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MEGACOLON. VIKAS.K.M 2002 MBBS. MEGACOLON. DEFINITION Distention of the colon to greater than 6 or 7 cm in diameter. HIRSCHSPRUNG’S DISEASE. CONGENITAL. HIRSCHSPRUNG’S DISEASE
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MEGACOLON VIKAS.K.M 2002 MBBS
MEGACOLON • DEFINITION Distention of the colon to greater than 6 or 7 cm in diameter
CONGENITAL HIRSCHSPRUNG’S DISEASE • Neurogenic form of intestinal obstruction in which there is an absence of ganglion cells in the myenteric & submucosal plexus • 1 in 4500 • Sex ratio 4:1 Harald Hirschsprung (1830-1916)
HIRSCHSPRUNG’S DISEASE GENETICS • Hetrogeneous • Mutations RET gene & RET ligands Endothelin receptor system • 3-5% have down’s syndrome
HIRSCHSPRUNG’S DISEASE • Hydrocephalus VSD Meckel’s diverticulum • Definite family history
PATHOLOGY • FAILURE OF MIGRATION of neuroblasts into the gut from vagal nerve trunks • ABSENCE of ganglion cells in neural plexus • HYPERTROPHY of nerve trunks
MACROSCOPICALLY • The affected segment is NOTDISTENDED • Properly innervated upstream segment DILATES • Wall may be thinned or thickened • Stercoral ulcers
HIRSCHSPRUNG’S DISEASE Dilation of bowel proximal to the affected region
TOTAL COLONIC HIRSCHSPRUNG’S DISEASE The transition zone (arrow) is in the small intestine
MICROSCOPICALLY ABSENCE OF GANGLION CELLS
CLINICAL FEATURES • Delayed passage of meconium(95%) • Abdominal distension • Bilious vomiting • Severe diarrhoea altrenating with constipation(10-15%) Enterocolitis of hirchsprung’s disease
DIAGNOSIS ABDOMINAL RADIOGRAPH • Dilated bowel loops with fluid levels • Intramural gas – enterocolitis • Free peritonial gas - perforation
ABDOMINAL RADIOGRAPH Dilated bowel loops Fluid levels
DIAGNOSIS BARIUM ENEMA • Indicate length & site • No definitive cutoff point indicating transition zone • Evacuation of contrast may take 24 – 48 hours • Transition zone clear on delayed x-ray
BARIUM ENEMA • Coning down of transition zone • Irregularity in the mucosa • Abnormal contractions TZ
BARIUM ENEMA Contracted diseased segment (black arrow), dilatation of normal bowel segment (red arrow) and the transitional zone (TZ)
BARIUM ENEMA TZ
DIAGNOSIS RECTAL BIOPSY • Submucosal suction biopsy is adequate in 90% • Full thickness operative biopsy in more emergent circumstances • Absence of ganglion cells in at least 10 sections – diagnosis confirmed • Increased Ach staining of neurofibrils
Ach STAINING NORMAL INSCREASED Ach STAINING
DIAGNOSIS ANORECTAL MANOMETRY • Measures anorectal intraluminal pressure • Absent rectoanal inhibitory reflex indicating a lack of relaxation of the internal sphincter characteristic of aganglionosis
ANORECTAL MANOMETRY
DIFFRENTIAL DIAGNOSIS • HYPOTHYROIDISM • MECONIUM PLUG SYNDROME • COLONIC NEURONAL DYSPLASIA • ADYNAMIC ILEUS WITH SEPSIS • INTESTINAL PSEUDO-OBSTRUCTION
TREATMENT • Depends on Age Length of involved segment Severity of symptoms Presence of enterocolitis
TREATMENT NEONATAL PERIOD • TEMPORARY DECOMPRESSING COLOSTOMY • At least 10 cm proximal to transition zone
TREATMENT 6 MONTH – ONE YEAR A definitive pull-through procedure using • SOAVE(endorectal) • DUHAMEL(retrorectal) • SWENSON(rectosigmoidectomy)
PULL-THROUGH PROCEDURE • Each is done a little differently, but all involve removing the part of the intestine that isn't working and connecting the healthy part that's left to the anus. After pull-through surgery, the child has a working intestine
PROGNOSIS • Overall survival in > 90% cases • Rare deaths due to – Delayed diagnosis Complications • > 96% continent • Long term follow up is important
ACQUIRED MEGACOLON CAUSES • Chagas disease • Organic obstruction of bowel • Toxic megacolon • Fuctional psychosomatic disorder
ACQUIRED MEGACOLON • Can occour at any age • Except for chagas disease,where inflammatory involvment of ganglia is evident,the remaining forms are not associated with deficiency of mural ganglia
CHAGAS DISEASE • Protozoosis • Flagellate protozoa Trypanosoma cruzi • Destruction of the autonomic nervous system innervation of the colon leads to a loss of the normal smooth muscle tone of the wall and subsequent gradual dilation REDUVID BUG
TOXIC MEGACOLON • DEFINITION Toxic megacolon is the clinical term for an acute toxic colitis with dilatation of the colon • Total or segmental • Hallmarks - nonobstructive colonic dilatation larger than 6 cm and signs of systemic toxicity
TOXIC MEGACOLON TOXIC MEGACOLON
TOXIC MEGACOLON Colon is dilated and shows hemorrhagic necrosis
TOXIC MEGACOLON CLASSIC ETIOLOGIES • Ulcerative colitis • Crohn colitis • Pseudomembranous colitis Ulcerative colitis Crohns disease Pseudomembranous colitis
INFECTIOUS CAUSES Salmonella species Shigella species Campylobacter species Yersinia species Clostridium difficile Entamoeba histolytica Cytomegalovirus OTHER CAUSES Radiation colitis Ischemic colitis Nonspecific colitis secondary to chemotherapy TOXIC MEGACOLON