Thursday, August 12, 2010

Basic Medical Pathology: Neoplasis I

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Hemostasis Lecture

A concise lecture on basics of hemostasis; the triggers of the development of the hemostatic plugs (primary) and (secondary). The differences between Hemostasis and Thrombosis.
Clinical presentation and importance are also discussed.

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Aortic Dissection

* 3:1 male to female predominance
* Over the age of 40
* Hemorrhage in the media (at vasa vasorum) leading to either
  1. Hemorrhage in the wall (less common)
  2. Hemorrhage separate media from adventitia

· Predisposing factors
o Hypertension (most commonly)
o Atherosclerosis
o Cystic medial necrosis
o Coarctation of the aorta
o Aortic stenosis
o S/P prosthetic aortic valve
o Trauma (rare)
o Pregnancy (rare)

· Aneurysm defined by size criteria
o In general, ascending aorta > 5 cm
o Descending aorta > 4 cm

· Vessels involved with dissection
o Any artery can be occluded
o Usually the right coronary and three arch vessels are involved with arch
o Right pulmonary artery and left-sided pulmonary veins may be occluded

· Types
o DeBakey Type I...............................................Involves entire aorta
o DeBakey Type II "Least common"...............Ascending aorta only
o DeBakey Type III "Most common"...............Descending aorta only
o Stanford Type A................................................Ascending aorta involved
----- Over half develop aortic regurgitation
o Stanford Type B.................................................Ascending aorta NOT involved
· Most dissections arise either just distal to the aortic valve or just distal to aortic isthmus

o Sharp, tearing, intractable chest pain

o Murmur or bruit of aortic regurgitation

o Previously hypertensive, now possible shock

o Asymmetric peripheral pulses

o Pulmonary edema

· Imaging Findings
o Chest films
  • - Mediastinal widening
  • - Left paraspinal stripe
  • - Displacement of intimal calcifications
  • - Apical pleural cap
  • - Left pleural effusion
  • - Displacement of endotracheal tube or nasogastric tube

  • - Intimal flap
  • - Slow flow or clot in false lumen

o CT
  • - Intimal flap
  • - Displacement of intimal calcification
  • - Differential contrast enhancement of true versus false lumen

CT of abdominal aorta shows intimal flap (dark line -red arrow)
with true lumen anteriorly and false lumen posteriorly

o Angiography
  • - Intimal flap
  • - Double lumen
  • - Compression of true lumen by false channel
  • - Increase in aortic wall thickness > 10 mm
  • - Obstruction of branch vessels

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Phototherapy in Hyperbilirubinemic baby

You are called to see an infant in the newborn nursery. The child was delivered 60 hours prior to your visit. The child appears jaundiced but otherwise healthy. A total serum bilirubin level is measured at 18 mg/dL. Appropriate treatment includes

  • A) observation
  • B) stop breast feeding and switch to formula feedings
  • C) begin phototherapy
  • D) perform a septic workup
  • E) start IV hydration

Answer and Discussion
Hyperbilirubinemia is very common in term newborns. Current recommendations include the following: phototherapy should be instituted when the total serum bilirubin level is >=15 mg/dL (257 آµmol/L) in infants 25 to 48 hours old, 18 mg/dL (308 آµmol / L) in infants 49 to 72 hours old, and 20 mg/dL (342 آµmol/L) in infants older than 72 hours.

It is unlikely that term newborns with hyperbilirubinemia have serious underlying pathology. Physiologic jaundice peaks on the third or fourth day and declines over the first week following birth. Infants who are breast fed are more likely to develop physiologic jaundice because of relative caloric deprivation in the first few days of life. If jaundice occurs in breast-fed infants, feedings should be increased to more than ten times/day.In some cases formula supplementation may be necessary.

Pathologic jaundice occurs if it presents within the first 24 hours after birth, the total serum bilirubin level rises by >5 mg/dL (86 آµmol/L) per day or is >17 mg/dL (290 آµmol/L), or an infant has signs and symptoms suggestive of serious illness. The management consists of excluding pathologic causes of hyperbilirubinemia and initiating treatment to prevent harmful neurotoxicity.The answer is C.

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