Sep 212013
 

A diverticular disease is a sac like out pouching of the lining of the bowel that extends through a defect in the muscle layer. In diverticular disease, bulging pouches (diverticula) in the GI wall push the mucosal lining through the surrounding muscle.

Most common site of diverticula:

  • Sigmoid colon (95%)
  • Develop anywhere, from the proximal end of the pharynx to the anus.
  • Other typical sites includes;

– duodenum, stomach
– near the pancreatic border or the ampulla of voter.
– jejunum, ileum

Common in western countries, suggesting that a low fiber diet reduces bulk and leads to diminished colonic motility. The consequent increased intraluminal pressure causes herniation of the mucosa.

Incidence:

  • Common in developed countries.
  • Prevalence increases with age.
  • 35% of Americans older than 60years age are affected.
  • Incidences increase to 50% among those in the ninth decade of life (Keighley, 1999)
  • Congenital predisposition is suspected when the disorder occurs in those younger than 40 years of age.
  • Most prevalent in men and who eats low fiber diet.
  • More than one-half of all the patients older than age 50 have colonic diverticula.

Diverticular disease of the stomach is rare and is usually the precursor of peptic or neo-plastic disease. Diverticular disease of the ileum (Meckel’s diverticulum) is the most common congenital anomaly of the GI tract.

Forms of Diverticular disease:
Two clinical forms which includes;

  • Diverticulosis
  • Diverticulitis

Diverticulosis: Multiple diverticula are present but don’t cause symptoms (no inflammation)

Diverticulitis: In which diverticula are inflamed and may cause potentially fatal obstruction, infection or haemorrhage. It results from food and bacteria that retains in the diverticulum and produce infection and inflammation.

Causes / Etiology:

  • Defects in colon wall strength.
  • Diminished colonic motility and increased intraluminal pressure.
  • Low-fiber diet.

 Pathophysiology


Diverticula probably result from high intraluminal pressure on an area of weakness in the GI wall where blood vessels enter. Diet may be a contributing factor because insufficient fiber reduces fecal residue, narrow the bowel lumens, and leads to high intra abdominal pressure during defecation.

In diverticulitis, retained undigested food and bacteria accumulate in the diverticular sac. This hard mass cut off the blood supply to this wall of the sac, making them more susceptible to attack by colonic bacteria. Inflammation follows and may lead to perforation, abscess, peritonitis, obstruction or hemorrhage. Occasionally, the inflamed colon segment may adhere to the bladder or other organs and cause a fistula.

Signs and Symptoms:

Chronic constipation often precedes the development of diverticulosis by many years. Frequently no problematic symptoms occur with diverticulosis. Signs of acute ficerticulosis are;

  • Bowel irregularity
  • Intervals of diarrhea
  • Abrupt onset of crampy pain in LLQ (Left Lower Quadrant)
  • Low grade fever
  • Nausea and Anorexia
  • Bloating
  • Abdominal distention

Typically the c/f of Diverticulosis is asymptomatic and will remain so unless diverticulitis develops.

Mild Diverticulitis:

  • Moderate left sided lower abdominal pain secondary to inflammation of diverticula.
  • Low grade fever from trapping of bacteria rich stool in the diverticula.
  • Leukocytosis from infection secondary to trapping of bacterial rich stool in the diverticula.

Severe Diverticulitis:

  • Abdominal rigidity from rapture of the diverticula, abscesses and peritonitis.
  • Left Lower Quadrant pain secondary to rapture of the diverticula and subsequently inflammation and infection.
  • High fever, chills, hypertension from sepsis and shock from the release of fecal material from the rapture site.
  • Microscopic or massive hemorrhage from rupture of diverticulum near a vessel.

Chronic Diverticulitis:

  • Constipation, ribbon like stools, intermittent diarrhea and abdominal distention resulting from intestinal obstruction (possible when fibrosis and adhesion narrow the bowel’s lumen)
  • Abdominal rigidity and pain, diminishing or absent bowel sounds, nausea and vomiting secondary to intestinal obstruction.

Complication:

  • Abscesses
  • Peritonitis
  • Intestinal obstruction
  • Rectal hemorrhage
  • Septicemia

Diagnosis:

  • History taking
  • Physical examination
  • Laboratory findings
  • Radiological examination
  • Abdominal x-ray reveals free air under the diaphragm if a perforation has occurred from the diverticulitis.
  • Barium Enema- shows narrowing of the colon and thickened muscle layers (contraindicated in peritonitis)
  • Colonoscopy – may be performed if there is no acute diverticulitis or after resolution of an acute episode to visualize the colon, determine the extent of the disease and rule out other conditions.
  • Biopsy reveals evidence of benign disease, ruling out cancer.
 Posted by at 11:48 am
Sep 182013
 


Halo-alkanes are one of the most widely used and important hydrocarbons. When one or more hydrogen atoms of hydrocarbon are replaced by halogen, then the hydrocarbon is called halo-alkane. It is represented by the general formula R-X, where R is alkyl group and X is halogen. Some examples of halo-alkanes are CH3Cl (Chloro-methane), CH3CH2Br (Bromo-ethane) etc.

Types of Halo-Alkanes

According to the bonds with different types of carbon atoms, hal0-alkanes can be classified into three types. They are given below:

i) Primary halo-alkane: The carbon atom which is directly bonded with only one alkyl group is called primary carbon atom. When halogen atom is directly bonded with primary carbon atom, the halo-alkane is called primary halo-alkane. The general formula of primary halo-alkane along with its examples are given below:Primary Haloalkane

ii) Secondary halo-alkane: The carbon atom which is directly bonded with two alkyl groups is called secondary carbon atom. When halogen atom is directly bonded with secondary carbon atom, the halo-alkane is called secondary halo-alkane. The general formula of secondary halo-alkane along with its examples are given below:Secondary Haloalkane

iii) Tertiary halo-alkane: The carbon atom which is directly bonded with three alkyl groups is called tertiary carbon atom. When halogen atom is directly bonded with tertiary carbon atom, the halo-alkane is called tertiary halo-alkane. The general formula of tertiary halo-alkane along with its examples are given below:Tertiary Haloalkane