The document discusses adverse effects of contrast agents, which can be idiosyncratic anaphylactoid reactions or non-idiosyncratic reactions. Idiosyncratic reactions are most serious and frequent, occurring during or within 20 minutes of contrast injection in predisposed patients. Non-idiosyncratic reactions are dose dependent and relate to contrast medium concentration, volume, and osmolality, causing chemotoxic, hyperosmolar, or vasomotor reactions. Minor, intermediate, and severe life-threatening reactions require different emergency treatments. Prevention emphasizes patient screening, hydration, and premedication in high risk cases.

1. ADVERSE EFFECTS OF CONTRAST
AGENTS

2. ADVERSE REACTIONS
• 1. IDIOSYNCRATIC ANAPHYLACTOID
• 2.NON-IDIOSYNCRATIC
• 3.COMBINED

4. IDIOSYNCRATIC ANAPHYLACTOID
REACTIONS
• Most dreaded
• Most serious & fatal complications
• Most frequent
• Without warning
• Cannot be reliably predicted
• Begin during/within 20 mins of CM injection

5. IDIOSYNCRATIC ANAPHYLACTOID
REACTIONS
• More frequent in pts with :
• h/o adverse rxns to CM
• Asthma
• Allergy & atopy
• CVS ds
• Renal ds
• Pts on beta blockers & NSAIDs

6. IDIOSYNCRATIC ANAPHYLACTOID
REACTIONS
• Mimic anaphylaxis-Anaphylactoid
• Not dose dependent
• Possible mechanisms:
• 1.inhibition of enzymes:
• eg: CM inhibits cholinesterase-increases Ach
at synapses-vagal stimulation-CV
collapse,bradycardia,bronchospasm

7. IDIOSYNCRATIC ANAPHYLACTOID
REACTIONS
• 2.release of vasoactive substances:
• Eg:histamine,bradykinin,serotonin-vasomotor
collapse
• 3.activation of physiological cascades:
• Complement activation
• Kinin system
• Coagulation system
• Fibrinolytic system

8. IDIOSYNCRATIC ANAPHYLACTOID
REACTIONS
• 4.immune system disease
• 5.anxiety & apprehension towards the Ix - can
aggravate

9. NON-IDIOSYNCRATIC REACTIONS
• Dose dependent
• Relates to-
• 1.osmolality
• 2.conc. of CM
• 3.volume that is injected

10. NON-IDIOSYNCRATIC REACTIONS
• 3 types:
• 1. chemotoxic rxns
• 2. hyper osmolar rxns
• 3. vasomotor rxns

11. Chemotoxic reactions
• d/t toxicity of the CM molecule as a whole
• Cardiac s/e
• Renal s/e
• CNS s/e
• Vascular s/e

12. Chemotoxic reactions
• Caused by toxicity to contrast medium molecule as a
whole, and is more often due to cations , particularly -Na.
• They may be cardiac, neurological,renal or vascular
• Nephrotoxicity of contrast media is due to
• * decreased renal perfusion (low BP, peripheral
vasodilatation).
• * glomerular injury – manifests as proteinuria.
• *Tubular injury- due to osmolality, chemotoxicity, ichaemia
• *CM precipitation of Tamm Horsefall proteins that blocks
tubules
• *Swelling of renal tubular cells causing obstruction

13. Hyperosmolar reactions
• Due to high osmolarity of the contrast media than plasma, more common
with conventional CM.
• Erythrocyte damage: loss of H2O from RBC –dehydrated shrunken RBC-
increased internal viscosity- loss of ability of RBC to deform to traverse
capillaries- obstruction of imp capillary beds (cerebral, coronary, renal,
pulmonary)
• Endothelial damage & BBB damage: shrinkage of endothelial cells-
widening of intercellular gaps- capillary permeability.
• Vasodilatation :of the arteriolar or capillary bed of the injected artery, due
to direct effect of hyperosmolar CM, manifested as warmth, heat
discomfort or severe pain during peripheral arteriography.
• Hypervolemia : due osmotic extraction of extravascular fluid- ^ blood
volume by about10 to 20%.
• Cardiac depression with hypotension, diminished venous return,
myocardial ischaemia and direct depression of myocardial contractility

14. Vasomotor & vasovagal reactions
• Occur either following idiosyncratic or
nonidiosyncratic reactions or may occur
independently.
• Vasomotor reactions are characterized by severe
hypotension, tachycardia or bradycardia with
depression of myocardial contractility , reduced
cardiac output, cardio respiratory collapse and
possibly death.
• Vasovagal reactions are characterized by
bradycardia

15. Combined Reactions
• Anaphylactoid reactions and nonanaphylactoid
reactions can occur or appear to occur
simultaneously.The end result may be a complex,
life-threatening situation with a patient in shock.
• Careful attention to the specific signs and
symptoms of a reaction should help in identifying
the exact causes of the reaction.
• A careful history of any medications ingested
prior to the exam can aid in identifying possible
contributory effects of the medications.

16. Severity of reactions
• Minor reactions: 1 in 20cases (5 to 15%)- nausea vomiting ,
arm pain , pruritus, light headache and mild dyspnoea.
no treatment, assurance.
• Intermediate reactions: 1 in 100 (0.5 to 2%), more serious
degrees of above symptoms, moderate hypotension &
bronchospasm.
• * Chlorpheniramine (4 to 10mg orally, im or iv).
• * Diazepam (5mg) for anxiety.
• * Salbutamol inhalation for bronchospasm.*
Hydrocortisone mg im/iv.
• * Adrenaline 0.3 –1ml of 1/1000 im/sc

17. Severe life threatening reactions
• Occur 1 in 2000 (0.2 to 0.04%) :Convulsions, unconsciousness, laryngeal edema, severe
bronchospasm, pulmonary edema, severe cardiac dysrhythmias, cardiac arrest, cardiovascular &
pulmonary collapse.
• Treatment :
• Airway must be secured & o2 , artificial respiration, external cardiac massage & electrical DC
defibrillation administered as and when required.
• IV line is secured to restore blood volume and administer drugs
• A powerful diuretic such as frusemide 20 –40mg im/iv for pul edema
• Diazepam and barbiturates for convulsions
• Hydrocortisone/ methyl prednisolone
• Aminophylline 250-500 mg iv for intense bronchospasm
• Chlorpheniramine for allergic reactions
• Vasopressors- noradrenaline/ dopamine iv infusion for hypotension
• Sodium bicarbonate for acidosis
• Atropine 0.6 to 1.2mg iv/im for vasovagal reactions
• Adrenaline 0.3 to 1.0ml of 1 in 1000 solution sc/im, repeated at 10 to 20mins , - bronchospasm,
angioneurotic edema and other anaphylactoid reactions

18. Patient Selection & Preparation
Strategies
• The approach to patients has two general aims:
• 1. to prevent a reaction from occurring and
• 2. to be fully prepared to treat a reaction should one occur.
• History should focus on the factors that may indicate either a
contraindication to contrast media use or an increased likelihood of
a reaction.
• Hemodynamic, neurologic, and general nutritional status should be
assessed. In regard to specific risk factors.
• True concern should be focused on patients with significant
allergies, such as prior anaphylactic response to one or more
allergens.A history of asthma indicates an increased likelihood of a
contrast reaction.
• Patients with any know allergies have a four fold chance of a
reaction to contrast media.

19. Administration of contrast medium to
breast feeding mothers:
• Less than 1 % of the administered dose of contrast
iodinated or gadolinium based is excreted in the breast
milk.
• Less than 1% of the contrast in breast milk taken in by and
infant is absorbed by the GI tract.
• Literature and data published by the ACR suggest that it is
safe to continue to breast feed after receiving contrast
iodinated or gadolinium. Contrast is nearly 100% excreted
from the body within 24 hours after receiving contrast.
• The practice standard should follow the manufacturers
guidelines and substitute bottle feedings for breast
feedings for the 24 hours following the injection of contrast
media.

20. Contrast Reactions In Children
• Children have a lower frequency of contrast reactions
that adults
• They tend to have allergic-type reactions rather that
cardiac problems.
• In addition to fewer reactions, nonionic contrast media
has the added benefit of decreased nausea and
vomiting and the possibility of diminished morbidity
from extravasation into soft tissue. NOTE: Children’s
airways are smaller and more easily compromised that
those in adults. It is important to have pediatric
emergency equipment, contrast kit and protocols
available in the radiology department.

21. Deaths/ Mortality
• 1 in 14000 to 1 in 170000 following iv inj of
HOCM or LOCM
Usually results from intractable cardiopulmonary
collapse, pul edema or intense bronchospasm.
• It is not proven that LOCM reduces fatality rate
but there is no doubt that it produces less
discomfort on iv inj , less pain on intraarterial inj,
fewer physiological & haemodynamic
disturbances and fewer adverse reactions to
contrast agents than does HOCM.

22. Contrast medium nephrotoxicity
• Defined as rise in serum creatinine by >25% or
44umol/L occurring within 3 days of inj of iv CM for
which there is no other explanation.
• Risk factors:
• *Impaired renal function, esp sec to dia nephropathy
• *Dehydration
• *HOCM
• *Large doses of CM
• *Concurrent nephrotoxic drugs- gentamicin, NSAIDS

23. Guidelines for avoiding CM
nephrotoxicity in patients with
impaired renal function
• Use of LOCM
• Use of minimum CM necessary to achieve
diagnosis
• Patient should be well hydrated (100ml fluid
per hr for 4 hr)
• No further CM for another 48hrs.
• Nephrotoxic drugs should be discontinued.

24. Treatment
• Premedication strategies:
• It is most important to target premedication to those who, in the
past, have had moderately severe or severe reactions requiring
treatment.
• Two frequently used regimens are:
• 1. Prednisone – 50 mg by mouth at 13 hours, 7 hours, and 1 hour
before contrast media injection, plus Diphenhydramine (Benadryl®)
– 50 mg intravenously, intramuscularly, or by mouth 1 hour before
contrast medium. or
• 2. Methylprednisolone (Medrol®) – 32 mg by mouth 12 hours and 2
hours before contrast media injection.An anti-histamine (as in
option 1) can also be added to this regimen injection.
• If the patient is unable to take oral medication, 200 mg of
hydrocortisone intravenously may be substituted for oral
prednisone.(Greenberger protocol)

25. Treatment
• In evaluating a patient for a potential contrast reaction, five
important immediate assessments should be made:
• How does the patient look?
• Can the patient speak? How does the patient’s voice sound?
• How is the patient’s breathing?
• What is the patient’s pulse strength and rate?
• What is the patient’s blood pressure? The level of consciousness,
the appearance of the skin, quality of phonation, lung auscultation,
blood pressure and heart rate assessment will allow the responding
physician to quickly determine the severity of a reaction. These
findings also allow for the proper diagnosis of the reaction including
urticaria, facial or laryngeal edema, bronchospasm, hemodynamic
instability, vagal reaction, seizures, and pulmonary edema.

26. Management of acute reactions in
adults
• Urticaria:
• 1. Discontinue injection if not completed
• 2. No treatment needed in most cases
• 3. Give H1-receptor blocker: diphenhydramine
(Benadryl®) PO/IM/IV 25–50 mg.
• If severe or widely disseminated: give alpha-
agonist (arteriolar and venous constriction):
epinephrine SC (1:1,000) 0.1–0.3 ml (= 0.1–0.3
mg) (if no cardiac contraindications).

27. Facial or Laryngeal Edema
• 1. Give O2 6–10 liters/min (via mask).
• 2. Give alpha agonist (arteriolar and venous
constriction): epinephrine SC or IM (1:1,000) 0.1–
0.3 ml (= 0.1–0.3 mg) or, especially if hypotension
evident, epinephrine (1:10,000) slowly IV –3 ml (=
0.1–0.3 mg). Repeat as needed up to a maximum
of 1 mg.
• If not responsive to therapy or if there is obvious
acute laryngeal edema, seek appropriate
assistance (e.g., cardiopulmonary arrest response
team).

28. Hypotension with Tachycardia
• 1. Legs elevated 60 degree or more (preferred).
• 2. Monitor: electrocardiogram, pulse oximeter, blood
pressure.
• 3. Give O2 6–10 liters/min (via mask).
• 4. Rapid intravenous administration of large volumes of
Ringer’s lactate or normal saline. If poorly responsive:
epinephrine (1:10,000) slowly IV 1 ml (= 0.1 mg)
Repeat as needed up to a maximum of 1 mg.
• If still poorly responsive, seek appropriate assistance
(e.g., cardiopulmonary arrest response team)

29. Hypotension with Bradycardia (Vagal
Reaction)
• 1 Secure airway: giveO2 6–10 liters/min (via mask)
• 2. Monitor vital signs.
• 3. Elevate legs.
• 4. Secure IV access: rapid administration of Ringer’s
lactate or normal saline.
• 5. Give atropine 0.6–1 mg IV slowly if patient does not
respond quickly to steps 2–4. Repeat atropine up to a
total dose of 0.04 mg/kg (2–3 mg) in adult.
• 6. Ensure complete resolution of hypotension and
bradycardia prior to discharge.

30. Hypertension, Severe
• 1. Give O2 6–10 liters/min (via mask).
• 2. Monitor electrocardiogram, pulse oximeter,
blood pressure.
• 3. Give nitroglycerine 0.4-mg tablet, sublingual
(may repeat × 3); or, topical 2% ointment, apply
1-inch strip.
• 4. If no response, consider labetalol 20 mg IV,
then 20 to 80 mg IV every 10 minutes up to 300
mg. Transfer to intensive care unit or emergency
department.

31. Seizures or Convulsions
• 1. Give O2 6–10 liters/min (via mask).
• 2. Consider diazepam (Valium®) 5 mg IV (or more,
as appropriate) or midazolam (Versed®) 0.5 to 1
mg IV.
• 3. If longer effect needed, obtain consultation;
consider phenytoin (Dilantin®) infusion — 15–18
mg/kg at 50 mg/min.
• 4. Careful monitoring of vital signs required,
particularly of pO2because of risk to respiratory
depression with benzodiazepine administration.

32. First-line emergency drugs and
instruments that should be in the
room where contrast medium is
injected
• Oxygen
• Adrenaline 1:1000
• Antihistamine H1 – suitable for injection
• Atropine
• B2 agonist metered dose inhaler
• Intravenous fluids-normal saline or ringer’s
solution
• Anti convulsive drugs (diazepam)
• Sphygmomanometer
• One-way mouth “breathing” apparatus

33. REFERENCES
• ACR Manual on Contrast Media Version 8 2012
ACR (American College of Radiology) Committee
on Drugs and Contrast Media
• RADCONT08 - Contrast Media Reactions :
Management and Preventions.
• Contrast Media,Wilbur L. Reddinger Jr.,
B.S.,R.T.(R)(CT),November 1996.