Acute Abdomen

Introduction

These are abdominal conditions causing sudden or severe pain, that require immediate or urgent attention. Cause may be surgical in nature or medical diseases.
Medical conditions should always be borne in mind as they would usually not require surgical intervention.
Common surgical and medical causes are detailed in Table 1. In newborns, intestinal obstruction (Table 2) is the commonest cause of acute abdomen and their care is different from that of adults and older children.

Causes of acute abdomen

Table 1

Causes of Neonatal Intestinal Obstruction

Table 2

Clinical Evaluation

A detailed history should be taken and
meticulous and thorough physical
examination done. However, prompt
resuscitation should not be sacrificed for
taking too much time for history and  examination.
Clinical evaluation and resuscitation should as much as feasible be done simultaneously to save time.
In Acute abdominal pain note the following:

  • Location
  • Onset and progression
  • Nature and character
  • Aggravating and relieving factors
  • Abdominal distension
  • A past history of similar pain suggests complication of an underlying condition

In typhoid perforation, fever precedes
abdominal pain, while the reverse is true for acute appendicitis
Nausea and vomiting:

  • A frequent finding
  • Common in intestinal obstruction

Altered bowel habits:

  • Diarrhoea may suggest an infective/ inflammatory condition

Constipation occurs in intestinal obstruction and late in peritonitis
The presence or absence of blood, mucus in stool should be ascertained
Fever:

  • An early feature in inflammatory/ infective conditions
  • A late feature in most other causes of acute abdomen

Gynaecologic history:

  • In every female, the following should be
    ascertained

Last menstrual period:

  • this will help in the suspicion of ectopic gestation and bleeding Graffian follicle

Vaginal discharge:

  • salpingitis

Urinary symptoms:
Ascertain the presence or absence of the following

  • Pain on micturition
  • Pus in urine or cloudy urine
  • Urethral discharge
  • Loin pain

Past medical history:

  • Diabetes mellitus
  • Sickle cell disease

Physical examination:

  • General examination
  • Dehydration
  • Temperature (the exact temperature should be taken with a thermometer: oral, axillary or rectal temperature)
  • Pallor
  • Jaundice
  • Foetor (as in diabetic ketoacidosis etc.)
  • Haemodynamic status:
  • Pulse rate: >100/minute is abnormal
  • Blood pressure: <100 mmHg systolic and <60 mmHg diastolic pressures indicate hypotension in an adult

Chest:

  • Examine carefully for evidence of chest infection

Abdomen:

  • Distension
  • Presence of scars of previous surgery or bruising in trauma
  • Visible peristalsis (suggests intestinal obstruction)

General peritonitis:

  • There may be no movement with respiration

Ascertain the site of tenderness
Localized:

  • Right iliac fossa (appendicitis, gynaecologic conditions etc.)
  • Right hypochondrium (cholecystitis)

Generalised:

  •  varied causes
  • As much as possible any palpable mass should be characterized
  • If tenderness is not too marked, ascertain the presence of free fluid in the peritoneal cavity by shifting dullness or fluid thrill (ascites)
  • Listen for bowel sounds
  • Diminished or absent in peritonitis;
    exaggerated in early stages of intestinal obstruction

Rectal examination:

  • Look for perianal soilage
  • Presence or absence of faeces in rectum
  • Palpate rectovesical pouch or
    rectouterine pouch (of Douglas) for  bogginess and tenderness indicating a pelvic collection of pus or blood
  • Examine the faeces on the examining finger for blood, mucus

Vaginal examination:

  • May be necessary to exclude gynaecological conditions

Differential Diagnosis

Give very careful thought to findings at
clinical evaluation and list of possible causes and then make a list 3 – 5 possible
differential diagnosis before proceeding to carry out relevant investigations.

Investigations

Plain radiography

Abdomen:

  • Supine and upright films to identify
    features of intestinal obstruction (dilated bowel loops and multiple fluid levels)
  • Aradio-opaque shadow may be seen in the region of the urinary tract in ureteric colic

Chest:

  • An upright film may identify gas under the diaphragm in gastrointestinal perforation
  • Chest infection should also be looked for

Abdomino-pelvic ultrasonography:

  • Should help to ascertain the cause of pain in a proportion of the patients (e.g. cholecystitis, gynaecologic conditions, urinary calculi, and degenerating masses)
  • May identify injured solid organ in
    trauma

Diagnostic peritoneal lavage:

  • Useful in abdominal trauma to identify haemoperitoneum and leakage of gastrointestinal contents and secretions of other organs into the peritoneal cavity

Biochemical tests:

  • Urinalysis: test the urine for sugar,
    protein, ketones, etc
  • Random blood sugar to exclude diabetes mellitus
  • Serum electrolytes and urea; correction may be needed
  • Serum amylase to exclude acute pancreatitis

Haematological tests:

  • Haemogram to exclude anaemia
  • Packed cell volume may not be reliable because of haemoconcentration from dehydration
  • If there is suspicion of sickle cell disease, the haemoglobin genotype should be obtained
  • A complete blood count may show
    evidence of acute infection (leucocytosis, neutrophilia)
  • Blood should be grouped, and compatible blood cross-matched and made ready

Other investigations:

  • Computed tomography may be needed when there is diagnostic confusion
  • Cultures: any suspicious fluid and
    materials should be obtained and sent for microbiology and culture (e.g. vaginal discharge, peritoneal fluid)

Management

Resuscitation and General Measures
In most patients, resuscitation and
institution of some general measures are
necessary before proceeding to definitive
treatment of the condition.
Time taken to adequately resuscitate the
patient is critical to achieving a good
outcome and preventing/minimizing
morbidity and mortality.,
Monitored very closely by repeated
examinations and electronic monitoring to identify when patient is adequately
resuscitated
Avoid time wasting as well as identify
patients who are not responding to
resuscitation and require additional
measures.
Surgery may become part of resuscitation as a damage control measure but such surgery is usually limited in extent.
General measures

  • Resuscitation
  • Rehydration and correction of electrolyte derangements
  • Correct shock by giving crystalloids (sodium chloride 0.9%, Ringer’s lactate) or colloid (e.g. dextran)
  • Maintenance fluids are calculated based on degree of dehydration
  • Correct electrolyte deficits (especially potassium)
  • Nasogastric decompression: the largest possible size of tube for patient
  • Aspirate intermittently using low pressure suction or large syringe
  • Urethral catheterization (to monitor urine output)
  • Correct anaemia (by blood transfusion)
  • Commence broad spectrum, intravenous antibiotics effective against likely microorganisms
  • Do not give aminoglycosides until
    urine output is adequate

Monitor the following parameters to ensure adequate rehydration:

  • Cardio-respiratory stability
  • Pulse rate
  • Blood pressure
  • Central venous pressure
  • Pulmonary capillary wedge pressure
  • Urine output, volume, colour
  • Hydration status
  • Skin turgor
  • Sensorium
  • Ascertain level of consciousness

Evidence of adequate resuscitation

  • Pulse rate begins to fall towards, or below 100 beats/minute
  • Blood pressure: begins to towards normal
  • Urine output: 50-100mL/hr (1 – 2 ml/kg/hr); clear or amber

Definitive Treatment

Once the patient is adequately resuscitated, definitive treatment can proceed. The treatment of newborns with intestinal obstruction is summarized in Table 3.

Surgical conditions:

Most of the surgical conditions will require urgent laparotomy after adequate resuscitation

  • Evacuation of pus, blood and all infected material
  • Meticulous examination of all organs and recesses
  • Identify primary pathology
  • Identify other associated/coexisting pathology
  • Treat identified pathologies on their merits
  • Cleanse peritoneal cavity with large volumes of warm sodium chloride 0.9%

Medical conditions:

Consult a physician as appropriate, to treat the condition accordingly
It’s important that repeated examination and monitoring continues during and after definitive treatment to identify any problems and promptly attend to them.
Table 3: Neonatal Intestinal Obstruction: recognition and management

Prognosis

Outcome and survival depends on:

  • Early presentation and diagnosis
  • Prompt and adequate resuscitation before surgery
  • Appropriate and meticulous surgery and other treatments as indicated