Page 128 - Medicine and Surgery

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124 Chapter 3: Respiratory system

1α-hydroxylation of vitamin D in sarcoid macro- Hepatitis (rare).
phages,whichresultsinraisedlevelsof1,25-dihydroxy Skin lesions such as erythema nodosum respond
vitamin D 3 . rapidly to a short course.
Constitutional symptoms may also respond.

Microscopy
Non-caseating granulomas consisting of focal accumu- Prognosis
lation of epithelioid cells, macrophages, (mainly T) lym- Once on steroids, many patients require long-term
phocytes and giant cells. medium dose prednisolone; however, many patients are
able to stop steroids after ∼2years. The disease has a
Investigations high spontaneous remission rate.
Chest X-ray: Bilateral hilar lymphadenopathy (differ- Sarcoidosis is more severe in Black Americans where

ential: lymphoma, TB, Ca). Pulmonary infiltration: the death rates are up to 10%.
mottling of mid and lower zones proceeding to bilat- IntheUnitedKingdomthedeathrateisapproximately
eralfinenodularshadowing.Maybenormalevenwith 1in20often due to respiratory problems.
infiltration. The chest X-ray provides a guide to prognosis:
Lung function tests show a restrictive pattern with i In patients with only hilar lymphadenopathy two

infiltration. thirds will remit in 2 years.
Full blood count: Mild normochromic, normocytic ii In patients with lymphadenopathy and infiltration

anaemia with raised ESR and/or CRP. one half will remit in 2 years.
Serum angiotensin converting enzyme (ACE): In 75% iii In patients with infiltration alone only one third

of patients with untreated sarcoid ACE is >2sd above will remit in 2 years.
the mean. Not diagnostic but useful to assess activity
of pulmonary infiltrates. Wegener’s granulomatosis
Transbronchial biopsy: Infiltration of the alveolar

walls and interstitial space with lymphocytes. Positive Definition
in 90% with or without X-ray evidence. Arare form of necrotising small vessel vasculitis of the
Tuberculin test: 80% show anergy, but this is not help- upper and lower respiratory tract and the kidneys asso-

ful diagnostically. ciated with granuloma formation.
Kveim test: Intradermal injection of sarcoid tissue is

not used now due to risk of infection. Incidence
Rare
Management
1 Acute sarcoidosis, e.g. hilar lymphadenopathy with Age
erythema nodosum usually resolves spontaneously More common over the age of 40 years.
over 2 years and usually does not require treatment
if asymptomatic. If symptomatic responds well to Sex
steroid therapy. M > F (2:1)
2 Themorechronicformwithevidenceofinfiltrationor
abnormal lung function is unlikely to improve with- Pathophysiology
out treatment and is initially treated with steroids and The aetiology is unknown, but it responds to immuno-
monitored with lung function tests, ESR, CRP and/or suppression. The small vessel vasculitis in the kidney
serum ACE levels. causes reduced glomerular filtration rate and ischaemia
Indications for systemic steroids: of the glomeruli and hence acute or chronic renal failure.
Progressive deterioration in lung function or symp-

tomatic pulmonary lesions. Clinical features
Cardiac, CNS or severe ocular involvement. General malaise is common. In the upper respiratory

Hypercalcaemia. tract it causes ulceration and granulomas in the nose and