Page 2064 - Cote clinical veterinary advisor dogs and cats 4th

Vasculitis 1031.e5

• Ventral or dependent edema (limbs, ventrum, Advanced or Confirmatory Testing Drug Interactions
prepuce) • Focus diagnostic efforts on identifying the Immunosuppressive glucocorticoids should be
VetBooks.ir tissues affected and underlying cause of • Infectious disease testing as appropriate (e.g., been ruled out. Diseases and Disorders
underlying cause (review vaccine/medication/
used with caution until infectious causes have
• Other complaints depend on organs/
travel/ectoparasite history)
vasculitis
PHYSICAL EXAM FINDINGS rickettsial titers [dogs], retroviral serology Possible Complications
[cats])
• Necrosis predisposes to infection or can neces-
• Lesions in dependent/ventral regions, over • Coagulation testing (platelet count, sitate surgical debridement or amputation
pressure points, extremities (pinna, tail): prothrombin time [PT], activated partial • Consumptive coagulopathy (DIC) in severe
nonblanching erythema typically sharply thromboplastin time [aPTT]), D-dimers, cases
demarcated from adjacent normal tissue; fibrinogen concentration • Glomerulonephritis (GN) if immune
may be focal or generalized • Direct immunofluorescence, immunohis- complex deposition in the kidneys
• Plaques, papules/pustules, necrosis/ulcers tochemical testing: often not useful for • Hypoalbuminemia with severe or diffuse
• Petechiae or ecchymotic hemorrhages diagnosis, due to short sampling window vasculitis or GN
• Dependent edema (4-24 hours of lesion formation) • Glucocorticoids: immunosuppression, iatro-
• Retinal petechiae, uveitis genic hyperadrenocorticism
• ± Fever TREATMENT
• ± Peripheral lymphadenopathy Recommended Monitoring
Treatment Overview • Recheck in 3-5 days to assess response to
Etiology and Pathophysiology Vasculitis may be acute and nonprogressive initial therapy (extent and severity of lesions);
• Toxic, immune-mediated, infectious, or chronic and recurrent. The therapeutic reassess blood test abnormalities if present.
inflammatory, and neoplastic disorders can goal is to identify the underlying cause and • CBC and serum biochemistry profile q 4-6
result in vasculitis, but ≈50% of cases are minimize end-organ damage if there is systemic weeks during initial treatment
idiopathic. involvement. Treatment of idiopathic cases is • Reassess potentially infarcted dermal regions
• Type III hypersensitivity is the predominant immunosuppressive or immunomodulatory. daily for evidence of necrosis; address surgi-
mechanism of cutaneous vasculitis. For the best chance of success, the underlying cally if necessary when patient is stable.
• Vasculitis is characterized histologically cause must be treated or removed.
by inflammatory cells in and around the PROGNOSIS & OUTCOME
vessel wall. Histologic classifications include Acute General Treatment
neutrophilic, eosinophilic, lymphocytic, • Discontinue all unnecessary drugs until the • Depends on the underlying cause
granulomatous, mixed, and cell-poor forms. inciting cause is identified. ○ Drug-induced vasculitis has a favorable
Neutrophilic vasculitis can be further classi- • Severe vasculitis can lead to peripheral prognosis after the inciting cause is
fied as leukoclastic or nonleukoclastic (more edema and hypoalbuminemia. Use judi- eliminated.
common). cious IV fluids and/or concurrent use of IV ○ Idiopathic vasculitis may require chronic
• Damage to vascular endothelium results in synthetic colloids (VetStarch 20-40 mL/kg/ therapy.
increased permeability, inflammation, and day or hetastarch 20 mL/kg/day) to maintain
microvascular thrombosis. oncotic pressure. PEARLS & CONSIDERATIONS
• Pentoxifylline can be used for its rheologic
DIAGNOSIS and immunomodulatory properties at doses Comments
of 20-25 mg/kg PO q 8-12h. Use with • In humans, there are multiple, well-described
Diagnostic Overview caution in patients with coagulopathies. primary or immune-mediated vasculitic
Dermal vasculitis is suspected based on the • Doxycycline 5 mg/kg PO q 12h can be used syndromes; this is not the case in veterinary
presence of nonblanching erythema with or for potential unconfirmed rickettsial disease medicine.
without edema; diagnosis is confirmed by and concurrently with niacinamide 22 mg/ • Most vasculitis in dogs and cats is thought
skin biopsy. Vasculitis is a clinical problem kg PO q 8h for additive antiinflammatory to be secondary, and intensive efforts should
with many possible causes, and efforts should effort. be made to identify the cause. Unfortunately,
be directed at identifying the underlying • Glucocorticoids may be considered if an no specific cause is identified in ≈50% of
cause. infectious cause has been ruled out: pred- cases.
nisone or prednisolone (cats) 0.5 mg/kg PO • A skin biopsy that includes the junction
Differential Diagnosis q 12-24h (antiinflammatory) or 2 mg/kg between affected and normal skin is critical
Coagulopathy, disseminated intravascular PO q 12-24h (immunosuppressive) to diagnose vasculitis and may be helpful in
coagulation (DIC), systemic lupus erythe- • Early referral should be considered if there identifying the underlying cause.
matosus, cold agglutinin disease, cutaneous is clinical progression or lack of response to
lupus erythematosus, bullous pemphigoid, initial therapies. Prevention
lymphoreticular neoplasia, hypersensitivity Mark patient charts with medications/vac-
(primarily urticaria) Chronic Treatment cinations associated with vasculitis to prevent
• Glucocorticoids: taper slowly by 20%-25% potential administration in the future.
Initial Database q 3-4 weeks to lowest effective dose
• CBC: changes related to underlying disease • Pentoxifylline: taper over 1-3 months to q Technician Tips
± mild leukocytosis, thrombocytopenia 12-24h Use precautions (e.g., gloves, clean coat/gown)
• Serum biochemistry panel: changes related ○ May take 1-3 months for complete when handling patients with disrupted skin to
to underlying disease ± hyperglobulinemia, response; synergistic action with gluco- minimize risk of secondary infection.
mild hypoalbuminemia corticoids
• Urinalysis: ± proteinuria if renal involvement • Therapy may be tapered over 4-6 months. Client Education
suspected Medical therapy may involve combinations of
• Skin biopsy: confirmatory test of choice. Nutrition/Diet medications and multiple dose adjustments
Biopsy is obtained at junction of normal Vitamin E supplementation may be of until therapeutic goal is reached. Frequent
and abnormal tissues. benefit. reassessment is critical.

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