Experts on Call Answers to your questions from our medical experts Indications for Iron Injections When are iron injections indicated? Are there strategies to decrease discomfort ? and optimize beneficial effects? Submitted by: Jana Holden, MD, Leduc, Nova Scotia The management of iron deficiency anemia Further, there has been an association with should be twofold: to determine the underlying ghluteta©l sarcomas. In the 201t0ioAmnerican cause of the condition and to pprescyribeririongSociety of HemaitoslotgyriEbducuation Program, supplementation. Oral iroCn is tohe preferred ini - Auerbach alndDBallard recnolomamde,nded that “the rcia n dow tial route of supplementation. Intramuscumlar euse of IMeinrjsecctiaons should be abandoned.” om sed us al use (IM) iron injections have beren Cused; howevuetrh, ori erson e o ted. A Referencye for p al rohibi le cop we woouldrdisScourage uthseeir puse for severaalsriena g- 1. Auerbach M, Ballard H: Clinical Use of Intravenous Iron: t f rised print Administration, Efficacy, and Safety. Hematology Am Soc Hematol Nosons. nIMauirtohnocan be pawinfaunl,dcan potentially U ay, vie Educ Program 2010; 338 –347. leave permdanisenptlskin discolouration, and is not Answered by: Dr. Cyrus Hsia more effective or safe than intravenous iron. Dr. Leonard Minuk Assessing ASA Effect Are urine tests helpful to assess ASA effect? ? Submitted by: Gail Dangoor, MD, Thornhill, Ontario There are several tests that can be used to assess In general, a second antiplatelet drug ( e.g. , the effects of ASA on platelet aggregation. Urinary clopidogrel) that acts by a different mechanism is 11-dehydro-thromboxane B2 levels should be added when a patient experiences a myocardial suppressed in the setting of ASA use. However, infarct while on ASA. Tests for ASA resistance are multiple factors can result in thrombotic events in not routinely indicated in clinical practice. patients who are prescribed ASA, including non- compliance, interaction with other drugs, strong Answered by: Dr. Bibiana Cujec thrombotic stimulus, and resistance to the effects of ASA. The Canadian Journal of Diagnosis / January 2012 19 Experts on Call Treatment Options for Thrombosed External Hemorrhoids Can you recommend practical non-surgical options for acutely thrombosed ? external hemorrhoids? Submitted by: P. Balcar, MD, New Westminster, British Columbia Hemorrhoids result from dilation of the submu - analgesics and sitz baths. All patients with cosal vascular tissue in the distal anal canal. hemorrhoids should be treated with dietary Normally these fibrovascular cushions con - changes aimed at increasing stool bulk. In tribute to resting anal pressure and fecal conti - addition to increased fluid intake, a meta- nence. When one of these cushions becomes analysis reviewing 378 patients found that abnormally large and produces symptoms, we those receiving fiber laxatives displayed call it a hemorrhoid. Although the etiology reduced hemorrhoid symptoms compared to remains unclear, it is likely that straining with those receiving nonfiber laxatives. 1 Practically defecation contributes to their development. speaking, sugar-free Metamucil, which con - External hemorrhoids, those located below tains psyllium fiber, is a good choice; start at 1 the dentate line, are prone to thrombosis, an tbs daily taken in yogurt. This can be increased acutely painful condition. The diagnosis is con - to reach the desired effect of a daily, soft firmed with physical exam. If left untreated, the formed bowel movement. Please note that pain usually resolves in 48 to 72 hours. If the there is no evidence for nonprescription topical patient presents with intolerable pain within 24 preparations containing steroids, anaesthetics, hours of symptom onset, the clot should be astringents, and antiseptics. removed under local anaesthesia with the skin References edges left to heal by secondary intention. 1. Alonso-Coello P, Guyatt G, Heels-Ansdell D, et al : Laxatives for the Those presenting after 24 hours should be Treatment of Hemorrhoids. Cochrane Database Syst Rev. 2005; (4):n.p. 2. Mounsey AL, Halladay J, Sadiq TS: Hemorrhoids. Am Fam Physician treated conservatively, since the pain of surgery 2011; 84(2):204 –210. in addition to the thrombosis is worse than the initial pain. These patients can be given topical Answered by: Dr. Robert Bailey and 0.3% nifedipine cream (with or without lido - Dr. Mike McCall caine cream), which relieves pain through anti- inflammatory and smooth muscle relaxing properties. This can be combined with oral 20 The Canadian Journal of Diagnosis / January 2012 Experts on Call RAST Testing Which patients would benefit from RAST testing? ? Submitted by: Julie Torrie, MD, Medicine Hat, Alberta Radioallergosorbent (RAST) testing is a radioim - hospital settings. 2 RAST testing to environmen - munoassay test to detect specific IgE antibodies tal allergens ( e.g. , pollens, animal dander) is gen - to suspected or known allergens. RAST testing erally not done due to the superior predictive can be used to detect specific antibodies to value of skin prick testing to standardized aller - food, environmental allergens, insect sting gens. In rare circumstances, it may be necessary venom, and -lactam antigens. The presence of to choose RAST testing over allergy skin prick or these antibodβies indicates that a patient is sen - intradermal testing. For example, if the patient sitized to that allergen (may still be clinically tol - recently suffered anaphylaxis, false negative skin erant). This is in contrast to being allergic, which tests may occur due to skin mast cell depletion also entails clinical reactivity. Therefore, the (better to wait a month, then perform skin tests). meaning of a positive RAST test is highly vari - Severe eczema may make interpretation difficult able and is dependent upon the clinical history (a rare situation), and some patients cannot dis - (i.e. , the likely presence of true allergy), the type continue antihistamines for an adequate period of allergen tested, as well as patient-specific fea - of time (these interfere with skin test responses). tures ( e.g. , total IgE level). For antibiotics, RAST Of note, specific IgE antibodies to more specific testing has poor predictive value. In the case of epitopes on certain allergens ( e.g. , Ara h2 vs Ara food and venom testing, the RAST suffers from h8 peanut protein allergens) look to give us even inferior sensitivity compared to skin prick test - more information about clinical reactivity pheno - ing, but use of serial RAST testing in the follow- types, and hopefully we’ll be seeing more of up of these patients over time may aid in clinical these tests in the near future. decision making as to whether tolerance to that References allergen is likely. To this end, “cut-off values” in 1. Sampson HA: Utility of Food-specific IgE Concentrations in Predicting Symptomatic Food Allergy. J Allergy Clin Immunol 2001; certain food specific IgE levels have been devel - 107(5):891 –896. oped. Specific IgE levels above these values are 2. Shek LP, Soderstrom L, Alstedt S, et al : Determination of Food Specific IgE Levels Over Time Can Predict the Development of Tolerance in indicative of a very high likelihood of clinical Cow's Milk and Hen's Egg Allergy. J Allergy Clin Immunol 2004; reactions upon exposure. 1 This can be helpful 114(2):387 –391. when timing oral food challenge in the clinic and Answered by: Dr. Tom Gerstner 22 The Canadian Journal of Diagnosis / January 2012 Experts on Call Cluster Migraines What are “cluster migraines” and what is the best treatment and prophylaxis for ? them? Submitted by: Paul Stephan, MD, Scarborough, Ontario Cluster headaches are characterized by short- Intranasal lidocaine in the ipsilateral nostril or lived attacks of peri-orbital pain for a period of inhalation of methoxyflurane are also effective. one to two months, followed by a pain-free inter - Triptan therapy commonly used in migraine val that may last up to one year. The chronic headaches is also effective in cluster head- form of cluster headaches is sometimes referred aches. Prophylactic drugs that are effective to as chronic migrainous neuralgia. in treating cluster headaches include pred - Cluster headaches are clinically different from nisone, lithium, methysergide, pizotifen, nifedip - migraines and have a prevalence of approxi - ine, verapamil, nimodipine, indomethacin, and mately 70 per 100,000 population. Males are cyproheptadine. affected more than females, and usual age of Blockade of the greater occipital nerve ipsi - onset is between 20 – and 50 –years –of –age. lateral to the side of attacks, trigeminal sensory The pain during an attack is usually excruci - rhizotomy, and percutaneous radiofrequency ating and starts without any aura. It reaches its trigeminal rhizotomy have been reported to be peak within 15 minutes and lasts from half an successfull as well. hour to two hours. Attacks may recur at the Reference same time each day, and most of the attacks 1. Rana AQ: Synopsis of Neurological Emergencies. Authorhouse, occur in late evening. Bloomington, Indianna, 2009. Lacrimation from the eye or nose on the Answered by: Dr. Abdul Qayyum Rana affected side may be seen in many cases. For acute attacks, ergotamine or inhalation of 100% oxygen for 10 to 15 minutes is very effective. Experts on Call Treatment of Onychomycosis What are the current recommendations for treatment of onychomycosis in ? older patients? Submitted by: Anna Byszewski, MD, Ottawa, Ontario The prevalence of onychomycosis in patients older with dermatophyte onychomycosis, oral from 60 – to 79 –years –of –age has been report - terbinafine gave a mycologic cure rate of 64% ed to be 18.2% in a multicentre Canadian sur - and a clinical efficacy rate of 62% at 18 months vey of 15,000 patients. 1 Elderly patients may from the start of therapy. 2 Importantly, there respond poorly to therapy for onychomycosis were no significant adverse events or clinically because of several factors. These include significant laboratory abnormalities in this slow growth of nails, frequent nail dystrophy, study in which 50 patients received oral and increased co-morbidities, such as periph - terbinafine.