HY USMLE HEMATOLOGY - #240 — Transcript

Full transcript

1. 0:00okay so this is a very valuable
2. 0:02high-yield question for usmle not just
3. 0:04this pianka versus sianka stuff but
4. 0:06also the hematologic uh parameters here
5. 0:10very tricky okay very very challenging
6. 0:13so and this will provide you some value
7. 0:15so this patient has epistaxis for a
8. 0:17couple days creatinine is 3.8 that's
9. 0:19very [ __ ] elevated normal creatinine
10. 0:21should be about 1.0
11. 0:22you can get a normal range theoretically
12. 0:240.7 to 1.2
13. 0:26but 1.0 is normal on usmle
14. 0:30and as a patient gets older 70s 80s 90s
15. 0:34creatinine can creep up 1.1 1.2
16. 0:37but it really shouldn't get above that
17. 0:39if you get a creatinine of 2.0
18. 0:41you've lost about 90 percent of your
19. 0:43renal function so this patient who has a
20. 0:44credit of 3.8
21. 0:46the implication is we have essentially
22. 0:48no renal function in this patient
23. 0:50and we've got positive antipronase 3
24. 0:52antibodies
25. 0:53which are synonymous with c inca for
26. 0:56usmle okay
27. 0:58cytoplasmic antineutrophilic cytoplasmic
28. 1:01antibody so
29. 1:01antiprotonase iii equals c anca
30. 1:05equals wegener or wedgener
31. 1:08granulomatosis
32. 1:09which is now the former name
33. 1:11unfortunately because cumbersomely
34. 1:13the new name is granulomatosis or
35. 1:16polyangiitis okay
36. 1:18in contrast anti-myeloperoxidase
37. 1:21antibodies are synonymous with pienka
38. 1:23peri-nuclear
39. 1:25anti-neutrophilic cytoplasmic antibody
40. 1:27and that corresponds to microscopic
41. 1:28polyangiitis
42. 1:30and church strauss the former name of
43. 1:32course turk strauss is now known as
44. 1:34eosinophilic granulomatosis of
45. 1:36palingitis okay
46. 1:38now just real quick looking at this real
47. 1:40biopsy no you don't need to know this
48. 1:42renal biopsy okay
49. 1:43nor can you really see anything too
50. 1:45clearly here i just
51. 1:46once again i'm uh being an [ __ ] by
52. 1:49putting an image in here just for the
53. 1:50sake of it
54. 1:51but this is in theory supposed to be
55. 1:54showing us a necrotizing
56. 1:55glomerulonephritis
57. 1:57for usmli purposes this is about getting
58. 1:59you points okay
59. 2:00if [ __ ] this biopsy for a second if they
60. 2:03just tell you in the question
61. 2:04they say eg dude has uh
62. 2:08septal nasal septal perforation he's got
63. 2:10otitis he's got red urine he's got
64. 2:12hemoptysis
65. 2:13any a renal biopsy shows necrotizing
66. 2:16glomerulonephritis
67. 2:17that's wegoner okay so we classically
68. 2:21get
69. 2:21with these vasculitis wegener's vascular
70. 2:24vasculitis
71. 2:24you get necrotizing glomerulonephritis
72. 2:27that's the descriptor you need to know
73. 2:29just say okay wegener
74. 2:32necrotizing glomerulonephritis got it
75. 2:35okay
76. 2:36so moving forward here we've already
77. 2:38established that
78. 2:39because this is wegener or
79. 2:41granulomatosis polyangiitis
80. 2:43uh antipronase three are we're only
81. 2:45looking at the c
82. 2:46inca answers okay so we eliminate all
83. 2:49the pianka ones
84. 2:50now this is where the value is this is
85. 2:52where it's tricky
86. 2:53in renal failure high
87. 2:56blood urea nitrogen can cause
88. 3:00uremic platelet dysfunction uremia
89. 3:03means renal failure don't [ __ ]
90. 3:06confuse it with hyperuricemia completely
91. 3:08different okay it's easy to confuse
92. 3:10uremia is just the name for the syndrome
93. 3:13of renal failure
94. 3:14how the patient presents when he or she
95. 3:16has renal failure
96. 3:17that's uremia nothing to do with
97. 3:19hyperuricemia okay just sounds similar
98. 3:22so high b when in the setting of uremia
99. 3:26can cause a qualitative not a
100. 3:29quantitative
101. 3:30a qualitative dysfunction of platelets
102. 3:33so
103. 3:33uremic platelet dysfunction i've also
104. 3:35seen it written as acquired platelet
105. 3:37dysfunction
106. 3:38and this is going to cause an increased
107. 3:39bleeding time but no change platelet
108. 3:41count so our answer is b
109. 3:42here okay very difficult because you'd
110. 3:45think if there's an increased bleeding
111. 3:47time
112. 3:47that we would get a decreased platelet
113. 3:48count but you need to know for
114. 3:50renal failure you're going to choose no
115. 3:52change
116. 3:53platelet count okay so bleeding time
117. 3:55should normally be two to seven minutes
118. 3:57we would see a bleeding time greater
119. 3:58than seven minutes here planet count is
120. 4:00one hundred fifty thousand four hundred
121. 4:01fifty thousand so we'd see something in
122. 4:02the normal range okay
123. 4:04and this is what's causing the epistaxis
124. 4:06so uh platelet problems can often
125. 4:08present as petechiae
126. 4:10okay uh epistaxis that's classic now
127. 4:14i don't want to make this too long of a
128. 4:15discussion stay concise but
129. 4:17another high yield talking point is
130. 4:19anemia chronic disease and renal failure
131. 4:21which would not which in and of itself
132. 4:24would not cause epistaxis
133. 4:25so let's say you have this patient right
134. 4:28here
135. 4:29in this question with episaxis and low
136. 4:31hemoglobin
137. 4:32and you ask a student why is the
138. 4:33hemoglobin low and they're like hmm
139. 4:34anemia chronic disease
140. 4:36not impossible but they're [ __ ]
141. 4:38bleeding
142. 4:39so it's reasonable that they have low
143. 4:41hemoglobin because they have epistaxis
144. 4:44right anemia of chronic disease in and
145. 4:46of itself doesn't cause epistaxis
146. 4:49you can have a patient with advanced
147. 4:51with chronic renal disease
148. 4:52who has low hemoglobin mcv can be normal
149. 4:55or decreased by the way in anemia
150. 4:57chronic disease and not just normal
151. 4:58but you can have a patient with anemia
152. 5:00chronic disease real failure who does
153. 5:01not have epistaxis
154. 5:03okay like even though they would have
155. 5:04uremic plate dysfunction so
156. 5:06it can be tricky but the the point i
157. 5:09want to convey to you
158. 5:10is that the epistaxis here is not due to
159. 5:13anemia of chronic disease
160. 5:14the epistaxis is due to uremic platelet
161. 5:18dysfunction
162. 5:18okay why does a patient get get
163. 5:20nosebleeds or petechiae
164. 5:22in in renal failure answer acquired
165. 5:25platelet dysfunction uremic platelet
166. 5:26dysfunction
167. 5:27play the count normal okay bleeding time
168. 5:30increased
169. 5:31that's it a lot we can talk about i know
170. 5:33you don't want to see a 19 minute clip
171. 5:35here all right i'm obviously going to
172. 5:36make more content
173. 5:37so if you liked this question subscribe
174. 5:40to my channel
175. 5:41and i appreciate your time that's it