Article Text

Back pain and fever
  1. Karim Raza,
  2. Paru King,
  3. Simon P Allison
  1. Department of Endocrinology, Queen's Medical Centre, Nottingham NG7 2UH, UK
  1. Karim Raza, Specialist Registrar, Department of Rheumatology, The Guest Hospital, Dudley DY1 4SE, UK

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A 39-year-old man was woken by mid-thoracic back pain and sweating. The back pain resolved spontaneously over an hour, and he was left with epigastric discomfort. There were no other symptoms, no history of trauma, no past medical or family history of note, and he had not been abroad. He was a smoker and took no medications. On examination, he was of normal appearance, apyrexial and comfortable. Pulse was 90 beats/min, blood pressure 135/80 mmHg, and all pulses symmetrical. Heart sounds were normal with no added sounds, and respiratory examination was unremarkable. There was epigastric tenderness but no peritonism. The spine was not tender and had a full range of movement. Investigations showed a raised white cell count (14 × 109/l), and neutrophil count (12 × 109/l), but haemoglobin, platelet count, electrolytes, creatine kinase, amylase, electrocardiogram, chest and thoracic spine radiographs, abdominal ultrasound and upper gastrointestinal endoscopy were all normal. Over the next 48 hours his epigastric pain settled, but he developed a persistent pyrexia (figure 1). There were no other abnormal physical findings besides a blood pressure of 170/100 mmHg. His white cell count remained raised, as did the erythrocyte sedimentation rate (81 mm/h), and C-reactive protein (107 mg/l, normal ⩽10). Blood and urine cultures, rheumatoid factor and antinuclear antibody were negative. An isotope bone scan, carried out because the original pain was mid-thoracic, was normal. A computed tomogram (CT) of the thorax (figure 2) and abdomen was performed.

Questions

1
What is the diagnosis?
2
What are the important risk factors for this condition?
3
How would you treat this patient?

Answers

QUESTION 1

Type A aortic dissection (Stanford classification1). The CT scan of the thorax shows a dissection involving the ascending and descending aorta (figure 2). A CT scan of the abdomen showed the dissection extending to the level of, but not involving, the renal arteries. A transoesophageal echocardiogram confirmed a dissection above the aortic valve with no associated regurgitation.

QUESTION 2

Important risk factors for aortic dissection are hypertension, cystic medial necrosis, ulcerating atherosclerotic lesions, pregnancy, a bicuspid aortic valve, aortic coarctation, blunt trauma, manipulation of and surgery to the aorta, and abnormalities of connective tissue components including fibrillin in Marfan's syndrome.2

QUESTION 3

Adequate analgesia and a reduction in systolic blood pressure to 100–110 mmHg, or the lowest level consistent with adequate urine output, are important. Blood pressure can be controlled with intravenous labetolol.3 The decision regarding repair depends on the chronicity, and site, of the dissection and the presence of complications.3 All acute (less than 2 weeks between the onset of symptoms and the time of diagnosis) type A dissections should be considered for surgery.2 Extensive injury to the central nervous system is usually the only contra-indication to surgery in this situation.2 Our patient was managed surgically and is well at follow-up, with a blood pressure controlled on atenolol 50 mg daily. Subsequent investigations including histological examination of the aorta and a search for secondary causes of hypertension were unremarkable.

Discussion

Arterial dissection occurs when blood separates the layers of the media, usually through an intimal tear. The incidence of thoracic aortic dissection has been estimated at 3.2 per 100 000 autopsies in a Swedish study.4

Clinical manifestations of aortic dissection are diverse.5Typically, patients present with a sudden onset of tearing chest pain that radiates to the back, neck and arms. As the dissection tracks along the aortic wall it may cause aortic regurgitation, myocardial infarction, limb ischaemia with unequal pulses, stroke, mesenteric and renal ischaemia, or it may rupture into the pericardial or pleural cavities.2 Dissections can be divided into type A (those involving the ascending aorta) and type B (all others, including those involving the aortic arch) according to the Stanford classification.1

This case was unusual in that many typical features of dissection were absent (age over 40 years, history of predisposing factors, chest pain, unequal pulses or shock) and the principal clinical finding was a prolonged fever. Only 15% of aortic dissections occur below the age of 40.5 The absence of chest pain, however, should not deter one from considering the diagnosis. In a review of 505 cases, the abdomen was the initial site of pain in 30%.5 In half of these cases, the pain was epigastric, as in our patient. Pain was actually absent, or negligible, in 15% of cases. Fever in aortic dissection is not uncommon. A temperature above 37.7oC has been reported in 31% of patients, and above 39oC in 8%.5 However, fever as the predominant clinical finding is rare, and has been reported in only a handful of cases.6-11

Learning point

Aortic dissection should be considered in patients presenting with pyrexia if preceded by chest, back, or abdominal pain

This case highlights that aortic dissection should be included on the list of rare causes of fever. The diagnosis should be considered in patients with prolonged fever following episodes of chest, back, or abdominal pain. Failure to do so may lead to an unnecessary and potentially dangerous pursuit of illnesses more commonly associated with a febrile response.

Final diagnosis

Type A aortic dissection.

References

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