Download diarrheal diseases

16/03/2015
DIARRHEAL DISEASES
Dr. Syed Waleem Pasha
Assistant Professor
Dept. of Medicine
• Three lecture series
• 1st (16/3/2015)
– Acute diarrhea – general & viral diarrhea
• 2nd
– Specific causes of diarrhea – bacterial
• 3rd
– Specific causes of diarrhea – bacterial and
protozoal
Objectives
• Definition
• Acute diarrhea
• Causes
– Infectious vs noninfectious
• Epidemiology
• Clinical features
• Management
– Fluid therapy
• Brief note on chronic diarrhea
Normal stool
• Frequency
• Consistency
• Quantity
• Frequency: 3/day to 1every third day
• Consistency: porridge-like to hard and pellety
• Quantity: <200 g/day
Diarrhea - definition
• Different for different people
• Increased frequency
• Loose or watery consistency
• Increased quantity >200 g/day
Duration of diarrhea
• Acute diarrhea
– <2 weeks
• Chronic diarrhea
– >4 weeks
• Persistent diarrhea
– 2-4 weeks
Acute diarrhea
• gastoenteritis vs food poisoning
Causes
• Infections
– Toxin-mediated
• Bacillus cereus
• Staph enterotoxin
• Clostridial spp enterotoxin
– Infective
•
•
•
•
•
•
•
•
Rotavirus
Campylobacter
Salmonella
E.coli
Shigella
Clostridium difficlie
Norovirus
Cholera
- Protozoal
• Giardiasis
• amebic dysentery
• Cryptosporidium
• Isospora
• Microsporidium
-Systemic illness
• Sepsis
• Meningococcal sepsis
• Pneumonia
• Malaria
Causes - contd
• Noninfectious
– Gastrointestinal
• Acute diverticulosis
• IBD
• Malignancy
– Metabolic upset
•
•
•
•
Ketosis
VIP
Carcinoid
Uremia
– Drugs and toxins
•
•
•
•
•
NSAIDs
Cytotoxic agents
Antibiotics
Plant toxins
Heavy metals
Bloody diarrhea
Infectious
Noninfectious
Campylobacter
Diverticular diseases
Shigella
Rectal or colonic malignancy
Non-typhoidal salmonella
IBD
EHEC
Bleeding hemorrhoids
EIEC
Ischemic colitis
Clostridium difficile
intussusception
Vibrio parahemolyticus
Entameba histiolytica
Epidemiology
•
•
•
•
•
Major cause of morbidity and mortality
Infants and young children/ elderly
MC cause: infection
Fecal-oral transmission
Fomites/ contaminated hands/ food/ water
Clinico-pathological correlation
• Diarrhea
–
–
–
–
Volume: small vs large intestinal involvement
Watery: secretory, toxin mediated
Blood: invasive, cytotoxic
Mucus
• Vomiting: upper GI involvement
• Fever: invasive
• Incubation period
Clinical history
•
•
•
•
•
•
Suspect food
Duration and frequency
Blood in stool
Abdominal pain and tenesmus
Fever
Incubation period
– <18 hours: toxin
– >5 days: protozoa/helminths
Physical examination
• Dehdration
– Skin turgor/ mucous membranes
– Blood pressure
– Urine output
• Severity
Investigations
• Stool examination
– Blood
– Leucocytes
– Parasites
– Culture
• Blood counts
• Electrolytes
• Renal functions
Treatment
• Isolation
• Principles:
– Fluid replacement
– Antimicrobial therapy
– Adjunctive antidiarrheal therapy
Fluid replacement
• Most important and life saving
• Fluid lost is isotonic
• Absorption of electrolytes from intestine is active,
needs energy
• ORS
• IV fluids
• Amount of fluid
– Replacement of established losses
– Replacement of ongoing losses
– Replacement of normal daily requirement
ORS
Fluid
Na
K
Cl
KCalories/l
WHO
90
20
80
54
Dioralyte
60
20
60
71
Pepsi
6.5
0.8
-
400
Orange
juice
0.2
49
-
400
Breast milk
22
36
28
670
Fluid replacement
• Replacement of ongoing losses
– Average: 200 ml of isotonic fluid/ stool
– One sachet of ORS: 200 ml
– One sachet per diarrhea stool is appropriate and
effective
• Replacement of normal daily requirement
– Minimal daily requirement: 1-1.5 L
• Replacement of established losses
– Diarrhea, vomiting
– ORS/ iv fluid
Antimicrobial therapy
• Shortens the illness by 1 day
• Potential for antimicrobial
resistance
• Salmonella: increase the stool carriage time
• EHEC: complicates HUS
• Indications:
–
–
–
–
Shigella dysentery
Cholera
Severe diarrhea
Certain clinical condns
Severity markers in AGE
• Chronic conditions
– Age>65
– Diabetes mellitus
– Rheumatoid or other autoimmune
diseases
– Chronic renal disease
– Valvular heart diseaase
– Acquired or secondary
immunodeficiency
– Any internal prosthesis
• Current drug therapy
–
–
–
–
–
Diuretic therapy
ACE inhibitor therapy
Corticosteroid therapy
Cytotoxic therapy
PPI/ H2 blockers
•Current illness
- Number of stools per 24 hours
- Blood per rectum
- Abdominal pain
- Associated systemic toxicity
Antimotility, antisecretory,
antidiarrheal drugs
• Not recommended or contraindicated
in infective diarrhea
Chronic diarrhea
• More than 14 days
• Most causes: noninfective
• Infective causes:
– Giardia lamblia
– Strongyloidiasis
– EPEC
– HIV enteropathy
– Intestinal flukes
Viral diarrhea
• Rotavirus
–
–
–
–
–
–
Major cause in young children
30-50% of diarrheal admissions; 10-20% of diarrheal deaths
Endemic in developing countries; Winter epidemics
Person to person spread, hospital
Incubation period of 48 hrs
Infects enterocytes, decreases surface area for absorption and loss of enzymes on brush
border
–Watery diarrhea, vomiting, abdominal
pain, fever
–
–
–
–
Diagnosis: stool – enzyme immunoassay kits
Self limiting
Hydration
Rotavirus vaccine; good protection but risk of intussusception
Viral diarrhea
• Norovirus (Norwalk agent)
–
–
–
–
–
Outbreaks related to food handlers
Endemic gastroenteritis
Feco-oral transmission
If vomiting: aerosol spread
Incubation period 48 hrs
–Nausea+, predominant vomiting, little
diarrhea
• Calcivirus: Seasonal diarrhea
• Astrovirus
• Adenovirus serotype 40 &41
Thank you