WordNet

a large dark-red oval organ on the left side of the body between the stomach and the diaphragm; produces cells involved in immune responses (同)lien
of or relating to the spleen (同)splenetic, lienal
fern with elongate silvery outgrowths enclosing the developing spores (同)Deparia acrostichoides, Athyrium thelypteroides
small rock-inhabiting fern of northern temperate zone and Hawaii with pinnate fronds (同)Asplenium trichomanes
any of various chiefly rock-inhabiting ferns of the genus Asplenium
a spleenwort of eastern North America (同)Asplenium montanum

PrepTutorEJDIC

脾臓(ひぞう) / 〈U〉不きげん,かんしゃく
脾臓(ひぞう)の,脾臓を冒す

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/11/12 22:10:04」(JST)

wiki en

The spleen (from Greek σπλήν—splḗn^[1]) is an organ found in virtually all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter.

The spleen plays important roles in regard to red blood cells (also referred to as erythrocytes) and the immune system.^[2] It removes old red blood cells and holds a reserve of blood, which can be valuable in case of hemorrhagic shock, and also recycles iron. As a part of the mononuclear phagocyte system, it metabolizes hemoglobin removed from senescent erythrocytes. The globin portion of hemoglobin is degraded to its constitutive amino acids, and the heme portion is metabolized to bilirubin, which is removed in the liver.^[3]

The spleen synthesizes antibodies in its white pulp and removes antibody-coated bacteria and antibody-coated blood cells by way of blood and lymph node circulation. A study published in 2009 using mice found that the spleen contains, in its reserve, half of the body's monocytes within the red pulp.^[4] These monocytes, upon moving to injured tissue (such as the heart), turn into dendritic cells and macrophages while promoting tissue healing.^[4]^[5]^[6] The spleen is a center of activity of the mononuclear phagocyte system and can be considered analogous to a large lymph node, as its absence causes a predisposition to certain infections.^[7]

In humans, the spleen is brownish in color and is located in the left upper quadrant of the abdomen.^[3]^[8]

Structure

The spleen, in healthy adult humans, is approximately 7 centimetres (2.8 in) to 14 centimetres (5.5 in) in length. It usually weighs between 150 grams (5.3 oz)^[9] and 200 grams (7.1 oz).^[10] An easy way to remember the anatomy of the spleen is the 1×3×5×7×9×11 rule. The spleen is 1" by 3" by 5", weighs approximately 7 oz, and lies between the 9th and 11th ribs on the left hand side.

Surfaces

Visceral surface of the spleen

The diaphragmatic surface of the spleen (or phrenic surface) is convex, smooth, and is directed upward, backward, and to the left, except at its upper end, where it is directed slightly to the middle. It is in relation with the under surface of the diaphragm, which separates it from the ninth, tenth, and eleventh ribs of the left side, and the intervening lower border of the left lung and pleura.

The visceral surface of the spleen is divided by a ridge into two regions: an anterior or gastric and a posterior or renal. The gastric surface (facies gastrica) is directed forward, upward, and toward the middle, is broad and concave, and is in contact with the posterior wall of the stomach. Below this it is in contact with the tail of the pancreas. Near to its mid-border is a long fissure, termed the hilum. This is pierced by several irregular openings, for the entrance and exit of vessels and nerves. The renal surface (facies renalis) is directed medialward and downward. It is somewhat flattened, considerably narrower than the gastric surface, and is in relation with the upper part of the anterior surface of the left kidney and occasionally with the left suprarenal gland.

Like the thymus, the spleen possesses only efferent lymphatic vessels. The spleen is part of the lymphatic system. Both the short gastric arteries and the splenic artery supply it with blood.^[11]

The germinal centers are supplied by arterioles called penicilliary radicles.^[12]

Development

The spleen is unique in respect to its development within the gut. While most of the gut viscera are endodermally derived (with the exception of the neural-crest derived suprarenal gland), the spleen is derived from mesenchymal tissue.^[13] Specifically, the spleen forms within, and from, the dorsal mesentery. However, it still shares the same blood supply—the celiac trunk—as the foregut organs.

Function

Micrograph of splenic tissue showing the red pulp (red), white pulp (blue) and a thickened inflamed capusule (mostly pink - top of image). H&E stain.

Area	Function	Composition
red pulp	Mechanical filtration of red blood cells. In mice: Reserve of monocytes^[4]	"sinuses" (or "sinusoids"), which are filled with blood "splenic cords" of reticular fibers "marginal zone" bordering on white pulp
white pulp	Active immune response through humoral and cell-mediated pathways.	Composed of nodules, called Malpighian corpuscles. These are composed of: "lymphoid follicles" (or "follicles"), rich in B-lymphocytes "periarteriolar lymphoid sheaths" (PALS), rich in T-lymphocytes

Other functions of the spleen are less prominent, especially in the healthy adult:

Production of opsonins, properdin, and tuftsin.
Creation of red blood cells. While the bone marrow is the primary site of hematopoiesis in the adult, the spleen has important hematopoietic functions up until the fifth month of gestation. After birth, erythropoietic functions cease, except in some hematologic disorders. As a major lymphoid organ and a central player in the reticuloendothelial system, the spleen retains the ability to produce lymphocytes and, as such, remains an hematopoietic organ.
Storage of red blood cells, lymphocytes and other formed elements. In horses, roughly 30% of the red blood cells are stored there. The red blood cells can be released when needed.^[14] In humans, up to a cup (236.5 ml) of red blood cells can be held in the spleen and released in cases of hypovolemia.^[15] It can store platelets in case of an emergency and also clears old platelets from the circulation. Up to a quarter of lymphocytes can be stored in the spleen at any one time.

Clinical significance

Enlarged spleen

Disorders include splenomegaly, where the spleen is enlarged for various reasons, such as cancer, specifically blood-based leukemias, and asplenia, where the spleen is not present or functions abnormally.

Traumas, such as a motor vehicle accident, can cause rupture of the spleen, which is a situation requiring immediate medical attention.

Decreased function

Asplenia refers to a non-functioning spleen, which may be congenital, damaged by trauma or caused by disease such as sickle cell anaemia. Hyposplenia refers to a partially functioning spleen. These conditions may cause:^[5] a modest increase in circulating white blood cells and platelets; a diminished response to some vaccines and an increased susceptibility to infection. In particular, there is an increased risk of sepsis from polysaccharide encapsulated bacteria. Encapsulated bacteria inhibit binding of complement or prevent complement assembled on the capsule from interacting with macrophage receptors. Natural antibodies are required for phagocytosis, which are immunoglobulins that facilitate phagocytosis either directly or by complement deposition on the capsule. They are produced by IgM memory B cells in the marginal zone of the spleen.^[16]^[17]

A splenectomy (removal of the spleen) also causes asplenia and results in a greatly diminished frequency of memory B cells.^[18] A 28-year follow-up of 740 World War II veterans who had their spleens removed on the battlefield showed a significant increase in the usual death rate from pneumonia (6 rather than the expected 1.3) and an increase in the death rate from ischemic heart disease (4.1 rather than the expected 3) but not from other conditions.^[19]

Accessory spleen

An accessory spleen is a small splenic nodule extra to the spleen usually formed in early embryogenesis. Accessory spleens are found in approximately 10 percent of the population^[20] and are typically around 1 centimeter in diameter. Splenosis is a condition where displaced pieces of splenic tissue (often following trauma or splenectomy) autotransplant in the abdominal cavity as accessory spleens.^[21]

Polysplenia is a congenital disease manifested by multiple small accessory spleens,^[22] rather than a single, full-sized, normal spleen. Polysplenia sometimes occurs alone, but it is often accompanied by other developmental abnormalities such as intestinal malrotation or biliary atresia, or cardiac abnormalities, such as dextrocardia. These accessory spleens are non-functional.

Society and culture

The word spleen comes from the Ancient Greek σπλήν (splḗn), and is the idiomatic equivalent of the heart in English, i.e. to be good-spleened (εὔσπλαγχνος, eúsplankhnos) means to be good-hearted or compassionate.^[23]

In English the word spleen was customary during the period of the 18th century. Authors like Richard Blackmore or George Cheyne employed it to characterise the hypochondriacal and hysterical affections.^[24]^[25] William Shakespeare, in Julius Caesar uses the spleen to describe Cassius' irritable nature.

Must I observe you? must I stand and crouch
Under your testy humour? By the gods
You shall digest the venom of your spleen,
Though it do split you; for, from this day forth,
I'll use you for my mirth, yea, for my laughter,
When you are waspish.^[26]

In French, "splénétique" refers to a state of pensive sadness or melancholy. It has been popularized by the poet Charles Baudelaire (1821–1867) but was already used before in particular to the Romantic literature (19th century). The word for the organ is "rate".

The connection between spleen (the organ) and melancholy (the temperament) comes from the humoral medicine of the ancient Greeks. One of the humours (body fluid) was the black bile, secreted by the spleen organ and associated with melancholy. In contrast, the Talmud (tractate Berachoth 61b) refers to the spleen as the organ of laughter while possibly suggesting a link with the humoral view of the organ. In eighteenth- and nineteenth-century England, women in bad humor were said to be afflicted by the spleen, or the vapours of the spleen. In modern English, "to vent one's spleen" means to vent one's anger, e.g. by shouting, and can be applied to both males and females. Similarly, the English term "splenetic" is used to describe a person in a foul mood.

Other animals

Laparoscopic view of a horse's spleen (the purple and grey mottled organ)

In cartilaginous and ray-finned fish it consists primarily of red pulp and is normally a somewhat elongated organ as it actually lies inside the serosal lining of the intestine. In many amphibians, especially frogs, it takes on the more rounded form and there is often a greater quantity of white pulp.^[27]

In reptiles, birds, and mammals, white pulp is always relatively plentiful, and in the latter two groups, the spleen is typically rounded, although it adjusts its shape somewhat to the arrangement of the surrounding organs. In the great majority of vertebrates, the spleen continues to produce red blood cells throughout life; it is only in mammals that this function is lost in adults. Many mammals have tiny spleen-like structures known as haemal nodes throughout the body that are presumed to have the same function as the spleen.^[27] The spleens of aquatic mammals differ in some ways from those of fully land-dwelling mammals. In general, they are bluish in colour. In cetaceans and manatees they tend to be quite small, but in deep diving pinnipeds, they can be quite massive, due to their function of storing red blood cells.

The only vertebrates lacking a spleen are the lampreys and hagfishes. Even in these animals, there is a diffuse layer of haematopoeitic tissue within the gut wall, which has a similar structure to red pulp and is presumed to be homologous with the spleen of higher vertebrates.^[27]

In mice, the spleen stores half the body's monocytes so that upon injury they can migrate to the injured tissue and transform into dendritic cells and macrophages and so assist wound healing.^[4]

Gallery

The celiac artery and its branch.
Horizontal disposition of the peritoneum in the upper part of the abdomen.
Transverse section of the spleen, showing the trabecular tissue and the splenic vein and its tributaries.
Back of lumbar region, showing surface markings for kidneys, ureters, and spleen.
Side of thorax, showing surface markings for bones, lungs (purple), pleura (blue), and spleen (green).
Spleen

References

^ ^a ^b σπλήν, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus Digital Library
^ Spleen, Internet Encyclopedia of Science
^ ^a ^b Mebius, RE; Kraal, G (2005). "Structure and function of the spleen". Nature reviews. Immunology 5 (8): 606–16. doi:10.1038/nri1669. PMID 16056254.
^ ^a ^b ^c ^d Swirski, FK; Nahrendorf, M; Etzrodt, M; Wildgruber, M; Cortez-Retamozo, V; Panizzi, P; Figueiredo, JL; Kohler, RH; Chudnovskiy, A; Waterman, P; Aikawa, E; Mempel, TR; Libby, P; Weissleder, R; Pittet, MJ (2009). "Identification of splenic reservoir monocytes and their deployment to inflammatory sites". Science 325 (5940): 612–6. doi:10.1126/science.1175202. PMC 2803111. PMID 19644120.
^ ^a ^b Jia, T; Pamer, EG (2009). "Immunology. Dispensable but not irrelevant". Science 325 (5940): 549–50. doi:10.1126/science.1178329. PMC 2917045. PMID 19644100.
^ Finally, the Spleen Gets Some Respect By NATALIE ANGIER, The New York Times, August 3, 2009
^ Brender, Erin (2005-11-23). Richard M. Glass, ed. Illustrated by Allison Burke. "Spleen Patient Page" (PDF). Journal of the American Medical Association (American Medical Association) 294 (20): 2660. doi:10.1001/jama.294.20.2660. PMID 16304080. Retrieved 2008-03-20.
^ Loscalzo, Joseph; Fauci, Anthony S.; Braunwald, Eugene; Dennis L. Kasper; Hauser, Stephen L; Longo, Dan L. (2008). Harrison's principles of internal medicine. McGraw-Hill Medical. ISBN 978-0-07-146633-2.
^ eMedicine > Splenomegaly Author: David J Draper. Coauthor(s): Ronald A Sacher, Emmanuel N Dessypris, Lewis J Kaplan. Updated: Oct 4, 2009
^ Spielmann, Audrey L.; David M. DeLong; Mark A. Kliewer (1 January 2005). "Sonographic Evaluation of Spleen Size in Tall Healthy Athletes". American Journal of Roentgenology (American Roentgen Ray Society) 2005 (184): 45–49. doi:10.2214/ajr.184.1.01840045. PMID 15615949. Retrieved 2008-09-09.
^ Blackbourne, Lorne H (2008-04-01). Surgical recall. Lippincott Williams & Wilkins. p. 259. ISBN 978-0-7817-7076-7.
^ "Penicilliary radicles". Medical-dictionary.thefreedictionary.com. Retrieved 2011-04-03.
^ Vellguth, Swantje; Brita von Gaudecker; Hans-Konrad Müller-Hermelink (1985). "The development of the human spleen". Cell and Tissue Research (Springer Berlin / Heidelberg) 242 (3): 579–592. doi:10.1007/BF00225424. Retrieved 2009-02-14.
^ Carey, Bjorn (May 5, 2006). "Horse science: What makes a Derby winner - Spleen acts as a 'natural blood doper,' scientist says". MSNBC.com. Retrieved 2006-05-09.
^ "Spleen: Information, Surgery and Functions". Childrens Hospital of Pittsburgh - Chp.edu. 2010-11-17. Retrieved 2011-04-03.
^ Di Sabatino, A; Carsetti, R; Corazza, GR (Jul 2, 2011). "Post-splenectomy and hyposplenic states". Lancet 378 (9785): 86–97. doi:10.1016/S0140-6736(10)61493-6. PMID 21474172.
^ Carsetti, R; Rosado, MM; Wardmann, H (February 2004). "Peripheral development of B cells in mouse and man". Immunological reviews 197: 179–91. doi:10.1111/j.0105-2896.2004.0109.x. PMID 14962195.
^ Kruetzmann, S; Rosado, MM; Weber, H; Germing, U; Tournilhac, O; Peter, HH; Berner, R; Peters, A; Boehm, T; Plebani, A; Quinti, I; Carsetti, R (Apr 7, 2003). "Human immunoglobulin M memory B cells controlling Streptococcus pneumoniae infections are generated in the spleen". The Journal of experimental medicine 197 (7): 939–45. doi:10.1084/jem.20022020. PMC 2193885. PMID 12682112.
^ Dennis Robinette, C.; Fraumeni, Josephf. (1977). "Splenectomy and Subsequent Mortality in Veterans of the 1939-45 War". The Lancet 310 (8029): 127–9. doi:10.1016/S0140-6736(77)90132-5. PMID 69206.
^ Moore, Keith L. (1992). Clinically Oriented Anatomy (3rd ed.). Baltimore: Williams & Wilkins. p. 187. ISBN 0-683-06133-X.
^ Abu Hilal M; Harb A; Zeidan B; Steadman B; Primrose JN; Pearce NW (January 5, 2009). "Hepatic splenosis mimicking HCC in a patient with hepatitis C liver cirrhosis and mildly raised alpha feto protein; the important role of explorative laparoscopy". World Journal of Surgical Oncology (England: BioMed Central) 7 (1): 1. doi:10.1186/1477-7819-7-1. PMC 2630926. PMID 19123935.
^ "polysplenia" at Dorland's Medical Dictionary
^ Robertson's Word Pictures of the New Testament, commentary on 1 Peter 3:8
^ Cheyne, George: The English Malady; or, A Treatise of Nervous Diseases of All Kinds, as Spleen, Vapours, Lowness of Spirits, Hypochondriacal and Hysterical Distempers with the Author's own Case at large, Dublin, 1733. Facsimile ed., ed. Eric T. Carlson, M.D., 1976, Scholars' Facsimiles & Reprints, ISBN 978-0-8201-1281-7;
^ Blackmore, Richard: Treatise of the spleen and vapors. London, 1725
^ Julius Caesar by William Shakespeare Act 4:1
^ ^a ^b ^c Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia: Holt-Saunders International. pp. 410–411. ISBN 0-03-910284-X.

External links

Anatomy figure: 38:03-01 at Human Anatomy Online, SUNY Downstate Medical Center—"The visceral surface of the spleen."
Anatomy image:7881 at the SUNY Downstate Medical Center
"spleen" from Encyclopædia Britannica Online
Spleen and Lymphatic System, Kidshealth.org (American Academy of Family Physicians)
Spleen Diseases from MedlinePlus
"Finally, the Spleen Gets Some Respect" New York Times piece on the spleen
Normal range of spleen size for a given age in children

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 脾腫およびその他の脾疾患を有する成人患者に対するアプローチ approach to the adult patient with splenomegaly and other splenic disorders
2. 脾腫を有する小児に対するアプローチ approach to the child with an enlarged spleen
3. 成人外傷患者における脾損傷のマネージメント management of splenic injury in the adult trauma patient
4. 小児における腹部の鈍的外傷の概要 overview of blunt abdominal trauma in children
5. 鈍的腹部外傷のある子供の肝臓、脾臓、および膵臓の損傷 liver spleen and pancreas injury in children with blunt abdominal trauma

English Journal

Cytokine and Phenotypic Cell Profiles of Leishmania infantum Infection in the Dog.

Maia C, Campino L.SourceUnidade de Parasitologia Medica, Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa (UNL), Rua da Junqueira 100, 1349-008 Lisboa, Portugal.
Journal of tropical medicine.J Trop Med.2012;2012:541571. Epub 2011 Aug 9.
Leishmaniasis has reemerged in recent years showing a wider geographic distribution and increased global incidence of human and canine disease than previously known. Dogs are the main domestic/peridomestic reservoir hosts of zoonotic visceral leishmaniasis caused by Leishmania infantum. Since the ev
PMID 21845197

Differential Regulation of the Immune Response in the Spleen and Liver of Mice Infected with Leishmania donovani.

Bankoti R, Stager S.SourceDepartment of Molecular and Comparative Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Journal of tropical medicine.J Trop Med.2012;2012:639304. Epub 2011 Jul 21.
Immunity to pathogens requires generation of effective innate and adaptive immune responses. Leishmania donovani evades these host defense mechanisms to survive and persist in the host. A better understanding and identification of mechanisms that L. donovani employs for its survival is critical for
PMID 21811511

Strain-dependent arthritogenic potential of the zoonotic pathogen Corynebacterium ulcerans.

Dias AA, Silva FC Jr, Santos LS, Ribeiro-Carvalho MM, Sabbadini PS, Santos CS, Filardy AA, Myioshi A, Azevedo VA, Hirata R Jr, Villas-Boas MH, Mattos-Guaraldi AL.SourcePrograma de Pos-Graduacao em Vigilancia Sanitaria/Instituto Nacional de Controle de Qualidade em Saude - Fundacao Oswaldo Cruz, Brazil.
Veterinary microbiology.Vet Microbiol.2011 Dec 15;153(3-4):323-31. Epub 2011 Jun 15.
During the last decade the majority of diphtheria cases in Europe had Corynebacterium ulcerans as the etiologic agent with dogs and cats as the reservoir hosts. However, little has been documented about the virulence factors of this zoonotic pathogen. To set up an in vivo experimental C. ulcerans in
PMID 21742447

Japanese Journal

Enteric duplication cyst of the pancreas with duplicated pancreatic duct

Fujishiro Jun,Kaneko Michio,Urita Yasuhisa,Hoshino Noriko,Jinbo Takahiro,Sakamoto Naoya,Suzuki Hideo,Komuro Hiroaki,藤代準,瓜田泰久,鈴木英雄,小室広昭,金子　道夫
Journal of pediatric surgery 46(8), e13-e16, 2011-08
… The patient underwent spleen-preserving distal pancreatectomy and complete cyst excision without complication. …
NAID 120003339038

Superior vena cava syndrome causedby adult T-cell leukemia/lymphoma: a case report

Ikeda Takaya,Fukuda Minoru,Nakamura Yoichi,Motoshima Kohei,Nagashima Seiji,Matsuo Masatoshi,Yamamura Masaomi,Abe Kuniko,Irie Junji,Kohno Shigeru
Acta Medica Nagasakiensia 56(2), 59-61, 2011-08
… ATL usually runs an aggressive course with multiple organs involving lymph nodes, liver, spleen, skin, lung, peripheral blood and bone marrow. …
NAID 120003307688

Systemic delivery of siRNA to tumors using a lipid nanoparticle containing a tumor-specific cleavable PEG-lipid

Hatakeyama Hiroto,Akita Hidetaka,Ito Erika,Hayashi Yasuhiro,Oishi Motoi,Nagasaki Yukio,Danev Radostin,Nagayama Kuniaki,Kaji Noritada,Kikuchi Hiroshi,Baba Yoshinobu,Harashima Hideyoshi
Biomaterials 32(18), 4306-4316, 2011-06
… Furthermore, in a DNA microarray analysis in liver and spleen tissue, less gene alternation was found for the PPD-MEND compared to that for the PEG-unmodified MEND due to less accumulation in liver and spleen. …
NAID 80021793994

Related Pictures

★リンクテーブル★

リンク元	「100Cases 33」「脾臓」「splenic」「脾」
拡張検索	「spleen index」「spleenocyte」「palpable spleen」

「100Cases 33」

Spleen
	Human Spleen removed from a cadaver
	Spleen
Details
Latin	Lien
Greek	splḗn–σπλήν
Precursor	Mesenchyme of dorsal mesogastrium
System	Immune system (Lymphatic system & Mononuclear phagocyte system)
Artery	Splenic artery
Vein	Splenic vein
Nerve	Splenic plexus
Identifiers
Gray's	p.1282
MeSH	A10.549.700
Dorlands; /Elsevier	Spleen
TA	A13.2.01.001
FMA	7196
	Anatomical terminology

　　[★]

☆case33　頭痛と混乱

■glossary

accompany

vt.

(人)と同行する、(人)に随行する。(もの)に付随する。～と同時に起こる。～に加える(添える、同封する)(with)

slurred n. 不明瞭

強直間代痙攣 tonic-clonic convulsion

　意識消失とともに全身の随意筋に強直痙攣が生じ(強直痙攣期tonic convulsion)、次いで全身の筋の強直と弛緩とが律動的に繰り返される時期(間代痙攣期clonic convulsion)を経て、発作後もうろう状態を呈する一連の発作。

■症例

28歳、女性　黒人　南アフリカ　手術室看護師　ロンドン住在

主訴：頭痛と混乱

現病歴：過去3週間で頭痛が続いており、ひどくなってきた。現在も頭痛が持続しており、頭全体が痛い。友人曰く「過去六ヶ月で体重が10kg減っていて、最近、混乱してきたようだ」。発話は不明瞭。救急室にいる間に強直間代痙攣を起こした。

・診察 examination

やせている。55kg。38.5℃。口腔カンジダ症(oral candidiasis)。リンパ節腫脹無し。心血管、呼吸器系、消化器系正常。痙攣前における神経検査では時間、場所、人の見当識無し。神経局所症状無し(no focal neurological sign)。眼底両側に乳頭浮腫有り。

・検査 investigation

血算：白血球増多

血液生化学：ナトリウム低下

CT：供覧

■キーワード＆着目するポイント

・口腔カンジダ症(oral candidiasis)

・頭痛、精神症状、強直間代痙攣

・眼底両側に乳頭浮腫

・CT 所見

・低ナトリウム血症は二次的なもの

■アプローチ

・口腔カンジダ症(oral candidiasis)　→　細胞免疫低下状態(DM、免疫抑制、AIDSなど) or 常在細菌叢の攪乱(長期の抗菌薬の使用)

　・The occurrence of thrush in a young, otherwise healthy-appearing person should prompt an investigation for underlying HIV infection.(HIM.1254)

　・More commonly, thrush is seen as a nonspecific manifestation of severe debilitating illness.(HIM.1254)

・精神症状、強直間代痙攣　→　一次的、あるいは二次的な脳の疾患がありそう

・頭痛　→　漠然としていて絞れないが、他の症状からして機能性頭痛ではなく症候性頭痛っぽい。

・眼底両側に乳頭浮腫　→　脳圧亢進の徴候　→　原因は・・・脳腫瘍、ことにテント下腫瘍と側頭葉の腫瘍、クモ膜下出血、脳水腫など、そのほか、眼窩内病変、低眼圧などの局所的要因、悪性高血圧、血液疾患、大量出血、肺気腫などの全身的要因 (vindicate本のp342も参考になる)

　・頭痛と脳圧亢進　→　頭蓋内圧占拠性病変、脳炎(IMD.274)

・CT 所見　→　ringformの病変、脳浮腫、脳圧亢進

・低ナトリウム血症　→　脳ヘルニアに続発して起こることがあるらしい。実際には下垂体にトキソプラズマによる病変が形成されることにより起こりうる。

・そのほか出身地、体重減少もHIVを疑わせる点

パターン認識でHIV + 精神症状 + てんかん発作(強直間代痙攣) + 脳圧亢進 + CT 所見 = 一番ありそうなのはToxoplasma gondiiによるトキソプラズマ脳症 cerebral toxoplasosis (トキソプラズマ脳炎 toxoplasmic encephalitis)

■Toxoplasma gondii

　原虫　胞子原虫類

(感染予防学 080521のプリント、CASES p,92、HIM p.1305-)

・疫学：西洋では30-80%の成人がトキソプラズマの感染の既往がある・・・うぇ(CASES)。日本では10%前後(Wikipedia)。

・生活環

　・終宿主：ネコ：ネコの小腸上皮細胞で有性・無性生殖　糞便にオーシストの排泄

　・中間宿主：ヒト.ブタを含むほ乳類と鳥類：無性生殖で増殖、シストの形成

　　　急性期の増殖盛んな急増虫体 tachyzoiteとシスト内の緩増虫体 bradyzoite

・病原、病因 phathogenesis

　・緩増虫体(bradyzoite)、接合子嚢(oocyst)

・感染経路

　1. オーシストの経口摂取

　2. 中間宿主の生肉中のシストの経口摂取

　3. 初感染妊婦からの経胎盤感染。既感染なら胎盤感染しないらしい(HIM.1306)

　(4)移植臓器、輸血。確率は低い(at low rate)(HIM.1306)

・病態

　1. 先天性トキソプラズマ症　congenital toxoplasmosis

　　　①網脈絡膜炎、 ②水頭症、 ③脳内石灰化、 ④精神・運動障害

　2. 後天性トキソプラズマ症　acquired toxoplasmosis

　　(1) 健常者

　　　・多くは不顕性感染。発熱、リンパ節腫脹、皮疹(rash)

　　　・(少数例)筋肉痛、暈疼痛、腹痛、斑状丘疹状皮疹(maculopapular rash)、脳脊髄炎、混乱(HIM.1308)

　　　・(まれ)肺炎、心筋炎、脳症、心膜炎、多発筋炎

　　　・網膜、脈絡叢に瘢痕や、脳に小さい炎症性の病変を残すことあり(CASES)。

　　　・急性感染の症状は数週間で消失　筋肉や中枢神経系に緩増虫体が残存

　　(2)HIV 感染者、臓器移植例、がん化学療法例

　　　シスト内緩増虫体→急増虫体→播種性の多臓器感染

　　　AIDSでは、トキソプラズマ性脳炎が指標疾患 AIDS-defineing illness(CASES)

・治療

　(日本)アセチルスピラマイシン、ファンシダール(感染予防学 080521)

■トキソプラズマ脳炎 toxoplasmic encephalitis、トキソプラズマ脳症 cerebral toxoplasosis

・症状

　発熱、頭痛、混乱ｍ、痙攣、認知の障害、局所神経徴候(不全片麻痺、歯垢、脳神経損傷、視野欠損、感覚喪失)(CASES)

・画像検査

　(CT,MRI)多発性、両側性、ring-enhancing lesion、特に灰白質-白質境界、大脳基底核、脳幹、小脳が冒されやすい(CASES)

・鑑別診断(臨床症状・画像診断の所見で)

　リンパ腫、結核、転移性脳腫瘍(CASES)

・病歴と画像所見からの鑑別診断

　リンパ腫、結核、転移性腫瘍

？

このCTがcerebral toxoplasmosisに特徴的かは不明

□最後に残る疑問

　AIDSでWBC(leukocyte)の数はどうなるんだろう？？？AIDSの初診患者ではWBCが低い人が多いらしいし()、HIVはCD4+ T cellとmacrophageに感染して殺すから、これによってB cellは減るだろうし、CD8+ T cellも若干減少するだろうからWBCは減るんじゃないか？！好中球はAIDSとは関係ない？好中球は他の感染症に反応性に増加している？ちなみに、好酸球は寄生虫(原虫)の感染のために増える傾向にあるらしい(HIMのどこか)。

葉酸拮抗剤である。

サルファ剤と併用され、抗トキソプラズマ薬、抗ニューモシチス・カリニ薬として相乗的に働く。

ST 合剤

SMX-TMP

スルファメトキサゾール・トリメトプリム合剤 sulfamethoxazole and trimethoprim mixture

□AIDSの定義(http://en.wikipedia.org/wiki/CDC_Classification_System_for_HIV_Infection_in_Adults_and_Adolescents)