Intra-abdominal infections: pathophysiology, diagnosis and treatment

Posted by Doctor Le Van Binh - Intensive Care Unit - Vinmec Times City International Hospital

Intra-abdominal infection is a complicated disease in both diagnosis and treatment, when the disease has a high risk of death if not promptly intervened. So how is the examination and treatment done?

Intra-abdominal infections including peritonitis, biliary tract infection, splenic abscess, appendicitis, diverticulitis, and infection following loss of intestinal integrity due to trauma or surgery. Most common syndromes are infections at a sterile site of the abdomen caused by intestinal flora.
Peritonitis is a common syndrome caused by many causes. As for peritoneal infections, it is often severe because of easy access to existing pathogens and easy to spread to the entire peritoneal cavity.
The peritoneum (peritoneum) has two leaves, an area of ​​about 1.6 - 2m2 (equal to the area of ​​the skin). Parietal leaves have nerve fibers to go to, so they are easy to respond and sensitive to stimuli, inflammation....the visceral receptors are less. In terms of pathophysiology, the peritoneum is an osmotic membrane, capable of rapidly reabsorbing a volume of fluid put into the peritoneal cavity (the basis for peritoneal dialysis), but the absorption is non-selective, causing inflammation. heavier peritoneum.
The peritoneum has the ability to resist infection due to phagocytic activity and inflammatory response by the encirclement of intestinal loops, omentum, mesentery... When the peritoneal inflammation will move a large amount of water , electrolytes and proteins into the peritoneal cavity, the subperitoneal connective tissue, into the dilated intestinal lumen, but unable to absorb. Finally, the body loses water and electrolytes, giving the face a general, peritoneal appearance (Facies Feritoneal).
Peritoneal shock is also caused by the above phenomenon, in addition, it is also caused by bacterial toxins that damage the myocardium.

2.1. By progression divided into acute generalized peritonitis Focal peritonitis (abscesses) 2.2. According to etiology, it is divided into primary peritonitis Secondary peritonitis

3.1. Learn about general characteristics Bacteria are usually only one type (2/3 are hemolytic streptococci, 1/3 are staphylococcus aureus) and are common in children under 10 years of age. Some of the symptoms that the patient may experience are:
Signs and symptoms at the time of diagnosis in 489 patients with
spontaneous bacterial peritonitis

3.2. Treatment of primary peritonitis Basically, when primary peritonitis is diagnosed, the patient is usually prescribed by the doctor for the main medical treatment. In case of doubt, surgery is necessary to avoid missing secondary peritonitis.
In particular, in primary peritonitis, it is important to pay attention to primary peritonitis caused by tuberculosis
Common in young age 10 - 40 years old (usually over 10 -20 years old). Most are associated with tuberculosis elsewhere, especially in the lungs. Progression by blood and lymphatic routes, or from tuberculosis appendages Ascites, if poke is characterized: yellow fluid, Rivalta reaction (positive) (40 -70g Protein / liter), sometimes showing semi-obstruction. Treatment: specific antibiotics, nutrition and rest.

4.1. General Features This is a common clinical type, infection usually begins in an intra-abdominal viscera and then diffuses infection, sometimes due to rupture. Commonly associated bacteria are Ecoli, pyogenic streptococci, staphylococci, pneumococci....
Table 1: Bacteria causing complex intra-abdominal infections

Pathological anatomy: serosa, mainly visceral peritoneum thickened, vascular proliferation, edema, mesenteric omentum thicken.

Figure 2: Picture of peritonitis
Peritoneal fluid is often cloudy, may be odorless, based on the nature of peritoneal fluid, we can diagnose the cause.
4.2. Common etiology Perforated appendicitis Perforated peptic ulcer Perforated diverticulum Necrotizing bowel torsion Cholecystitis Peritoneal perforation Peritoneal perforation Perforated liver abscess Postoperative fistula... 4.3. Possible symptoms Clinical symptoms usually depend on 2 factors: Bacterial toxicity and body resistance. There are 2 syndromes including:
Infectious syndrome Peritonitis syndrome The patient may experience some functional symptoms such as:
Localized pain at first, then diffuse. Vomiting is often caused by reflex stimulation in the early stages, and later, it is caused by paralytic ileus. Hiccups due to diaphragmatic irritation (early stage). The patient is usually in the analgesia position (thigh flexion of the knee). In the desired stage, you may encounter manifestations such as bowel obstruction, vomiting, bowel obstruction... Physical symptoms are important and common symptoms such as:
Abdomen does not participate in breathing Straight muscles are clearly prominent Indian hard as wood. Abdominal wall spasticity is common in early, young, healthy patients with obvious spasticity where the viscera were injured from the beginning.
Sotkin-Blumberg sign (-) (peritoneal induction sign). Percussion is often low-pitched, high-pitched echoes (due to intestinal distention) or pre-hepatic echoes in perforated peptic ulcers. Auscultation is often seen with loss of bowel motility or decreased bowel movements due to paralytic ileus. Examination of the sac is rectally or transvaginally, often with bulging and painful Donglas signs. (Donglas sound) The puncture has pus or cloudy fluid. Emergency endoscopy for diagnosis and treatment.

Subclinical factors are factors that help confirm the diagnosis.
X-ray of the abdomen without preparation can show: Abdomen is translucent, bowel wall is thicker than normal, bowel loops are dilated (due to functional bowel paralysis), there may be a crescent below the diaphragm in perforation of hollow viscera. Blood tests: Help to monitor and evaluate the progress of the disease. White blood cells increase (weak patients, severe poisoning sometimes when white blood cells decrease). Hematocrit increases due to dehydration. Electrolyte disturbances often decrease K, Cl. Blood urea is elevated in severe conditions with kidney failure. 4.4. Diagnosis of secondary peritonitis The definitive diagnosis is based on the following:
Systemic infection syndrome There is abdominal wall reaction, peritoneal induction. Positive Blumberg sign. On rectal examination, the vaginal sac is also distended and painful. Differential diagnosis: peptic ulcer, renal colic, hepatic colic, intestinal obstruction (crushing pain). Diagnosis of the cause should be based on:
History. The nature of pain and initial pain location ... It is necessary to pay attention to the common causes in clinical practice first (acute appendicitis ruptured, perforated peptic ulcer, biliary obstruction due to stones ...).

4.5. Treatment of secondary peritonitis The first principle should be surgical treatment combined with aggressive surgical resuscitation. Surgical resuscitation:
Fluids, electrolytes to rehydrate, electrolytes. Adjust acid-base balance. Strong, broad-spectrum antibiotics, preferably by antibiogram. Ensure respiration, cool down ... Table 2: Antibiotic experience in the treatment of intra-abdominal infections

For surgical treatment include:
Principle: Surgery as soon as possible on the basis of active resuscitation. Sometimes both resuscitation and surgery.
Content of surgery to solve the cause: Cut the appendix, stitch the hole.... Wipe the abdominal cavity clean, pay attention to the low areas, the pits. Effective drainage (location, size, ... of the drain, early withdrawal, no adhesions, infection).

These are essentially abscesses in the peritoneal cavity. The name depends on the location of the abscess
5.1. Subdiaphragmatic Abscess Abscesses located above the transverse colon are uncommon, more difficult to diagnose and treat, and have a high mortality rate of 10-90%. The condition often occurs after perforation of a peptic ulcer of the stomach - duodenum, necrotizing cholecystitis, acute necrotizing pancreatitis, liver abscess .....
Some specific symptoms can be mentioned such as:
Increased pain when breathing deeply Pulmonary and bronchial symptoms such as irritable cough, shortness of breath. Diaphragm is pushed up, poor mobility, exudate at costal angle of diaphragm........ Treatment, first of all, prevention is important, because 50% of Abces below the diaphragm are due to postoperative fistula due to anastomosis, Poor hemostasis, poor drainage, infection during surgery...
True treatment such as:
Broad-spectrum antibiotics Open drainage of pus, depending on the location, there are different entrances. Pay attention not to infect the peritoneal cavity, the drainage must be wide, can be prolonged 5.2. Appendiceal abscess The cause was determined to be localized ruptured acute appendicitis. Diagnosis and treatment is difficult when the appendix is ​​located in an abnormal position such as under the liver, left iliac fossa, as in the right iliac fossa, is common.
Major manifestations:
There is a history of acute appendicitis. At the right iliac fossa: There is a bulging mass, clearly demarcated on the inside, sharp pain, not mobile. Surgery is the main treatment, the aim is to drain the abscess. The main rule is to go low (Roux), extraperitoneal does not spread pus into the abdomen, do not seek appendectomy.

5.3. Abscess in the baby's pelvis is caused by an infection from the organs in the pelvis. Some individual symptoms can be mentioned such as:
Symptoms of irritation of the rectum, bladder (sadness to have bowel movements, mucus discharge, painful urination, frequent urination ...). Proctoscopy, vagina: Douglas tension and pain. Treatment of purulent incision through the rectum and vagina.
Because this is a disease with complicated and dangerous developments, so when the body shows the initial signs of onset, the patient should go to medical facilities to be checked by a doctor and have instructions. timely card.
Treatment of the peritoneal cavity is very important and requires good technique, so you should choose a reliable and reputable medical facility. Vinmec International General Hospital is one of the prestigious and quality medical addresses that is highly appreciated by experts and patients. When here, there is a team of highly qualified domestic and international doctors and nurses who will directly participate in the process of diagnosing and treating patients. In addition, the system of equipment and facilities at the hospital is modern and advanced, effectively supporting accurate disease detection and effective treatment.

REFERENCES
https://www.uptodate.com/contents/spontaneous-bacterial-peritonitis-in-adults diagnosis/print?search = peritonitis&source = search_result & selectedTitle = 2~150&usage_type=default&display_rank=2 https:// www.uptodate.com/contents/pathogenesis-of-spontaneous-bacterial-peritonitis?search=peritonitis&source=search_result&selectedTitle=6~150&usage_type=default&display_rank=6 https://www.uptodate.com/contents/spontaneous-bacterial-peritonitis-in -adults-clinical-manifestations?search=peritonitis&source=search_result&selectedTitle=4~150&usage_type=default&display_rank=4 https://www.uptodate.com/contents/spontaneous-bacterial-peritonitis-in-adults-treatment-and-prophylaxis?search= peritonitis&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1