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CONGENITAL MEGACOLON

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									                     CONGENITAL MEGACOLON

INTRODUCTION
    Congenital abscence of the myenteric parasympathetic nerve ganglia of the distal colon
    20% of neonatal intestinal obstructions
    Hirschsrprung’s disease


PAHTOPHYSIOLOGY
    Congenital aganglionsis of colon
    Absence of ganglion cells in myenteric plexus of distal colon
    Anus invariably involved; extends proximally 4 - 25 cm
    Poor ability of segment to RELAX thus creates a functional bowel obstruction
    Stool dilation of more proximal colon leads to megacolon


CLINICAL FEATURES
    Neonates: failure to pass meconium
    Infants: constipation, vomiting, irritability, distension, poor weight gain, FTT
    May be subtle presentations
    Usually diagnosed in infancy but may present later with milder disease (15% present late)
    Need to differentiate from toxic megacolon: fever, bloody stools, diarrhea, leukocytosis
    AXR: fecal impaction, proximal obstruction, A/F levels, dilated colon
    Barium enema with narrowed segment
    Diagnosis by rectal biopsy


DIFFERENTIAL DIAGNOSIS
    Constipation common problem in peds
    Think of ddx when considering constipation
                    Hirschsprung’s
                    Cystic fibrosis
                    Hypothyroidism
                    Infantile botulism
    Acquired megacolon
                   Anal fissures
                   Fecal impaction
                   Toilet training
                   Neurologic conditions
                   Drugs
                   Metabolic causes




MANAGEMENT
    Fluid and electrolyte balance; AXR
    Acquired megacolon: rectal tube for decompression if massive dilation
    R/O toxic megacolon/enterocolitis ------> iv fluids, cultures, amp/gent/flagyl, consult
     surgery
    Referral as outpatient to pediatric surgeon for removal of aganglionic segment
    Constipation: clean out and maintenance
    ADULTS: consider dx with chronic severe constipation



                       ACQUIRED MEGACOLON

INTRODUCTION
    Megacolon = colon > 6 cmin diameter
    Etiology
                   Chronic severe constipation
                   Postoperative anorectal stricture
                   Radiation proctitis
                   Anorectal injury
                   Lymphogranuloma venereum
                   Endometriosis
                   Myxedema
                   Scleroderma
                   Amylososis
                   Hypokalemia
                   Paraplegia
                   Psychogenic: common in toilet trainers
                   Chaga’s dz: trypanosma cruzi (parasitic destruction of ganglia, common in
                    people from south and central america)


CLINICAL FEATURES
    Chronic constipation with concomitant laxative abuse
    Rectal exam is plugged full with stool (rectum is empty in hirchsprungs)
    Prone to sigmoid volvulus or fecal impaction
    Ba enema confirms
    AXR: dilated large bowel




MANAGEMENT
    Fluid and electrolyte balance
    Treat underlying causes
    Laxatives and enemas
    Rectal tube for decompression if massive dilation
    R/O toxic megacolon/enterocolitis ------> iv fluids, cultures, amp/gent/flagyl, consult
     surgery
                  IRRITABLE BOWEL SYNDROME

INTRODUCTION
    Abnormal state of sensing intestinal mobility
    Abdominal pain with consitpation or diarrhea that is modified by psych factors and has no
     demonstratable organic etiology
    Middle aged females are MC
    Exact pathophysiology unknown


CLINICAL FEATURES
    Manning Criteria = Abdominal pain + 2 or more of:
                     Pain relieved by defacation
                     Paine associated with looser stools
                     Pain associated with more frequent stools
                     Abdominal distention
                     Feeling of incomplete evacuation
                     Mucus in stools
    Pencil like stools commonly described
    Small hard pellet stools (scybala) is also common
    Associated with periods of psychosocial stress
    Bloating, heartburn, weak, fatigue, etc common
    No diagnostic strategies


MANAGEMENT
    Fluids
    Fiber
    Avoid caffeine
    F/u with GP
                    RADIATION PROCTOCOLITIS

INTRODUCTION
    Common with radiation to cervix, testis, prostate, bladder
    Can be immediate or delayed MANY YEARS
    Should consider dx in anyone with a history of radiation to abdomen or pelvis
    Cervical radiation: 40% will get
    Bladder radiation: almost all will get


CLINICAL FEATURES
    Early
                    Symptoms begin withing the first week or two
                    Maximal inflammation occurs within a few weeks
                    Diarrhea, cramps, tenesmus, abdominal pain
                    May becomne chronic
                    May lead to fistula, strictures, proctitis
                    Fistulas may occur to bladder, vagina
                    Intermitten bleeding is common
    Diagnosis
                    Clinical dx
                    R/o stricture, carcinoma, infection if delayed or atypical
                    DDX: IBD, infectious colitis, ischemic colitis, cdiff


MANAGEMENT
    Lomotil
    Fe supplementation for bleeding

								
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