GIT GUT - Diarrhea

Question 1

Diarrhea differentials

Answer 1

1. Giardiasis
2. Pseudomembranous Colitis
3. Inflammatory disease

Probability diagnosis 
Acute:
•Gastroenteritis/infective enteritis
•Dietary indiscretion
•Antibiotic reaction

Chronic:
•Irritable bowel syndrome (IBS)
•Drug reactions (e.g. laxatives)
•Chronic infections

Serious disorders not to be missed  
Neoplasia/cancer:
•colorectal cancer
•ovarian cancer
•peritoneal cancer

Infection:
•cholera
•typhoid/paratyphoid 
•amoebiasis
•malaria
•enterohaemorrhagic E. coli enteritis
•HIV infection (AIDS)

OthersInflammatory bowel disease:
•Crohn/ulcerative colitis
•pseudomembranous colitis

Intussusception
Pelvic appendicitis/pelvic abscess

Pitfalls (often missed) 
Coeliac disease
Faecal impaction with spurious diarrhoea
Lactase deficiency
Giardia lamblia infection
Cryptosporidium infection
Malabsorption states (e.g. coeliac disease)
Vitamin C and other oral drugs

Nematode infections:
•strongyloides (threadworm)
•whipworm
•hookworm

Radiotherapy
Diverticulitis
Post-GIT surgery
Ischaemic colitis (elderly)

Rarities:
•Addison disease
•carcinoid tumours
•short bowel syndrome
•amyloidosis
•toxic shock 
•Zollinger–Ellison syndrome

Masquerades checklist
Diabetes
Drugs (see list)
Hyperthyroidism

Is the patient trying to tell me something? Yes, diarrhoea may be a manifestation of anxiety state or irritable bowel syndrome.

Question 2

Diarrhea - Key History

Answer 2

Key history

Establish what the patient means by diarrhoea.
Analyse the nature of the stools, frequency, associated symptoms (e.g. abdominal pain) and constitutional symptoms such as fever and weight loss.
Drug history, travel history and family history.

Question 3

Diarrhea - Key PE

Answer 3

Key examination

• Focus on the general state (esp. of severe gastroenteritis), the abdomen, rectum and skin
• Ideally the stool should be examined (note the presence of blood, mucus or steatorrhoea)

Question 4

Diarrhea - Key Investigation

Answer 4

Key investigations 
In some instances such as acute self-limiting diarrhoea nil is required.
 Consider:
•microscopy and culture of stool
•FBE
•ESR/CRP
•C. difficile tissue culture assay
•U&E
•specific tests for organisms
•endoscopy
•selective radiology (e.g. small bowel enema).

Question 5

Diarrhea - Diagnostic Tips

Answer 5

Diagnostic tips

•Giardiasis (profuse bubbly diarrhoea) is more common than realised.
•Remember spurious diarrhoea and the rectal examination in the elderly.
•IBS rarely causes nocturnal diarrhoea but causes recurrent pain in the right hypochondrium.
•Some drugs that can cause diarrhoea:
alcohol, antibiotics, digoxin, colchicine, cytotoxic agents, H2-receptor antagonists, iron compounds, laxatives, metformin, sildenafil, statins, thyroxine.