Toxicology and Extracorporeal therapies (SACCM + Dobratz) Flashcards
For which toxicoses can ILE be considered as a life saving antidote?
- Macrocyclic lactones (ivermectin, moxidectin)
- Baclofen - muscle relaxants
- Ca channel blocker and B blockers
- Cholecalciferol
- Bromethalin
- NSAIDS (Ibuprofen, Naproxen)
- Marijuana
- Methamphetamine, cocaine
- Local anesthetics
- TCAs
List indications and contraindication to induce emesis
When is activated charcoal contraindicated
- Heavy metals (Fe, Zn), xylitol, alcohols (EG, ethanol, methanol) ? don’t reliably bind to AC
- Symptomatic patients who are at risk for aspiration pneumonia
- AC with a cathartic should be used cautiously in hypovolemic, in dehydrated patients or those with excessive free water loss (e.g., diabetes mellitus, renal disease, diabetes insipidus)
- Endoscopy
- GI obstruction, hemorrhage or perforation
- Recent surgery
- Ileus
- Ingestion of caustic substance or hydrocarbons
What are indication for multidose of AC?
- Enterohepatic circulation
- XR (extended release) / LA (long acting) / SR (sustained release)
Complications of activated charcoal
- Hypernatremia
- aspiration pneumonia
- the use of AC could confuse the diagnosis of intoxication of substances that can increase the osmolal gap such as ethylene glycol
- difficult endoscopy
- constipation
- corneal abrasion (if contact with eyes)
List catartics that can be used in VM
- sorbitol
- sodium sulfate
- magnesium sulfate
- magnesium citrate
List potential toxins that can cause CNS stimulation
- SSRIs, TCAs, amphetamines, 5-FU, Bromethalin, methylxantines, pyretrins, metaldehyde, strychnine, tremorgenic mycotoxins, sleep aids
List potential toxins that can cause CNS depression
Muscle relaxants (baclofen), opioids, sleep aids, marijuana, macrocyclic lactones (ivermectin, moxidectin)
T/F - α-agonist activity (such as imidazole decongestants found in nasal sprays and eyedrops or amitraz collars) can be reversed with the use of α-adrenergic antagonists such as yohimbine or atipamezole
TRUE
Explain mechanism of action of SAMe
- Acts as a methyl donor
- Generates sulfur-containing compounds that are imporant for conjugation reactions used in detoxfication.
- Acts as a precursor of glutathione
Explain mechanism of action of NAC for acetaminophen toxicosis
- Limits the formation of toxic metabolite NAPQI by providing alternative glutathione substrate with acetaminophen toxicosis (it is a glutathione precursor).
- Binds with APAP metabolites making them inactive
- Increases sulfate conjugation by being a sulfur donor.
Explain the lipid sink hypothesis of ILE therapy
compartimentalization of the drug in the lipid phase results in a decreased free drug concentration available to tissues
List effects of ILE other than “lipid sink”
- provides energy substrates to myocytes augmenting cardiac performance (remember FFAs are the preferred substrate for myocardial cells)
- restores myocardial function by increasing intracelular calcium
- Increasing the overall fatty acid pool, which overcomes inhibition of mitochondrial fatty acid metabolism (e.g., bupivacaine toxicosis).
What are the dosage recommendations of ILE in VM?
- Initial 20% ILE bolus 1.5 to 4 ml/kg (between 0.3 g/kg and 0.8 g/kg IV over 1 minute)
- followed by 0.25 ml/kg/min CRI (0.05 g/kg/min IV over 30 to 60 minutes)
- If not response: Intermittent bolusing at 1.5 ml/kg q4-6h for 24 hours can be considered; C19follow-up CRI doses of 0.5 ml/kg/hr (0.1 g/kg/ hr) can be continued until clinical signs improve (not to exceed 24 hours) or until serum is lipemic.
List adverse effects of ILE therapy
- fat embolism
- fat overload syndrom
- phlebitis
- local systemic infection if injection site is contaminated
- pancreatitis
- Interaction with lipophilic medications being given to patient
- worsening of ARDS (decreased PaO2:FiO2 ratio)
- allergic reactions, anaphylatic reactions
- interferance with lab tests
- Fat overload syndrome is reported in humans (not yet in VM) –> associated with excessive administration that overwhelms lipid clearance mechanisms and leads to: hyperlipidemia, hepatomegaly, splenomegaly, icterus, coagulopathy, hemolysis
Which components in regular therapies for toxicities can make a cageside Ethylene glycol test false positive?
- Propylene glycol in Diazepam
- Glycerol in activated charcoal
T/F - Chocolate increases the pyloric sphincter tone and can be recovered inducing emesis up to 8h after ingestion
TRUE
Emetis generally empty __% of gastric content
40% to 60%
T/F In general gastric lavage is more efficacious than emesis for decontamination
FALSE
In which circumstances is recommended to administer milk, water or liquid from water-packed tuna?
- SOME household products
- corrosive or irritant products
- exposure to toad secretions
- taste reactions due to topically aplied products (foaming kitties following flea spray application)
What is a side effect of administration of 3% hydrogen peroxide in cats?
25% of cats can develop severe hemorrhagic gastritis, rarely death
What is a consequence of inducing vomiting in a patient that ingested petroleum distillates or hydrocarbons (kerosene, gasoline, motor oil, transmision fluid)?
toxicants can easily be aspirated –> severe aspiration pneumonitis
What’s the mechanism of action of Apomorphine and in which species is not effective
- Acts on CRTZ (chemoreceptor trigger zone)
- cats
Xylazine causes emesis in ~___% of cats
50%
Over the counter urine ilicit drug screening tests are used for detection of…..
What is the disadvantage?
- They test for: heroin, cocaine, THC, methanphetamines, PCP
- Can give false positive if patient is on: opioids, trazodone, lidocaine, diphenhydramine, NSAIDS, others
- Can give false negative for some THC metabolytes
What is the composition of ILE and how are they metabolized
Composition:
- Medium to long chain tryglicerides (soybean oil, saffloer oil, etc)
- Glycerin
- Phospholypid emulsifier
Metabolism:
- tipically cleared by skeletal muscle, myocardium, splanchnic viscera and SC tissues where they are broken into glycerol, free fatty acids and choline to be used as energy by the tissues
What is the Log p?
Is the measure of the solubility of a compound between two solvents, one hydrophilic and one lipophilic
A compound is considered lipophilic is the log p is > ____
> 1
List the 4 RRTs
- Intermitent hemodialysis (IHD)
- Continuous Renal Replacement therapy (CRRT)
- Hemoperfusion (HF)
- Total plasma exchange (TPE)
What are the two main mechanisms of solute removal in RRT
- Diffusion = movement of solute across semi-permeable membrane driven by transmembrane concentration membrane.
- convection (aka. ultrafiltration) = movement of water and solvent drag across permeable membrane that occurs due to transmembrane pressure gradient. Convection allows for removal of middle (MW 500- to 60,000 Da) and large (MW > 60,000 Da) molecular weight solutes during dialysis
In which modes removal of solute occurs mainly by diffusion
- IHD
- Continuous Venovenous Hemodyalysis (CVVHD) –> mode or CRRT
- Peritoneal dyalysis
In which modes removal of solute occurs mainly by convection
- Continuous venovenous hemofiltration (CVVHF) –> mode of CRRT
- SCUF
Which methods combine diffusive and convective modalities?
- Continuous venovenous hemodiafiltration (CVVHDF)
- Application of ultafiltration during IDH and PD
The permeability of a dialyzer membrane is determined by
- Pore size
- surface area
- thickness
- membrane material
What are benefits of IHD over CRRT
- Rapid solute removal
- Smaller molecular weight water-soluble intoxicants are removed most efficiently by IHD.
- IHD + charcoal hemoperfusion (CH) allows for removal of large solutes.
What are benefits of CRRT
- slow and continuous solute removal
- better tolerated than IHD in hemodynamically unstable patients, however, rapid toxin removal is almost always more ideal, and when performed by an experienced RRT team, IHD rarely leads to hemodynamic instability.
- better clearance of larger molecular weight solutes due to:
- diffusive and convective properties
- membranes used in CRRT are often more permeable than IHD membranes
Solutes with a large Vd that are redistributed into the IV compartment have better clearance with……..CRRT or IHD?
solutes with a large Vd that are redistributed into the IV compartment have better clearance with CRRT compared with shorter IHD treatments
Does TCAs go enterohepatic recirculation?
- Toxins with high protein binding capacity
- Toxin with large molecular weight (up to 40.000 Da)
What are potential complications of charcoal hemoperfusion and how can you eliminate this potential side effects?
- Hypocalcemia
- Hypoglycemia
- Thrombocytopenia
- *Due to non selective properties
- priming volume of commercially available CH cartridges ranges from 150 ml to 240 ml can lead to hemodynamic instability in < 10 kg animals
- CH is performed in tandem with HD to decrease or eliminate these potential side effects: blood passes through the dialyzer after contact with HF cartridge normalization of electrolyte abnormalities.
- priming the extracorporeal circuit with blood, can be considered when treating smaller patients
Define the mechanism of action of TPE (aka. Plasmapheresis)
- Separates the blood into its various components either by centrifugation or filtration
- The plasma component of the blood is removed and replaced with a replacement s/n:
?colloid (albumin, Hetastarch, or plasma)
? or a combination of crystalloid and colloid
What are the advantages of TPE?
- independent of the toxin size and protein binding
- Removes the inciting toxin and toxic byproducts:
- mediators of inflammation and other endogenous substances
- Ideal for treatment of intoxications shortly after ingestion and for those toxins that have a small volume of distribution (Vd), because only the blood compartment is being treated and procedures are performed over a shorter period
What’s the molecular weight of albumin
69000 Da
Define volume of distribution
sum of all compartmental volumes that account for the total toxin distribution at an equilibrated state
What is the ideal Vd for maximal clearance of a substance with ECT
Equal or less than the blood volume because toxin removal occurs directly from the intravascular compartment.
- For toxins with a large Vd, concentration within the intravascular compartment decreases as the solute distributes between the body fluid compartments (intercompartmental equilibration
The speed of equilibration of a toxin depends on:
The characteristics of the toxin as well as the Vd
- Ex. a highly lipid-soluble, large-MW toxin with large Vd is likely to have a slower compartmental equilibration time.
Explain how post-treatment rebound occurs and give an example of a toxin that does that:
Plasma [ ] of the intoxicant may return to a toxic level as intercompartmental equilibration occurs –> after cessation of toxin removal via ECT, as the toxin redistributes from the other compartments into the IV space
** Ex. Phenobarbital
T/F uremia can alter the tissue binding capacity of some solutes, resulting in a decreased Vd
TRUE
What would happen with the Vd of a substance that is highly protein bound in a hypoproteinemic patient
The free fraction of drug increases but can re-equilibrate in tissue compartments and result in a higher Vd
What makes ethylene glycol toxicity a good option for IHD and what special consideration needs to be applied during the treatment
- Low molecular weight (62Da) and non-protein binding capacity –> approx. 90 to 100% of the toxin and metabolites can be removed from circulation with a single session of IHD (with traditional medical management the toxic metabolites are not removed)
- ethanol is added to the dialysate to inhibit ongoing metabolism of EG to its more toxic metabolites (conversion of glycoaldehyde by alcohol dehydrogenase)
T/F Acetaminophen is a small (151 Da), non–protein bound, highly water-soluble compound with a small Vd that could be treated with ECT
TRUE
Describe the general pharmacokinetics of NSAIDS
small size, highly protein bound (90-95% to mostly albumin) and small Vd - Some undergo enterohepatic recirculation (diclofenac, indomethacin, sulindac, etodolac, ibuprofen, naproxen, piroxicam, meloxicam, carprofen)
What method of ECT would you consider for an NSAID intoxication? What are potential limitations?
- The high protein binding property of the drug favors the use of CH over conventional HD
- in veterinary medicine, hemoperfusion is almost always performed simultaneously with HD to prevent the potential complications associated with CH.
- The large extracorporeal volume needed to perform combined HD/HP limits the application for this modality to larger patients.
- It is difficult to determine when a HP cartridge is saturated, although in the author’s experience this typically occurs 4 to 6 hours after the start of therapy
What are benefits and limitations of the use of ECT in Amanita Phalloides toxicity?
- It is an ideal toxin to remove via ECT due to it’s small Vd, however it’s rapid absorption and short plasma half life limit the benefit of the treatment
- Has high affinity for AC
What could be indications of using ECT in barbiturate toxicity?
- when severe intoxication with long-acting barbiturates occurs, ECTs can be used to decrease hospital stay and to avoid complications such as aspiration pneumonia that can occur in severely obtunded or comatose patients
- Given the large Vd, rebound of drug into the intravascular space is likely to occur after treatment with HD/HP, with resultant recurrence of clinical signs. In these situations, multiple or prolonged ECT sessions may be indicated
T/F - barbiturates undergo enterohepatic recirculation
TRUE
Differences between IHD and CRRT equipment. Describe the different modes
IDH
- has mainly diffusion mode and a bit of convection
CRRT (Prismaflex machine common in VM)
- Predominantely convection
- Combines up to 4 modes of diffusion and convection:
**Slow coninuous untrafiltration (SCUF) (convection)–> ultrafiltrate gets discarded, hemoconcentrated blood goes back to patient
**CVVH (convection)–> A a balanced electrolyte solution replaces the ultrafiltrate
** CVVHD (diffusion)–> similar to IHD but the rate is very slow
**CVVHDF –> combines diffusion and convection, the grade of convection and diffusion can be adjusted independently
List indications for RRT
- Severe electrolyte/acid-base disturbances non responsive to medical management/ AKI (BUN >100mg/dL, creat >10mg/dL)
- Fluid overload (specially when anuria/oliguria are present)
- CHF
- Refractory hyperkalemia
- compromised patients secondary to uremic toxemia
T/F CRRT is a continuous modality, which most closely mimics endogenous renal function.
TRUE
Which RRT modality has a high maximum removal ratio to low molecular weight solutes per unit of time
IHD
T/F The physiologic peritoneal membrane is defined to have three different pore sizes, allowing for movement of both small and larger molecular weight solutes
TRUE. Large pores, 100 to 200 A˚in diameter, correspond to clefts in the endothelium and allow the transport of macromolecules such as albumin. They are present in very small numbers, accounting for less than 0.01% ofthe total pore surface area. Small pores, 20 to 25 A˚ in diameter, also correspond to clefts in the endothelium. They present in large numbers, representing more than 90% ofthe pore surface area, and allow the passage of low molecular weight substances such as urea. creatinine, and glucose. Ultra small pores, 4 to 6 A˚ in diameter, are aquaporin I channels found within peritoneal capillary and mesothelial cells, and transport only water
Define ultrafiltration
Ultrafiltration is the process of plasma water removal from the intravascular compartment (and ultimately from the interstitial and intracellular spaces as redistribution occurs)
List contraindications for peritoneal dialysis
Contraindications for PD in veterinary medicine include peritonitis, recent abdominal surgery, and hypoalbuminemia.
T/F In IHD and the CVVHD and CVVHDF modes of CRRT, the dialysate flows countercurrent to the blood to allow for maximum solute removal. In
TRUE
Which are the three mechanisms by which fluids and solutes are transported aross the peritoneal membrane
- Diffusion
- Convection (Solvent drag) –> when solutes are carried along with the bulk flow of water during ultrafiltration (not very relevant in PD)
- ultrafiltration –> removal of fluid (water) during PD –> desired when performing PD in animals that are overhydrated
T/F Urea has a relatively low molecular weight of 60 and diffuses more rapidly than creatinine, which has a molecular weight of 113
TRUE
List possible indications for peritoneal dialysis
- AKI, severe uremia
- Toxicities where toxin is highly diffusible (EG, ethanol. Barbiturates)
severe metabolic disturbances (hyperkalemia, hypercalcemia, hepatic encephalopathy) - life threatening fluid overload
Dialysis for removal of solutes generally is performed using ____% dextrose. Dialysates containing___% and ___% dextrose are used in moderate to severely overhydrated patients.
- 1.5% dextrose.
- 2.5%
- 4.25%
How would you prepare a dialysate solution for PD?
Adding dextrose to lactated Ringer’s solution can make a suitable dialysate solution. Osmolality should closely approximate that of the patient, and the dextrose concentration should be at least 1.5%. Adding 30 mL of 50% glucose to 1 L of lactated Ringer’s solution will result in a 1.5% dextrose solution.
- Heparin (250 to 1000 U/L) should be added to the dialysate for the first few days after catheter placement to help prevent occlusion of the catheter by fibrin deposition. This heparin is minimally absorbed by the patient’s circu- lation and is unlikely to prolong clotting times.
Describe the exchange procedure of peritoneal dialysis
Dialysate is infused at a dosage of30 to 40 mL/kg during a 10-minute period.12,14,39,57 The dialysate is allowed to remain in the peritoneal cavity for 30 to 40 minutes (dwell time) and then is drained into a collection bag by gravity during a 20- to 30-minute period. A 90% to 100% recovery of dialysate is expected. This process is repeated continually, and the dialysate formula and dwell times are adjusted every 12 to 24 hours according to the animal’s need.
What is a disadvantage of using highly concentrated dextrose solutions for peritoneal dialysis
Although more concentrated dextrose solutions allow for effective fluid removal from the patient, these concentrates are more likely to lead to secondary peritonitis and dysfunction of the peritoneal membrane
- Glucose activates the polyol pathway and the secretion of transforming growth fac- tor-b1 (TGF-b1), monocyte chemoattractant protein-1 (MCP-1), and fibronectin. in vitro data suggest that glu- cose is involved in the development of peritoneal fibrosis. Glucose is likely to be involved in the development of peritoneal neoangiogenesis.
- A third mechanism by which glucose can damage the peritoneal tissue is by inducing nonenzymatic glycosylation oftissue proteins, which leads to the formation of advanced glycosylation end products (AGEs). The depo- sition ofAGEs in the vascular wall also leads to ultrafiltration failure
Which anticoagulation methods are most commonly used in IHD and CRRT?
- Systemic heparinization –> IHD
- Regional citrate –> for CRRT
Define dialysis disequilibrium syndrome
In severely uremic patients, rapid removal of uremic toxins should
be avoided to prevent dialysis disequilibrium syndrome. Rapid removal of osmotically active solutes from the blood compartment creates osmotic pressure gradients between the blood, extravascular, and intracellular compartments. This gradient allows plasma water to shift from the vascular compartment and into the intracellular compartments. When this phenomenon occurs in brain tissue, sec- ondary swelling occurs and this can lead to irreversible neurologic damage or death
The goal of PD for an animal with renal failure is to remove enough urea to maintain the BUN concentration at ____mg/dL
70mg/dL
How can you prevent dialysis disequilibrium syndrome
- when severe uremia is present, initial treatments must be designed to achieve slow solute removal. (CRRT?)
What is the normal dialysate volume per exchange cycle in peritoneal dialysis? Why is this important?
- 30-40ml/kg
- In PD, precise measurements of dialysate inputs and outputs must be recorded to avoid overhydration of the patient
- If fluid balance becomes positive or returning volume decreases to less than 90% of what was administered, the dialysate should be changed to encourage ultrafiltration
What are disadvantages of CRRT
The intensive prolonged treatments required with CRRT and the need to have a dedicated and trained technical staff for the duration of the treatments make it difficult to carry out quality treatments in many veterinary practices. In addition, the cost for premade dialysate can become cost-prohibitive when high dialysate flows were required. In addition, since CRRT is not designed to be a long-term treatment modality, it is necessary to have facilities available to provide longer-term care for patients that remain dependent on RRT
Describe the 4 cathegories of applications for apheresis in human medicine based on the defined or proven benefit that apheresis provides
I - considered standard of care for that condition (ex. Myastemia gravis)
II - considered suppoertive therapy in combination with other therapies (ex. Amanita poisoning)
III - condition in which controlled trials are limited or their results inconclusive
IV - condition in which therapy appeared to be ineffective or harmful
How many plasma volumes are removed with each plasmapheresis treatment? Why?
- One
- For most higher-molecular-weight substances, such as immunoglobulins, the efficiency of patho- logic substance removal is not increased when more than 1 or 1.5 plasma volumes are exchanged in a single treatment.
In which disease processes has apheresis been used most commonly in the CC setting in VM?
- Myastenia gravis
- IMHA
** Although case numbers are low, the anecdotal success in these cases is promising
Mention advantages of TPE in IMHA patients
Use of TPE allowed patients that were previously crossmatch incom- patible due to severe agglutination to receive blood transfusions. likely because of a reduction in antibody load
- Use of TPE allowed for successful control of disease with the same immunosuppressive protocols that had been previously unsuccessful in those patients
Explain the arachidonic acid pathway
After a tissue has been damaged, arachidonic acid is released from cell membranes, precipitating a chain of events known as the arachi- donic acid cascade. Two enzyme groups metabolize arachidonic acid: the lipoxygenases (LOX) and the cyclooxygenases (COX). Products from the LOX cascade include leukotrienes and chemotactic factors. Products of the COX cascade include prostacyclin, thromboxanes, and prostaglandins.
List functions of the prostaglandins
Important in maintaining local blood supply to tissues
Define constitutive vs inducible prostaglandins
- Continuously produced (constitutive) prostaglandins are required for the normal function of the brain, kidneys, gastrointestinal tract, primary hemostatic system, and reproductive system.
- Inducible prostaglandins are produced in response to tissue injury. They escalate the inflammatory response and increase peripheral nerve sensitization; they also have protective actions and play a role in tissue repair
What is the difference between COX 1 and COX2 prostaglandins?
- most COX-1–induced prostaglandins are constitutive and have homeostatic effects, some are also produced in response to tissue injury.
- although many prostaglandins produced by COX-2 are inducible, there are constitutive COX-2 prostaglandins found in the brain, intestine, and kidneys in many species. COX2 appears to be constitutive in canine pyloric and duodenal mucosa and these products are important for healing of gastoduodenal ulcers
Mention COX dual acting medications and COX2 selective medications
- Dual acting –>Aspirin, ketoprofen, tepoxalin
- COX2 selective: carprofen, meloxicam, deracoxib, firocoxib
Explain the mechanism of gastric ulceration secondary to COX medications
- COX1 induced prostaglandins in gastric mucosa have protective effects –> mucous production and enhance local blood flow –> COX 2 is stimulated when damage to the gastric mucosa occurs and produces prostaglandins important in mucosal healing –> NSAIDS can inhibit all these
- Some NSAIDs, such as aspirin, can cause direct injury to the gastric mucosa by disrupting surface phospho- lipids, allowing gastric acid to penetrate directly to the cells in the wall of the stomach
What could be an explanation of why the gastric mucosa is more susceptible o NSAID even at lower doses when compared to other tissues?
NSAIDs are weak acids that become lipid soluble in the highly acidic environment in the stomach. This allows them to penetrate easily into gastric cells, where they become trapped in the relatively more alkaline environment. This leads to a high local concentration of NSAIDs in the gastric mucosa and may be an explanation for adverse effects occurring in the gastrointestinal system at lower doses than in other organ systems.
Which NSAID medication seems to have the lowest incidence of gastrointestinal ulceration?
Carprofen
List the effects of COX inhibitors in the kidneys
- Inhibition of prostaglandins production by the juxtaglomerular apparatus –> inhibitis prostaglandin mediated local vasodilation of afferent arteriole in cases where GRF is decreased –> decreased renal blood flow –>AKI
- Inhibition of renin release by the JGA (this process is mediated by COX1-COX2 enzymes
T/F NSAID use has been associated with an increase in liver enzymes and hepatocellular injury in some patients. This toxicity depends on dose and duration of treatment
FALSE - NSAID use has been associated with an increase in liver enzymes and hepatocellular injury in some patients. This toxicity does not depend on dose or duration of treatment and therefore is classified as an idiosyncratic reaction. –> typically occurs within the first 3 weeks of administration, but can happen after months/years.
What are the effects of COX-1 and COX-2 in coagulation?
- COX-1 –> promotes production of TXA2 –> more platelet agregation and vasoconstriction
- COX-2 –> promotes production of PGI2 (prostacyclin) –> vasodilation and inhibits platelet aggregation
T/F Aspirin is the most effective NSAID for reducing platelet aggregation because it binds permanently and decreases TXA2 production for the life of the platelet.
TRUE. Platelets lack a nucleus and are unable to synthesize new COX enzymes
Which medications can reach toxic plasma concentrations when combined with an NSAID
Protein-bound drugs –> other antiinflammatory agents, warfarin, phenytoin, penicil- lins, and sulfonamide antibiotics. NSAIDs can also increase plasma levels of digoxin and can decrease the efficacy of furosemide.
T/F - Drugs that induce cytochrome P450 metabolic pathway in the liver (e.g., phenobarbitone) can decrease NSAID metabolism, increasing their analgesic efficacy
FALSE -Drugs that induce cytochrome P450 metabolic pathway in the liver (e.g., phenobarbi- tone) can increase NSAID metabolism, reducing their analgesic efficacy
Which findings in the UA are idicative of renal damage and can help differentiale renal from pre-renal azotemia?
- isostenuria can be indicative of acute renal insuficiency
- casts in urine sediment can indicate renal tubular injury as an early sign of toxicity
- proteinuria can indicate glomerular damage
In general, how many half lifes are going to determine treatment duration in a case of NSAID overdose?
In most cases of medication overdose, treatment duration depends on the half-life of the drug that has been ingested; treatment should continue until at least three half- lives have passed.
List the half life of NSAID medications –> fill table
Which antinausea medication is contraindicated in a case of NSAIDs toxicity and why?
Metoclopramide should be avoided because this dopamine antagonist could decrease renal blood flow.
NSAIDS-induced renal injury is characterized by:
Papillary necrosis and interstitial nephritis
What is the mechanism of action of misoprostol?
PGE1 analog
What is the proposed toxic substance within grapes, raisins and currants?
Two dogs that ingested potasium bitartrate (cream or tartar) developed acute azotemia and isostenuria, one ingested 2 tea spoon of cream of tartar, the second one ingested homemade play dough made with cream of tartar. Second dog died and necropsy revealed changes similar to the ones reported in raising toxicosis –> cortical tubular degeneration,
necrosis, and mineralization, with some evidence of regeneration.
- Potassium bitartrate is the salt of tartaric acid, and both potassium bitartrate and tartaric acid are uniquely present in high concentrations in grapes and tamarinds.
- Interestingly, the ASPCA Animal Poison Control Center has had reports of severe vomiting and acute renal failure in dogs following large exposures to tamarinds, which are also uniquely high in tartaric acid.
What are the effects of lily toxicity in cats
- proximal tubular epithelial cells necrosis, edeme and tubular obstruction in the kidneys
- pancreatitis
- vomiting, lehtargy and hypersalivation appear within 1 to 5 days (some as soon as 1-3h)
- seizures, ataxia (40% of cats)
T/F A common finding in cats with Lily toxicosis is a more markedly elevated serum creatinine concentration compared to a more moderate blood urea nitrogen
TRUE
Approximately ______% of dogs will remain asymptomatic following grape or raisin exposure. Dogs which developed AKI reportedly had a _____% survival rate. The median time until resolution of azotemia in surviving dogs was 16 days for BUN and ____days for creatinine.
- 25-60%
- 53%
- 30 days
The prognosis for cats which have been given supportive care shortly after exposure to Lilys is good, up to 100% survival in one study. Cats developing AKI have reportedly had a grave prognosis, _______% mortality in several studies. Survival rate for cats treated with dialysis is reportedly ______%
- 50-100%
- 50%
What’s the mechanis of action of benzodiazepines
What’s the mechanis of action of imidazopyridines, oyrazolopyridines, cyclopyrrolones?
What’s the mechanis of action of penothiazines, alpha-agonist and barbiturates?
Is there an specific therapy for sedatives overdose?
only reversals for opioids, benzodiazepines and alpha-2 agonist. Other than than is supportive and sympthomatic care.
What is the LD50 of Diazeman and Midazolam
> 20mg/kg (dogs) and 1600mg/kg IV respectively
what is the LD50 of acepromacine?
257mg/kg PO / 61mg/kg IV (mice)
what is the LD50 of Pentobarbital?
85mg/kg PO or 50mg/kg IV (dogs)
T/F Flumazenil can also revert effects of imidazopyridines, pyrazolopirimidines and cyclopyrrolones
TRUE
List alpha-2 agonist reversals
- Atipamezol
- Yohimbine
- Tolazoline
**last 2 are less specific and have more side effects
Fill table of skeletal muscle relaxants of clinical and toxicologic importance and their mode of action
What are the indications of AC use for muscle relaxant toxicity?
For patients that ingest baclofen or carisoprodol, only one dose of activated charcoal with a cathartic is necessary because these drugs do not undergo enterohepatic circulation. For the remaining muscle relaxants, efficacy of multidose activated charcoal regimens has not been established