Anatomy and Physiology of the GIT System
The gastrointestinal (GIT) system is responsible for the digestion and absorption of food and the excretion of waste products. It consists of the GIT tract and accessory organs.
GIT Tract Organs
| Organ | Function |
|---|---|
| Oesophagus | Connects the mouth to the stomach; uses peristalsis to move food. |
| Stomach | Uses gastric secretions (HCl, pepsin) to break down food; muscular walls churn food into chyme. |
| Small Intestine | Primary site for digestion and absorption of nutrients. Consists of the duodenum, jejunum, and ileum. |
| Large Intestine | Absorbs water. Consists of the caecum, colon (ascending, transverse, descending, sigmoid), and rectum. |
| Appendix | Small pouch at the end of the caecum. |
| Rectum & Anus | Stores stool before excretion through the internal and external sphincters. |
Accessory Organs
| Organ | Function |
|---|---|
| Liver | Produces bile for fat digestion; detoxifies chemicals. |
| Gallbladder | Stores and concentrates bile. |
| Pancreas | Secretes digestive enzymes into the duodenum; produces insulin. |
| Spleen | Part of the lymphatic system; filters blood and stores blood cells. |
History Taking for Abdominal Complaints
SOCRATES for Abdominal Pain: A systematic approach to understanding the patient's pain.
- Site, Onset, Character, Radiation, Associated Symptoms, Timing, Exacerbating/Relieving Factors, Severity.
Types of Abdominal Pain
| Pain Type | Description | Innervation | Common Descriptors |
|---|---|---|---|
| Visceral | Stimulation of nociceptors in the visceral peritoneum lining the organs. | Autonomic nerve fibers. | Poorly localized, dull, aching, colicky, nauseating. |
| Somatic (Parietal) | Irritation of the parietal peritoneum lining the abdominal wall. | Somatic nerves. | Well-localized, sharp, intense, constant. Worsened by movement. |
| Referred | Pain perceived at a site distant from its source due to convergence of nerve pathways at the spinal cord. | Shared spinal segments. | Varies by source (e.g., gallbladder pain referred to the right shoulder). |
Pain Location and Potential Causes
The location of somatic pain can provide strong clues to the underlying pathology. The abdomen is divided into nine regions or four quadrants.
| Region/Quadrant | Common Pathologies |
|---|---|
| Epigastric | Gastritis, peptic ulcer, pancreatitis, myocardial infarction. |
| Right Upper Quadrant (RUQ) | Cholecystitis (gallbladder), hepatitis (liver), duodenal ulcer, renal colic. |
| Left Upper Quadrant (LUQ) | Spleen pathology, pancreatitis, renal colic. |
| Periumbilical | Early appendicitis, small bowel obstruction, aortic aneurysm. |
| Right Lower Quadrant (RLQ) | Appendicitis, ectopic pregnancy, ovarian cyst, diverticulitis, hernia. |
| Left Lower Quadrant (LLQ) | Diverticulitis, ectopic pregnancy, ovarian cyst, hernia. |
| Suprapubic | Cystitis (bladder infection), urinary retention, pelvic inflammatory disease. |
Physical Abdominal Examination
Correct Sequence: The abdominal assessment must be performed in the correct order to avoid altering bowel sounds:
- General Appearance
- Inspection
- Auscultation
- Percussion
- Palpation
Key Examination Findings
| Component | What to Look For | Potential Significance |
|---|---|---|
| General Appearance | Jaundice, conjunctival pallor, palmar erythema, finger clubbing, spider naevi, gynaecomastia. | Signs of chronic liver disease, anaemia, or other systemic issues. |
| Inspection | Scars, distension (Fat, Fluid, Fetus, Flatus, Faeces, 'Filthy' big tumour), hernias, pulsations, caput medusae, stomas. | Previous surgeries, ascites, bowel obstruction, aortic aneurysm, portal hypertension. |
| Auscultation | Presence and character of bowel sounds. | High-pitched sounds suggest obstruction. Absent sounds (after 4 mins) suggest paralytic ileus. |
| Percussion | Tympany (air-filled) vs. Dullness (solid/fluid-filled). Shifting dullness. | Helps identify organ size (hepatomegaly, splenomegaly) and presence of ascites. |
| Palpation | Tenderness, voluntary vs. involuntary guarding, rebound tenderness, masses. | Identifies areas of pain, peritonitis, and abnormal masses. Palpate tender areas last. |
Specific Clinical Signs for Acute Abdominal Pain
These are specific manoeuvres used to elicit signs of inflammation of particular organs.
| Sign | How to Perform | Positive Finding & Indication |
|---|---|---|
| Murphy's Sign | Place fingers at the right costal margin in the mid-clavicular line. Ask the patient to take a deep breath. | Sharp pain and inspiratory arrest as the inflamed gallbladder descends onto the examiner's hand. Suggests Cholecystitis. |
| Kehr's Sign | Patient is supine. Palpate the upper left quadrant. | Pain referred to the tip of the left shoulder. Suggests diaphragmatic irritation from a Ruptured Spleen or ectopic pregnancy. |
| Rovsing's Sign | Palpate deeply and evenly in the left lower quadrant (LLQ). | Pain is felt in the right lower quadrant (RLQ). Suggests peritoneal irritation and Appendicitis. |
| McBurney's Point Tenderness | Palpate the point two-thirds of the way from the umbilicus to the anterior superior iliac spine. | Maximal tenderness at this point. A classic sign of Appendicitis. |
| Blumberg's Sign (Rebound Tenderness) | Press down deeply and slowly in a tender area, then release the pressure quickly. | Pain is worse on the quick release of pressure than on the initial pressing down. Indicates Peritonitis. |
| Psoas Sign | Patient lies supine. Ask them to lift their right leg against your resistance. OR, have them lie on their left side and extend their right leg backwards. | Pain is elicited as the psoas muscle rubs against the inflamed appendix. Suggests Appendicitis. |
| Obturator Sign | Patient lies supine. Flex their right hip and knee to 90 degrees, then internally rotate the hip. | Pain is elicited as the obturator muscle stretches and irritates the inflamed appendix. Suggests Appendicitis. |