food poisoning

Question 1

Symptoms of Microbial food poisoning due to

Answer 1

1-invasion of intestinal mucosa e.g. E coli, Salmonella,
Shigella, Lesteria (fever, faecal leucocytosis)
2-toxin production in the GIT by bacteria and virus
(mild –self limiting )

Question 2

Toxigenic
I.P.
Duration of illness

Answer 2

< 6 hours

Self limited<24 h

Question 3

Toxogenic
C/P:
Vomiting
Diarrhoea
Abdominal pain
 Fever
Bloody stool

Answer 3

Prominent 
Profuse and watery
\++++
-ve
-ve

Question 4

Toxigenic
Pus cells in stools
Treatment

Answer 4

-ve
Fluid replacement
No antibiotics

Question 5

Invasive
I.P.
Duration of illness

Answer 5

> 8-24 h

Several days

Question 6

Invasive
C/P:
Vomiting
Diarrhoea
Abdominal pain
 Fever
Bloody stool

Answer 6

Less prominent
Mucoid and bloody
\+ve
\+ve
\+ve

Question 7

Invasive
Pus cells in stools
Treatment

Answer 7

+ve
I.V. fluids
Antibiotics are indicated

Question 8

Diagnosis of food poisoning

Answer 8

History of food consumption. Possibly within a group

C/P of food poisoning

Question 9

Investigations of food poisoning

Answer 9

a) CBC: (leucocytosis in invasive type)
b) Stool analysis and culture(for epidemiologic concern).
c) Pus cells indicates bacterial invasion of the wall of intestine)
d) Serum electrolytes, blood glucose and renal function tests

Question 10

Complications of food poisoning

Answer 10

1-In neglected cases with severe vomiting:
  -Dehydration
  -Hypotension 
  -Pre-renal failure
2-Rarely with enteroinvasive:
  -Haemorrhagic colitis 
  -Haemolytic- uremic syndrome
  -Septicaemia
  -Peritonitis.

Question 11

Treatment

Answer 11

1-Fluid replacement by I.V. saline (oral rehydration if possible).
2-Antiemetic
3-Antispasmodics
4-Antibiotics for enteroinvasive (bacterim, quinolone) then according to stool culture and sensitivity.

Question 12

Food poisoning with Muscle weakness (Botulism) Caused by:

Answer 12

Clostridium botulinum toxin

Question 13

Epidemiology of Botulism :

Answer 13

• Ingestion of preformed toxin by the bacteria in improperly preserved food (canned , fermented or smoked).
• In outbreaks with consumption of the salted fish ( fesikh)

Question 14

Botulism How it is formed

Answer 14

1-Spores of clostridium botulium
2-Germination and release of botulinum toxin
(if anaerobic medium)
3- The toxin is very potent but heat labile

Question 15

Botulism How it works

Answer 15

The toxin binds irreversibly to peripheral neuromuscular junction so prevents the release of ACh and produces block. The toxin does not cross the blood brain barrier

Question 16

C/P of botulism

Answer 16

Incubation period: few hours to 8 days
Initially nausea, vomiting, abdominal pain
Anticholinergic manifestations
Neurological: Progressive paralysis of cranial nerves ( squint , ptosis, dysarthria—dysphagia)
Descending paralysis may involve resp. ms.
No sensory effect or coma (does not cross B.B.B.)

Question 17

How to confirm diagnosis of botulism

Answer 17

History
Presenting picture( dry throat, squint or ptosis, gastro -enteritis)
Investigation:
1-Toxin assay by mouse neutralization test: suspected samples are inoculated in rat peritoneal cavity, test is +ve if the rat develops paralysis
2-Anaerobic culture of serum, stool, vomitus, consumed food)

Question 18

Treatment of botulism

Answer 18

I.Emergency measures (ABC) : Maintain an open airway and assist ventilation if necessary.
II.Antidote:
-Botulinum antitoxin (trivalent ABE) is given.
-One vial /4 hours for at lease 4-6 vials
-Most effective when given in first 24 h
-It can only bind with the circulating toxin.
-It prevents further deterioration of the condition. Does not reverse already existing neurological complications)
III. Decontamination: gastric lavage and activated charcoal in asymptomatic patients shortly after the consumption of contaminated food.
IV. Symptomatic treatment
V. Notification of health authorities.

Question 19

A. Infant botulism

Answer 19

It is not caused by ingestion of spore-contaminated food consumption with subsequent in vivo bacterial germination and toxin elaboration in the immature infant gut (which lacks gastric and bile acids).

The disease is characterized by hypotonia, constipation, tachycardia, difficulty in feeding, head lag, and diminished gag reflex.

It is rarely fatal, and infants usually recover strength within 4–6 weeks.

Treatment consists mainly of respiratory support.

Question 20

B. Wound botulism

Answer 20

-It Occurs in crush injuries where the wound is dirty
and in intravenous drug abusers .
-Treatment consists of botulinum antitoxin, antibiotic
(penicillin) and wound debridement and irrigation.

Question 21

C. Therapeutic botulism

Answer 21

• This is either botulinum toxin type A (Botox) or type B (Myobloc) which is injected in muscles to induce temporary weakness
• It is used to treat cases of blepharospasm, facial nerve disorders, torticollis and to eliminate frown lines.

-The affected muscles then weaken by atrophy over a 3-week period, but recover within 2–4 months as nerve transmission is restored through new nerve endings and functional connections at motor endplates.

Question 22

Ciguatera poisoning

Ciguatoxin is produced by

Answer 22

tiny organisms eaten by small fish then eaten by larger fish, the toxin is concentrated in their flesh and fat tissue.

Question 23

The toxin does not harm the

Answer 23

fish, or change its smell or colour

Mostly large sized fish are affected

Question 24

Clinical picture of Ciguatera poisoning

Answer 24

-Incubation Period: 2-6 hours
-The typical patient presents with gastrointestinal then 2–24 hours later develops neurologic symptoms.
Other symptoms as can be present but not usual
-GIT manifestations: Nausea, vomiting, abdominal pain, watery diarrhea
-Neurological manifestations(mainly sensory):
numbness in the mouth and limbs, reversed sensation of heat (feels cold) and cold (feels electric), ataxia
-Cardiovascular manifestations: Hypotension and bradycardia

Question 25

Treatment of Ciguatera poisoning

Answer 25

• Mainly supportive treatment.
• Charcoal administration within 4 hours of ingestion.
• Toxin-specific measures: mannitol to reverse the acute neurologic symptoms of ciguatera poisoning

Question 26

Scombroid Cause

Answer 26

Scombrotoxin (histamine and histamine like compound)
Bacteria on the skin of the fish produce enzymes decomposes histidine in flesh of the fish not refrigerated (Tuna and Mackerel)

Question 27

Scombroid
Time delay
C/P
Treatment

Answer 27

Time delay: minutes to 3 hours.
C/P:Headache and erythema of the head &chest flushing,itching and bronchospasm
Treatment : antihistaminic