Abdominal compartment syndrome (ACS) is a life-threatening clinical state of increased intra-abdominal compartment pressure (IAP) of more than 20 mmHg. Radiological diagnosis is difficult and usually suggested when a collection of imaging findings are present in the appropriate clinical setting or if the signs on sequential imaging studies are seen to progress. Diagnosis is usually clinically supported by elevated intravesicular pressure which closely parallels intra-abdominal compartment pressure.
Abdominal compartment syndrome is defined as elevated intra-abdominal compartment pressure (IAP) >20 mmHg with dysfunction of at least one thoracoabdominal organ. It may be known as intra-abdominal hypertension (IAH), but this specifically refers to IAH >12 mmHg without the clinical manifestations.
Patients present with one or many organs failing due to the elevated pressure in the abdomen having direct or indirect effects on the major body systems. Most patients will have abdominal distension. Patients often have multifactorial disease and injuries, and abdominal compartment syndrome is particularly associated with:
- acute respiratory distress syndrome (ARDS)
- hypovolemic shock
- systemic inflammatory response syndrome (SIRS)
- multiorgan dysfunction syndrome (MODS)
Typically, the severely ill patient is in the intensive care/therapy unit (ICU/ITU) and clinically presents with massive abdominal distention, anuria or progressive oliguria despite adequate cardiac output and/or increasingly difficult mechanical ventilation.
The elevated intra-abdominal compartment pressure (IAP) in abdominal compartment syndrome has numerous causes which can be subdivided accordingly:
- primary (abdominopelvic disease or injury)
- secondary (disease or injury outside the abdomen and pelvis)
There are several overlapping CT and sonographic signs that may support the diagnosis but none are considered specific or sensitive for abdominal compartment syndrome (ACS) 2:
- elevated diaphragm
- rounded appearance of the abdominal wall (round belly sign 4)
- flattened inferior vena cava and renal veins
- displacement of solid abdominal viscera
- mosaic liver perfusion
- increased bowel and gastric wall thickening and enhancement
- gastric distention
- increase in ascites over subsequent scans
- bilateral inguinal herniation
- pulmonary basal consolidation, collapse and/or pleural effusion
- reduced diastolic flow in portal, hepatic, and/or renal veins
Treatment and prognosis
Mortality is high in abdominal compartment syndrome ranging between 60-70% 2. Treatment is aimed at reducing the elevated pressure within the abdomen to correct the reduced perfusion of the affected viscera and prevent irreversible organ failure. This is achieved surgically with decompressive laparotomy but mortality remains high after surgery, reflecting the multifactorial physiological disturbances in these critically ill patients 3. After laparotomy, the abdomen is often left open in those who are at high risk of developing abdominal compartment syndrome.
Other treatment strategies include drainage of fluid collections with non-operative methods and muscle relaxation.
- 1. Sugrue G, Malbrain MLNG, Pereira B, et al. Modern imaging techniques in intra-abdominal hypertension and abdominal compartment syndrome: a bench to bedside overview. (2018) Anaesthesiology intensive therapy. 50 (3): 234-242. doi:10.5603/AIT.a2017.0076 - Pubmed
- 2. Patel A, Lall CG, Jennings SG, et al. Abdominal compartment syndrome. (2007) AJR. American journal of roentgenology. 189 (5): 1037-43. doi:10.2214/AJR.07.2092 - Pubmed
- 3. De Waele JJ, Hoste EA, Malbrain ML. Decompressive laparotomy for abdominal compartment syndrome--a critical analysis. (2006) Critical care (London, England). 10 (2): R51. doi:10.1186/cc4870 - Pubmed
- 4. Pickhardt PJ, Shimony JS, Heiken JP, et al. The abdominal compartment syndrome: CT findings. (1999) AJR. American journal of roentgenology. 173 (3): 575-9. doi:10.2214/ajr.173.3.10470882 - Pubmed