Splenomegaly

Splenomegaly is an enlargement of the spleen.[1] The spleen usually lies in the left upper quadrant (LUQ) of the human abdomen. Splenomegaly is one of the four cardinal signs of hypersplenism which include: some reduction in number of circulating blood cells affecting granulocytes, erythrocytes or platelets in any combination; a compensatory proliferative response in the bone marrow; and the potential for correction of these abnormalities by splenectomy. Splenomegaly is usually associated with increased workload (such as in hemolytic anemias), which suggests that it is a response to hyperfunction. It is therefore not surprising that splenomegaly is associated with any disease process that involves abnormal red blood cells being destroyed in the spleen. Other common causes include congestion due to portal hypertension and infiltration by leukemias and lymphomas. Thus, the finding of an enlarged spleen, along with caput medusae, is an important sign of portal hypertension.[2]

Splenomegaly
CT scan in a patient with chronic lymphocytic leukemia, showing splenomegaly. Yellow arrows point at the spleen.
SpecialtyGeneral surgery

Definition
Maximum dimension of the spleen on abdominal ultrasonography.

The standard system for classifying splenomegaly on radiography is:[3][4]

  • Normal (not splenomegaly): the largest dimension is less than 11 cm
  • Moderate splenomegaly: the largest dimension is between 11 and 20 cm
  • Severe splenomegaly: the largest dimension is greater than 20 cm

Also, a cutoff of a craniocaudal height of 13 cm is also used to define splenomegaly.[5] In addition, individual intervals have been established:

90% confidence interval of maximum spleen length by abdominal ultrasonography by height of the person[6]
HeightSpleen length
WomenMen
155 – 159 cm6.4 – 12 cm
160 – 164 cm7.4 - 12.2 cm8.9 - 11.3 cm
165 – 169 cm7.5 – 11.9 cm8.5 – 12.5 cm
170 – 174 cm8.3 – 13.0 cm8.6 – 13.1 cm
175 – 179 cm8.1 – 12.3 cm8.6 – 13.4 cm
180 – 184 cm9.3 – 13.4 cm
185 – 189 cm9.3 – 13.6 cm
190 – 194 cm9.7 – 14.3 cm
195 – 199 cm10.2 – 14.4 cm
AgeCutoff[7]
3 months6.0 cm
6 months6.5 cm
12 months7.0 cm
2 years8.0 cm
4 years9.0
6 years9.5 cm
8 years10.0 cm
10 years11.0 cm
12 years11.5 cm
15 years
  • 12.0 cm
    for girls
  • 13.0 cm
    for boys

For children, the cutoffs for splenomegaly are given in this table, when measuring the greatest length of the spleen between its dome and its tip, in the coronal plane through its hilum while breathing quietly.[7]

At autopsy, splenomegaly can be defined as a spleen weight above the upper limit of the standard reference range of 230 g (8.1 oz).[8][9]

Splenomegaly refers strictly to spleen enlargement, and is distinct from hypersplenism, which connotes overactive function by a spleen of any size. Splenomegaly and hypersplenism should not be confused. Each may be found separately, or they may coexist. Clinically, if a spleen is palpable (felt via external examination), it means it is enlarged as it has to undergo at least twofold enlargement to become palpable. However, the tip of the spleen may be palpable in a newborn baby up to three months of age.[10]

Signs and symptoms

Symptoms may include abdominal pain, chest pain, chest pain similar to pleuritic pain when stomach, bladder or bowels are full, back pain, early satiety due to splenic encroachment, or the symptoms of anemia due to accompanying cytopenia.

Signs of splenomegaly may include a palpable left upper quadrant abdominal mass or splenic rub. It can be detected on physical examination by using Castell's sign, Traube's space percussion or Nixon's sign, but an ultrasound can be used to confirm diagnosis. In patients where the likelihood of splenomegaly is high, the physical exam is not sufficiently sensitive to detect it; abdominal imaging is indicated in such patients.[11]

In cases of infectious mononucleosis splenomegaly is a common symptom and health care providers may consider using abdominal ultrasonography to get insight into a person's condition.[12] However, because spleen size varies greatly, ultrasonography is not a valid technique for assessing spleen enlargement and should not be used in typical circumstances or to make routine decisions about fitness for playing sports.[12]

Causes

The most common causes of splenomegaly in developed countries are infectious mononucleosis, splenic infiltration with cancer cells from a hematological malignancy and portal hypertension (most commonly secondary to liver disease, and sarcoidosis). Splenomegaly may also come from bacterial infections, such as syphilis or an infection of the heart's inner lining (endocarditis).[13] Splenomegaly also occurs in mammals parasitized by Cuterebra fontinella.[14]

The possible causes of moderate splenomegaly (spleen <1000 g) are many, and include:

Splenomegaly grouped on the basis of the pathogenic mechanism
Increased function Abnormal blood flow Infiltration
Removal of defective RBCs

Immune hyperplasia

Response to infection (viral, bacterial, fungal, parasitic)

Disordered immunoregulation

Extramedullary hematopoiesis

 Organ Failure

Vascular

Infections

 Metabolic diseases

Benign and malignant "infiltrations"

Normal spleen (in green)

The causes of massive splenomegaly (spleen >1000 g) are

Pathophysiology

Splenomegaly can be classified based on its pathophysiologic mechanism:

[1]

Diagnosis

Abdominal CT is the most accurate. The spleen needs to be 2–3 times larger than normal to be palpable below the costal margin in physical examination.

Treatment

If the splenomegaly underlies hypersplenism, a splenectomy is indicated and will correct the hypersplenism. However, the underlying cause of the hypersplenism will most likely remain; consequently, a thorough diagnostic workup is still indicated, as, leukemia, lymphoma and other serious disorders can cause hypersplenism and splenomegaly. After splenectomy, however, patients have an increased risk for infectious diseases.

Patients undergoing splenectomy should be vaccinated against Haemophilus influenzae, Streptococcus pneumoniae, and Meningococcus. They should also receive annual influenza vaccinations. Long-term prophylactic antibiotics may be given in certain cases.

As an adaptation

An enlarged spleen may be an inherited, adaptive trait selected in populations that need extra oxygen carry capacity such as deep sea divers.[21][22]

See also

References
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  2. Ghazi, Ali (2010). "Hypercalcemia and huge splenomegaly presenting in an elderly patient with B-cell non-Hodgkin's lymphoma: a case report". Journal of Medical Case Reports. 4 (334): 330. doi:10.1186/1752-1947-4-330. PMC 2974746. PMID 20959010.
  3. Neetu Radhakrishnan. "Splenomegaly". Medscape. Retrieved February 16, 2018. Updated Apr. 2012 (referring the classification system to Poulin et al.
  4. Page 1964 in: Florian Lang (2009). Encyclopedia of Molecular Mechanisms of Disease. Springer Science & Business Media. ISBN 9783540671367.
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  6. Chow, Kai Uwe; Luxembourg, Beate; Seifried, Erhard; Bonig, Halvard (2016). "Spleen Size Is Significantly Influenced by Body Height and Sex: Establishment of Normal Values for Spleen Size at US with a Cohort of 1200 Healthy Individuals". Radiology. 279 (1): 306–313. doi:10.1148/radiol.2015150887. ISSN 0033-8419. PMID 26509293.
  7. Rosenberg, H K; Markowitz, R I; Kolberg, H; Park, C; Hubbard, A; Bellah, R D (1991). "Normal splenic size in infants and children: sonographic measurements". American Journal of Roentgenology. 157 (1): 119–121. doi:10.2214/ajr.157.1.2048509. ISSN 0361-803X. PMID 2048509.
  8. Molina, D. Kimberley; DiMaio, Vincent J.M. (2012). "Normal Organ Weights in Men". The American Journal of Forensic Medicine and Pathology. 33 (4): 368–372. doi:10.1097/PAF.0b013e31823d29ad. ISSN 0195-7910. PMID 22182984. S2CID 32174574.
  9. Molina, D. Kimberley; DiMaio, Vincent J. M. (2015). "Normal Organ Weights in Women". The American Journal of Forensic Medicine and Pathology. 36 (3): 182–187. doi:10.1097/PAF.0000000000000175. ISSN 0195-7910. PMID 26108038. S2CID 25319215.
  10. Pelizzo, G.; Guazzotti, M.; Klersy, C.; Nakib, G.; Costanzo, F.; Andreatta, E.; Bassotti, G.; Calcaterra, V. (2018). "Spleen size evaluation in children: Time to define splenomegaly for pediatric surgeons and pediatricians". PLOS ONE. 13 (8): e0202741. Bibcode:2018PLoSO..1302741P. doi:10.1371/journal.pone.0202741. PMC 6107197. PMID 30138410.
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  12. American Medical Society for Sports Medicine (24 April 2014), "Five Things Physicians and Patients Should Question", Choosing Wisely: an initiative of the ABIM Foundation, American Medical Society for Sports Medicine, retrieved 29 July 2014, which cites
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  14. Durden LA (1995). "Bot Fly (Cuterebra fontinella fontinella) Parasitism of Cotton Mice (Peromyscus gossypinus) on St. Catherines Island, Georgia". The Journal of Parasitology. 81 (5): 787–790. doi:10.2307/3283977. JSTOR 3283977. PMID 7472877.
  15. Sproat, LO.; Pantanowitz, L.; Lu, CM.; Dezube, BJ. (Dec 2003). "Human immunodeficiency virus-associated hemophagocytosis with iron-deficiency anemia and massive splenomegaly". Clin Infect Dis. 37 (11): e170–3. doi:10.1086/379613. PMID 14614691.
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  19. Dascalescu, CM.; Wendum, D.; Gorin, NC. (Sep 2001). "Littoral-cell angioma as a cause of splenomegaly". N Engl J Med. 345 (10): 772–3. doi:10.1056/NEJM200109063451016. PMID 11547761.
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  21. Rappaport, Lisa (19 April 2018). "Large spleen helps explain deep-diving skills of Southeast Asian 'sea nomads'". Reuters. Retrieved 20 April 2018.
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