Intra-abdominal abscess: Clinical sciences

Intra-abdominal abscesses are a dangerous type of infection that, if left untreated, can progress to sepsis and death. They commonly arise from disruptions in the gastrointestinal or genitourinary tract, either from inflammation that causes microscopic leaks in the mucosal barrier or on a gross level from surgery or trauma. Disruption allows intra-luminal bacteria to leak into the abdominal cavity and cause infection.

Now, the immune system may try to contain the infected fluid by forming a discrete, walled-off pocket, called an intra-abdominal abscess. If the infection doesn’t remain contained within the abscess, the free fluid containing the pathogen can lead to diffuse peritonitis. Based on the location, localization, and contents of the abscess, they can be grouped as abscesses with and without complicating features.

When a person presents with signs and symptoms suggestive of an intra-abdominal abscess, you should first perform an ABCDE assessment to determine whether they are stable or unstable. If the individual is unstable, you need to stabilize their airway, breathing, and circulation, which usually involves intubation, establishing an IV access, or administering fluids.

Once you stabilize them, the next step is to obtain a focused history and physical examination, which might reveal signs and symptoms of diffuse peritonitis. These patients often report severe, diffuse abdominal pain that worsens with movement. Additionally, the physical exam might reveal distention, rigidity, guarding, and rebound tenderness. If this is the case, start empiric IV antibiotics and consult the surgical team immediately for further management, including imaging like CT scan, or bedside ultrasound if the patient is too unstable, followed by emergent laparotomy to explore and treat the infection.

Alright, now let’s take a look at a stable patient that presents with signs and symptoms suggestive of intra-abdominal abscess. Start with a thorough history and physical exam, and obtain labs like CBC, CMP, blood cultures, and urinalysis. Patients with an intra-abdominal abscess usually report abdominal pain, loss of appetite, constipation, diarrhea, nausea, vomiting, or bloating.

Next, ask about any recent surgeries, since many intra-abdominal abscesses occur after abdominal surgery. Another major risk factor is a history of recent gastrointestinal inflammatory conditions, such as appendicitis, diverticulitis, Crohn’s disease, as well as cholecystitis, pancreatitis, and pelvic inflammatory disease. Finally, some patients will have a history of a perforated ulcer, penetrating abdominal trauma, or bowel infarction that eventually resulted in an intra-abdominal abscess.

On the other hand, the physical exam might reveal focal tenderness and a mass in the region of the abscess. Additionally, there might be signs of dehydration and infection or a systemic inflammatory response, like elevated temperature, tachycardia, and tachypnea. Some high-yield facts to keep in mind! Depending on the abscess location, individuals might have specific symptoms caused by local inflammation in the area of the abscess. A subphrenic abscess right below the diaphragm can cause shoulder pain or hiccups due to irritation of the diaphragm. On the flip side, a pelvic abscess can cause frequent urination or tenesmus.

Now, when it comes to labs, the CBC usually reveals leukocytosis and the lactate level can be elevated. In addition, labs may reveal abnormal results specific to the organ system or abdominal region involved, such as elevated amylase or lipase if there’s pancreatitis, elevated liver enzymes if there’s a liver source or septic shock causing organ failure, and abnormal urinalysis results like leukocyte esterase if there’s a genitourinary source. Lastly, blood cultures might be positive for bacterial growth. Specifically, blood cultures positive for anaerobes should make you suspect an intra-abdominal abscess.