Page 827 - Clinical Immunology_ Principles and Practice ( PDFDrive )

CHaPtEr 58 Small- and Medium-Vessel Primary Vasculitis 799

ORGAN INVOLVEMENT IN GPA systemic inflammatory syndrome. The child typically has mucosal
100 inflammation with strawberry tongue; approximately 10 days
90 after the onset, skin desquamation is a very typical feature. The
most worrying feature of KD is the development of coronary
80 artery aneurysms, which occur in around 2–4% of children
70 and can be fatal, if untreated. This can be detected by using
echocardiography.
60
Laboratory Investigations
50
The investigation of patients with suspected small- or medium-
40
vessel vasculitis should follow a careful history and examination
30 to determine the likely diagnosis and underlying illness. The
20 differential diagnosis is very wide. It is important to be vigilant
in looking for positive signs of vasculitis, but it is equally
10 important not to forget to look for more common causes of the
0 clinical presentation. Many of the studies performed can result
ENT Lung Kidney Heart GI Skin CNS PNS in nonspecific findings, such as an elevated white blood cell
FIG 58.2 Organ involvement in patients with granulomatosis count, platelet count, or the erythrocyte sedimentation rate. The
with polyangiitis (GPA). (Data compared across seven cohorts— C-reactive protein (CRP) level is typically raised. Patients may
reviewed by Luqmani R, Ponte C. ANCA associated vasculitides be anemic. Liver or, more importantly, renal function may be
and polyarteritis nodosa. In: Bijlsma JWJ, Hachulla E, eds. EULAR abnormal. The presence of hypereosinophilia can be suggestive
Textbook on Rheumatic Diseases. London, UK: BMJ Publishing of a diagnosis of EGPA, but there are other causes of hypereo-
Group Ltd; 2015. Chapter 27, p.717-753) 75 sinophilia, particularly drug reactions. It is important to test
renal function in patients with suspected vasculitis in case there
is nephritis, and it is always important to perform urinalysis for
microscopic hematuria or proteinuria. Although these might be
ORGAN INVOLVEMENT IN MPA explained by the presence of a kidney infection or other causes,
120 they raise a strong suspicion of glomerular inflammation. An
abnormal urinary sediment in combination with hypertension
100 should alert the physician to the possibility of kidney involvement
12
by small-vessel vasculitis. Since the 1980s, the discovery of ANCA
80 has transformed the recognition of renal vasculitis, so that these
60 patients can be managed more effectively.
Histology remains a very important diagnostic test, not only
40 to make a positive diagnosis but also to exclude other causes.
20 Although histology from the airways can be nondiagnostic, this
may still assist in ensuring that the patient does not have cancer,
0 sarcoidosis, o tuberculosis, or IgG4-related disease, all of which
ENT Lung Kidney Heart GI Skin CNS PNS could present in a similar way with inflammation of the upper
FIG 58.3 Organ involvement in patients with microscopic or lower airway. Renal histology is still the gold standard to
polyangiitis (MPA). (Data compared across seven cohorts— diagnose suspected glomerulonephritis and may be useful in
reviewed by Luqmani R, Ponte C. ANCA Associated Vasculitides predicting the prognosis. Four categories of renal lesion have
76
and Polyarteritis Nodosa. In: Bijlsma JWJ, Hachulla E, eds. EULAR been proposed: focal, crescentic, mixed, and sclerotic. Follow-up
TEXTBOOK ON RHEUMATIC DISEASES. London, UK: BMJ of patients with different patterns has shown outcomes: progres-
Publishing Group Ltd; 2015. Chapter 27, p.717-753) 75 sively worse renal outcome from focal (the best) through to
sclerotic (the worst) over the subsequent 5 years.

ASSESSMENT
membranous glomerulonephritis is a recognized complication.
Most cases appear to be associated with hepatitis C (>90% in The outcome of small- and medium-vessel vasculitis has been
some series), and eradication of hepatitis C appears to be effective completely transformed by immunosuppressive therapy. With
in reducing the manifestations of disease. treatment almost all patients with KD recover from their initial
True PAN typically presents with neuropathies, systemic illness. In AAV, >70% survive at least 5 years from starting treat-
inflammation, and ischemic abdominal pain (difficulty eating ment. The majority of patients with PAN respond to initial
because of medium-vessel supply to the gut and nerves). If it is therapy. However, the risk of recurrence of disease is high in
associated with hepatitis B, the patient may or may not have small-vessel vasculitides. Relapse rates are likely to exceed 50%
46
obvious signs of liver disease. over time. Patients experience comorbidities as a consequence
Isolated cutaneous vasculitis typically presents as purpuric of the disease or its treatment and can suffer from infections or
lesions, skin ulceration, or broken livedo, and biopsy of the skin other complications that contribute to their overall poor health.
will show typical changes of a necrotizing vasculitis. In the long term, small-vessel vasculitides and their treatment
KD usually presents in childhood as an acute illness, with can be associated with effects on the cardiovascular system with
relapsing high fevers, significant lymphadenopathy, and a increased risk of hypertension, coronary heart disease, and stroke.