Vasculitides

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This article deals with the vasculitides (singular vasculitis). Vascular disease that is not vasculitides is covered in the article vascular disease.

The histology of normal vessels is dealt with in normal blood vessels.

Overview

Most common[1]

  • Polyarteritis nodosa (PAN).
  • Microscopic polyangiitis.
  • Wegener's granulomatosis.
  • Predominantly cutaneous vasculitis.
  • Giant cell arteritis (GCA).

Grouping by size

Small vessel vasculitides

Definition

Small vessel vasculitis = vasculitis of vessels smaller than arteries; affects arterioles, venules, and capillaries.[2]

  • What is an arteriole?
    • There is no histologic definition according to Sternberg's Histology for Pathologists; however, a diameter of <100 micrometers is suggested as a definition.[3]
Types
  • Predominantly cutaneous vasculitis.
  • Henoch-Schoenlein purpura.
  • Essential cryoglobulinemic vasculitis.
  • ANCA-associated:
    • Wegener's granulomatosis (c-ANCA > p-ANCA).
    • Churg-Strauss syndrome (50% ANCA +ve).
    • Microscopic polyangiitis (usually p-ANCA).

Notes:

  • ANCA = anti-neutrophil cytoplasmic antibodies.

Medium vessel vasculitides[4]

  • Polyarteritis nodosa (PAN).
  • Kawasaki disease.

Large vessel vasculitides[4]

  • Giant cell arteritis (AKA temporal arteritis).
  • Takayasu's arteritis.

Pathologist's role in the diagnosis of vasculitis

General

  • Pathologists often cannot, based on morphology alone, arrive at the definitive diagnosis.
  • The presentation & distribution are more characteristic than the pathology.[5][6]

Microscopic

Features:[7]

  1. Inflammatory cells within the blood vessel wall.
  2. Vessel injury:
    • Frank fibrinoid necrosis or nuclear dust:
      • Fibrinoid necrosis = anucleate amorphous intensely eosinophilic material.
        • Amorphous = no definite form.[8]
      • "Nuclear dust" = punctate hyperchromatic material ~ 1 micrometre.

Notes:

  • Involvement is usually patchy.
    • If there is an inkling of vasculitis... it should prompt deeper cuts.

Features to consider

  1. Presence of granuloma.
  2. Type inflammatory cells, i.e. eosinophils, mononuclear cells.
  3. Size of vessels involved.
  4. Extent of involvement.
  5. Acuity (acute vs. subacute vs. chronic vs. acute on chronic).
    • Chronic = thick fibrotic appearing vessels with a small lumen.

Vasculitis vs. neuropathy

Vasculitis Neuropathy
Clinical pain, diffuse/
patchy distribution 		focal/isolated
Pathological
(inflammatory cells) 		epineurium endoneurium

Vasculitides

The follow section has information specific to the individual types of vasculitis.

Giant cell arteritis

General

  • AKA temporal arteritis.

Clinical

Features:

  • Classic finding: jaw claudication, in a patient older than 50 years.
  • Other findings: headache, vision loss or diplopia, scalp tenderness, polymyalgia, weight loss, chills, fever.

Work-up:

  • CRP, ESR, temporal artery biopsy.

Treatment:

  • Treat right away with high dose steroids.
    • Biopsy is confirmatory.

Microscopic

Features:

  • Classical: granulomas.

Image(s):

Takayasu's arteritis

General

Features:[9]

  • Disease of medium/large arteries.
    • Classically involves the aortic arch (leading to decreased pulses in the upper limbs).
  • Typically in patients <40 yrs old.
  • Usually asian.

Microscopic

Features:[9]

  • Adventitial mononuclear infiltrate with perivascular cuffing of the vasa vasorum.
  • Mononuclear inflammation in media.
  • Granulomas, giant cells.
  • +/-Patchy necrosis of media.

Polyarteritis nodosa

General

  • Abbreviated PAN.
  • Involves small and medium sized vessels.
  • Often - renal vessels, mesenteric vessels.[10]
  • Strong association with hepatitis B (see medical liver diseases); ~1/3 of patients with PAN have HBV.

Serology:

  • ANCA is usually negative.

Microscopic

Features:

  • Inflammatory cells (neutrophils, lymphocytes) within the tunica media.
  • Fibroid necrosis: dead vessel wall - pink anucleate stuff, nuclear debris (black specks of nuclear material).

Image: PAN (immunologyclinic.com).

Wegener's granulomatosis

Clinical

  • Epistasis.
  • Renal failure - present as nephritic syndrome.
    • Renal biopsy: crescentic glomerulonephritis (AKA rapidly progressive glomerulonephritis).
  • Pulmonary hemorrhage.

Serology:

Notes:

  • Pulmonary hemorrhage syndromes:[12]
    • Goodpasture syndrome.
    • Idiopathic pulmonary hemosiderosis.
    • Vasculitis-assoc. hemorrhage (hypersensitivity angiitis, Wegener's granulomatosis).
    • Systemic lupus erythematosus.

Microscopic

Features:

  • Granulomas typically poorly formed.[13]

Image: Wegener's granulomatosis (flickr.com).

LAMP-2 vasculitis

  • Associated with pauci-immune necrotizing and crescentic glomerulonephritis.[14]
  • Grouped with the ANCA-associated vasculitides.[15]

See also

References

  1. ↑ TN05 RH3.
  2. ↑ Jennette JC, Falk RJ (November 1997). "Small-vessel vasculitis". N. Engl. J. Med. 337 (21): 1512–23. doi:10.1056/NEJM199711203372106. PMID 9366584. http://www.nejm.org/doi/full/10.1056/NEJM199711203372106.
  3. ↑ Sternberg, Stephen S. (1997). Histology for Pathologists (2nd ed.). Lippincott Williams & Wilkins. pp. 769. ISBN 978-0397517183.
  4. ↑ 4.0 4.1 Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 512. ISBN 978-1416031215.
  5. ↑ URL: http://www.pathology.ubc.ca/path425/PrincipleofPathophysiology/CirculatoryDisorders/SystemicVasculitisDrBWalker.doc. Accessed on: 26 November 2010.
  6. ↑ URL: http://www.icapture.ubc.ca/who/who_bios_david_walker.shtml. Accessed on: 26 November 2010.
  7. ↑ URL: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2908435/. Accessed on: 26 November 2010.
  8. ↑ URL: http://dictionary.weather.net/dictionary/amorphous. Accessed on: 26 November 2010.
  9. ↑ 9.0 9.1 Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease (7th ed.). St. Louis, Mo: Elsevier Saunders. pp. 538. ISBN 0-7216-0187-1.
  10. ↑ Klatt, Edward C. (2006). Robbins and Cotran Atlas of Pathology (1st ed.). Saunders. pp. 14. ISBN 978-1416002741.
  11. ↑ TN05 RH6.
  12. ↑ Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease (7th ed.). St. Louis, Mo: Elsevier Saunders. pp. 745. ISBN 0-7216-0187-1.
  13. ↑ Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease (7th ed.). St. Louis, Mo: Elsevier Saunders. pp. 747. ISBN 0-7216-0187-1.
  14. ↑ Bosch X, Mirapeix E (May 2009). "Vasculitis syndromes: LAMP-2 illuminates pathogenesis of ANCA glomerulonephritis". Nat Rev Nephrol 5 (5): 247–9. doi:10.1038/nrneph.2009.51. PMID 19384321. http://www.nature.com/ki/journal/v76/n1/abs/ki2009123a.html.
  15. ↑ Chen M, Kallenberg CG (2009). "New advances in the pathogenesis of ANCA-associated vasculitides". Clin. Exp. Rheumatol. 27 (1 Suppl 52): S108–14. PMID 19646356.
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