platelets unless life threatening bleed
May need splenectomy

HUS

Haemolytic uremic syndrome is characterised by thrombocytopenia. It is normally triggered by E-coli 0157, which is found in healthy cattle. May also be caused by shigella, yersinia, campylobacter, salmonella
Most cases occur in child
ren <10years, and 2/3 of cases occur in <5years. Incidence is increased if antibiotics or antimotility agents have been used.

Clinical Features
With or without diarrhoea
Diarrhoea may be bloody (70%) or just watery.
Lethargy 2- 14 days after diarrhoea
Neurological symptoms in 33% (irritability, seizures, altered mental status)
Decreased urine output in a patient that is clinically well-hydrated
Pallor
Oedema - often periorbital, in the morning


References
http://pedemmorsels.com/wet-purpura-and-itp/
https://umem.org/educational_pearls/1170/
http://wikem.org/wiki/ITP_in_Pregnancy
http://wikem.org/wiki/Idiopathic_Thrombocytopenic_Purpura
http://www.bestbets.org/bets/bet.php?id=2593
http://www.foamem.com/category/ped-em-morsels/page/11/
https://umem.org/educational_pearls/279/
http://www.guidelinesforme.com/guidelines/133-immune-thrombocytopenia-purpura-itp
http://www.rch.org.au/clinicalguide/guideline_index/Immune_Thrombocytopenic_Purpura/
http://www.pemcincinnati.com/blog/http://bloodjournal.hematologylibrary.org/content/117/16/4190.full
http://www.rch.org.au/clinicalguide/guideline_index/Immune_Thrombocytopenic_Purpura/
http://www.pemcincinnati.com/blog/briefs-itp/http://calgaryguide.ucalgary.ca/slide.aspx?slide=TTP%20HUS.jpg 
http://pedemmorsels.com/nonspecific-diarrheal-illness-or-hus/
http://wikem.org/wiki/Hemolytic_Uremic_Syndrome_%28HUS%29
http://emupdates.com/2009/05/22/916-hemolytic-uremic-syndrome-hus-usual-age-pathophys-ssx-dx-rx/
http://myemergencymedicineblog.blogspot.co.uk/2013/01/what-is-treatment-of-hemolytic-uremic.html
http://wikemerg.ca/wiki/ttphus

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