HY USMLE Q #456 – Biochem / Immuno — Transcript

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1. 0:00how's it going guys we have a medium
2. 0:01difficulty question for biochem slash
3. 0:03let me know for step one it's a past
4. 0:04level vignette plus slightly challenging
5. 0:07answer choices as far as how the
6. 0:08integration of the content is concerned
7. 0:10so before we get started please
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9. 0:13it give the video like really appreciate
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11. 0:16underscore medical me hlman underscore
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14. 0:22channel are down below now let's start
15. 0:24the clip six-year-old boy two-day
16. 0:26history of fever and productive cough
17. 0:27he's had recurrent chest infections
18. 0:29since the age of two years temperature
19. 0:31is 102 fahrenheit he's at the third
20. 0:32percentile for height and weight
21. 0:34question just wants to know what's most
22. 0:36likely to be seen in this patient let's
23. 0:37just walk the answer choices we'll go
24. 0:38backwards choices systolic murmur wrong
25. 0:41[ __ ] answer obviously very
26. 0:42non-specific could refer to a myriad of
27. 0:44things if we were to entertain what this
28. 0:46could be in a pediatric case with an
29. 0:49immunodeficiency we could conjecture to
30. 0:52george syndrome where you get tetralogy
31. 0:54of fellow classically which the vsd
32. 0:57component is systolic murmur the
33. 0:58pulmonic stenosis component also
34. 1:00systolic murmur so they'll often give
35. 1:02you harsh systolic murmur in the george
36. 1:05center okay
37. 1:07wrong [ __ ] answer
38. 1:09choice d scanty lymph node tonsils wrong
39. 1:11answer this refers to b cell deficiency
40. 1:13classic for burton x-linked a gamma
41. 1:15globulinemia or severe combined
42. 1:17immunodeficiency syndrome now whilst
43. 1:19this kid does have recurrent pneumonia
44. 1:22since the age of two years you say well
45. 1:24those are presumably bacterial why
46. 1:26couldn't not actually not necessarily
47. 1:28bacterial you could get pneumocystis you
48. 1:29get viral but my point is
49. 1:31if one of you watching this [ __ ] clip
50. 1:34were to say why is this not necessarily
51. 1:36bruin that's because the age of onset at
52. 1:39two years it's not classic okay usually
53. 1:41the age of six months most questions
54. 1:42were brewing four to seven months i've
55. 1:44seen one question on one of the
56. 1:45pediatrics forms where it was from birth
57. 1:48but the b cell deficiency for both
58. 1:50burden as well as skid they like to say
59. 1:52scanty lymph nodes and tonsils
60. 1:55wrong [ __ ] answer
61. 1:57choice c diminished leukocyte migration
62. 1:59a size infection wrong answer is
63. 2:00leukocyte adhesion efficiency a
64. 2:02deficiency of lfa1 cd18 integrin you're
65. 2:05gonna have deficient
66. 2:07diapedesis of white blood cells to
67. 2:10situ infection causing decreased pus
68. 2:14at the sites of infection as well as
69. 2:16recurrent staph infections is classic
70. 2:18and of course some students lean on the
71. 2:20crutch of delayed separation of
72. 2:22umbilical cord at birth
73. 2:25wrong [ __ ] answer
74. 2:28choice b decreased endocrine pancreas
75. 2:30function wrong answer a bit tricky and
76. 2:32this is because i was a flagrant [ __ ]
77. 2:33and i wrote endocrine pancreas here
78. 2:36which is completely different from
79. 2:37exocrine pancreas endocrine pancreas
80. 2:39refers to
81. 2:40what secreted the hormones secreted into
82. 2:43the blood by the pancreas okay insulin
83. 2:46glucagon somatostatin by the islet cells
84. 2:48in the tail the pancreas in contrast
85. 2:50exocrine pancreas refers to lipases
86. 2:53proteases bicarb uh secreted into the
87. 2:55duodenum so this kid has cystic fibrosis
88. 2:59and he would have exocrine pancreas
89. 3:02insufficiency okay but exocrine all
90. 3:05right not endocrine and that's because
91. 3:07we get in insane secretions okay fancy
92. 3:10vocab word inspication refers to
93. 3:13decussation uh dried up secretions
94. 3:15within a lumen that's what happens in
95. 3:17cystic fibrosis
96. 3:19we get exocrine pancreas insufficiency
97. 3:21fat soluble vitamin mal absorption adek
98. 3:24all dogs eat kittens those of the fat
99. 3:26soluble vitamins but classically d and e
100. 3:28are the deficiencies they get with
101. 3:31exocrine pancreas insufficiency and in
102. 3:33this case decreased bone marrowization
103. 3:35is the correct answer okay because
104. 3:37the the role of vitamin d at bone is to
105. 3:40convert unmineralized osteoid into
106. 3:42mineralized hydroxyapatite and whilst i
107. 3:45didn't give you any uh signs of rickets
108. 3:48i didn't give you bowed tibias
109. 3:51okay classic finding
110. 3:52but
111. 3:54we
112. 3:55nevertheless are going to have exocrine
113. 3:56pancreas insufficiency very high yield
114. 3:58okay and also vitamin e deficiency super
115. 4:02[ __ ] high yield on the biochem
116. 4:04questions for uh exocrine pancreas
117. 4:06insufficiency okay which presents as
118. 4:08hemolysis
119. 4:09so
120. 4:10and also neuropathy similar to b12
121. 4:12deficiency okay
122. 4:14vitamin e deficiency that is so cystic
123. 4:17fibrosis autosomal recessive chromosome
124. 4:197
125. 4:20the cftr channel it's a chloride channel
126. 4:22normally located at the cell membrane in
127. 4:24cystic fibrosis however if you do
128. 4:26electron microscopy you'll visualize the
129. 4:28channel misfolded and sequestered in the
130. 4:30rough endoplasmic reticulum of the
131. 4:32cytosol
132. 4:33we could do
133. 4:34a very [ __ ] extended discussion of
134. 4:37all the little mechanisms for different
135. 4:39things in cf but my point of
136. 4:41recapitulation here for this short clip
137. 4:44is that you need to know
138. 4:46cystic fibrosis okay crohn disease if we
139. 4:49have
140. 4:50malabsorptive disorders in pediatrics we
141. 4:54can get fat soluble vitamin mal
142. 4:56absorption classically vitamin d and
143. 4:58vitamin e
144. 4:59are the ones that are highest yield for
145. 5:01u.s smelly okay you need to
146. 5:03have that on the forefront of your mind
147. 5:04when you see a vignette such as this
148. 5:06you know the deal i'm gonna continue to
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151. 5:10and appreciate your time that's it