IBS

IRRITABLE BOWEL SYNDROME

الدكتور خلدون ذنون- كلية طب نينوى المرحلة الرابعة
Objectives
To know that IBS is a common functional disease of the GIT.
Diagnosis is mainly clinical rather than by investigation.
To know its features and management.
To know the serious symptoms and signs that alerts you to the diagnosis of organic GIT diseases rather than IBS.

Introduction

Functional GIT disorders are very common.
Disorder of the gut function in the absence of gut pathology.
IBS is a functional bowel disorder characterized by abdominal pain, change in bowel habit, distension & disordered defeacation.

Epidemiology

20% of the population may be affected.
Most common cause of GIT referral causes frequent absence from work & impairs quality of life.
Young women are mostly affected.
IBS overlapses with non-ulcer dyspepsia, chronic fatigue syndrome, dysmenorrheal & fibromyalgia.


Pathophsiology
A-psychosocial factors
50% of those referred to hospitals have a psychiatric disorder e.g anxiety , depression , somatisation , neurosis, phobias(panic attacks)
Psychological stress alters GIT motility.
Frequent consultation for minor symptoms.

B-altered GIT motility

Patients with frequent diarrhea exhibit rapid jejunal contraction waves , rapid intestinal transit& increased number of colonic contractions
Those with constipation have decreased orocaecal transit & decreased number of colonic contractions.

C-abnormal visceral perceptions increased sensitivity to intestinal distensions due to altered CNS perception of visceral sensation.

D- infection and allergy ● 10-20% of patients develop IBS following gastroenteritis.
● Abnormalities of gut microflora.
● Others are intolerant of specific type of food e.g lactose and wheat.
● Some have histologically undetectable mucosal inflammation.
Clinical features
Most common is recurrent abdominal pain, colicky or cramping, felt in the lower abdomen or left side of the abdomen and is relieved by defaecation. Symptoms is more than 6 months.
Abdominal bloating (distension), it may be due to excess gases or may be not.
Altered bowel habit: most patients alternate between diarrhea & constipation, some may have predominant diarrhea or constipation. Constipated type tend to pass infrequent pellety stools , diarrhea type have frequent defaecation with low-volume stools & rarely have nocturnal symptoms .
Passage of mucus is common but without bleeding.
Feeling of incomplete defaecation .
No loss of weight & patient looks well.
It may be associated with dyspepsia, urinary frequency, headache, backache, poor sleep & chronic fatigue syndrome.
Usually negative physical findings apart from abdominal bloating & some tenderness on palpation.


Diagnosis
Investigations are normal.
Under 40y: no need for complicated investigations, routine investigations which are done: full blood count, ESR, sigmoidoscopy.
Barium enema & colonoscopy should be done for elderly patients to exclude cancer.
Those with predominant diarrhea require stool examination looking for RBC, pus cells & parasites e.g amoeba, giardia. Also exclude microscopic colitis, lactose intolerance, bile acid malabsorption, celiac disease & thyrotoxicosis.
Those with rectal bleeding require colonoscopy or barium enema to exclude cancer& IBD.

Management

Assure the patient that the disease is functional and not organic as some are worried about cancer.
Pain & bloating need spasmolytic drugs e.g mebeverine , peppermint oil. if symptom persist we add amitriptyline 10-25 mg at night , if no benefit shift to relaxation therapy, biofeed back & hypnotherapy .
Diarrhea: avoid legumes & excess dietary fibre, if symptom persists give lopermide 2-8mg/day, codeine phosphate 30- 90mg/day or colestyramine,
Predominant constipation: high roughage diet & if symptom persists add ispaghula & lactulose.
Intractable symptoms: several months of amitriptyline 10-25 mg which is lower than the dose of depression (side effect: dry mouth & drowsiness).
5HT4 agonists.
Elimination diets are generally unhelpful, but some patients may benefit from wheat free diet and others from lactose intolerance.
The role of probiotics is not clearly established

Prognosis most patients have relapsing & remitting course, exacerbation may follow psychological stresses & socioeconomic troubles.

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