back with a vengeance…

the case.

a 59 year old male presents to ED at 2am with a two week history of progressive back pain. He is worried because it is worsening in severity and now radiates to the left flank & left-lower quadrant.

HPIx.

• Two weeks of constant, progressive midline back pain (~L2 level).
• Much more severe over the past two days; required 20mg IV morphine pre-hospital to get comfortable !!
• Pain now radiating from left-flank to his left-lower quadrant.
• Reports feeling “hot & sweaty at night”, but no one has taken his temperature.
• Relevant negatives.
  • No weight loss.
  • No constipation, dysuria or urinary frequency.
  • No leg weakness, numbness or difficulty mobilising.
  • No saddle anaesthesia.

PMHx.

• Ischaemic heart disease.
  • On-pump CABG (4-vessel grafts) two years earlier.
• Hypertension
• Hypercholesterolaemia

His medications include aspirin, atorvastatin & metoprolol.

Examination.

• P 110, BP 156/90, SaO2 97% (RA), RR 18, Temp 38.2*C 
• No cardiac murmurs
• Clear chest.
• Mild left lower quadrant tenderness, without peritonism.
• Midline back pain L2-3.
• Normal lower limb neuro-exam.

[DDET Where to now ?] Well, our basic first-line investigations were unhelpful.

• White cells: 16 !! [Hb 144, PLT 270]
• EUC/LFTs/Lipase: normal.
• CRP: 86…
• Chest x-ray: no collapse or consolidation. no effusions.
• Urinalysis: No leukoesterases. No nitrites. Trace blood.
• Abdominal x-ray: No air-fluid levels or abnormal gas patterns.

During his 6 hour ED stay, the patient remains relatively pain-free & requests to go home ‘when the sun comes up’…

However despite 2 litres of IV fluids, he remains tachycardic at 110. Unnerved by this & his yet unexplained fever; I convince him to stay & arrange a bed under the general physicians.

Just prior to finishing my night shift, I arrange a CT-KUB; ?pyelonephritis ?discitis……

[/DDET]

[DDET Here’s the CT…]

httpv://www.youtube.com/watch?v=g24ySXWDHVY

A CT-Aortogram was arranged immediately… httpv://www.youtube.com/watch?v=qM2y-zOpMNU

[/DDET]

[DDET The diagnosis]

Aortitis.

“An all-encompasing term ascribed to inflammation of the aorta”.

Causes of Aortitis:
Most commonly large-vessel vasculitides (GCA) & Takayasu arteritis.

• Inflammatory.
  • Large-vessel vasculitis [eg. GCA, Takayasu arteritis, RA, SLE & ankylosing spondylitis]
  • Other vasculitides
    • ANCA + [Wegener’s, Polyarteritis nodosum]
    • Behcet disease
  • Sarcoidosis
  • Isolated aortitis
• Infectious.
  • Bacterial
    • Salmonella spp.
    • Staphylococcus spp.
    • Streptococcus pneumoniae
    • others…
  • Luetic [Syphilis]
  • Mycobacterial [ie. TB]
  • Others…

A pre-existing aneurysm can become secondarily infected, but aneurysmal degeneration of the arterial wall can also be the result of infection, due to bacteraemia or septic embolisation (ie. mycotic aneurysm).

Risk Factors for Infected Aneurysm:

• Arterial injury.
  • IV drug use (self-inflicted)
  • Iatrogenic (invasive monitoring & angiography)
  • Traumatic (GSW or stabbing)
  • GIT perforation
• Antecedent infection.
  • including pneumonia, cholecystitis, UTIs, endocarditis, diverticulitis, soft-tissue infections or osteomyelitis.
  • Contiguous infection vs embolic seeding (bacteraemia).
• Impaired immunity.
  • Diabetes
  • Alcoholism
  • Chronic steroid therapy
  • HIV/AIDS
  • Chemotherapy or malignancy
  • Cirrhosis
  • Haemodialysis
• Atherosclerosis.
  • Presence of atherosclerosis alone (especially in the elderly) is a risk for bacterial seeding.

Clinical Presentation.
Large spectrum of symptoms & clinical signs.

• Back or abdominal pain [with fever !]
• Systemic inflammatory syndrome [caused by vasculitis]
• Aneurysmal disease [thoracic or abdominal]
• Cardiac abnormalities.
  • Aortic insufficiency
  • Stable angina or acute coronary syndromes
• Aortic thrombosis with distal embolisation
• Aortic dissection [or rupture]
• Upper &/or lower-extremity claudication with pulse deficits.
  • Mesenteric ischaemia can also occur
• Hypertension in a young patient [ie. Takayasu arteritis]
• Massive GIT haemorrhage [aorto-enteric fistula]
  • Massive haemoptysis [in the case of thoracic mycotic aneurysms]

Diagnosis.

• Clinical suspicion.
  • Presenting complaint, symptoms & risk factors.
• Bloods.
  • Elevated WCC [64-71% of patients]
  • Elevated inflammatory markers [ESR + CRP]
  • Cultures – not enough to exclude diagnosis. [Negative in 25-50% of cases]
• CT.
  • Definitive diagnosis of aneurysm & suggests infection.
  • CT findings include;
    • Saccular, eccentric aneurysm or multi-lobulated aneurysm
    • Soft tissue inflammation or mass around vessel
    • Aneurysm with intramural gas or gas-collection around vessel
    • Perivascular fluid collection
• Other imaging.
  • Ultrasound – helpful in diagnosing aneurysm only.
  • MRI / MRA.
  • Digital-subtraction angiography

Management.

• Infectious Aortitis.
  • Rapid diagnosis
  • Empiric broad-spectrum antibiotics [including Staph and gram-negatives]
    • This will later by tailored to culture & sensitivity results.
    • May require tissue sampling.
    • Treatment course of 6-12 weeks is expected
  • Urgent consultation with Vascular Surgery.
    • Despite aggressive medical therapy, mortality associated with infectious aortitis remains high, largely owing to high rates of aortic rupture !!
    • Surgical debridement +/- aortic aneurysmal repair.
• Vasculitis.
  • Immunosuppressive therapy is the primary treatment – consult your Rheumatologists.
  • Prednisolone is mainstay of therapy.
  • Still needs consultation with Vascular Surgery for consideration of surgical vs endovascular aneurysm repair.

[/DDET]

[DDET The case continues….]

Our patient is whisked away to the operating theatres by the vascular surgeons…

Post-operatively, our patient is taken to ICU for aggressive blood-pressure management. His transoesophageal ECHO showed no evidence of endocarditis.

On day 3, he undergoes tissue biopsy/sampling with the help of interventional radiology.

Peri-aortic biopsies = Salmonella !!

He is discharged from hospital on day 8, with a PICC line & a long-haul of ceftriaxone therapy ahead of him !!

[/DDET]

[DDET References.]

1. Gornik HL & Creager MA. Aortitis. Circulation. 2008;117:3039-3051.
2. UpToDate.com – Overview of infected (mycotic) arterial aneurysm.
3. Laohapensang K et al. Management of the infected aortoiliac aneurysms. Ann Vasc Dis. 2012;5(3):334-41.
4. Wang JH et al. Mycotic aneurysm due to non-typhi Salmonella: Report of 16 cases. Clin Infect Dis. 1996 Oct;23(4):743-7.

[/DDET]