Henoch-Schonlein Purpura (HSP)

Study guide:

Definition:

  • It is a type of immune complex vasculitis with unknown cause characterized by

inflammation of the small vessels, lymphocytic infiltration of tissues, hemorrhage, and ischemia.

Epidemiology:

  • The most common systemic vasculitis of childhood.

  • Usually affecting children between 3-15 years old.

  • Slightly more common in males.

  • Winter season predominance has been reported to be associated with HSP.

  • 80% of the HSP was preceded by viral upper respiratory infection or streptococcal infection.

Pathophysiology:

  • Increased serum IgA concentration, IgA- containing immune complexes, and IgA deposition in walls of the vessels and renal mesangium.

  • IgA1 abnormalities are more associated with HSP than IgA2.

  • This deposition will evoke various inflammatory mediators including vascular prostaglandins, which may play a central role in the pathogenesis of HSP.

  • Type III hypersensitivity reaction.

Clinical presentation:

  • Acute purpura in lower extremities and buttocks:

    • The hallmark of HSP is palpable purpura.

    • Start as maculopapular erythema to petechiae or purpura.

    • Usually appears below the waist covering the buttocks and lower limbs.

  • Arthritis:

    •  Appears in 80% of HSP patients.

    •  Painful, in large joints of lower limb (hips, knees, and ankles joints) and disappear after few days.

    • ANCA negative

  • Diffuse colicky abdominal pain:

    • Presents in the acute phase of HSP preceding the purpura.

    • Positive occult stool for blood and bloody diarrhea.

    • Intussusception (ileoileal/rare).

    • Pancreatitis, protein losing enteropathy/ hyrops of the gallbladder.

  • Renal involvement

    •  Mostly mild with microscopic or macroscopic hematuria and low grade

      proteinuria.

    •  Hypertension and acute renal failure might occur.

    •  Acute IgA glomerulonephritis:

      • Focal segmental proliferative glomerulonephritis with mesangial hypercellularity.

  • Might also present with orchitis, and subcutaneous edema.

Diagnosis:

  • Blood tests:

    •  ESR, C-reactive protein, and WBCs are elevated.

    •  Normal or high platelet count.

    •  Must do urine analysis every week while disease is active

      and every 3 months after resolved disease.

  • Skin punch biopsy:

    • Granulocytes on the walls of the vessels that consist of IgA1 depositions and C3.

    • Leukocytoclastic vasculitis.

  • Criteria of diagnosis (2 out of the 4 criteria):

    • Palpable purpura.

    • Bowel angina/ diffuse abdominal pain.

    • Diagnostic skin biopsy.

    • Age group < 20 years old.

HSP can be confused with Acute Hemorrhagic Edema, which is a triad of non-pitting edema, fever, and purpura in face and extremities (trunk is spared). It occurs in children < 2 years -old and it is a self-limiting disease

  

 

Management:

  • Therapy is mainly supportive for HSP.

  • Short course of NSAIDs for acute arthritis.

  • Systemic steroids are reserved for those with severe gastrointestinal disease.

  • Acute nephritis is treated with steroids, but may require more potent immunosuppressive therapy.

Complications:

  • Temporary dysfunctional peristalsis increasing the risk of
    intussusception.

    • Any patient presents with abdominal pain and diarrhea with history of HSP should be
      evaluated for the possibility of intussusception.

  • Renal insufficiency and IgA nephropathy. 

Intussusception is the most common GI complication of HSP

 

Prognosis:

  • Excellent prognosis as it usually disappears within 4-6 months without significant 
    complications.

  • Poor prognosis if >50% of glomeruli are affected in renal biopsy.

References:

  1. Kumar P, Clark M. Kumar & Clark's clinical medicine.

  2. Fischer C. Master the boards.

  3. Cvetnic W, Pino E, Koerner C. USMLE step 2 CK pediatrics. [New York]: Kaplan; 2011.

  4. Kliegman R. Nelson textbook of pediatrics.

  5. Shah S, Ronan J, Alverson B. Step-up to pediatrics.

  6. Emedicine.medscape.com. Henoch-Schonlein Purpura Clinical Presentation: History, Physical Examination,

    Complications [Internet]. 2016 [cited 2 March 2016]. Available from:

    http://emedicine.medscape.com/article/984105-clinical

  7. Wikipedia. Henoch–Schönlein purpura [Internet]. 2016 [cited 2 March 2016]. Available from:

    https://en.wikipedia.org/wiki/Henoch–Schönlein_purpura (Figure 1).

  8. Medlibes.com. Henoch-Schonlein purpura — Medlibes: Online Medical Library [Internet]. 2016 [cited 2 March

    2016]. Available from: http://medlibes.com/entry/henoch-schonlein-purpura (Figure 2).

  9. Worldallergy.org. World Allergy Organization [Internet]. 2016 [cited 2 March 2016]. Available from:

    http://www.worldallergy.org/professional/allergic_diseases_center/vasculitis/ (Figure 3).

Written by:       Eman bablghaith

Reviewed by:    Basmah Allugmani

                        Roaa Amer

Format editor:  Roaa Amer

Published on:   03/02/2016