Toxicology

1. CORROSIVES
H2SO4 HNO3
NaOH H2O2
I2

2. Contents:
• 1.) Definitions
• 2.) Factors affecting degree of toxicity
• 3.) Classes of corrosives:
a.) Acids: H2SO4, HNO3
b.) Bases: NaOH
c.) Oxidants: H2O2, I2
In each: i.) Physical characters
ii.) Mechanism of
corrosion
iii.) Clinical manifestation
iv.) Management
v.) Appearance of the
intestine

3. 1.) Definitions
CORROSION
Simple inflammation
followed by formation of
necrotic tissue
CORROSIVES
•Substances that can
cause corrosion, mostly
inorganic acids & bases
•Their main toxic action is
their local action at the site
of contact e.g. skin, GIT,
respiratory tract

4. 2.) Factors affecting degree of
toxicity
a.) Strength (Amount):
e.g. Small concentrated>Large
diluted
b.) Type:
e.g. Inorganic>Organic
c.) Time of contact
d.) Site of contact

5. 3.) Classes of corrosives: a.) Acids
H2SO4, HNO3
H2SO4 HNO3
i.) Physical
characters
1.) 95-98%
2.) Heavy, oily, viscous
3.) Odorless, colorless,
fuming liquid
1.) Colorless or yellow
fuming liquid
2.) Less corrosive than H2SO4
3.) Strong oxidant
Xanthoproteic reaction:
HNO3+proteins
trinitrophenol+ NO
(yellow) (gas)
ii.) Mechanism
of corrosion
1.) Acid+ProteinAcid proteinate
2.) Acid+HemoglobinAcid haematin (dark brown ppt)
3.) In GIT: PerforationDestruction of secretory gland
constriction of oesophagus & starvation
4.) Suffocation+ShockDeath
5.) Burning by:
a.) Dehydration
 charring of tissues
b.) Heat generation upon dilution
by equal volume of water

6. H2SO4, HNO3
H2SO4
HNO3
iii.) Clinical
manifestations
1.) GIT:
a.) Burning sensation
b.) Irritation reflex
followed by uncontrollable
vomiting resulting in:
i.) Acid return to mouth
 further corrosion
ii.) BV errosion in stomach
brown hematemesis???
iii.) Dehydration
 thirst
iv.) Perforation & disintegration
of stomach wall
c.) Peritonitis
2.) Resp. tract:
a.) Coughing,
choking
b.) Inflammation
 Laryngeal edema
tracheostomy
c.) Pulm. Edema
d.) Hemoptysis
3.) Skin
contact:
3 burn
degrees:
a.) 1st 
reddness,
hottness,
pain
b.) 2nd 
Edema,
vesicles,
scar
c.) 3rd 
deep
ulceration
4.) Eye:
a.) Conjunctival
edema
b.) Corneal
destruction
c.) Photophobia

7. H2SO4, HNO3
H2SO4
HNO3
iii.) Clinical
manifestations
Differs from H2SO4 in:
1.) Yellow discoloration of the biological
tissue including teeth crowns
2.) Yellow stains on clothing
3.) Greater abdominal distension d.t. gas
production
4.) Achlorhydra d.t. oxyntic cells damage

8. H2SO4, HNO3
H2SO4 HNO3
iv.) Management
v.) Appearance
of intestine
Shrunken, charring Shrunken, yellow
Oral ingestion
1.) Water, milk,
albumin
dilution, soothing
2.) Morphine
analgesic
3.) Prednisolone
anti-inflammatory
4.) 5% dextrose infusion
for shock
Gastric lavage
NO Emesis
Antidotes
Inhalation
1.) Ventilation
2.) Antibiotics
for bacterial
pneumonia
3.) Prednisolone
4.) 5% dextrose
Skin
contact
1.) Wash
2.) Thermal
burn
treatment
e.g. Silver
sulphadia-
zine cream
NO
Antidotes??
Eye
contact
1.)Wash
with
running
water
2.)Add a
sterile
bandage
3.)Consult
an ophthal-
mologist

9. b.) Bases
NaOH
i.) Physical characters Colorless, odorless in solution form
ii.) Mechanism
of corrosion
1.) Base+ProteinProtein liquefaction
2.) Base+HbAlkaline hematin (tea colour)
3.) Base+LipidLipid saponification
Swelling with soapy or slimy
leading to feeling without characteristic colour
Erosion of BV leading to hemorrhage
4.) Dehydration
iii.) Clinical
manifestations
Oral
1.) Intense pain from mouth to abdomen
2.) Soapy taste
3.) Vomiting with tea/coffee colour
containing shreds of necrotic mucosa
4.) Diarrhea or tenesmus
5.) Oesophageal stenosis
Eye
1.) Conjunctival edema
2.) Corneal destruction

10. NaOH
iv.) Management
v.) Appearance
of intestine
Red, soft, gelatinous
Oral
1.) Milk, water  diluents
2.) Milk, olive oil  demulcents
NO Gastric lavage
Emesis
Eye
As in acids

11. c.) Oxidants
H2O2, I2
H2O2 I2
i.) Mechanism
of corrosion
Strong oxidant
ii.) Clinical
manifestations
1.) GIT inflammation with N & V
2.) Watery or bloody diarrhea
iii.) Management Milk, albumin demulcents
iv.) Appearance
of intestine
Froth Brown surrounding

12. Combined Spots of corrosives(5):

13. Thank you