experts on call · 2015-06-01 · 28 the canadian journal of diagnosis / july 2008 experts on call?...

Copyright

©

Not for Sa

le orComm

ercial Dist

ribution

Unauthoris

ed use pro

hibited. Au

thorised us

ers can do

wnload,

display, vie

w andprint

a single cop

y forperso

nal use

Experts on Call

The Canadian Journal of Diagnosis / July 2008 21

?Rising Creatine Phosphokinase on Fenofibrate

Recently, a patient put on fenofibrate had a creatine phosphokinase (CPK)increase from 160 to > 600. Is this common? What management fortriglyceride increase would be best? This patient is asymptomatic.Submitted by: R. K. Edwards, MD, Coquitlam, British Columbia

A large trial on long-term fenofibrate therapyin patients with Type 2 diabetes involved9,795 subjects, of which half took fenofi-brate. Safety data showed that < 1% hadCPK elevations between five to 10 times ormore. Other causes of an increased CPKelevation should be checked or the patientcan be carefully rechallenged to see if therise occurs again. If the CPK continues to be

significantly elevated other medications tolower triglycerides can be used, such asniacin.

Answered by: Dr. Vincent Woo

What are the advantages of endoscopic vs. open removal of the prostate andwhat, if any, are the different indications for surgery?Submitted by: Thomas Maxwell, MD, Hawkesbury, Ontario

Laparoscopic radical prostatectomy isbecoming more and more popular as thedemand from patients increases steadily.Although this remains somewhat debatable,the advantages of laparoscopic prostatecto-my include:• better vision for the surgeon,• less pain,• faster recovery and• minimal incision size.

Cancer control and functional results (erec-tile function and continence) are similar.

Answered by: Dr. Hugues Widmer

Endoscopic vs. Open Removal of the Prostate

?

Answers to your questionsfrom our medical experts

The Canadian Journal of Diagnosis / July 200822

Experts on Call

Management Options for Gout

What are the best management options for intermittent gouty episodes in therenally impaired?Submitted by: Valerie Rapson, MD, Barrie, Ontario

Management of gout in patients withadvanced renal failure not on dialysis can bechallenging. During acute flares, sinceNSAIDs are contraindicated, glucocorticoidsshould be used. Because of the adverseeffects of corticosteroids, long-term use isnot encouraged.

With regards to gout prophylaxis, the onlytherapy currently available is allopurinol forlong-term uric acid reduction and colchicinefor prevention of gouty flares until a steadystate is reached. In the setting of renal fail-ure, the adverse effects of these drugs tendto be more common. This is why they shouldbe used with caution and at reduced dosesadjusted to creatinine clearance with carefulmonitoring for adverse outcomes. In theCompendium of Pharmaceuticals andSpecialties there are guidelines on allopuri-nol dosing based on creatinine clearance.However, these guidelines were developedyears ago and never fully validated.

Studies have shown that strict adherenceto published allopurinol dosing guidelines inrenal failure may lead to suboptimal controlof hyperuricemia.1 Because the benefit oflowering uric acid in this population is felt tooutweigh the risk of allopurinol hypersensi-tivity reactions, allopurinol should be titratedslowly and with careful monitoring, with agoal towards achieving normalization ofserum uric acid.

Another method of modestly lowering uricacid in this population is with phosphatebinders used to control hyperphosphatemiawhich also coincidentally binds uric acid.2

Although this effect is modest and cannot bea substitute for allopurinol, their use mayallow for lower doses of allopurinol to beused, thus reducing the risks of adverseeffects. Phosphate binders should not beused in patients with normal serum phos-phate levels.

References1. Dalbeth N, Kumar S, Stamp L, et al: Dose Adjustment of

Allopurinol According to Creatinine Clearance Does Not ProvideAdequate Control of Hyperuricemia in Patients with Gout. JRheumatol 2006; 33(8):1646-50.

2. Garg JP, Chasan-Taber S, Blair A, et al: Effects of Sevelamer andCalcium-Based Phosphate Binders on Uric Acid Concentrationsin Patients Undergoing Hemodialysis: A Randomized ClinicalTrial. Arthritis Rheum 2005; 52(1):290-5.

Answered by: Dr. Sabrina Fallavollita; andDr. Michael Starr

?


Experts on Call

? What about seeds and nuts and diverticulitis? I can’t find any evidence for oragainst this old wives’ tale.Submitted by: Steve Sullivan, MD, Victoria, British Columbia

Seeds and Nuts and Diverticulitis

The pathogenesis of diverticuli in the colon isdue to increased intraluminal pressure,abnormal motility and decreased dietaryfiber. Most cases of diverticular disease areasymptomatic with only 15% to 20% devel-oping inflammation (diverticulitis) or compli-cations (i.e., bleeding, perforations, abscess,fistulas and strictures). The pathogenesis ofdiverticulitis is uncertain, but the theory ofdiverticulitis revolves around a fecalith causingstasis or obstruction of the neck of the diverti-culi. This may lead to bacterial overgrowth,

local tissue ischemia and microperforations.Though it may be reasonable to surmise thatcorn, small seeds or nuts can get “stuck” inthe narrow neck of a diverticuli, there is noevidence in the literature to support this. Infact, a high fiber diet is the recommendationfor prevention of diverticulitis. Therefore, inmy practice, I do not recommend avoidanceof nuts or foods with seeds to patients withdiverticular disease.

Answered by: Dr. Richmond Sy

? What is a good antihypertensive to use in aortic insufficiency? Why arecalcium channel blockers often used?Submitted by: Shanti Rao, MD, Windsor, Ontario

There is a lack of evidence for the use ofvasodilator therapy in order to prevent pro-gression of severe aortic insufficiency (AI) inpatients who are asymptomatic with normalleft ventricular function. There is some con-flicting literature evaluating the use of specif-ic vasodilators nifedipine or enalapril, whichis perhaps why the use of calcium channelblockers (CCBs) has become “popular.” Todate, and despite these studies, there is noevidence that specifically treating AI withvasodilator therapy is helpful.1 BP should be

managed and the choice of medication(including CCBs) should be based onpatient/physician preference and tolerabilityof the specific therapy.

Reference1. Mahajerin A, Gurm HS, Tsai TT, et al: Vasodilator Therapy in

Patients with Aortic Insufficiency: A Systematic Review. Am HeartJ 2007; 153(4):454-61.

Answered by: Dr. Richard Sheppard

Recommended Antihypertensive for Aortic Insufficiency


Experts on Call

?Significance of Sputum Colour

Does the colour of sputum aid in the diagnosis of respiratory infections?Submitted by: Jerry Graner, MD, Toronto, Ontario

The significance of sputum colour has beeninvestigated in the setting of acute exacer-bation of chronic obstructive pulmonary dis-ease (COPD). The presence of purulent spu-tum is predictive of a high bacterial load,increased likelihood of a positive sputumculture for bacteria and increased neutrophilnumbers in sputum.1,2 Therefore, sputumpurulence during an acute exacerbation ofCOPD may help in selecting patients whowill benefit from antibiotic treatment.1-3

References1. Stockley RA, O'Brien C, Pye A, et al: Relationship of Sputum Color

to Nature and Outpatient Management of Acute Exacerbationsof COPD. Chest 2000; 117(6):1638-45.

2. Soler N, Agustí C, Angrill J, et al: Bronchoscopic Validation of theSignificance of Sputum Purulence in Severe Exacerbations ofCOPD. Thorax 2007; 62(1):29-35.

3. O'Donnell DE, Aaron S, Bourbeau J, et al: Canadian ThoracicSociety Recommendations for Management of ChronicObstructive Pulmonary Disease—2007 Update. Can Respir J2007; 14(Suppl B):5B-32B.

Answered by: Dr. Paul Hernandez

?Stopping the Itch of Insect Bites

When an insect bites the skin, a complexmixture of venoms and salivary proteins cantrigger a local reaction.

For mosquitoes, the best treatment is pre-ventative. Suggest a combination of protectiveclothing and use of insect repellants contain-ing N,N-Diethyl-meta-toluamide (DEET).Concentrations should be lowest in children(six months and up) at 10% DEET to up to30% in adults. Clothing, bed nets, campingnets are available that are treated with insecti-cide such as permethrin.

Medical treatment consists of antihista-mines, soothing lotions, topical anestheticsand corticosteroids. Antihistamines used dailyjust before and after exposure to mosquitoesmay reduce immediate and early symptoms.Menthol (0.25%) and camphor (0.25%) in a

glaxol base can be applied to affected areasas needed to reduce itch (keeping this mixturein the fridge and applying cold may be evenmore soothing). Topical anesthetics can beused to provide temporary relief from extreme-ly itchy local reactions. Mid- to high-potencytopical corticosteroids can be applied to indi-vidual lesions twice daily for five to sevendays. Try applying the steroid under occlusion(e.g., under a piece of plastic wrap or aTegaderm™ patch) for one or two nights andthen open until resolved. If lesions persist,intralesional steroid injections (e.g., triamci-nolone acetonide 10 mg/ml) are helpful.Systemic corticosteroids are reserved for relieffrom extensive or severe reactions.

Answered by: Dr. John Kraft; andDr. Charles Lynde

Any helpful tips with regards to treating the itch of insect bites (i.e., mosquitoes,spiders, bees, etc.)Submitted by: Katherine Abel, MD, Leduc, Alberta

25

Experts on Call


ARBs for Isolated Hypertension

Can ARBs be used as first-line treatment for isolated hypertension?Submitted by: Fawzi Mankal, MD, Winchester, Ontario

ARBs are an effective, well-tolerated andsafe class of drugs to reduce hypertension.Based on their demonstrated efficacy andtolerability in the landmark LosartanIntervention For Endpoint Reduction inHypertension (LIFE) study, ARBs have beenrecommended by the Canadian HypertensionEducation Program (CHEP) for first-linetreatment of both systolic-diastolic hyperten-sion as well as isolated systolic hypertensionwithout concomitant conditions since 2003.

Patients with isolated systolic hyperten-sion frequently require multi-drug therapy toachieve the currently recommended targetsystolic BP values of 140 mmHg in generaland 130 mmHg in the presence of diabetesmellitus or renal failure from any cause. Inthis setting, ARBs can be combined withother classes of antihypertensive medica-tions such as diuretics, long acting calciumantagonists or ß-blockers for synergistic BP-lowering effect.

All six currently approved and marketedARBs in Canada come in a variety ofdosages and in fixed dose combinationswith a thiazide diuretic at no additional cost.This provides physicians with a great deal oftreatment flexibility and patients with anextremely effective therapeutic option thatfavours long-term adherence and thereforemaximizes the potential for CV disease pre-vention. Since their first introduction in 1995,ARBs have become the fastest growingclass of antihypertensive medications pre-scribed in Canada.

Resource1. Lindholm LH, Ibsen H, Dahlöf B, et al: Cardiovascular Morbidity

and Mortality in Patients with Diabetes in the LosartanIntervention For Endpoint Reduction in Hypertension Study(LIFE): A Randomised Trial Against Atenolol. Lancet 2002;359(9311):1004-10.

Answered by: Dr. George N. Honos

?

Patients with isolated systolic hypertensionfrequently require multi-drug therapy to

achieve the currently recommended target systolicBP values.


Experts on Call

?Treatment for Peripheral Vertigo

Betahistine dihydrochloride is marketed inEurope, Canada, Mexico, Australia and else-where around the world, as a specific treat-ment for Meniere’s disease. No brand ofbetahistine is approved for sale within theUS. Meniere’s disease (episodic vertigo, tin-nitus and deafness) requires audiometricallydocumented hearing loss, on at least oneoccasion and exclusion of other causes(including acoustic neuroma), according tothe American Academy of OtolaryngologyHead and Neck Surgery guidelines.

The pathophysiology of Meniere’s remainsillusive. As a result of this, medical treatmentoptions are not clear. Meniere’s disease orendolymphatic hydrops is believed to resultfrom abnormalities in the quantity, composi-tion and/or pressure of the endolymph withinthe inner ear. Betahistine dihydrochloride isthought to cause vasodilation in ischaemicareas of the inner ear. Therefore, any drug thatincreases blood flow to the organs responsi-ble for producing endolymph should theoret-ically worsen hydrops. In addition, it seemscounter-intuitive to treat patients withhistamine, for a disease that is relieved bysystemic antihistamines.

Despite its considerable use in England(113,000 prescriptions each month), specificguidelines are difficult to find. There is noconsistent evidence in the literature support-ing the use of betahistine dihydrochloride forthe treatment of Meniere’s disease. Thereare some centers in Europe that also usebetahistine dihydrochloride for non-Meniere’s peripheral vertigo; the evidencefor benefit in this group of patients is evenmore limited. However, there is a large clinicaltrial currently underway (the ObservationalStudy in patients suffering from recurrentperipheral vestibular Vertigo to Assess theeffect of betahistine 48 mg q.d. on quality ofLife and Dizziness symptoms [OSVaLD]),collecting data from North and SouthAmerica, Asia and Europe on > 2,000patients with peripheral vertigo. The resultshave not yet been published, but this trialmay help direct prescribing habits for thisgroup of patients that are hard to manage.

Answered by: Dr. Emma Barker; andDr. Jonathan Irish

What is the appropriate use of betahistine dihydrochloride in the peripheralvertigo?Submitted by: Gregory Belchetz, MD, Brampton, Ontario


Experts on Call

Best Antidepressant During Pregnancy

What is the best antidepressant to use in a pregnant, drug-withdrawingwoman in a (residential) treatment program (i.e., for cocaine, crystal meth,alcohol)?Submitted by: Elizabeth Watt, MD, Abbotsford, British Columbia

The cessation of regular cocaine and/oramphetamines use is associated with rela-tively mild symptoms of depression, anxiety,anhedonia, sleep disturbance (insomnia orhypersomnia), increased appetite and psy-chomotor retardation; however, these symp-toms decrease steadily over several weeks.No pharmacological agents reliably reducethe intensity of withdrawal, which usuallydoes not include physiological disturbancesas seen in opioids or alcohol withdrawal.Residential treatment is helpful for patientswho experience intense craving to providethem with the appropriate psychosocial inter-ventions that include psychotherapy.Residential treatment will also limit theiraccess to cocaine and/or amphetamineswhich has specific adverse effects on:• the health of the pregnant woman,• the course of the pregnancy,• fetal and early childhood development

and• parenting behaviour.

Symptoms of alcohol withdrawal includephysiological disturbances, which if not man-aged properly, could lead to serious conse-quences including withdrawal seizures, hallu-cinations and delirium tremens, all of whichcould adversely affect the course of the preg-nancy. Symptoms of alcohol withdrawal typi-cally begin four to 12 hours after cessation ofalcohol use, peak in intensity during the sec-ond day of abstinence and generally resolve

within four to five days. Patients with mild tomoderate withdrawal symptoms will respondto conservative measures in the form of gen-eralized support, reassurance and frequentmonitoring. Patients in moderate to severealcohol withdrawal will require the use of thi-amine, fluids and benzodiazepines. The liter-ature is less clear about which specific ben-zodiazepine to use during pregnancy.Unfortunately all benzodiazepines are desig-nated as category D in terms of fetal risk(i.e., there is positive evidence for a humanfetal risk, but the benefits from its use inpregnant women may be acceptable despitethe risk).

Unless the diagnosis of a major depres-sion has been established, there is no indica-tion to give antidepressant medication to thepregnant, drug-withdrawing woman in a resi-dential treatment program (for cocaine, crys-tal meth, alcohol). If an antidepressant is indi-cated, then selective serotonin reuptakeinhibitors, such as fluoxetine or sertraline,would be a possible choice. They are desig-nated as category C in terms of fetal risk(i.e., the drug could be given only if thepotential benefit justifies the potential risk tothe fetus).

Resource1. APA Practice Guidelines for the Treatment of Psychiatric

Disorders, 2006. Drugs in Pregnancy and Lactation, Seventh edi-tion.

Answered by: Dr. Hany Bissada

?


Experts on Call

?CT vs. MRI for Pituitary Adenoma

Pituitary adenomas are tumours of the ante-rior pituitary characterized by size and cell oforigin. These are typically benign tumourswhich may present with suprasellar symp-toms or hormonal abnormalities. About 10%of the normal adult population have pituitaryabnormalities on MRI scans that are com-patible with the diagnosis of asymptomaticpituitary adenomas (“incidentalomas”). Mostpituitary adenomas remain asymptomatic

and do not require treatment. MRI imaging isthe superior imaging procedure for work-upof pituitary adenoma. CT scans are a rea-sonable alternative and may be more timelyand cost-effective to perform. However, thesensitivity of a CT scan is less than an MRI,particularly for very small microadenomas.

Answered by: Dr. Sharlene Gill

In the work-up for pituitary adenoma, which is the best, CT or MRI?Submitted by: Karen Packer, MD, Cochrane, Alberta

Efficacy of Imiquimod for Plantar Warts

Is imiquimod an effective treatment for plantar warts? When should it be usedinstead of liquid nitrogen?Submitted by: Charles Cheng, MD, Vancouver, British Columbia

Imiquimod is a topical immune modulatingcream that stimulates the innate immunesystem through toll-like receptors. The onlyofficial indications for imiquimod in Canadaare for genital and perianal warts in adults,actinic keratoses and superficial basal cellcarcinoma. Any treatment for warts must betempered with the knowledge that mostwarts spontaneously resolve with time withouttreatment when the body eventually mountsan immune response to the HPV.

Treating plantar warts with imiquimodwould be an off-labeled use of this medica-tion as it is not officially indicated for plantarwarts or in children, in whom most plantarwarts are seen. However, if one chose to useimiquimod off-labeled for plantar warts, themajor obstacle is the poor penetration of thecream through the thick hyperkeratinized

plantar surface of the wart. Therefore, theefficacy is poor.

There are no controlled trials ofimiquimod in plantar warts, but there are iso-lated case reports in the literature ofresponse. Some of these cases involvedusing concomitant salicylic acid as a kera-tolytic to try to enhance penetration as wellas using imiquimod under occlusion.

In view of the poor response of plantarwarts to imiquimod, the cost of the drug andthe fact that treatment is off-labeled, I wouldnot recommend treating plantar warts withimiquimod and would consider liquid nitro-gen to be much more efficacious.

Answered by: Dr. Richard Haber

?


Experts on Call

Firstly, the flu shot is not contraindicated inpatients with egg allergies. Influenza vac-cines grow in chick eggs and the final prod-uct may contain very small amounts of eggproteins (large variation in egg protein con-tent has been reported). Most studies havedemonstrated safety of influenza vaccineadministration in children with egg allergy,1

with the caveat of some simple precautions.For those children who have suffered fromsystemic reactions in response to egg inges-tion and have had a confirmed IgE mecha-nism established by radioallergosorbent testand/or skin testing, a protocol has beenestablished in which skin testing to the flu vac-cine is followed by a graded administration of

the full vaccine dose.2 In this way, almost allpatients with an egg allergy may be immu-nized, even those with severe reactions toegg. In addition, it should be noted that eggallergy tends to occur in an older age groupof kids (usually toddler/preschool) and not inthe first six months of age, when milk is thepredominant food allergen.

References1. James JM, Zeiger RS: Safe Administration of Influenza Vaccine to

Patients with Egg Allergy. J Pediatr 1998; 133(5):624-8.2. Zeiger RS: Current Issues with Influenza Vaccination in Egg

Allergy. J Allergy Clin Immunol 2002; 110(6):834-40

Answered by: Dr. Tom Gerstner

?Safety of Flu Shots in Infants

Since the flu vaccine is contraindicated if a patient has an egg allergy andeggs are not supposed to be introduced before one-year-of-age, how can wesafely recommend flu shots as early as six-months-of-age?Submitted by: Norman Blustein, MD, Richmond Hill, Ontario

? How common is asymptomatic pelvic vein thrombosis following delivery?Submitted by: James Goertzen, MD, Thunder Bay, Ontario

Commonality of Asymptomatic Pelvic Vein Thrombosis

The incidence of asymptomatic pelvic veinthrombosis in the postpartum patient isunknown and therefore of uncertain impor-tance. In a small study attempting to deter-mine the frequency of deep vein thrombosisin moderate- to high-risk patients post C-section, using magnetic resonance venogra-phy, the rate of deep pelvic vein thrombosiswas 46%; however, the clinical significanceof this surrogate finding is unknown forobstetrical thromboprophylaxis.

Suggested reading:1. Rodger MA, Avruch LI, Howley HE, et al: Pelvic Magnetic

Resonance Venography Reveals High Rate of Pelvic VeinThrombosis after Cesarian Section. Am J Obs Gyn 2006;194(2):436-7.

Answered by: Dr. Victoria Davis


Experts on Call

?HPV Vaccine in Boys

The current recommendation for the HPVvaccine is for girls aged 11 to 12; however, itcan be given to girls as young as nine. Therationale for vaccinating young femalesbefore they are sexually active is becausethe vaccine is most effective in this popula-tion who have not been exposed to the fourtypes of HPV included in the vaccine. Theobvious question that arises is whether thereis a benefit to vaccinating girls/women atrisk, would there be such a benefit in vacci-nating boys. Intuitively, this would makesense as there may be health benefits to

preventing genital warts in men which mayultimately lead to penile and anal cancers. Inaddition, men may serve as a vehicle bywhich HPV is transmitted to women.Therefore, if boys/men are immune, thechain of transmission may be blocked.Unfortunately, however, it is not knownwhether the vaccine is effective in boys/menand hopefully within the next few years, theanswer will be known.

Answered by: Dr. John M. Embil

Should boys receive the HPV vaccine?Submitted by: Anonymous, Edmonton, Alberta

Replacing an ACE Inhibitor with an ARB

A patient experienced facial angioedema on ACE inhibitors (after six years ofuse). Can this patient safely use an ARB?Submitted by: Aloke De, MD, Westville, Nova Scotia

Angioedema secondary to an ACE inhibitorcan occur after years of treatment. Themechanism is felt to be increased bradykininbecause of decreased degradation.Angioedema is an ACE inhibitor class effectand is not drug specific. A patient whodevelops angioedema on an ACE inhibitorshould not be exposed to any other ACEinhibitor in the future. Much less commonly,angioedema may also be secondary toARBs. Losartan and valsartan have bothbeen implicated in case reports. In a caseseries of 13 patients who experiencedangioedema with losartan, three patientshad previously experienced angioedemawith an ACE inhibitor.1 Angioedema due to

an ACE inhibitor or an ARB may also besecondary to unmasking of hereditary oracquired deficiency of complement1-esterase inactivator, which is anothercause of kinin-mediated angioedema

The safest approach is not to use ARBs ina patient who has angioedema with ACEinhibitor. However, if the indication is com-pelling (e.g., heart failure with left ventricularejection fraction < 40%) an ARB should beused with caution.

Reference1. van Rijnsoever EW, Kwee-Zuiderwijk WJ, Feenstra J:

Angioneurotic Edema Attributed to the Use of Losartan. ArchIntern Med 1998; 158(18):2063-5.

Answered by: Dr. Bibiana Cujec

?

Experts on Call

?Diagnosing Diabetes in the Pediatric Population

How to diagnose diabetes mellitus in the pediatric population? Are the labsinvestigations and values the same as in adults?Submitted by: Sakina Raj, MD, Calgary, Alberta

The diagnosis of diabetes in the pediatricpopulation is made the same as in adults.The investigations are also similar for diagnos-ing Type 1 and Type 2 diabetes; however, Type2 is much less common in children than inadults, although unfortunately the preva-lence is increasing.

Answered by: Dr. Vincent Woo

?Length and Dose of PPI Treatment for Reflux

The atypical manifestations of gastroe-sophageal reflux disease (GERD) are oftenvery difficult to treat. Symptoms of coughing,asthma, hoarseness and chest pain have allbeen attributed to or exacerbated by acidreflux. The literature lacks controlled trials inthe therapy of atypical symptoms of GERDand the bulk of the evidence for manage-ment is largely empirical. The studies that arepublished often fail to show improvement ofsymptoms with treatment compared toplacebo. Most clinicians will use an empirictrial of high-dose PPIs at double dose for atleast three months to assess response. The

obvious shortcoming of this strategy is inter-preting PPI treatment failure. The sensitivityof empiric therapy is proposed to be muchlower in extra-esophageal manifestationscompared to classic GERD symptoms.Furthermore, it is often difficult to prove thatGERD is responsible for extra-esophagealsymptoms even after pH monitoring studiesor upper endoscopies, which are often normal.

Answered by: Dr. Richmond Sy

How long and at what dose of PPI do you treat your patients who haveextra-esophageal manifestations of reflux?Submitted by: Jean-Pierre Souaid, MD, Ottawa, Ontario

The diagnosis ofdiabetes in the

pediatric population ismade the same as inadults.

Visit www.EpiPen.ca

© 2007 King Pharmaceuticals Canada Ltd. EpiPen is a registered trademark of EMD Chemicals, Inc. under license to Dey, L.P., Napa, CA, U.S.A.

EpiPen® Auto-Injectors are indicated for the emergency treatment of anaphylactic reactions and for patientsdetermined by a physician to be at increased risk for anaphylaxis. Please consult Prescribing Information forfull indication, warnings, adverse events and patient selection criteria.

A


Experts on Call

? How successful is the obturator tape procedure in the treatment of bladderprolapse and urinary incontinence?Submitted by: Roshan Dheda, MD, Bradford, Ontario

The obturator tape procedure is very effec-tive in the treatment of urinary stress inconti-nence, with a success rate of around 85% to90%. Also, it is a minimally invasive tech-nique that can be performed as an outpa-tient surgery. It is not a corrective measure

used to treat prolapses; thus, it should beaccompanied by another technique if theprolapse is of concern to the patient.


The Success of the Obturator Tape Procedure

?Chronic Inflammatory Demyelinating Polyneuropathy

CIDP is caused by an abnormal immuneresponse against particular epitopes on theSchwann cells of the peripheral nervous sys-tem. Unlike its more acute cousin, Guillain-Barre syndrome, it progresses continuouslyfor more than two months. Because the ill-ness is a manifestation of the immune sys-tem gone wrong, current treatments arebased on interfering with the immune sys-tem’s ability to attack peripheral myelin. Atthis time, there are three regimens that havebeen proven equally effective in the treatmentof CIDP:• IV immune globulin (IVIg, a pooled blood

product),• plasmapheresis and• corticosteroids.

What guides treatment is usually verypractical concerns, such as availability ofregular treatment (which can be a problem

with plasmapheresis) and side-effects(which can be a major problem with longterm steroid use). For most people, themainstay of treatment is chronic, usuallymonthly, administration of IVIg.

If these treatments are not successful,other immune suppressant agents havebeen tried in small trials, as well as interfer-on agents; however, there are no clearresults at this time.

What is clear is that the earlier treatmentis started, the better the response, no matterwhat treatment is used.

Resource1. Koller H, Keiseiner BC, Jander S, et al: Chronic Inflammatory

Demyelinating Polyneuropathy. N Engl J Med 2005;352(13):1343-56.

Answered by: Dr. Inge Loy-English

What is the current treatment for chronic inflammatory demyelinatingpolyneuropathy (CIDP)?Submitted by: Robert Ecclestone, MD, Langley, British Columbia


Experts on Call

?Treating Osteoporosis in Patients with Renal Failure

Treatment of osteoporosis in the setting of renalfailure is challenging secondary to the metabol-ic abnormalities that are concurrent with renaldisease and because of the poor excretion ofthe agents used to treat osteoporosis.

As glomerular filtration rate (GFR)declines, there are a number of metabolicbone conditions that may be present. Thesespan a spectrum from mild-to-severe sec-ondary hyperparathyroidism in early stagesof chronic kidney disease (CKD), to thedevelopment of additional heterogeneousforms of bone diseases, such as renal osteody-strophy, each with its distinct bone histomor-phometric characteristics. Osteoporosis canalso develop in patients with CKD and end-stage renal disease for many reasons beyondage-related bone loss and postmenopausalbone loss.

The diagnosis of osteoporosis in patientswith severe CKD or end-stage renal diseaseis not as clearly defined as it is in patients withpost-menopausal osteoporosis. All forms ofrenal bone disease may result in increasedfracture risk, or have low T scores. BMD alonehas not been found to be a reliable indicatorof increased fracture risk, particularly in ahemodialysis population. Gold standard formaking the diagnosis of osteoporosis in thispopulation of patients is bone biopsy withdecreased trabecular bone formation.

In patients with moderate-to-severe renaldysfunction, first-line therapy centers aroundmeasures to minimize bone turnover andregulate calcium/phosphate homeostasis.The treatment of osteoporosis using bispho-sphonates, selective estrogen receptor mod-ulators, calcitonin, estrogen and anabolicsteroids is controversial as they maydecrease bone turnover and increase thedevelopment of adynamic bone disease oreven osteomalacia. This is the population ofpatients that could benefit most from bonebiopsy to exclude other renal related bonedisease prior to considering therapy.

The use of bisphosphonates is generallysafe if creatinine clearance is > 30 ml/min to35 ml/min. The use with decreasing creati-nine clearance is not well studied. There aresome reports that bisphosphonates can beused in reduced doses in this population ofpatients, however the trial data is not available.

Resources1. Ersoy F: Osteoporosis in the Elderly with Chronic Kidney Disease.

Int Urol Nephrol 2007; 39(1):321-31.2. Gal-Moscovici A, Sprague S: Osteoporosis and Chronic Kidney

Disease. Semin Dial 2007; 20(5):423-30.

Answered by: Dr. Sabrina Fallavollita; andDr. Michael Starr

Please comment on the treatment of osteoporosis in patients who have renalfailure, both mild and moderate.Submitted by: Anonymous


Experts on Call

?Investigating Angioedema During Pregnancy

What investigations should be done on a patient who presents withangioedema during pregnancy?Submitted by: C. Lynde, MD, Markham, Ontario

It is important in pregnancy that treatmentoptions consider the potential impact on thedeveloping fetus and the mother, whereasinvestigations may be carried out in mostcases in a similar manner as with non-pregnantindividuals. The most common considera-tions for angioedema are allergic, infectious(acute), or chronic causes such as idiopath-ic, hereditary, complement disorders, colla-gen vascular diseases, or malignancy(acquired C1 esterase inhibitor depletion).

The presence or absence of urticaria isalso very important, as both inherited andacquired forms of C1 esterase inhibitor defi-ciency occur without hives. The presence ofhives would allow for consideration of vari-ous physical urticarias (cold, exercise, heat)or vasculitis causes (serum sickness, hyper-sensitivity vasculitides).

As in all cases, a detailed history andphysical exam is essential, with the goals ofcategorizing angioedema and/or hives asacute or chronic (longer than six weeks) and

vasculitic (lesion bruises are painful and last> 24 hours).

Considerations for investigations include:• white blood cell count and differential,• erythrocyte sedimentation rate,• antinuclear antibody,• stool for ova and parasites, or• a skin biopsy if vasculitis is likely.Complement studies and thyroid antibodiesshould also be done. Liver function studiesand hepatitis serology may also be consid-ered.

Women may commonly complain thaturticaria exacerbates during menses andalthough immunologic reactions to endoge-nous hormones have been proposed, thereis little evidence to support such a mecha-nism. However, hormones may certainlyhave a role in modulating the severity ofsymptoms. Specifically, pregnancy and OCuse have been associated with exacerba-tions of hereditary angioedema, so the C1inhibitor level and functional assay would beimportant to assess in a pregnant womanwith angioedema without hives.

Answered by: Dr. Tom Gerstner

I t is important inpregnancy that

treatment optionsconsider the potentialimpact on thedeveloping fetus andthe mother.

Experts on Call

?Treating Psychogenic Pruritis

Psychogenic pruritus is a diagnosis of exclusion.There are no primary lesions, but patients maydevelop lesions from scratching, such as exco-riations and skin thickening. Sleep is rarelyinterrupted. Psychogenic pruritusmay be associ-ated with other psychiatric conditions, such aspsychosis and delusions of parasitosis, depres-sion and generalized anxiety disorder.

When approaching a patient with possible psy-chogenic itch, ensure that dermatological andsystemic causes of itch have been thoroughlyinvestigated. Dermatological causes of systemicitch include “winter itch,” pruritus of senescentskin, infestations (lice, scabies) and drug eruptions(opiates, ASA). Systemic causes of itch to con-sider screening for include:• Chronic renal failure• Endocrine:

- Diabetes- Hyperthyroidism

• Hematologic:- Iron deficiency- Hemochromatosis- Polycythemia rubra vera

• Infectious- HIV- Hepatitis C- Trichinosis

• Liver disease:- Obstructive biliary disease- Cholestatic liver disease of pregnancy

• Malignancy:- Lymphoma- Leukemia- Multiple myeloma- Carcinoid- Solid organ tumours

• Neurologic:- Peripheral nerve injuries- Post-herpetic neuralgia- Multiple sclerosisTreating psychogenic pruritus is often more

challenging than for other causes of itch.Topical therapies (e.g., menthol, camphor) arerarely effective. Antihistamines can be triedand sedating antihistamines are helpful whentaken at night if sleep is interrupted.

For itch that is not responding to the abovestrategies, consider other underlying causes,need for a psychiatric consultation and referralto a dermatologist, who may try novel agentsthat act on various pathways in the perceptionof itch. These agents include antidepressants(e.g., Selective serotonin reuptake inhibitors, nor-epinephrine and serotonin enhancer-mirtazapine),anticonvulsants (e.g., gabapentin) and opioidantagonists (e.g., butorphanol, naltrexone).

See our recent review for details:1. Lynde CB, Kraft JN, Lynde CW: Novel Agents for Intractable Itch. Skin

Therapy Letter 2008; 13(1): 6-9.


What are the treatments for psychogenic pruritus?Submitted by: Alan Russell, MD, Leamington, Ontario

Product Monograph available upon requestWyeth Consumer Healthcare Inc. Mississauga, ON, Canada L4Z 3M6


?Chelation Therapy

Are there any scientific studies on chelation therapy for coronary arterydisease (CAD)/cerebrovascular accident?Submitted by: Anonymous

IV infusion of ethylenediaminetetraaceticacid (EDTA), a lead chelating agent is calledchelation therapy. Vitamins are commonlygiven as part of the treatment. There aremany uncontrolled studies (involving a totalof 5,852 patients) of chelation therapy inpatients with CAD. It is difficult to draw anyvalid conclusions from these studies. Therewas no effect of EDTA on exercise durationor angiographic progression of CAD in twoplacebo-controlled studies with a total of 25patients.1 A randomized, placebo-controlled,double-blind Canadian study from Calgaryshowed no benefit of chelation therapy onbrachial artery endothelial function in 47patients with CAD.2 There is no reliable evi-dence to suggest that chelation therapy is ofbenefit to patients with CAD or cerebrovas-cular disease.

The risks associated with this treatmentare substantial and include:• renal failure,• arrhythmias,• tetany,• hypocalcemia,• hypotension,• bone marrow depression,• prolonged bleeding time,• convulsions,• respiratory arrest and• auto-immune diseases.Patients should be dissuaded from tryingchelation therapy.

References1. Ernst E: Chelation Therapy for Coronary Heart Disease: An

Overview of All Clinical Investigations. Am Heart J 2000;140(1):139-41.

2. Anderson TJ, Hubacek J, Wyse DG, et al: Effect of ChelationTherapy on Endothelial Function in Patients with Coronary ArteryDisease: PATCH Substudy. J Am Coll Cardiol 2003; 41(3):420-5.

Answered by: Dr. Bibiana Cujec

There are manyuncontrolled studies

(involving a total of5,852 patients) ofchelation therapy inpatients with CAD.

Experts on Call


Experts on Call

?Managing Acutely Increasing Creatinine

What are some ways to manage a patient with many comorbidities whodevelops an acutely increasing creatinine?Submitted by: P. Sullivan, MD, Sussex, New Brunswick

Acute dialysis is often suggested to be thefirst step in the management of acuteincreases in creatinine or acute renal failure,but this can often be avoided with carefulmanagement of the comorbidities accompa-nying renal dysfunction.

A step-by-step approach can be summa-rized as follows:• STEP 1: determine urgency of acute renal

failure and initiate emergency managementas necessary. This includes treatment oflife-threatening hyperkalemia(i.e., potassium > 6.0 mEq/L or EKGchanges consistent with hyperkalemia)and volume overload/pulmonary edema

• STEP 2: achieve euvolemia. If a patient isvolume depleted, administer IV fluidresuscitation to treat a pre-renal cause ofacute renal failure

• STEP 3: achieve urine output. Foleyinsertion can be followed by diureticadministration and an abdominalultrasound should be ordered

• STEP 4: search for reversible causes.Discontinue ACE inhibitors or ARBs;historically look for contrast,aminoglycoside antibiotic or NSAID use

• STEP 5: renally adjust medicationdosages. Antibiotics, allopurinol and oralhypoglycemics often require dosageadjustments while Metformin should beheld due to risk of lactic acidosis

• STEP 6: initiate a renal diet. A lowpotassium, low sodium, low phosphatediet should be initiated with a fluidrestriction of < 1 L q.d.

• STEP 7: achieve fluid balance. If theoliguria develops, IV fluid should belimited to maintainence requirements plusthe amount of urine output

• STEP 8: monitor carefully. Repeatelectrolytes and creatinine frequently andcontinually assess volume status forsigns of fluid overload

• STEP 9: avoid further insults.Hypotension, IV contrast,aminoglycosides and NSAIDs should beavoided as they worsen the renal injury

• STEP 10: indications for dialysis.Hyperkalemia refractory to medicaltreatment, severe acidosis refractory tomedical treatment, uremic pericarditis orencephalopathy, overdose and volumeoverload refractory to medical treatmentshould prompt rapid consideration foracute dialysisThese management steps should be

done in conjunction with consultation by aNephrologist or Internal Medicine specialist.

Answered by: Dr. Manish M. Sood


?Reducing Scarring After Surgery

Scars develop over months after surgery andcan be a major concern for patients. Duringany procedure that involves tissue apposi-tion, scar formation can be minimized byproper technique and material selection(e.g., using non-absorbable sutures and/orlong-lasting absorbable sutures). Also,avoiding locations prone to scar or keloidformation such as the trunk, upper back,shoulders, neck and ear lobes is helpfulwhen possible. Some patients have a dispo-sition to keloid formation or a family historyof excessive scarring and incisions should bekept to a minimum in these patients.

Post-surgery, scarring can be reduced in anumber of ways. If scar looks hypertrophic orkeloidal (e.g., extends beyond wound mar-gin), early intervention helps prevent growth

of a scar. Massaging helps prevent excessivefibrosis. Hydration/occlusion or use of siliconegel sheeting applied daily for a half to full dayfor two months can improve scar appearance.

Avoid possible pigmentary changes to scars(e.g., hyper/hypopigmentation) by strictly pro-tecting the wound from the sun using strictavoidance, clothing blockage and sunscreen.

High-potency topical or intralesionalsteroids are helpful for hypertrophic orkeloidal scars. Patients should be cautionedof corticosteroid risks including decreasedwound healing, local telangiectasias andatrophy. Other options that may be helpfulinclude dermabrasion one to two monthspost injury and laser therapy.


Are there any proven remedies that reduce scarring after surgery?Submitted by: Barbara Campbell, MD, Kingston, Ontario

Urologic Work-Up for Enuresis in a Child

Does a seven-year-old, otherwise healthy boy with normal blood and urinetests, suffering from enuresis, need a urological work-up before initiatingmedical therapy with desmopressin acetate?Submitted by: Dennis Glubish, MD, St. Albert, Alberta

In a perfectly healthy patient suffering frommonosymptomatic enuresis (incontinencepresent only at nighttime), only history, phys-ical examination and urine analysis are suffi-cient before initiating therapy. If there is ahistory (of urinary tract infections, dailysymptoms, constipation, etc.) or a physical

examination shows signs of spina bifida, forexample, or you suspect a urological or neu-rological anomaly, then a urological exami-nation should be performed.


?

Experts on Call

Experts on Call

?Lotions to Lighten Brown Spots

By solar “brown spots,” one is referring tosolar lentigines, but flat seborrheic keratoseson the face can look identical.

Any treatment of solar lentigines wouldbegin with sun avoidance and use of a SPF 30sunscreen containing UVB and UVA protection.

I am not aware of any OTC treatmentsthat have been shown to be effective in treat-ing solar lentigines. The only OTC productsthat would be available are 2% and 4%hydroquinone-containing topical products,some also containing small concentrationsof glycolic acid. These have not been scien-tifically shown to be effective in lighteningsolar lentigines.

The Pigmentary Disorders Academyreviewed treatment of solar lentigines in2006. The treatments were divided into topi-cal therapy and physical therapy. The con-sensus of the group was that first-line thera-py for solar lentigines was ablative therapywith cryotherapy. Lasers were also felt to bean effective treatment.

Topically, a fixed combination of 2%mequinol and 0.01% retinoic acid was shownto be effective in lightening solar lentigines indouble-blind, randomized controlled trials.Also, topical retinoids in the form of adapa-lene and tretinoin were felt to be effectivetreatments.

Resource1. Ortonne JP: Treatment of Solar Lentigines. J Am Acad Dermatol

2006; 54(5 Suppl 2):S262-71.

Answered by: Dr. Richard Haber

Are there any OTC lotions that will lightensolar “brown spots” on the face?Submitted by: Steve Sullivan, MD, Victoria, British Columbia

Pennsaid® is indicated for the treatment of

symptoms associated with osteoarthritis of

the knee(s) only, and for a treatment regimen

of not more than three months duration,

whether continuous or intermittent.

Serious GI toxicity, such as peptic ulceration,

perforation or GI bleeding can occur at any

time in patients treated with NSAIDs, including

diclofenac sodium. In clinical studies, Pennsaid® has

not been associated with serious GI toxicity.

Renal toxicity has been seen in patients taking

NSAIDs, and those with impaired renal function, heart

failure, liver dysfunction, those taking diuretics, and

the elderly are at greatest risk. In clinical studies with

Pennsaid®, no increase in urea or creatinine, or any

other renal toxicity has been observed.

Pennsaid® is contraindicated in patients with active

peptic ulcer, a history of recurrent ulceration or active

inflammatory GI disease, signifi cant hepatic or renal

impairment, active liver disease or deteriorating

kidney function. Pennsaid® is contra-

indicated in patients with hypersensitivity

to diclofenac, dimethyl sulfoxide, propylene glycol,

glycerine, alcohol or to other ASA/NSAID products.

The potential for cross- reactivity with other NSAIDs

must be borne in mind. Pennsaid® is contraindicated in

patients with complete or partial ASA intolerance

syndrome: fata l anaphylactoid reactions have

occurred in such individuals.

Pennsaid® should be given under close medical

supervision to patients with a history of ulcer or

infl ammatory disease of the GI tract, such as

ulcerative colitis or Crohn’s disease.

Commonly reported application site side effects,

Pennsaid® (vs. placebo) were: dry skin, 41.9%

(6.9%); rash, 9.6% (2.9%); and paresthesia,

7.9% (10.3%).

For full information, please see Pennsaid®

Product Monograph.

www.pennsaid.ca

n, th

est ris

in ur

as be

ted in

of rec

e, sig

er di

n. Pe

ts w

hyl su

to ot

s- rea

d. Pe

e or

a l an

h in

be g

ts w

se of

or Cr

ed ap

bo) we

% (2.

n, ple

ed fo

ded w

and fo

an th

us or

ty, su

GI ble

ts tre

In clin

ed wit

s be

h im

i

o

h

r

e

n

t

e

m

ho

s

re

e

c

g

s

e

w

u

t

a

e

r

n

n

i

w

f

e

t

a

h

o

t

G

t

I

e

a

t

te

h

t

e

n

n

h

t

s

d

t

a

c

b

r

te p

b e

o e

h

s

r

e

c

g

i

e

w

u

t

a

e

r

n

n

i

w

f

n

e

h

te

o

e

e

n

t

h

t

s

d

t

a

b

t

s

r

e pp

b e

% .

o e

e

t

o

w

o

h

r

u

e

e

n

t

e

m

t

a

o

t

G

t

I

e

a

th


Experts on Call

?Medroxyprogesterone Acetate and BMD

Medroxyprogesterone acetate is a contra-ceptive injection which suppresses estrogenlevels. Studies have shown that women whouse this injection have lower bone densityand long-term users under the age of 21 hadthe lowest bone density, especially if theystarted at a very young age. However, itappears that bone density recovers when itis stopped and there are no studies thatanswer the question of whether its early useleads to fragility fractures later in life.

The World Health Organization has sug-gested that medroxyprogesterone acetatebe used with caution in women < 18 and> 45 and that alternative means of contra-ception be considered if possible.

A young woman with a normal diet shouldbe counseled regarding adequate vitamin Dand calcium intake, regular weight-bearingexercise and to avoid smoking and exces-sive alcohol intake.

Regarding the need for BMD measure-ment, it is not practical or useful to recom-mend scanning all woman onmedroxyproges-terone acetate. However, in some situations,

BMD testing may be appropriate since theresults may influence management deci-sions. For example, women who have otherrisk factors for osteoporosis may benefitfrom BMD testing so that those with a bonedensity that is already low can consideralternative methods of contraception. It mayalso be appropriate to test women usingmedroxyprogesterone acetate who areapproaching menopause, since this is a timewhen risk of osteoporosis may be increasing.

Answered by: Dr. Michael Starr

What is the evidence that use of medroxyprogesterone acetate can lead toosteoporosis and what guidelines do we give to a young woman with a normaldiet?Submitted by: D. Chambers, MD, Banff, Alberta

Dx

experts on call · 2015-06-01 · 28 the canadian journal of diagnosis / july 2008 experts on call?...

Documents