The most common cause of a ruptured spleen is blunt abdominal trauma, such as in traffic collisions or sports accidents. Direct, penetrating injuries, for example, stab or gunshot wounds are rare.

Non-traumatic causes are less common. These include infectious diseases, medical procedures such as colonoscopy, haematological diseases, medications, and pregnancy.

In less than one percent of cases of infectious mononucleosis splenic rupture may occur.

The spleen is an organ in the left upper quadrant of the abdomen that filters blood by removing old or damaged blood cells and platelets. While not essential to sustain life, the spleen performs protective immunological functions in the body. It also helps the immune system by destroying bacteria and other foreign substances by opsonization and phagocytosis, and by producing antibodies. It also stores approximately 33 percent of all platelets in the body.

Blunt splenic trauma most often occurs in automobile accident victims, in which it is a leading cause of internal bleeding. However, any type of major impact directed to the spleen may cause splenic trauma. This can happen in bicycling accidents, when the handlebar is forced into the left subcostal margin, and into the spleen. The degree of injury ranges from subcapsular hematoma, to splenic rupture.

Blunt splenic trauma occurs when a significant impact to the spleen from some outside source (i.e. automobile accident) damages or ruptures the spleen. Treatment varies depending on severity, but often consists of embolism or splenectomy.

Causes include:

- acute pancreatitis, where methemalbumin formed from digested blood tracks around the abdomen from the inflamed pancreas

- bleeding from blunt abdominal trauma

- bleeding from aortic rupture

- bleeding from ruptured ectopic pregnancy

Importance of the sign is on a decline since better diagnostic modalities are now available.

Causes include

- Acute pancreatitis, whereby methemalbumin formed from digested blood tracks subcutaneously around the abdomen from the inflamed pancreas.

- Pancreatic hemorrhage

- Retroperitoneal hemorrhage

- Blunt abdominal trauma

- Ruptured / hemorrhagic ectopic pregnancy.

- Spontaneous bleeding secondary to coagulopathy (congenital or acquired)

- Aortic rupture, from ruptured abdominal aortic aneurysm or other causes.

Mortality of IIA is high, unruptured IIA are associated with a mortality reaching 30%, while ruptured IIA has a mortality of up to 80%. IIAs caused by fungal infections have a worse prognosis than those caused by bacterial infection.

Treatment varies according to severity, ranging from monitoring of the hematoma (in haemodynamic stability) to emergency surgery (when patients develop hypovolemic shock requiring seminephrectomy or nephrectomy). Vascular causes lead to surgery due to severity of hemorrhage. Robotic-assisted partial nephrectomy has been proposed as a surgical treatment of a ruptured angiomyolipoma causing retroperitoneal hemorrhage, combining the advantages of a kidney preservation procedure and the benefits of a minimally invasive procedure without compromising the safety of the patient.

IIAs are uncommon, accounting for 2.6% to 6% of all intracranial aneurysms in autopsy studies.

Cullen's sign is superficial edema and bruising in the subcutaneous fatty tissue around the umbilicus.

It is named for gynecologist Thomas Stephen Cullen (1869–1953), who first described the sign in ruptured ectopic pregnancy in 1916.

This sign takes 24–48 hours to appear and can predict acute pancreatitis, with mortality rising from 8–10% to 40%. It may be accompanied by Grey Turner's sign (bruising of the flank), which may then be indicative of pancreatic necrosis with retroperitoneal or intraabdominal bleeding.

Grey Turner's sign refers to bruising of the s, the part of the body between the last rib and the top of the hip. The bruising appears as a blue discoloration, and is a sign of retroperitoneal hemorrhage, or bleeding behind the peritoneum, which is a lining of the abdominal cavity. Grey Turner's sign takes 24–48 hours to develop, and can predict a severe attack of acute pancreatitis.

Grey Turner's sign may be accompanied by Cullen's sign. Both signs may be indicative of pancreatic necrosis with retroperitoneal or intraabdominal bleeding. Grey Turner's sign is named after British surgeon George Grey Turner.

Several factors may increase the tendency for clot formation, such as specific infections (such as infectious mononucleosis, cytomegalovirus infection, malaria, or babesiosis), inherited clotting disorders (thrombophilia, such as Factor V Leiden, antiphospholipid syndrome), malignancy (such as pancreatic cancer) or metastasis, or a combination of these factors.

In some conditions, blood clots form in one part of the circulatory system and then dislodge and travel to another part of the body, which could include the spleen. These emboligenic disorders include atrial fibrillation, patent foramen ovale, endocarditis or cholesterol embolism.

Splenic infarction is also more common in hematological disorders with associated splenomegaly, such as the myeloproliferative disorders. Other causes of splenomegaly (for example, Gaucher disease or hemoglobinopathies) can also predispose to infarction. Splenic infarction can also result from a sickle cell crisis in patients with sickle cell anemia. Both splenomegaly and a tendency towards clot formation feature in this condition. In sickle cell disease, repeated splenic infarctions lead to a non-functional spleen (autosplenectomy).

Any factor that directly compromises the splenic artery can cause infarction. Examples include abdominal traumas, aortic dissection, torsion of the splenic artery (for example, in wandering spleen) or external compression on the artery by a tumor. It can also be a complication of vascular procedures.

Splenic infarction can be due to vasculitis or disseminated intravascular coagulation. Various other conditions have been associated with splenic infarction in case reporters, for example granulomatosis with polyangiitis or treatment with medications that predispose to vasospasm or blood clot formation, such as vasoconstrictors used to treat esophageal varices, sumatriptan or bevacizumab.

Wunderlich syndrome is spontaneous, nontraumatic renal hemorrhage confined to the subcapsular and perirenal space. It may be the first manifestation of a renal angiomyolipoma (AML), or rupture of renal artery or intraparechymal aneurysm.

Wandering spleen is most commonly diagnosed in young children as well as women between the ages of 20 and 40. Even so, the disease is very rare and fewer than 500 occurrences of the disease have been reported as of 2005, of which around 148 (including both children and adult cases) were documented to have been from between 1960 and 1992. Less than 0.5% of all splenectomies, surgical removal of the spleen, are performed due to having this disorder.

Characteristics of the disorder include the loss, weakening, or malformation of the ligaments that help to keep the spleen located in the upper left part of the abdomen. Though not a genetic disease, wandering spleen is often found at birth. It can occur in adults as the result of injuries and other similar conditions that cause the ligaments to weaken, such as connective tissue disease or pregnancy. Wandering spleen (splenoptosis) predisposes the spleen to complications such as torsion, splenic infarction, pancreatic necrosis and rarely pseudocyst formation.

In 1992, the youngest case of the literature of torsion of wandering spleen at two days of birth was reported in Lebanon, by Dr Edouard Sayad.

Splenic infarction can be induced for the treatment of such conditions as portal hypertension or splenic injury. It can also be used prior to splenectomy for the prevention of blood loss.

There are many causes of subcutaneous hematomas including ecchymoses. Coagulopathies such as Hemophilia A may cause ecchymosis formation in children. The medication betamethasone can have the adverse effect of causing echhymosis.

Wandering spleen (or Pelvic spleen) is a rare medical disease caused by the loss or weakening of the ligaments that help to hold the spleen stationary.

If properly treated, typical cases of surgically correctable peritonitis (e.g., perforated peptic ulcer, appendicitis, and diverticulitis) have a mortality rate of about <10% in otherwise healthy patients. The mortality rate rises to about 40% in the elderly, or in those with significant underlying illness, as well as cases that present late (after 48 hours).

Without being treated, generalised peritonitis almost always causes death. The stage magician Harry Houdini died this way, having contracted streptococcus peritonitis after his appendix ruptured and was removed too late to prevent spread of the infection.

If splenectomy is performed for conditions in which blood cells are sequestered in the spleen, failure to remove accessory spleens may result in the failure of the condition to resolve. During medical imaging, accessory spleens may be confused for enlarged lymph nodes or neoplastic growth in the tail of the pancreas, gastrointestinal tract, adrenal glands or gonads.

Intracranial hemorrhage is a serious medical emergency because the buildup of blood within the skull can lead to increases in intracranial pressure, which can crush delicate brain tissue or limit its blood supply. Severe increases in intracranial pressure (ICP) can cause brain herniation, in which parts of the brain are squeezed past structures in the skull.

Peritonitis is inflammation of the peritoneum, the lining of the inner wall of the abdomen and cover of the abdominal organs. Symptoms may include severe pain, swelling of the abdomen, fever, or weight loss. One part or the entire abdomen may be tender. Complications may include shock and acute respiratory distress syndrome.

Causes include perforation of the intestinal tract, pancreatitis, pelvic inflammatory disease, stomach ulcer, cirrhosis, or a ruptured appendix. Risk factors include ascites and peritoneal dialysis. Diagnosis is generally based on examination, blood tests, and medical imaging.

Treatment often includes antibiotics, intravenous fluids, pain medication, and surgery. Other measures may include a nasogastric tube or blood transfusion. Without treatment death may occurs within a few days. Approximately 7.5% of people have appendicitis at some point in time. About 20% of people with cirrhosis who are in hospital have peritonitis.

An ecchymosis is a subcutaneous spot of bleeding (from extravasation of blood) with diameter larger than . It is similar to (and sometimes indistinguishable from) a hematoma, commonly called a bruise, though the terms are not interchangeable in careful usage. Specifically, bruises are caused by trauma whereas ecchymoses, which are the same as the spots of purpura except larger, are not "necessarily" caused by trauma, often being caused by pathophysiologic cell function, and some diseases such as Marburg virus disease.

A broader definition of ecchymosis is the escape of blood into the tissues from ruptured blood vessels. The term also applies to the subcutaneous discoloration resulting from seepage of blood within the contused tissue.

Intracranial bleeding occurs when a blood vessel within the skull is ruptured or leaks. It can result from physical trauma (as occurs in head injury) or nontraumatic causes (as occurs in hemorrhagic stroke) such as a ruptured aneurysm. Anticoagulant therapy, as well as disorders with blood clotting can heighten the risk that an intracranial hemorrhage will occur.

Accessory spleens may be formed during embryonic development when some of the cells from the developing spleen are deposited along the path from the midline, where the spleen forms, over to its final location on the left side of the abdomen by the 9th–11th ribs. The most common locations for accessory spleens are the hilum of the spleen and adjacent to the tail of the pancreas. They may be found anywhere along the splenic vessels, in the gastrosplenic ligament, the splenorenal ligament, the walls of the stomach or intestines, the pancreatic tail, the greater omentum, the mesentery or the gonads and their path of descent. The typical size is approximately 1 centimeter, but sizes ranging from a few millimeters up to 2–3 centimeters are not uncommon.

Splenogonadal fusion can result in one or more accessory spleens along a path from the abdomen into the pelvis or scrotum. The developing spleen forms near the urogenital ridge from which the gonads develop. The gonads may pick up some tissue from the spleen, and as they descend through the abdomen during development, they can produce either a continuous or a broken line of deposited splenic tissue.

Splenosis is a condition where foci of splenic tissue undergo autotransplantation, most often following physical trauma or splenectomy. Displaced tissue fragments can implant on well vascularized surfaces in the abdominal cavity, or, if the diaphragmatic barrier is broken, the thorax.

Mortality from aortic rupture is up to 90%. 65–75% of patients die before they arrive at hospital and up to 90% die before they reach the operating room.