presentation on contrast media used in urology.pptx

various contrast medias used in urology . all copyright to their respective owners.

1. Contrast Media in Urology Dr Divyanshu Joshi

2. Contrast Media Urologists ordering a radiographic study of a patient must first consider the risks and benefits associated with a contrast-enhanced imaging study, as well as alternative imaging modalities that could provide the same information without the need for radiation or contrast exposure.

3. Adverse Reactions to Intravascular Contrast Media ARs associated with current intravenous contrast media are uncommon: iodinated: 0.6% aggregate and 0.04% severe (Wang et al., 2008) Gadolinium(Gd) based: 0.01% to 0.22% aggregate and 0.008% severe.

4. Low-osmolality contrast media (LOCM) are associated with low incidence of ARs, and most are not life threatening. Reports of the overall acute AR rates for allergic-like and physiologic reactions (PRs) for nonionic LOCM is 0.2% to 0.7% Serious acute reactions have an incidence of 0.04%

5. The American College of Radiology has divided AR contrast agents into two categories: allergic-like reactions (ALRs) or PRs, and each is subdivided into three categories: mild, moderate, or severe

6. Allergic-Like Reactions “allergic-like” because they are usually idiosyncratic and usually differ immunologically from true Ars. The exact mechanism of ALRs is not known but is thought to be a combination of systemic effects. ALRs have not been shown to result from a true IgE antibody immunologic reaction to the contrast media

7. ALRs are not dose-dependent. Severe reactions have been reported after only 1 cc was injected at the beginning of the procedure and have also occurred after the completion of a full dose despite no response to the initial test dose. The PRs are not allergic-like and represent a physiologic response to the contrast medium molecular properties creating chemotoxicity, effects resulting from hyperosmolality, or binding of specific contrast molecules to activators. Their reactions are often dose and concentration-dependent.

8. Vasovagal reactions are common PRs, characterized by hypotension and bradycardia and usually self-limiting. These reactions can be related to anxiety and have been known to occur when obtaining consent for the imaging procedure, during venous cannulation, or during administration of contrast medium.

9. Treatment of Contrast Reactions ASSESS General appearance • Ability to speak and characterization of the voice • Respiratory status and oxygen saturation • Pulse rate and characterization • Blood pressure.

10. Treatment: Mild Allergic-Like and Physiologic Reactions. Observation and reassurance are often all that is needed. Usually, no intervention or medication is required. If needed, an H1-receptor blocker such as diphenhydramine (Benadryl) PO/IM/IV 1 to 2 mg/kg up to 50 mg. Consequently, these patients should be observed for 20 to 30 minutes. If necessary, administer chlorpheniramine 4 to 10mg orally, intravenously, or intramuscularly and diazepam 5 mg for anxiety. For bronchospasm, oxygen 6 to 10 L/min should be administered, and a β- agonist inhaler should be used at two puffs (90 mcg/puff) for a total of 180 mcg; this can be repeated up to three times.

11. Treatment: Moderate Allergic-Like and Physiologic Reactions. Moderate ARs occur in 0.5% to 2% of patients. These reactions are usually transient and require treatment with close observation, using hydrocortisone 100 to 500 mg IM or IV , or β- agonist inhalation for bronchospasm bronchiolar dilators (metaproterenol, terbutaline or albuterol) 2 to 3 puffs; repeat as necessary. For bronchospasm, oxygen 6 to 10 L/min should be administered and a β- agonist inhaler used at 2 puffs (90 mcg/puff) for a total of 180 mcg; this can be repeated up to three times. Epinephrine can be added to moderate or severe bronchospasm.

12. Treatment: Severe Allergic-Like and Physiologic Reactions. Life-threatening reactions occur in approximately 1/1000 uses for high osmolar agents and are far less frequent for LOCM, with both types of agents resulting in mortality rates of 1/170,000 uses. Rapid administration of epinephrine is the treatment of choice for severe contrast reactions. Epinephrine can be administered IV in the dose of 0.1 mL/kg of 1:10,000 dilution or (0.01 mg/kg) slowly into a running IV infusion of saline and can be repeated every 5 to 15 minutes as needed. The maximum single dose is 1.0 mL (0.1 mg) and can be repeated as needed to a total dose of 1 mg.

13. If no IV access is available, the recommended intramuscular dose of epinephrine is 0.01 mg/kg of 1:1000 dilution (0.01 mL/kg) to a maximum of 0.15 mg of 1:1000 if less than 30 kg (0.3 mg if weight is >30 kg) is injected intramuscularly in the lateral thigh. Epinephrine must be administered with care to patients who have cardiac disease can cause hypertension or anginas

14. Premedication No known premedication strategy will eliminate the risk of a severe adverse reaction to contrast media. The regimens suggested in the literature include the use of corticosteroids, antihistamines, H1 and H2 antagonists, and ephedrine.

15. Corticosteroid Premedication A randomized trial of premedication for average-risk patients before high-osmolality iodinated contrast medium showed a reduction in mild, intermediate, and severe reactions

16. Premedication Strategies. One consistent finding is that steroids should be given at least 6 hours before the injection of contrast media regardless of the route of steroid administration. The administration for 3 hours or less before contrast does not decrease the incidence of ARs. Oral administration is preferred. Two doses of 32 mg of oral methylprednisolone, one taken 12 hours before contrast and the second taken 2 hours before contrast.

17. Supplemental administration of an H1 antihistamine (e.g., diphenhydramine), orally or intravenously, may reduce the frequency of urticaria, angioedema, and respiratory symptoms. Although rare, ARs have been reported after extravascular instillation of contrast agents (e.g., retrograde pyelography). In patients with a positive history of previous severe reactions to contrast agents undergoing a nonvascular study, premedication with corticosteroids should be considered.

18. Accelerated IV Premedication Methylprednisolone sodium succinate (e.g., Solu-Medrol) 40 mg IV or hydrocortisone sodium succinate (e.g., Solu- Cortef ) 200 mg IV immediately and then every 4 hours until contrast medium administration, plus diphenhydramine 50 mg IV 1 hour before contrast medium administration. This regimen usually lasts 4 to 5 hours. Others include Dexamethasone and methyl prednisolone regimens.

19. Delayed Contrast Reactions Delayed contrast reactions can occur from 3 hours to 7 days after the administration of contrast. These reactions are identified in as many as 14% to 30% of patients after the injection of ionic monomers and in 8% to 10% of patients after the injection of nonionic monomers. The most common delayed reactions are allergic-like and cutaneous reactions with reported incidences of 0.5% to 9%. The most common reactions include a cutaneous xanthema or pruritis without urticaria. Nausea, vomiting, drowsiness, headache, and flu-like symptoms also may occur. These signs and symptoms typically resolve spontaneously.

20. Specific Contrast Considerations Allergy. Patients who have had a prior ALR to contrast medium have a fivefold increased risk of developing a future ALR if exposed to the same class of contrast agent. Patients who have had a reaction to one class of contrast medium are not at higher risk or chance of having a reaction to another type of contrast medium.

21. Others Anxiety. Asthma. Beta-Blockers. Cardiac Abnormalities. Hyperthyroidism(Patients with hyperthyroidism may develop thyrotoxicosis after exposure to an iodinated contrast medium, but this is a rare).

22. Myasthenia Gravis. Pheochromocytoma. Sickle Cell Trait and Disease. Extravasation of Contrast Material- hyperosmolality of the contrast agent. It can cause compartment syndrome.

23. Postcontrast Acute Kidney Injury acute, sudden deterioration in kidney function within 48 hours after IV administration of contrast medium. vasoconstriction, direct tubular toxicity, osmotic mechanisms, and chemo-toxic mechanisms are considered. Although there are no standard criteria for CIN , the diagnosis can be made if one of the following occurs within 48 hours after administration of iodinated contrast medium: - increase in serum creatinine of >0.3 mg/dL, >50% increase in serum creatinine from baseline, or urine output reduced to <0.5 mL/kg/h for at least 6 hours

24. IV iodinated contrast material appears to be an independent risk factor for CIN in patients with stage IV and stage V chronic kidney disease whose eGFR is less than 30 mL/min/1.73 m2. High doses of IV contrast medium can impair renal function in some patients for 3 to 5 days, and the creatinine level usually returns to baseline in 10 to 14 days. CIN is the third most common cause of acute kidney failure in hospitalized patients (Nash et al., 2002)

25. Risk factors for CIN The most common patient-related risk factors for CIN are chronic kidney disease (creatinine clearance <60 mL/min), Diabetes mellitus, dehydration, diuretic use, advanced age, congestive heart failure, age, hypertension, low hematocrit, and ventricular ejection fraction less than 40%. The patients at the highest risk for developing CIN are those with both diabetes and preexisting renal insufficiency. The most common non–patient-related causes are high osmolar contrast agents, ionic contrast, increased contrast viscosity, and multiple contrast-enhanced studies performed within a short period and large contrast volume infused.

26. The American College of Radiology recommends a baseline serum creatinine level before receiving an IV iodinated contrast medium if one or more of the following risk factors are present: Age >60 years History of renal disease: Dialysis Kidney transplant Solitary kidney Renal cancer Renal surgery Hypertension requiring medical management History of diabetes mellitus Metformin drug combinations.

27. Hydration is the major preventative action against CIN. Periprocedural IV hydration with 0.9% saline at 100 mL/h 12 hours before to 12 hours after has been shown to decrease the incidence of CIN after intravenous contrast use The use of sodium bicarbonate has not been definitively shown to prevent CIN in patients receiving IV iodinated contrast material. (The use of N-acetylcysteine for the prevention of CIN is controversial Furosemide was found to increase the risk of developing CIN

28. Metformin and Iodinated Contrast. Patients with type 2 diabetes mellitus on metformin may have an accumulation of the drug after administering IRCM, resulting in biguanide lactic acidosis. They experience vomiting, diarrhea, and somnolence. This condition is fatal in approximately 50% of cases. In patients with normal renal function and no known comorbidities, there is no need to discontinue metformin before IV contrast use, nor is there a need to check creatinine after the imaging study. However, in patients with renal insufficiency, metformin should be discontinued the day of the study and withheld for 48 hours.

29. Postprocedure creatinine should be measured at 48 hours, and metformin should be started once kidney function is normal. It is not necessary to discontinue metformin before gadolinium-enhanced magnetic resonance (MR) studies when the amount of gadolinium administered is in the usual dose range of 0.1 to 0.3 mmol per kg of body weight.

30. Magnetic Resonance Imaging Contrast Agents Gadolinium: The frequency of all acute adverse events after an injection of 0.1 or 0.2 mmol/kg of gadolinium chelate ranges from 0.07% to 2.4%. Interfere with some serum chemistry assays. For example, hypocalcemia for 24 hours after MRI with gadolinium enhancement, Other tests, including iron, magnesium, iron-binding capacity, and zinc.

31. Nephrogenic Systemic Fibrosis NSF is a fibrosing disease of the skin, subcutaneous tissues, lungs, esophagus, heart, and skeletal muscles. Initial symptoms typically include skin thickening and/or pruritus. Symptoms and signs may develop and progress rapidly, with some affected patients developing contractures and joint immobility within days of exposure. The condition was previously known as nephrogenic fibrosing dermopathy. It is now accepted that exposure is a necessary factor in developing NSF. The onset of NSF varies between 2 days and 3 months, with rare cases appearing years after exposure (Shabana et al., 2008). Early manifestations include subacute swelling of distal extremities, followed by severe skin induration and later even organ involvement.

32. The most difficult patient population to choose an imaging modality is patients with a glomerular filtration rate (GFR) less than 30 mL/min/1.73 m2 who are not on chronic dialysis. They are at risk for CIN if exposed to iodinated contrast media for CT imaging and are at significant risk of developing NSF if exposed to GBCM during MRI. Recent data suggest that the risk of NSF may be greatest in patients with a GFR of less than 15 mL/min/1.73 m2 who have a 1% to 7% chance of developing NSF after GBCM MRI, with the incidence being much less in patients with higher GFRs

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