Splenic rupture is usually evaluated by FAST ultrasound of the abdomen. Generally this is not specific to splenic injury; however, it is useful to determine the presence of free floating blood in the peritoneum. A diagnostic peritoneal lavage, while not ideal, may be used to evaluate the presence of internal bleeding a person who is hemodynamically unstable. The FAST exam typically serves to evaluate the need to perform a CT. Computed tomography with IV contrast is the preferred imaging study as it can provide high quality images of the full peritoneal cavity.

American Association for the Surgery of Trauma Organ Injury Scaling: Splenic Injury Grading

Diagnosis is confirmed with CT, or bedside ultrasound for less stable patients. Exploratory laparotomy is rarely used, though it may be of benefit in patients with particularly severe hemorrhage. A set of CT scan grading criteria was created to identify the need for intervention (surgery or embolization) in patients with splenic injury. The criteria were established using 20 CT scans from a database of hemodynamically stable patients with blunt splenic injury. These criteria were then validated in 56 consecutive patients retrospectively and appear to reliably predict the need for invasive management in patients with blunt injury to the spleen (sensitivity of 100%, specificity 88%, overall accuracy was 93%).

The study suggested that the following three CT findings correlate with the need for intervention:

1. Devascularization or laceration involving 50% or more of the splenic parenchyma

2. Contrast blush greater than one centimeter in diameter (from active extravasation of IV contrast or pseudoaneurysm formation)

3. A large hemoperitoneum.

Treatment has traditionally been splenectomy. However, splenectomy is avoided if possible, particularly in children, to avoid the resulting permanent susceptibility to bacterial infections. Most small, and some moderate-sized lacerations in stable patients (particularly children) are managed with hospital observation and sometimes transfusion rather than surgery. Embolization, blocking off of the hemorrhaging vessels, is a newer and less invasive treatment. When surgery is needed, the spleen can be surgically repaired in a few cases, but splenectomy is still the primary surgical treatment, and has the highest success rate of all treatments.

A diagnosis of peritonitis is based primarily on the clinical manifestations described above. Rigidity (involuntary contraction of the abdominal muscles) is the most specific exam finding for diagnosing peritonitis (+ likelihood ratio: 3.9). If peritonitis is strongly suspected, then surgery is performed without further delay for other investigations. Leukocytosis, hypokalemia, hypernatremia, and acidosis may be present, but they are not specific findings. Abdominal X-rays may reveal dilated, edematous intestines, although such X-rays are mainly useful to look for pneumoperitoneum, an indicator of gastrointestinal perforation. The role of whole-abdomen ultrasound examination is under study and is likely to expand in the future. Computed tomography (CT or CAT scanning) may be useful in differentiating causes of abdominal pain. If reasonable doubt still persists, an exploratory peritoneal lavage or laparoscopy may be performed. In patients with ascites, a diagnosis of peritonitis is made via paracentesis (abdominal tap): More than 250 polymorphonucleate cells per μL is considered diagnostic. In addition, Gram stain is almost always negative, whereas culture of the peritoneal fluid can determine the microorganism responsible and determine their sensitivity to antimicrobial agents.

In normal conditions, the peritoneum appears greyish and glistening; it becomes dull 2–4 hours after the onset of peritonitis, initially with scarce serous or slightly turbid fluid. Later on, the exudate becomes creamy and evidently suppurative; in dehydrated patients, it also becomes very inspissated. The quantity of accumulated exudate varies widely. It may be spread to the whole peritoneum, or be walled off by the omentum and viscera. Inflammation features infiltration by neutrophils with fibrino-purulent exudation.

MRI use has become increasingly common for diagnosis of appendicitis in children and pregnant patients due to the radiation dosage that, while of nearly negligible risk in healthy adults, can be harmful to children or the developing fetus. In pregnancy, it has been found to be more useful during the second and third trimester, particularly as the enlargening uterus displaces the appendix, making it difficult to find by ultrasound. The periappendiceal stranding that is reflected on CT by fat stranding on MRI appears as increased fluid signal on T2 weighted sequences. First trimester pregnancies are usually not candidates for MRI, as the fetus is still undergoing organogenesis, and there are no long-term studies to date regarding its potential risks or side effects.

Ultrasonography and doppler sonography are useful to detect appendicitis, especially in children. Ultrasound can show free fluid collection in the right iliac fossa, along with a visible appendix with increased blood flow when using color Doppler, and noncompressibility of the appendix, as it is essentially a walled off abscess. Other secondary sonographic signs of acute appendicitis include the presence of echogenic mesenteric fat surrounding the appendix and the acoustic shadowing of an appendicolith. In some cases (approximately 5%), ultrasonography of the iliac fossa does not reveal any abnormalities despite the presence of appendicitis. This false negative finding is especially true of early appendicitis before the appendix has become significantly distended. In addition, false negative findings are more common in adults where larger amounts of fat and bowel gas make visualizing the appendix technically difficult. Despite these limitations, sonographic imaging in experienced hands can often distinguish between appendicitis and other diseases with similar symptoms. Some of these conditions include inflammation of lymph nodes near the appendix or pain originating from other pelvic organs such as the ovaries or Fallopian tubes.

The U.S. Preventive Services Task Force recommends a single screening ultrasound for abdominal aortic aneurysm in males age 65 to 75 years who have a history of smoking. There is an estimated number needed to screen of approximately 850 people. It is unclear if screening is useful in women aged 65 to 75 who have smoked and they recommend against screening in women who have never smoked.

Repeat ultrasounds should be carried out in those who have an aortic size greater than 3.0 cm. In those whose aorta is between 3.0 and 3.9 cm this should be every three years, if between 4.0 and 4.4 cm every two year, and if between 4.5 and 5.4 cm every year.

In the United Kingdom one time screening is recommended in all males over 65 years of age. Australia has no guideline on screening.

Diagnosis of IIA is based on finding an intracranial aneurysm on vascular imaging in the presence of predisposing infectious conditions. Positive bacterial cultures from blood or the infected aneurysm wall itself may confirm the diagnosis, however blood cultures are often negative. Other supporting findings include leukocytosis, an elevated erythrocyte sedimentation rate and elevated C-reactive protein in blood.

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.

The usual treatment is splenopexy, fixation of the spleen, but if there is no blood flow after unwinding the spleen through detorsion then splenectomy must be performed. Although there have been few reported cases of treatment through laparoscopic surgery due to the rarity of the disease, it has been proven to be an effective surgical technique.

Stable patients presenting to A&E (accident and emergency department) or ER (emergency room) with severe abdominal pain will almost always have an abdominal x-ray and/or a CT scan. These tests can provide a differential diagnosis between simple and complex pathologies. However, in the unstable patient, fluid resuscitation and a FAST-ultrasound are done first, and if the latter is positive for free fluid, straight to surgery. They may also provide evidence to the doctor whether surgical intervention is necessary.

Patients will also most likely receive a complete blood count (or full blood count in the U.K.), looking for characteristic findings such as neutrophilia in appendicitis.

Traditionally, the use of opiates or other painkillers in patients with an acute abdomen has been discouraged before the clinical examination, because these would alter the examination. However, the scientific literature does not reveal any negative results from these alterations.

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.

CT scan (computed tomography) is the definitive tool for accurate diagnosis of an intracranial hemorrhage. In difficult cases, a 3T-MRI scan can also be used.

When ICP is increased the heart rate may be decreased.

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.

A "subarachnoid hemorrhage" is bleeding into the subarachnoid space—the area between the arachnoid membrane and the pia mater surrounding the brain. Besides from head injury, it may occur spontaneously, usually from a ruptured cerebral aneurysm. Symptoms of SAH include a severe headache with a rapid onset ("thunderclap headache"), vomiting, confusion or a lowered level of consciousness, and sometimes seizures. The diagnosis is generally confirmed with a CT scan of the head, or occasionally by lumbar puncture. Treatment is by prompt neurosurgery or radiologically guided interventions with medications and other treatments to help prevent recurrence of the bleeding and complications. Since the 1990s, many aneurysms are treated by a minimal invasive procedure called "coiling", which is carried out by instrumentation through large blood vessels. However, this procedure has higher recurrence rates than the more invasive craniotomy with clipping.

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.

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.

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.

First symptoms may be subtle such as mild pain, flank tenderness, haematuria. Depending on blood loss, symptoms of hypovolemic shock may develop. Hematoma is usually contained in the retroperitoneum, allowing for a period of haemodynamic stability. Sometimes massive acute hemorrhage is seen when a hematoma ruptures Gerota's fascia and extends into the peritoneum. An ultrasound or CT scan can establish diagnosis, while lab tests may be inconclusive as changes of haematocrit or haemoglobin are not specific to the syndrome, while haematuria is not always present.

Abdominal aortic aneurysms are commonly divided according to their size and symptomatology. An aneurysm is usually defined as an outer aortic diameter over 3 cm (normal diameter of the aorta is around 2 cm), or more than 50% of normal diameter. If the outer diameter exceeds 5.5 cm, the aneurysm is considered to be large.

A ruptured AAA is a clinical diagnosis involving the presence of the triad of abdominal pain, shock, and a pulsatile abdominal mass. If these conditions are present, indicating AAA rupture, no further clinical investigations are needed before surgery.

Symptoms include an enlargement in the size of the spleen, or a change from the spleen's original position to another location, usually in either other parts of the abdomen or into the pelvis. This ability to move to other locations is commonly attributed to the spleen's pedicle being abnormally long.

Physical factors may cause ischuria, constipation, as well as numerous spleen-related diseases such as hypersplenism, thrombocytopenia, and lymphoma. Blocking of the arteries and torsion in the spleen can also result in abdominal pain or swelling. However, lack of visible symptoms — except in incidents of abdominal pain — makes the disease difficult for doctors to diagnose, though medical imaging techniques such as medical ultrasonography, magnetic resonance imaging, or computed tomography can be used to confirm its occurrence.

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.