Posterior Pituitary Diseases Dr.Ahmed Adlan — Transcript

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1. 0:02Okay, the posterior gland doesn't have
2. 0:05much to it. We have two hormones, just
3. 0:10oxytocin and ADH. Oxytocin, of course,
4. 0:15is released in both males and females,
5. 0:18in specific amounts. It means. Touch.
6. 0:29All touch can trigger the secretion of
7. 0:31oxytocin; that’s why when a baby
8. 0:33touches, a large amount of oxytocin is
9. 0:35secreted, and if you greet people with
10. 0:38a hug, it releases oxytocin. A mother
11. 0:45hugging her child releases oxytocin. So
12. 0:47all of this is part of why they call it
13. 0:49the "love hormone." Love hormone,
14. 0:51oxytocin. Oxytocin is one of those
15. 1:00hormones that doesn't have any specific
16. 1:02clinical disease. There’s no
17. 1:04condition that a patient would come in
18. 1:06with regarding it. But it does cause
19. 1:08uterine contractions in pregnant women.
20. 1:12Uterine contraction and milk ejection;
21. 1:14it causes milk release. Not secretion,
22. 1:16secretion is by prolactin. But ejection
23. 1:19, and it also causes muscle contraction
24. 1:21. In males, what does it help with? It
25. 1:25helps in the ejection, also in what?
26. 1:27Ejection of the. Semen. And it's
27. 1:33involved in love, but we don't need to
28. 1:34dwell on that. Oxytocin is simple;
29. 1:36there’s no clinical disease
30. 1:38associated with it. There’s no
31. 1:39disease linked to it. But let's move to
32. 1:41ADH. ADH's other name is Vasopressin.
33. 1:46Vasopressin. It’s called the
34. 1:51Anti-Diuretic Hormone, the hormone that
35. 1:53prevents urination. Why is it called
36. 1:55Vasopressin? "Vaso" means vessels, "
37. 1:57press" means pressure, it puts pressure
38. 1:59on what? On the blood vessels. So,
39. 2:01vasopressin is extremely important. It
40. 2:03has two receptors, called V1 and V2. V1
41. 2:06and V2. V1 in the vessels. V2 in the
42. 2:11kidney. V1 causes vasoconstriction, it
43. 2:15narrows the vessels, vaso--constriction
44. 2:19. While V2 works on what? On the kidney
45. 2:24, and it does what? It works on the
46. 2:30collecting duct, making the kidney
47. 2:31reabsorb more of the.
48. 2:34Water. That's why it's called the
49. 2:36anti-diuretic hormone, the hormone that
50. 2:38prevents urination. Since, if it's high
51. 2:40, it means the body will have a large
52. 2:42amount of fluids. It prevents, it works
53. 2:45on the collecting duct. The collecting
54. 2:48duct of the nephron doesn't respond to
55. 2:49anything else. The hormone it responds
56. 2:53to is ADH. ADH works on the collecting
57. 2:56duct. It reabsorbs a large amount of
58. 2:59fluids. However, it has no relation to
59. 3:03sodium. Keep this in mind. It works on
60. 3:06channels called aquaporins for water.
61. 3:09Aqua, aquaporin, aquaporin. "Aqua"
62. 3:13means water. Aqua in French means water
63. 3:15. Isn't there an "Aqua Line" company
64. 3:17for water? Aqua Line, aqua means water.
65. 3:20Porin, there are five, from one to five
66. 3:23. What concerns us here is aquaporin 2,
67. 3:26aquaporin 2 causes reabsorption of
68. 3:29water. No sodium, it reabsorbs only
69. 3:31water. Sodium has no relation to it.
70. 3:36That’s why they have reabsorption of
71. 3:38sodium, which is low. Clear? So it’s
72. 3:43useful for later in MCQs. Now let's
73. 3:45look at the diseases. The diseases we
74. 3:48have are SIADH. SIADH, which is
75. 3:52Syndrome of Inappropriate ADH Secretion
76. 3:55. Syndrome of Inappropriate,
77. 4:04Inappropriate ADH Secretion. They call
78. 4:11it SIADH. SIADH is when ADH is released
79. 4:15in excessive amounts. It is released in
80. 4:18large amounts, so does that mean the
81. 4:20body is retaining water or releasing
82. 4:22water?
83. 4:25It will be retaining water; this is one
84. 4:27of the distinctive things. Where is the
85. 4:32problem always? SIADH problems can be
86. 4:39at the pituitary level or the kidney
87. 4:41level, but we are talking here about
88. 4:43what level? At the pituitary level.
89. 4:51SIADH patients present with
90. 4:53hyponatremia problems. Why hyponatremia
91. 4:56? I said they reabsorb water, not
92. 4:59sodium, so the body will be retaining
93. 5:01water, but not what? Not retaining
94. 5:04sodium. Hyponatremia, which is low
95. 5:07sodium. It is three types. We classify
96. 5:09them in medicine. We have hypervolemic.
97. 5:13Meaning the volume is increased. An
98. 5:15increase in volume. Let me write it for
99. 5:17you. We have hypovolemic. Hypovolemic
100. 5:22hyponatremia. We have euvolemic.
101. 5:33Hyponatremia and we have hypervolemic
102. 5:36hyponatremia. So they are all low
103. 5:44sodium, but how is the volume? They
104. 5:48said either the volume is low, or the
105. 5:50volume is normal, or the volume is high
106. 5:52. Let's look at one. Who are we looking
107. 5:56for? We are looking for SIADH. Where
108. 5:59does SIADH cause euvolemic hyponatremia
109. 6:01? Meaning it does not. Affect the
110. 6:03volume. Euvolemic hyponatremia.
111. 6:08Euvolemic hyponatremia. Okay, what
112. 6:10about the hypovolemic one? These are
113. 6:12people who have what? Low volume. And
114. 6:15at the same time, low sodium.
115. 6:18Dehydration, dehydration with signs.
116. 6:21And symptoms of dehydration. So what is
117. 6:24dehydration? How do you know the
118. 6:28patient has entered dehydration? And
119. 6:33also. And what. Signs? Okay, the
120. 6:46hypervolemic ones, the volume is
121. 6:48increased, but the sodium is low. When
122. 6:50is the body retaining water? In cases
123. 6:52of heart. Failure. So heart failure can
124. 6:54cause it. Also, people with nephrotic
125. 6:57syndrome. They all cause hypervolemic.
126. 7:04So, heart failure, nephrotic. Signs.
127. 7:13The euvolemic one, who is it? It is
128. 7:15SIADH itself. It has a problem. Okay,
129. 7:26what are the causes of SIADH? What
130. 7:29makes the body enter SIADH? We said.
131. 7:33Right, so brain. Or. Because they found
132. 7:43that the lung can have a tumor that
133. 7:45works by releasing ADH. You know. So if
134. 7:52it releases a lot of ADH, it means it
135. 7:54will work how? It will work as if this
136. 7:58ADH. And it will also cause what? SIADH
137. 8:01. So SIADH is either from above,
138. 8:03directly a brain issue, the pituitary
139. 8:05is damaged. In brain pathology, or it
140. 8:08could be lung pathology. Brain
141. 8:10pathology might be a tumor. Or it might
142. 8:13be what? It might be meningitis. It
143. 8:15might be encephalitis. It might even be
144. 8:18a hemorrhage, which could what? Cause
145. 8:21it. I don't think there is anything
146. 8:26else. So this is what? This is SIADH.
147. 8:28SIADH is all there is to it. The
148. 8:30patient presents with what? An increase
149. 8:32in what? An increase in ADH. And a
150. 8:38decrease in what? Sodium. You check the
151. 8:40serum sodium and find it is what? Low.
152. 8:42The volume, how do you find it? Normal.
153. 8:44The word "eu" means normal. The volume
154. 8:46is normal, it has no effect on the
155. 8:48volume. Why didn't it affect the volume
156. 8:49? Why.
157. 8:54It actually has nothing to do with
158. 8:55sodium. After all, what pulls the water
159. 8:57? Sodium. You know that sodium pulls
160. 9:00the water, right? Do you know this,
161. 9:02guys? You can take a salad and chop it
162. 9:05up. Once you add salt to it, you find
163. 9:08it's all watery, right? You guys who
164. 9:10make "fatta" and those things know this
165. 9:12. What did we say the causes were?
166. 9:17Either brain pathology, or what, lung
167. 9:19pathology? Brain pathology, we said
168. 9:21like meningitis, surgery, tumor,
169. 9:23anything in your head there. Or lung
170. 9:25pathology, what kind of thing? Lung
171. 9:27cancer, or maybe pneumonia, or maybe
172. 9:29anything that could have caused it for
173. 9:31us. But what is the most famous one?
174. 9:33Lung carcinoma. Lung carcinoma, so this
175. 9:37is the first disease of ADH, which is
176. 9:39its excess. Okay. We have a famous
177. 9:45disease. They call it diabetes
178. 9:51insipidus. D. I. Insipidus. It means
179. 10:05they call it the "tasteless diabetes."
180. 10:07The person has diabetes but there is no
181. 10:09what? They have diabetes, but there is
182. 10:11no sugar. This tasteless diabetes, the
183. 10:14problem is either above or in the
184. 10:16kidney. Is it called "genic" or
185. 10:19nephrogenic? Neurogenic or nephro?
186. 10:24Neuro means it's not releasing. ADH is
187. 10:28not being released. This means the
188. 10:29person will be what?
189. 10:32Passing urine in large quantities. A
190. 10:35normal person urinates how many liters?
191. 10:37Half a liter. But when there is no ADH,
192. 10:40they will urinate more than 20 liters,
193. 10:4215 liters. Imagine someone urinating
194. 10:45all that amount daily. Right. So we
195. 10:53said what, neuro-neurogenic? Neurogenic
196. 11:00. And where is the problem here? In the
197. 11:03brain. That is why they call it a
198. 11:05cranial cause. Causes that are always
199. 11:10related to what? To the brain. And here
200. 11:16, the patient's pituitary is not
201. 11:18releasing it at all, or the problem is
202. 11:20from the hypothalamus above; it's not
203. 11:22releasing ADH. It is famous in
204. 11:29pediatrics, a syndrome they call
205. 11:31Wolfram syndrome. Wolfram syndrome is
206. 11:37pediatric. In pediatric Wolfram
207. 11:43syndrome, the small child will have a
208. 11:45problem: first, deafness; they cannot
209. 11:47hear. And they will have a vision
210. 11:51problem; they have optic atrophy. And
211. 11:54they have diabetes, diabetes. So the
212. 11:58patient will have four things. First,
213. 12:01they have deafness. The second thing,
214. 12:08they have optic atrophy; they don't see
215. 12:10well. The third thing is they have
216. 12:14diabetes insipidus. And the fourth
217. 12:16thing, diabetes mellitus. They call it
218. 12:21Wolfram, what, syndrome. This is very
219. 12:24important. Well, what else could be the
220. 12:28cause of neurogenic? A problem in
221. 12:30neurogenic might be trauma; they had an
222. 12:32accident, trauma. So the second thing
223. 12:35is trauma. The third thing might be
224. 12:40surgery. Meaning they operated on them
225. 12:45and it stopped releasing, or radiation.
226. 12:47Radiation also, what, can cause it.
227. 12:50Well, if we come to kidney problems, if
228. 12:52we said neurogenic is what? This is the
229. 12:54first cause. The second, what do they
230. 12:56call it? Nephrogenic, nephro. Genic.
231. 13:04Nephrogenic cause, which is a kidney
232. 13:06cause. These are problems of what? Of
233. 13:08the kidney. Meaning that the body is
234. 13:11releasing it well, it's working, but
235. 13:13the receptors that are there are not
236. 13:15working. So it's a problem of...Of the
237. 13:21receptor. Receptor problem. The problem
238. 13:27of the receptor located where? In the
239. 13:29kidney. What is the cause? It might be
240. 13:31familial, in the family like that, it
241. 13:33could be a genetic cause. And if it
242. 13:35were a genetic cause, it is X-linked,
243. 13:37often in females, often in females. It
244. 13:40is X-linked, familial, maybe it's X--
245. 13:47linked genetic, meaning in others it
246. 13:49could be normal. Or it could be what?
247. 13:53Electrolyte disturbance problems. Which
248. 13:56electrolyte disturbances can cause
249. 13:58nephrogenic diabetes insipidus? That is
250. 14:02decreased potassium and increased
251. 14:04calcium. Decreased potassium is called
252. 14:09hypokalemia, and increased calcium is
253. 14:11hypercalcemia. Both of these can cause
254. 14:17what? Nephrogenic diabetes insipidus.
255. 14:24There are some drugs that do this; any
256. 14:26drug that stops the action of ADH. So,
257. 14:29we have drugs called ADH antagonists.
258. 14:34What does the ADH antagonist drug give
259. 14:36the patient? Which is, what is it
260. 14:41called? Demeclocycline...demeclo...drug
261. 14:45? Like demeclocycline. Demeclocycline
262. 14:56is a drug called an ADH antagonist.
263. 15:04Also, there is a drug given to people
264. 15:06with mood problems, meaning psychotic
265. 15:08disease; it is called lithium. What
266. 15:11does it do? It is a mood stabilizer;
267. 15:14what does he take? Lithium. So lithium
268. 15:18is also, let's add it with lithium.
269. 15:33Also, there could be problems with
270. 15:35sickle cell anemia, sickle cell anemia.
271. 15:38Because doesn't sickle cell damage the
272. 15:40kidney? It causes sickle cell disease,
273. 15:42which is sickle cell in the kidney.
274. 15:44Damage to the kidney means the kidney
275. 15:46will not work well anymore. Meaning ADH
276. 15:48will not work well. Correct? You know,
277. 15:51so sickle cell anemia is also sickle.
278. 15:54So that if you find it in an MCQ,
279. 15:56sickle cell anemia. These are the
280. 15:59causes, whether neurogenic or
281. 16:01nephrogenic, what will the patient
282. 16:03present with? Ah.
283. 16:10First, they come with polyuria. They
284. 16:13urinate a lot. And this is a
285. 16:15characteristic feature. The person
286. 16:17urinates a lot as a compensatory
287. 16:18mechanism. It will activate what? The
288. 16:21thirst center. It will immediately make
289. 16:23you want to drink a lot. So your
290. 16:25frequent urination makes you want to
291. 16:27drink a lot. The primary presentation
292. 16:30is polyuria. But because of polyuria,
293. 16:32they will come with polydipsia. They
294. 16:36immediately have polyuria associated
295. 16:38with polydipsia together. Because it is
296. 16:40impossible for someone to urinate a lot
297. 16:42and not be thirsty. Alright. The one
298. 16:44who has a problem in the brain. So the
299. 16:47patient will come with polyuria and
300. 16:49polydipsia. That is why we called it
301. 16:53diabetes insipidus. Insipidus, check
302. 16:55the level of glucose, what is it?
303. 16:57Normal, he has no problem with glucose.
304. 16:59But what is this person's whole problem
305. 17:01? That he urinates a lot and is thirsty
306. 17:03, so he drinks a lot. He tells you, "
307. 17:06Doctor, I urinate a lot and drink a lot
308. 17:08, even sleep is difficult for me." This
309. 17:12is from what? From his presentation of
310. 17:15polyuria and polydipsia. If we talk
311. 17:18about differential diagnosis and things
312. 17:20, how do you differentiate it from
313. 17:22diabetes mellitus? Diabetes mellitus
314. 17:24from diabetes insipidus. With what?
315. 17:28Investigation, one investigation is
316. 17:31enough, just one.
317. 17:34Oral glucose tolerance test. Oral
318. 17:39glucose tolerance test. If you find the
319. 17:43glucose is high, that means it is
320. 17:44diabetes mellitus. Glucose is normal,
321. 17:46meaning this is the patient. We have
322. 17:50people, people who have psychological
323. 17:52issues and drink a lot. It is called
324. 17:56psychogenic polydipsia, it is called
325. 17:58psycho-genic poly-dipsia. Psychogenic
326. 18:10polydipsia, they drink a lot. They want
327. 18:12to drink, they want to drink, they keep
328. 18:14drinking like that. Consequently, the
329. 18:15urine volume will be what? A lot, and
330. 18:17since the urine volume is high, it
331. 18:19means they will drink a lot. To confirm
332. 18:24this person has diabetes. As for other
333. 18:28tests, as for differential
334. 18:29investigation. First, what do I do?
335. 18:38Urine output monitoring. See how much
336. 18:41urine. I always find it to be a lot, a
337. 18:45lot. We measure serum osmolarity. And
338. 18:52this is very important. Osmolarity
339. 18:57helps distinguish between them. And
340. 19:00then psychogenic from who, from
341. 19:02diabetes insipidus. How is the
342. 19:08osmolarity? I mean, do you understand
343. 19:10osmolarity? Meaning the amount of
344. 19:12sodium in the urine. For diabetes
345. 19:16patients, will it be high or low?
346. 19:20It will be high, they will have high
347. 19:23osmolarity, high osmolarity if serum
348. 19:25osmolarity, no, urine osmolarity, your
349. 19:27urine. Osm-What will we find? High.
350. 19:39Yes.
351. 19:41And serum, what about the serum? It is
352. 19:52basically. The urine will all be what?
353. 19:59Low sodium.
354. 19:59They will have, yes, serum, sorry.
355. 20:02Serum, so what is the serum osmolarity?
356. 20:04Serum, but urine will be what? Low.
357. 20:07Urine osmolarity will be low. Because
358. 20:11we said earlier they have what, sodium.
359. 20:15They have what, sodium. So it will be
360. 20:18what, high. While the urine will be
361. 20:21what. Okay, the gravity of the urine
362. 20:23will be what too? The urine gravity
363. 20:28will be what too, low gravity. Gravity,
364. 20:31of course, we aren't using it here. But
365. 20:34they call it, yes, low gravity. So our
366. 20:36output tests, we measure them. Serum
367. 20:38osmolarity high. And urine osmolarity
368. 20:41we find what? Low. And the gravity we
369. 20:43find what? Also low. This is how you
370. 20:47confirm your patient has diabetes
371. 20:48insipidus. There is a test called the
372. 20:53water deprivation test. They bring the
373. 20:56patient and give them ADH. Make ADH,
374. 21:00desmopressin. If we give it, we want to
375. 21:05distinguish. Is the problem in their
376. 21:07head or in their kidneys? If we give it
377. 21:09and they respond. It means their
378. 21:11problem was in their head. Because it
379. 21:14means I gave them ADH. And if it worked
380. 21:17well, it means this person was what? It
381. 21:19is neurogenic. Okay, if we give it and
382. 21:21they don't respond, it means what?
383. 21:23Nephrogenic. It's called the water
384. 21:25deprivation test. This distinguishes
385. 21:28between what and what? Between whether
386. 21:31it is neurogenic or nephrogenic. We
387. 21:34said this is called pressin, it is ADH.
388. 21:37It is ADH, but synthetic. ADH is called
389. 21:41desmo--pressin. And the ADH is called
390. 21:48what? Vaso-vasopressin. This is how we
391. 21:52distinguish. Okay, so this means, why
392. 21:56did I distinguish them? Why distinguish
393. 21:58them? For the sake of the treatment
394. 22:00later. Meaning, if the patient's
395. 22:02problem is neurogenic, what treatment
396. 22:03do we give? Desmopressin. That pressin,
397. 22:06they will continue with it, and that's
398. 22:08it. Okay, if the problem is in the
399. 22:10kidney, what will we do for them? They
400. 22:13will have a fluid loss problem. Which
401. 22:17is, they lose a lot of fluids, and they
402. 22:19will have a problem that their body
403. 22:20sodium is high. Okay, this fluid loss
404. 22:24problem, what will you give them? We
405. 22:27will give them non-steroidal
406. 22:28anti-inflammatories. Yeah.