Acute abdomen – how to arrive at a diagnosis 

Dr. HARSHAVARTHINI.M

• An acute abdomen” denotes any sudden, spontaneous, non traumatic disorder whose chief manifestation is in the abdominal area and for which urgent operation may be necessary. Because there is frequently a progressive underlying intra-abdominal disorder, undue delay in diagnosis and treatment adversely affects outcome
• The approach to a patient with an acute abdomen must be orderly and thorough. An acute abdomen must be suspected even if the patient has only mild or atypical complaints. 

CAUSES:

• Common Causes of the Acute Abdomen. 
• Gastrointestinal tract disorders 
• Nonspecific abdominal pain
• Appendicitis
• Small and large bowel obstruction
• Perforated peptic ulcer
• Incarcerated hernia 
• Bowel perforation 
• Diverticulitis
• Inflammatory bowel disorders 
• Gastroenteritis 
• Acute gastritis 
• Parasitic infections 
• Acute cholecystitis
• Acute cholangitis
• Hepatic abscess
• Acute hepatitis
• Pancreatic disorders
• Acute pancreatitis 

URINARY TRACT DISORDERS

• Urethral or renal colic
• Acute pyelonephritis
• Acute cystitis
• Renal infarct

GYNECOLOGIC DISORDERS 

• Ruptured ectopic pregnancy
• Twisted ovarian tumor
• Ruptured ovarian follicle cyst
• Acute salpingitis
• Dysmenorrhea 
• Endometrios 

VASCULAR DISORDERS

• Ruptured aortic and visceral aneurysms
• Acute ischemic colitis
• Mesenteric thrombosis
• Peritoneal disorders 

SYMPTOMS:

• Nausea
• Vomiting
• Appetite alteration
• Faintness
• Previous indigestion
• Jaundice
• Bowel habit
• Micturation
• Gynaecological symptoms 
• VISCERAL PAIN: Elicited by distension, by inflammation or ischemia stimulating the receptor neurons, or by direct involvement (e.g., malignant infiltration) of sensory nerves. 
• The centrally perceived sensation is generally slow in onset, dull, poorly localized, and protracted
• PARIETAL PAIN : is mediated by both C and A delta nerve fibers, the latter being responsible for the transmission of more acute, sharper, better-localized pain sensation. 
• Direct irritation of the somatically innervated parietal peritoneum (especially the anterior and upper parts) by pus, bile, urine, or gastrointestinal secretions leads to more precisely localized pain Referred pain :denotes noxious (usually cutaneous) sensations perceived at a site distant from that of a strong primary.
• Referred pain :denotes noxious (usually cutaneous) sensations perceived at a site distant from that of a strong primary.
• Spreading or shifting pain parallels the course of the underlying condition. 
• The site of pain at onset should be distinguished from the site at presentation•
• Mode of Onset and Progression of Pain The mode of onset of pain reflects the nature and severity of the inciting process. Onset may be explosive (within) 

OTHER SYMPTOMS

• Associated with Abdominal Pain
• Vomiting.
• The absence of bile in the vomitus is a feature of pyloric stenosis. Where associated findings suggest bowel obstruction, the onset and character of vomiting may indicate the level of the lesion.
• Severe, uncontrollable retching provides temporary pain relief in moderate attacks of pancreatitis. 

CHARACTER OF PAIN : 

• The nature, severity, and periodicity of pain provide useful clues to the underlying cause
• Sharp superficial constant pain due to severe peritoneal irritation is typical of perforated ulcer or a ruptured appendix, ovarian cyst, or ectopic pregnancy
• The gripping, mounting pain of small bowel obstruction (and occasionally early pancreatitis) is usually intermittent, vague, deep-seated, and crescendo at first but soon becomes sharper, unremitting, and better localized
• Unlike the disquieting but bearable pain associated with bowel obstruction, pain caused by lesions occluding smaller conduits (bile ducts, uterine tubes, and ureters) rapidly becomes unbearably intense.
• colic if there are pain-free intervals that reflect intermittent smooth muscle contractions, as in ureteral colic
• “biliary colic” is a misnomer because biliary pain does not remit. The reason is that the gallbladder and bile duct, in contrast to the ureters and intestine, do not have peristaltic movements
• The “aching discomfort” of ulcer pain
• The “stabbing, breathtaking” pain of acute pancreatitis and mesenteric infarction
• The “searing” pain of ruptured aortic aneurysm. 

Physical Examination

• The tendency to concentrate on the abdomen should be resisted in favour of a methodical and complete general physical examination.
• A systematic approach to the abdominal examination.
• One should search for specific signs that confirm or rule out differential diagnostic possibilities. 

SYSTEMIC SIGNS: 

• Extreme pallor,
• Hypothermia, 
• Tachycardia, 
• Tachypnea, 
• Sweating suggest major intra-abdominal hemorrhage (e.g., ruptured aortic aneurysm or tubal pregnancy).
• Fever:• Constant low-grade fever is common in inflammatory conditions such as diverticulitis, acute cholecystitis, and appendicitis.
• High fever with lower abdominal tenderness in a young woman without signs of systemic illness suggests acute salpingitis.
• Disorientation or extreme lethargy combined with a very high fever (> 39 C) or swinging fever or with chills and rigors signifies impending septic shock. This is most often due to advanced peritonitis, acute cholangitis, or pyelonephritis. However, fever is often mild or absent in elderly, chronically ill, or immuno suppressed patients with a serious acute

GENERAL INSPECTION:

• Observe the patient
• Body structure [ obese, healthy, cachectic]
• Pulse
• Respiration
• Blood pressure
• Look for discolouration
• Look for distension [ascites, organomegaly]

OBSERVE THE EXTREMITIES:

• Look for leukonychia
• Koilonychias
• Look for clubbing
• Pallor [ chronic liver disease]
• Dupuytren’s contracture[ liver cirrhosis]

• Asterixis [ flapping tremor – hepatic encephalopathy]. 
• Look for any bruises
• Spider navy
• Petechiae
• Look for hyper pigmentation – acanthosis nigricans [ GI Malignancy]
• EYES:
• Look for pallor and jaundice
• MOUTH:
• Angular stomatitis [ iron deficiency]
• Glossitis 
• Mouth ulcer [ crohn’s disease]

AUSCULTATION:

•           Auscultate for bowel sounds are any obstructions if any.

PALPATION:

• Superficial palpation:
• Mass
• Tenderness
• Muscle guarding
• Rebound tenderness
• Observe the patient face while examining

DEEP PALPATION:

• Lay your hand flat on the abdomen and flex the fingers.
• Assess the shape, size and consistency of any mass if found 
• LIVER PALPATION: feel for spleen moving towards your index finger during inspiration. Examination of the acute abdomen : Inspection: The abdomen should be thoughtfully inspected before palpation.
• A tensely distended abdomen with an old surgical scar suggests both the presence and the cause (adhesions) of small bowel obstruction.
• A scaphoid contracted abdomen is seen with perforated ulcer. visible peristalsis occurs in thin patients with advanced bowel obstruction.

PERCUSSION:

        To note if any abnormality is heard in case of ascites, cirrhosis of liver etc.

• Percussion serves several purposes.
• Tenderness on percussion is akin to eliciting rebound tenderness; both reflect peritoneal irritation and parietal pain.
• With a perforated viscus, free air accumulating under the diaphragm may efface normal liver dullness.
• Tympany near the midline in a distended abdomen denotes air trapped within distended bowel loops.

INVESTIGATION:

•  General Principles of Timing of Diagnostic Studies in an Acute Abdomen Immediate Same Day Next Day Blood Hematocrit, white Clotting studies, Specific tests. blood cell count, amylase, liver urea, creatinine, function tests. cross matching, arterial gases.
• Urine Microscopy, Specific tests. dipstick testing, culture.
• Urine Tests: Dark urine or a raised specific gravity reflects mild dehydration in patients with normal renal function.
• Hyper bilirubinemia may give rise to tea- colored urine that froths when shaken.
• Microscopic hematuria or pyuria can confirm ureteral colic or urinary tract infection and obviate a needless operation.o Dipstick testing (for albumin, bilirubin, glucose, and ketones) may reveal a medical cause of an acute abdomen.Pregnancy tests should be ordered if there is a history of a missed period.
• Stool Occult blood. Warm smear, culture.
• Stool Tests: Occult fecal blood :• positive test points to a mucosal lesion that may be responsible for large bowel obstruction or chronic anemia, or it may reflect an unsuspected carcinoma.o Warm stool smears :for bacteria, ova, and animal parasites may demonstrate amebic trophozoites in patients with bloody or mucous diarrhea.o Stool samples for culture should be taken in patients with suspected gastroenteritis.
• Radiography and Chest, abdomen Ultra sonography Repeat abdominal ultrasound or CT scan, films; barium angiography, enema or small water-soluble.
• Imaging Studies Plain Chest X-Ray Studies : An erect chest x-ray is essential in all cases of an acute abdomen. it is vital for preoperative assessment, but it may also demonstrate supra diaphragmatic conditions that simulate an acute abdomen (e.g., lower lobe pneumonia or ruptured esophagus). 
• An elevated hemi diaphragm or pleural effusion may direct attention to subphrenic inflammatory lesions.
• Plain Abdominal X-Ray Studies: Plain supine films of the abdomen should be obtained only selectively. erect (or lateral decubitus) views contribute little additional information except in suspected intestinal obstruction. 
• Plain films are indicated in patients who have appreciable abdominal tenderness or distension, abnormal bowel sounds, a history of abdominal surgery, suspected foreign body ingestion, or who have a depressed sensorium or are in a high-risk category. 
• They are helpful in patients with possible intestinal obstruction or ischemia, perforated viscus, renal or ureteral calculi, or acute cholecystitis. They are seldom of value in patients suspected to have appendicitis or urinary tract infection