Page 866 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 67: Endocarditis and Other Intravascular Infections 597

MYCOTIC ANEURYSMS • Pupillary dilatation
• An abnormal CSF
Mycotic aneurysms (MA) are the result of bacteremic seeding of
medium or large arteries with resultant irreversible localized dilata- S aureus is the cause of cavernous sinus thrombosis in about 60%
tion due to destruction of the arterial wall. These may occur anywhere to 70% of patients. Streptococci, anaerobes, and gram-negative bacilli
but are most commonly femoral (38%) or abdominal aortic (31%). account for most of the rest. Community-acquired MRSA has been
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Cerebral MA tend to occur toward the surface of the brain in distal reported to cause CST arising from a nasal infection in one patient and
branches of the middle cerebral artery as opposed to berry aneurysms, from primary bacteremia in another. 43,44 A case of CST and IE due to
which occur in the circle of Willis. pneumococcal sinusitis has also been reported. 45
IE accounts for 25% to 85% of cases of MA and direct arterial trauma Routine laboratory tests are neither sensitive nor specific. Blood cul-
accounts for 29% to 42%. Factors that have been associated with an tures are positive in 70% of patients, especially in those with a fulminant
increased risk of MA include diabetes, alcoholism, impaired immunity, presentation. Cerebrospinal fluid (CSF) usually shows a pleocytosis of
and advanced age. 33 mixed neutrophils and lymphocytes along with an elevated protein but
S aureus and Salmonella species are the most common pathogens to normal glucose. CSF cultures are only positive in 20% of cases. CT or
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cause MA with an increasing proportion being due to MRSA. The list MRI imaging may show changes in signal intensity as well as supportive
of microorganisms reported to cause MA is quite extensive and also signs such as dilation of feeding veins. 46
includes Empiric antimicrobial therapy is usually directed against the patho-
gens generally encountered in complicated facial cellulitis or sinusitis
• Treponema pallidum with adjustments made as definitive culture results are known.
• S Pneumoniae Vancomycin or another agent with activity directed against MRSA
• Gram-negative bacilli, including Pseudomonas, Klebsiella, Campylobacter, should be included in most cases with dosing adjusted to achieve
and Yersinia adequate levels to treat meningitis. Intravenous antibiotics should be
• Fungi, including Candida, Cryptococcus, and Aspergillus continued until all signs of active infection have resolved, which is
typically 3 to 4 weeks. Corticosteroids are usually begun when evidence
• Coxiella of cranial neuropathies develop and are continued until resolution.
• Corynebacteria Anticoagulation begun early, once intracranial hemorrhage has been
excluded, has been associated with decrease in morbidity; this is usually
The clinical findings include systemic signs such as fever and chills continued for 4 to 6 weeks. 47
along with localizing signs and symptoms due to the direct mass effect of
the MA. Patients may present with complications of MA as well, such as
gastrointestinal bleeding due to an aortoduodenal aneurysm, limb isch- INFECTION OF VENOUS STRUCTURES
emia, osteomyelitis and diskitis, or a psoas abscess. Garg et al reported Infection of venous structures is rare and results from direct extension
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a patient presenting with acute coronary syndrome caused by a coronary of infection or distal spread via venous structures. The most commonly
artery MA due to a late stent infection. 35 reported infections are those involving the internal jugular vein, portal
Routine laboratory tests are neither sensitive nor specific with half of veins, and ovarian veins (Table 67-4). Infection involving the internal
patients having a leukocytosis and anemia. Blood cultures are positive jugular vein usually follows acute oropharyngeal infection and is thus
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in 50% to 85% of cases so cannot be used to exclude the diagnosis. called postanginal sepsis; this was first characterized by Lemierre in
Angiography has been considered the definitive radiologic procedure; 1936 and is mostly seen in healthy young adults. Infection of the portal
however, computed tomography (CT) or magnetic resonance imaging veins (pylephlebitis) is an unusual complication of intra-abdominal
(MRI) is now used more often. 37 infection, such as diverticulitis, appendicitis, necrotizing pancreatitis,
Intravenous antibiotic therapy is typically continued for 6 to 8 weeks choledocholithiasis, pelvic infections, and inflammatory bowel disease.
and is culture directed. Regimens used to treat MA are generally the Septic pelvic vein thrombophlebitis occurs following an obstetric or
same as regimens used to treat IE. gynecologic procedure and most often involves the right pelvic vein.
Surgical resection of the MA is usually combined with medical
therapy except in the case of an unruptured cerebral MA. Unruptured ■ CLINICAL PRESENTATION
cerebral MA associated with IE may resolve with treatment of the IE.
Endovascular embolization is another treatment option in this setting. The signs and symptoms in addition to fever and chills are those
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The timing of surgery is also an important consideration in patients who associated with the initial infection as well as potential local and distal
require both urgent valve replacement and cerebral surgery. 39 complications. Patients with Lemierre syndrome will present with sore

CAVERNOUS SINUS THROMBOSIS TABLE 67-4 Infection Involving Venous Structures
Cavernous sinus thrombosis (CST) is a rare complication of sinusitis, Site Etiology Antibiotic Therapy Adjunctive Treatment
usually involving the ethmoid or sphenoid sinuses. CST has also been
reported following infection involving the face, nose, oropharynx, ears, Internal jugular Fusobacterium Clindamycin Pleuropulmonary evaluation
or orbits. Odontogenic infection, though common, rarely leads to CST. directed
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Infection is thought to result from either direct or bacteremic spread and is S aureus Ampicillin/sulbactam
facilitated by the fact that dural sinuses and emissary veins have no valves Portal Enterics Extended-spectrum Consider anticoagulation
so blood may flow in either direction according to pressure gradients. penicillin
Patients usually present with fever and headache and classically
exhibit proptosis, ptosis, and features of cranial nerve palsies related Carbapenem
to cranial nerves III, IV, and VI. CST primarily has to be differentiated Ovarian Enterics Extended-spectrum Anticoagulation
from orbital cellulitis. CST should be suspected when there is penicillin
• Bilateral eye involvement Streptococci Carbapenem
• Papilledema S aureus

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