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#HematologyTweetstory 17 is about el bazo, die Milz, селезенка, तिल्ली - whichever name you use for the mysterious organ that in English is the spleen. Ask the proverbial man on the street, “What does the spleen do?”; he won’t know. (Image: Gray's Anatomy; the book, not TV show.)
The function of most organs was obvious to the ancients based on orifices: heart, stomach, bladder, etc. But the #spleen? Not so much. #Galen was so puzzled that he called it the organ full of mysteries, "mysterii pleni organon". Plato thought it kept the liver bright & shiny./2
“The viola is like the spleen. We have one, but no one knows why, or what it’s doing there.” - Harry Rumpler, violist for the Roussel Trio circa 1940 [Insert your favorite viola joke here... or don't; violists have suffered enough from such jabs.] /3
In 2013, @harvardmed Class of 2016 students made a brilliant spoof music video that went viral: “What Does the Spleen Do?", a parody of #Ylvis’ catchy “What Does the Fox Say?” song. Here it is in all its glory:

Amusingly, the incomparable David Nathan @BostonChildrens was frustrated that year by @harvardmed students not attending his teaching sessions, and he told me, “If those students had come to any of my tutorials, they’d know *exactly* what the damn spleen does.” 🤣/5
It has been clear for a long time that we can live without a spleen. Renaissance anatomists noted that sometimes people lacked a spleen. Hua Tuo (aka Yuanhua 元化), a Chinese physician who lived in the Han dynasty, reportedly performed a post-trauma splenectomy ~1800 years ago./6
A stonecutter from Naples, Adrian Zaccarelli, supposedly did a successful splenectomy in a 24 year-old woman with malaria in 1549. (He may actually have removed an ovary.) Imagine being operated on by tools like these. Until the 20th century splenectomy had a high mortality./7
Roman naturalist Pliny the Elder, who has a good craft beer named after him, advised removing the spleen to make running more efficient. The Greeks reportedly did this, too. Presumably chronic malaria or thalassemia led to bulky spleens that hampered athletic performance./8
There used to be a French expression – maybe still used: “Courir comme un dératé”, “He runs like a man without a spleen”. This is Jean Bouin who won a silver medal for France in the 5000m the 1912 #StockholmOlympics. Contemporary sources are silent on the state of his spleen./9
In 1922, pharmacologist David Macht (1882-1961) at @HopkinsMedicine splenectomized 30 rats and found that (after recovery) they ran across a rope faster than 20 control rats -a genuine rat race! So the Greeks were onto something. Perhaps @DrMJoyner understands the physiology?/10
Another spleen legend is that the knobbled war clubs formerly used in #Polynesia were developed to target the spleen, since malaria was so common there. A single blow to the left side of the abdomen would rupture the victim's spleen, resulting in severe hemorrhage and death.😬/11
The spleen is often referred to as a seat of passion. In Gilbert & Sullivan's comic opera Patience, for example, there is a memorable lyric in a Reginald Bunthorne aria, “Then sentimental passion of a vegetable fashion must excite your languid spleen." Now say that 10x fast.😉/12
In the last Act (V) of Shakespeare’s "Richard III" there’s an appeal to the spleen: “Fair Saint George, Inspire us with the spleen of fiery dragons. Upon them! Victory sits on our helms.“ It didn’t work. The army he was rallying lost & he was buried under a Leicester car park./13
French poet Charles Baudelaire (1821–1867) wrote a collection of 50 prose poems he termed “Le Spleen de Paris”. This has nothing to do with the spleen as an organ - "splénétique" in French implies sadness or melancholy, another mood commonly attributed to the spleen./14
One night, when I was a college student @Calvin_Uni, talented organist John Hamersma dedicated a new college pipe organ. While a photo was being taken, his wife June said, "Oh, I will have to get a copy of that one. At home, we keep pictures of all of John's organs." 😜 /15
People still use phrases like “I was just venting my spleen” or “Do you need to vent?” – i.e., express anger. Since the spleen didn’t have an outlet, it was thought that its output must be emotion. The Talmudists thought that it was a seat of laughter, not anger./16
Ultimately, being “splenetic” meant having too much black bile. People think the Four Humor theory was just made up out of the ether, but it probably came from observing how blood settles into 4 layers, as Swedish pathologist Robin Fåhræus @UU_University pointed out in the 1920s.
We don’t send patients for splenectomy as often as we once did, in this era of JAK inhibitors etc. A landmark study @mpdrc did while we were fellows @MayoClinic showed ~10% mortality & >30% morbidity from the procedure. Most of those spleens were massive. Image: Lemaire @BjsOpen
Massive splenomegaly like that has a limited differential diagnosis: myelofibrosis, hairy cell leukemia, some lymphomas, CML, leishmaniasis (Kala-Azar), malaria, rare sarcomas or vascular malformations, thalassemia major, or a lysosomal storage disorder. Image source: @NEJM /19
The so-called “wandering spleen” is not a peripatetic spleen that moves, but a spleen that isn’t where it is expected to be found./20
However spleens are found in weird places, sometimes after trauma seeds other parts of the abdomen with bits of spleen and they survive & grow. No other organ does this. Here’s a ‘map’ of where accessory spleens or splenules like to hide. About 20% of people have one somewhere/21
A palpable spleen can be normal, especially in thin people. When I was running a lot and had BMI <10% I could feel my own spleen tip. In 1966 @dartmouth, 2200 incoming college students were examined on Orientation Day (!); 63 (2.9%) had a palpable spleen. Doubt they all had mono.
Speaking of spleen examination: in 1868, Ludwig Traube in Berlin described percussion of #TraubesSpace. A 1993 systematic review in The Rational Clinical Examination found percussion over Traube's space has sensitivity and specificity of 62% and 72% for splenomegaly - not super.
#CastellSign, percussion of lowest axillary L intercoastal space during inspiration, may be more sensitive/specific (82/83%) than Traube's space. Gastroenterologist Donald O. Castell, an esophagus expert @MUSChealth , first described this technique in the @AnnalsofIM in 1967./24
I’ve always thought of the spleen’s function at filtering blood - which took a long time for physiologists to work out - as similar to how a swimming pool strainer or filter removes insects from the water./25, starting a new thread...
Re: swimming, amazingly, the #Bajau “sea nomad” people of Indonesia, who are extraordinary divers, have larger spleens than others due to a germline variant in the phosphodiesterase PDE10A gene, and this may help them swim underwater longer, like whales who have many spleens./26
The spleen has a unique and remarkable microcirculation, which is a brutal gauntlet for cells to run through and serves to filter out senescent red cells./27
The Howell-Jolly body, subject of a prior #HematologyTweetstory, is one of many red cell changes that result when that circulation fails and the spleen doesn’t do what it is meant to do./28
I've published some odd cases & case series over the years - including one about myself! - but one of the strangest was a littoral cell angioma, a rare splenic vascular tumor. "Littoral" = coastal; these cells are named because they are on the "shoreline" of the splenic red pulp.
The spleen has its own endonuclease (“spleen endonuclease”), and its own tyrosine kinase: Syk, spleen tyrosine kinase, first identified in porcine spleen in 1990 by Tomoko Kobayashi and colleagues in Tokyo. It turned out to be important./30
Syk inhibitors are being developed for lymphoid malignancies and autoimmune disorders; one, fostamatinib, was FDA approved for ITP in 2018 (based on a made-up endpoint that @VPrasadMDMPH appropriately criticized. I have seen *rare successes with it as late-line therapy of ITP./31
Well that’s enough about this fascinating organ. Interested readers can read William Crosby’s chapter in Wintrobe’s book. Also I love that there’s a book called “The Complete Spleen”. (Though if the first edition were truly “Complete”, why was a second edition needed?)/32End
(Meant % body fat, not BMI... BMI < 10 would be scary unhealthy)
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