Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (108 page)

Findings on laboratory tests are due to changes in other organ systems and to underlying conditions such as cardiac, renal, and endocrine disorders and toxemia of pregnancy. Testing may also reveal changes that may occur due to progressive disorders following hypertensive encephalopathy such as focal intracerebral hemorrhage. The CSF frequently shows increased pressure and protein ≤100 mg/dL.

References

1.  Kitaguchi H, Tomimoto H, Miki Y, et al. A brain stem variant of reversible posterior leukoencephalopathy syndrome.
Neuroradiology.
2005;47:652.

2.  Hinchey J, Chaves C, Appignani B, et al. A reversible posterior leukoencephalopathy syndrome.
N Engl J Med.
1996;334:494.

THROMBOPHLEBITIS OF CAVERNOUS SINUS

   Definition

Thrombophlebitis or inflammation of the vein results from infected or septic thrombosis of the venous sinus

   Clinical Presentation

Septic dural sinus thrombosis has become a rare disease since the advent of antibiotics. Patients present with headache, occasionally eye swelling or diplopia, and alterations in mental status. The diagnosis is primarily made by imaging studies; however, lumbar puncture can be supportive, differentiating periorbital cellulitis from septic cavernous sinus thrombosis.

   Laboratory Findings

Laboratory findings that may be helpful include the CBC where an elevated peripheral WBC count may suggest an acute bacterial infection or other causes of venous thromboses such as sickle cell disease, polycythemia, or dehydration. The CSF reveals inflammatory cells in 75% of cases with increased neutrophils or mononuclear cells, elevated protein, normal glucose, and a negative culture. Thirty percent of patients have a CSF finding consistent with bacterial meningitis with a positive culture.
¹

Culture of the CSF may reveal organisms associated with septic cavernous sinus thrombosis.
Staphylococcus aureus
is seen in 70% of all infections and is associated with facial infection or sphenoid sinusitis, and MRSA is becoming more frequent.
²
Streptococci (including
Streptococcus pneumoniae, Streptococcus milleri
, and viridans group streptococci) are less commonly found. Anaerobes are most often found with accompanying sinus, dental, or tonsillar infections.
^3,4
Fungal pathogens have been less commonly reported and include
Mucor
,
Rhizopus
, and
Aspergillus
.
^5,6

References

1.  Southwick FS, Richardson EP Jr, Swartz MN. Septic thrombosis of the dural venous sinuses.
Medicine (Baltimore).
1986;65:82.

2.  Naesens R, Ronsyn M, Druwé P, et al. Central nervous system invasion by community-acquired methicillin-resistant
Staphylococcus aureus
.
J Med Microbiol.
2009;58:1247.

3.  Cannon ML, Antonio BL, McCloskey JJ, et al. Cavernous sinus thrombosis complicating sinusitis.
Pediatr Crit Care Med.
2004;5:86.

4.  Watkins LM, Pasternack MS, Banks M, et al. Bilateral cavernous sinus thromboses and intraorbital abscesses secondary to
Streptococcus milleri
.
Ophthalmology.
2003;110:569.

5.  Chitsaz S, Bagheri J, Mandegar MH, et al. Extensive sino-orbital zygomycosis after heart transplantation: a case report.
Transplant Proc.
2009;41:2927.

6.  Devèze A, Facon F, Latil G, et al. Cavernous sinus thrombosis secondary to non-invasive sphenoid aspergillosis.
Rhinology.
2005;43:152.

SPINAL CORD INFARCTION

   Definition

Spinal cord infarction may result from occlusion of the anterior spinal artery, the posterior spinal artery, or the Brown-Séquard syndrome in which no defined vascular pattern can be determined.

   Clinical Presentation

Symptoms of paresis either unilateral or bilateral occur with infarction of the anterior spinal artery and loss of touch, proprioception, and vibratory sense with infarction of the posterior spinal artery. Venous infarction may also occur and is usually associated with vascular malformations.
¹
The differential diagnosis includes transverse myelitis, compression, and acute polyneuropathy. Diagnosis is made primarily by neuroimaging (MRI) and vascular imaging (CTA or MRA).

   Laboratory Evaluation

A lumbar puncture should be performed in younger patients to rule out infectious or inflammatory etiologies. In spinal infarct, the CSF may be normal or may show mild pleocytosis with WBC <100 and elevation in protein (<119 mg/dL).
^2,3
CSF testing should include cell count, glucose, protein, gram stain, and culture. Infectious agents such as Lyme, herpes, varicella, coxsackie, EBV, and CMV should be ruled out with serology. In addition, OCB should be performed on CSF and serum to rule out MS. Blood and urine toxicology should be performed to rule out cocaine. Additional blood tests to rule out hypercoagulable state and collagen vascular disease may be of benefit.

References

1.  Mohr JP, Benavente O, Barnett HJ. Spinal cord ischemia. In: Barnett HJ, Mohr JP, Stein BM, et al., eds.
Stroke Pathophysiology, Diagnosis, and Management
. Philadelphia, PA: Churchill Livingstone; 1998:423.

2.  Cheshire WP, Santos CC, Massey EW, et al. Spinal cord infarction: etiology and outcome.
Neurology.
1996;47:321.

3.  Sandson TA, Friedman JH. Spinal cord infarction. Report of 8 cases and review of the literature.
Medicine (Baltimore).
1989;68:282.

CNS VASCULITIS

   Definition

Vasculitis is an inflammation of the vessels that may occur within the central nervous system, and most commonly it is due to collagen vascular disease but may also be due to infection, atherosclerosis, embolic disease, malignancy, and drugs.
¹
Primary angiitis of the central nervous system is a rare disorder of unknown etiology presenting predominantly in men and may occur at any age (see eBook Figure 4-34).
²
Giant cell arteritis is one of the more common forms of vasculitis.