1
00:00:05,540 --> 00:00:09,410
The appendix is the little one-ended tube that’s attached to the cecum of the large
2
00:00:09,410 --> 00:00:15,019
intestine, sometimes it’s called the vermiform appendix, where vermiform means “worm-shaped”,
3
00:00:15,019 --> 00:00:17,950
so, that should paint a pretty clear picture of what it looks like.
4
00:00:17,950 --> 00:00:23,460
This odd, yet kinda cute little worm-like structure’s function is actually unknown,
5
00:00:23,460 --> 00:00:28,160
though some theories suggest it might be a “safe-house” for the gut flora, and some
6
00:00:28,160 --> 00:00:33,300
evidence seems to suggests it plays a part in the lymphatic and immune system; other,
7
00:00:33,300 --> 00:00:37,910
arguably more cynical viewpoints maintain that it’s just a useless vestigial organ
8
00:00:37,910 --> 00:00:39,820
from our ancestors.
9
00:00:39,820 --> 00:00:44,250
Whatever the case, the fact remains, it’s pretty talented at getting inflamed and causing
10
00:00:44,250 --> 00:00:50,400
abdominal pain, a condition known as appendicitis, as much as 10% of the population develops
11
00:00:50,400 --> 00:00:57,280
appendicitis, and it’s the most common surgical emergency of the abdomen.
12
00:00:57,280 --> 00:01:01,100
Since the appendix is a hollow tube, the most common cause of inflammation is something
13
00:01:01,100 --> 00:01:06,490
getting stuck in or obstructing that tube, like a fecalith, a hardened lump of fecal
14
00:01:06,490 --> 00:01:10,890
matter that finds it’s way into the the lumen of the appendix and wedges itself there.
15
00:01:10,890 --> 00:01:15,810
It could also be other things though, like seeds that weren’t digested, or even pinworm
16
00:01:15,810 --> 00:01:19,720
infections, which are intestinal parasites.
17
00:01:19,720 --> 00:01:24,740
Another cause of obstruction, especially in children and adolescents, is lymphoid follicle
18
00:01:24,740 --> 00:01:28,390
growth, also known as lymphoid hyperplasia.
19
00:01:28,390 --> 00:01:32,440
Lymphoid follicles are dense collections of lymphocytes that get to their maximum size
20
00:01:32,440 --> 00:01:35,380
in the appendix during adolescence.
21
00:01:35,380 --> 00:01:38,210
Sometimes this growth can literally obstruct the tube.
22
00:01:38,210 --> 00:01:43,400
Also, when exposed to viral infections like adenovirus, measles, or even after immunizations,
23
00:01:43,400 --> 00:01:47,100
the immune system ramps up and these follicles can grow as well.
24
00:01:47,100 --> 00:01:51,590
Whatever the obstruction is, now this appendix is plugged up, right?
25
00:01:51,590 --> 00:01:56,380
Well, the intestinal lumen, including the appendix, is always secreting mucus and fluids
26
00:01:56,380 --> 00:02:00,909
from its mucosa to keep pathogens from entering the bloodstream and also to keep the tissue
27
00:02:00,909 --> 00:02:02,590
moist.
28
00:02:02,590 --> 00:02:06,670
Even when it’s plugged, the appendix keeps secreting as usual.
29
00:02:06,670 --> 00:02:11,280
When this happens, fluid and mucus builds up, which increases the pressure in the appendix,
30
00:02:11,280 --> 00:02:15,579
and just like when you fill up a water balloon, it gets bigger and physically pushes ons the
31
00:02:15,579 --> 00:02:20,260
afferent visceral nerve fibers nearby, causing abdominal pain.
32
00:02:20,260 --> 00:02:24,909
Along with that, the flora and bacteria in the gut are now trapped, and intestinal bacteria
33
00:02:24,909 --> 00:02:29,510
that are usually kept in check in the gut, like E. coli and Bacteroides fragilis are
34
00:02:29,510 --> 00:02:31,379
now free to multiply.
35
00:02:31,379 --> 00:02:35,859
This causes the immune system to recruit white blood cells and pus starts to accumulate in
36
00:02:35,859 --> 00:02:37,680
the appendix.
37
00:02:37,680 --> 00:02:41,499
This activation of the immune system can be seen in the lab as an increase in the serum
38
00:02:41,499 --> 00:02:43,980
white blood cell count.
39
00:02:43,980 --> 00:02:47,659
Patients might also develop a fever in response to the infection, which in combination with
40
00:02:47,659 --> 00:02:52,209
right lower quadrant abdominal pain at the point roughly where the appendix is, known
41
00:02:52,209 --> 00:02:56,909
as known as mcburney’s point, is a super important sign for identifying appendicitis.
42
00:02:56,909 --> 00:03:03,299
Also, along with fever, other classic symptoms include nausea and vomiting.
43
00:03:03,299 --> 00:03:07,299
Now if obstruction persists, the pressure in the appendix increases even more.
44
00:03:07,299 --> 00:03:12,129
At a certain point, as the pressure keeps growing and it continues to swell up, it pushes
45
00:03:12,129 --> 00:03:15,829
on and compresses the small blood vessels that supply the appendix with blood and oxygen.
46
00:03:15,829 --> 00:03:20,860
Without oxygen, the cells in the walls of the appendix become ischemic and eventually
47
00:03:20,860 --> 00:03:22,459
die.
48
00:03:22,459 --> 00:03:27,359
Since these cells were responsible for secreting mucus and keeping bacteria out, now the growing
49
00:03:27,359 --> 00:03:31,219
colony of bacteria can invade the wall of the appendix.
50
00:03:31,219 --> 00:03:36,739
As more cells die, the appendiceal walls become weaker and weaker and for a small proportion
51
00:03:36,739 --> 00:03:40,779
of patients, to the point where the appendix ruptures.
52
00:03:40,779 --> 00:03:45,129
Rupture of an infected appendix allows the bacteria to escape the appendix and get into
53
00:03:45,129 --> 00:03:50,839
the peritoneum, and patients often experience peritonitis with rebound tenderness, meaning
54
00:03:50,839 --> 00:03:56,609
pain when pressure is taken off, again around mcburney’s point.
55
00:03:56,609 --> 00:04:00,359
Patients might also have some abdominal guarding, where their abdominal muscles tense up when
56
00:04:00,359 --> 00:04:03,810
pressed to try and avoid pain.
57
00:04:03,810 --> 00:04:08,219
The most common complication with a ruptured appendix is pus and fluid gets out and forms
58
00:04:08,219 --> 00:04:13,079
an abcess around the appendix, called a periappendiceal abscess.
59
00:04:13,079 --> 00:04:17,109
Sometimes subphrenic abscesses might also form, these would be tiny abscesses below
60
00:04:17,109 --> 00:04:23,200
the diaphragm but above the liver or spleen.
61
00:04:23,200 --> 00:04:27,560
The standard treatment for appendicitis is appendectomy, which is surgical removal of
62
00:04:27,560 --> 00:04:29,870
the appendix along with antibiotics.
63
00:04:29,870 --> 00:04:34,940
If patients have abscesses these are also important to surgically drain.
64
00:04:34,940 --> 00:04:38,880
Removing the appendix isn’t known to have any negative side effects, and sometimes it’s
65
00:04:38,880 --> 00:04:42,810
removed if the surgeons are already doing an abdominal surgery for some other reason
66
00:04:42,810 --> 00:04:49,350
just to avoid an appendicitis down the road!