A 78 year old has swinging pyrexia. He has had a laparoscopic cholecystectomy complicated by gastrointestinal perforation and postoperative multiorgan failure two weeks previously. On examination his temperature was 39°C, pulse 100/min and irregularly irregular, blood pressure 120/80 mm Hg. He has an impaired percussion note and bronchial breathing at the right base.

Questions

(1) What does the photograph show ?
(2) Explain the patient's physical signs.
(3) List three important investigations in this case.
(4) What is the most likely cause of the sign shown?
(5) List three other causes of this sign.

Answers

(1) Vasculitic rash affecting both legs.

(2) His respiratory signs are due to consolidation secondary to right lower lobe pneumonia. He is in atrial fibrillation, which commonly occurs secondary to pneumonia in this age group.

(3) Arterial blood gases, urea and electrolytes, and blood cultures. Hypoxia and renal impairment are poor prognostic features of pneumonia. He will also require a chest x ray examination, a full blood count, and sputum culture.

(4) His vasculitis is most likely secondary to septicaemia from his pneumonia, the most likely organism being Streptococcus pneumoniae.

(5) Rheumatoid disease, polyarteritis nodosa, infective endocarditis.

Discussion

Vasculitis is defined as inflammation of the vessel wall, which is usually immunologically mediated. Several classifications exist, some based on the size of the affected vessels. We have divided causes into infective and non-infective.

Infective causes

• Subacute bacterial endocarditis is well known to cause vasculitis. Small petechial haemorrhages appear at the mucosa of the pharynx and conjunctiva. They can sometimes be seen in the retinas (Roth spots) or at the thenar and hypothenar eminences (Janeway lesions). Embolic lesions, such as hard, tender swellings, occur in fingers, toes, palms, and soles (Osler's nodes). The rash shown can also be a manifestation of subacute bacterial endocarditis.
• Other infection Almost any severe infection/septicaemic illness can cause a vasculitic rash.

Non-infective causes

• Rheumatoid arthritis is a common cause of systemic vasculitis. If affecting small vessels it can cause a widespread cutaneous vasculitis with necrosis of the skin or nail fold infarcts. Involvement of medium sized vessels can result in mononeuritis multiplex (vasculitis of the vasa nervorum), bowel infarction due to necrotising vasculitis of the mesenteric vessels, endocarditis, myocardial, or pericardial involvement.
• Systemic lupus erythematosus is characterised by widespread vasculitis of the capillaries, arterioles, and venules. Arthralgia and rashes are the most common features, but cerebral and renal disease are the most serious problems. B-cell activation results in increased autoantibody production to a variety of antigens. Circulating immune complexes are deposited in the tissues causing vasculitis. Serum antinuclear antibodies are positive in almost all cases but double stranded DNA binding is specific, although only present in half the cases. Treatment is with non-steroidal anti-inflammatory drugs, antimalarial drugs (chloroquine), corticosteroids, and immunosuppression in more severe disease.
• Drugs such as many antibiotics, hydralazine, methyldopa, isoniazid, and penicillamine are common causes of vasculitis.
• Polymyalgia rheumatica (PMR) and Giant cell (temporal) arteritis (GCA) are both inflammatory systemic illnesses of the elderly affecting large vessels. PMR causes shoulder and neck stiffness and pain typically worse in the morning. GCA is characterised by unilateral headaches, scalp tenderness, jaw claudication, and the danger of permanent visual loss due to involvement of the retinal artery. Investigations show a raised erythrocyte sedimentation rate (50-100 mm/hr) and C-reactive protein, abnormal liver biochemistry, and a mild normochromic normocytic anaemia. Diagnosis can be confirmed by temporal artery biopsy, which shows giant cells in the internal elastic lamina, but the biopsy may be normal. Treatment is with high dose corticosteroids.
• Behcet's disease is a systemic vasculitis of unknown cause with a typical geographical distribution in Turkey, Iran, and Japan. Oral and genital ulcers as well as uveitis and cutaneous lesions are characteristic. Other manifestations include a self limiting arthritis, gastrointestinal symptoms, pulmonary, and renal and cerebral lesions. Treatment is with immunosuppression.
• Other causes mainly affecting small vessels can be divided into those positive or negative for antineutrophilic cytoplasmic antibodies (ANCA). There is correlation between ANCA titres and disease activity.

ANCA-positive vasculitis:

Wegener's granulomatosis involves mainly the upper respiratory tract, lungs, and kidneys. It responds well to treatment with cyclophosphamide and corticosteroids.

Churg-Strauss syndrome is characterised by eosinophilic infiltration of the lungs, peripheral nerves, and skin. It responds well to corticosteroids.

Microscopic vasculitis (polyangiitis) results in haemoptysis and involves usually the lungs and kidneys.

Non-ANCA-positive small vessel vasculitis:

Henoch-Schoenlein-purpura is a common systemic vasculitis in children. It occurs after upper respiratory tract infection. There is IgA immune complex deposition in the small vessels and it usually manifests as purpura, a transient polyarthritis, abdominal pain, and glomerulonephritis. It is usually self limiting but can recur.