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70Stroke Diagnostics

ANSWERS

  1.  D The American Heart Association guidelines state that “only blood glucose must precede the initiation of IV tPA” (Class I, Level of Evidence B recommendation). They also state that except for patients without suspicion of bleeding abnormality or thrombocytopenia, not on heparin or Coumadin, and not on other anticoagulants, IV tPA administration should not be delayed waiting for any other lab tests. Patients whose creatinine comes back elevated will have a decision made on an individual-case basis as to whether to stop the tPA, or continue (Jauch et al., 2013).

  2.  C An INR of greater than 1.7 is a contraindication for administration of IV tPA.

  3.  D CT scans are more readily available in the majority of hospitals, are significantly quicker, and are reliable in ruling out hemorrhage.

  4.  B CTA is the most frequent emergent imaging test to visualize blood vessels. The prefix angio refers to blood vessels, so anytime you see angio in the name of a radiologic test it indicates that there will be evaluation of blood vessels. A plain CT looks at brain tissue, and a CTA looks at the cerebral vessels. An MRI looks at brain tissue, and a magnetic resonance 71 angiography (MRA) looks at cerebral vessels. A PET scan is used to detect cancer, and a TCD is used to detect vasospasm and measure the velocity of the blood flow in the major cerebral arteries.

  5.  A Perfusion–diffusion mismatch has been used in acute stroke to determine presence or absence of salvageable tissue. The difference between the diffusion (water content) of the tissue and perfusion (blood supply) abnormalities provides a measure of the ischemic penumbra, or salvageable tissue. If the perfusion abnormality is larger than the area of restricted diffusion, the difference identifies the region of reversible ischemia.

  6.  A The cause of up to 30% of ischemic strokes is cardiac problems, so an echocardiogram is an essential component of acute stroke workup.

  7.  B For patients with a high suspicion of a cardiac source, or if an abnormality was seen on the TTE that the provider wants to examine more closely, a TEE is used because it is not impeded by the structures of chest muscles or rib cage. It is superior at identifying atrial and aortic abnormalities, such as patent foramen ovale (PFO) or aortic arch atherosclerosis.

  8.  D A video fluoroscopic swallowing exam involves having the patient swallow contrast material while a visualization is done with fluoroscopic equipment. This provides information about swallowing ability as well as evidence of aspiration.

  9.  D For patients with a cryptogenic stroke (unknown cause), evidence has shown that implantable monitors detected atrial fibrillation during the months after discharge in up to 12% of patients who did not have atrial fibrillation detected on standard Holter monitor.

10.  A Encephalomacia is described as “softening of the brain tissue” and has numerous causes, one of which is stroke. It has a characteristic appearance on CT, and is also referred to as scar tissue after stroke.

11.  D Subarachnoid hemorrhage patients often have a classic presentation of thunderclap headache, often called “the worst headache of their life.” This is thought to be due to the irritation by the blood, increased pressure, and vasospasm.

12.  A If CT is negative in a patient with a high suspicion for SAH, lumbar puncture will provide evidence whether or not there is xanthochromia in the cerebrospinal fluid (CSF).

13.  72D TCD studies done during infusion of IV tPA to monitor for vessel patency were found to augment the effect of the tPA, supposedly via the effect of ultrasound waves on the clot—it can hasten the dissolution of the clot.

14.  A Common complications associated with diagnostic cerebral angiography are insertion site hematoma, stroke, and adverse reaction to dye. As this test is done via an artery, DVT would not be a complication.

15.  B The Brain Attack Coalition’s recommendations for timeframes for CT are initiation in 25 minutes and interpretation in 45 minutes.

16.  B CT angiography provides carotid vessel imaging superior to standard carotid ultrasound, making it generally unnecessary to do a carotid ultrasound during the acute workup (Jauch et al., 2013, p. 885).

17.  D Improved CT and MRI imaging has made it possible to see even miniscule infarcts. Today, events lasting less than 24 hours, with normal imaging, formerly labeled TIA, are often found to be tiny strokes (Kernan et al., 2014, p. 2166).

18.  C Young people with large vessel ischemic strokes whose workups are negative for cardiac abnormality often get a set of lab tests that evaluate for a hypercoagulable state, or an abnormal tendency to form clots (Kernan et al., 2014, p. 2204).

19.  A On CT, blood and bone appear white because they absorb x-rays better than the water content of CSF, which appears black; brain tissue is intermediate in its absorption, so it appears gray (Alexander, Gallek, Presciutti, & Zrelak, 2012, p. 11).

20.  C Noncontrast CT is the cornerstone of the diagnostic workup for SAH (Connolly et al., 2012, p. 1718).

21.  A More than 20% of ICH patients will experience a decrease in GCS of 2 or more points (Hemphill et al., 2015, p. 2034).

22.  B The identification of patients at risk of ICH expansion is based on the presence of contrast within the hematoma on CTA (Hemphill et al., 2015, p. 2036).

23.  73D Predictors of cerebral edema are early frank hypodensity on CT, involvement of one third or more of the MCA territory, and early midline shift (Wijdicks et al., 2014, p. 1228).

24.  B As TCD is done through the temporal bony window, the MCA and anterior cerebral artery (ACA) can be monitored, but not the posterior circulation (Jauch et al., 2013, p. 885).

25.  C Chest x-ray may be useful if specific additional conditions such as cardiac or pulmonary disease exist, but it should not be prioritized or delay administration of IV tissue plasminogen activator (tPA; Jauch et al., 2013, p. 881).

26.  D There are no specific lab tests to measure the effect of dabigatran (Jauch et al., 2013, p. 881).

27.  B Malignant MCA infarction is a devastating condition, with up to 80% mortality. The pathophysiology is a large core of severe ischemia involving over 50% of MCA territory and only a relatively small rim of penumbra. Cytotoxic edema occurs immediately in a large portion of the ischemic territory. The subsequent damage leads to the breakdown of the blood–brain barrier and vasogenic brain edema, resulting in space-occupying brain swelling. The progressive vasogenic edema reaches its maximum after 1 to several days and exerts a mechanical force on surrounding tissue structures leading to a midline shift and transtentorial herniation and finally brainstem compression and death.

28.  D Neither CT nor MRI were developed by 1957; CT was developed in 1971 in MRI in 1977, and while echocardiography was developed in 1953, it is not used in stroke diagnosis (Morrison, 2014).

29.  C An uncommon, but serious complication of angiography is possible arterial tear, with bleeding into the retroperitoneal area. This would produce the symptoms of back pain and abdominal pain.

30.  A Shellfish contain iodine, which is also present in most contrast dyes, making this allergy quite dangerous for contrast radiologic studies.

 

74References

Alexander, S., Gallek, M., Presciutti, M., & Zrelak, P. (2012). Care of the patient with aneurysmal subarachnoid hemorrhage. AANN clinical practice guideline series. Retrieved from http://www.aann.org/pubs/content/guidelines.html

Connolly, E., Rabinstein, A., Carhuapoma, R., Derdeyn, C., Dion, J., Higashida, R. T., . . . Vespa, P. (2012). Guidelines for the management of aneurysmal subarachnoid hemorrhage: A guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke, 43, 1711–1737.

Hemphill, J., Greenberg, S. M., Anderson, C. S., Becker, K., Bendok, B. R., Cushman M., . . . Woo, D. (2015). Guidelines for the management of spontaneous intracerebral hemorrhage: A guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke, 46, 2032–2060.

Jauch, E., Saver, J., Adams, H., Bruno, A., Connors, J., Demaerschalk, B. M., . . . Yonas, H. (2013). Guidelines for the early management of patients with acute ischemic stroke: A guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke, 44, 870–947.

Kernan, W. N., Ovbiagele, B., Black, H. R., Bravata, D. M., Chimowitz, M. I., Ezekowitz, M. D., . . . Wilson, J. A. (2014). Guidelines for the prevention of stroke in patients with stroke and transient ischemic attack: A guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke, 45, 2160–2236.

Morrison, K. J. (2014). Fast facts for stroke care nursing: An expert guide in a nutshell. New York, NY: Springer Publishing.

Wijdicks, E. F. M., Sheth, K. N., Carter, B. S., Greer, D. M., Kasner, S. E., Kimberly, W. T., . . . Wintermark, M. (2014). Recommendations for the management of cerebral and cerebellar infarction and swelling: A statement for healthcare professionals from the American Heart Association/American Stroke Association. Stroke, 45, 1222–1238.