What’s Your Diagnosis? Mosquitoes on the Attack? By Irving Salit, MD, FRCPC n early September, while in central Ontario, Peter, 61, noted fever, urinary frequency, dysuria, abdominal pain, back pain, and achiness in his legs. He was started on ciprofloxacin and phenazopyridine, but he did not improve. His urine culture was negative. He felt he had some leg weakness and had difficulty walking. Peter’s travel history included a trip to Italy in July and a stay at a cottage around Georgian Bay, Ontario in August. Because of the fever and back pain, he was admitted to hospital with a diagnosis of possible pyelonephritis or prostatitis. Investigations in hospital did not reveal any uriTable 1 nary tract obstruction, although there was a cyst in his Examination and laboratory test results right kidney. In hospital, he had chills and rigors, with a Physical examination temperature of 38.5 C. He was switched from • No definite flank tenderness ciprofloxacin to ampicillin and gentamicin. During hospitalization, he started to develop a slight • Tremor of the left hand left-sided tremor. Magnetic resonance imaging did not • Mild confusion reveal any new lesions to account for the tremor. He was previ• Neurologic exam: Otherwise normal ously noted to have an acoustic neuroma which was unchanged. Lab tests Results of the physical and laboratory examinations are shown in • Hemoglobin: 135 g/L Table 1. • White blood cells: 11.2 When seen in a followup one month after the onset of his orig• Creatinine: Normal inal symptoms, he still had a tremor and difficulty with fine • Transaminases: Normal motor skills. The tremor interfered with his ability to write and he • Albumin: Normal found it most noticeable when had to sign his name; his signature • Urinalysis/Urine culture: Negative was no longer recognizable as being his own. An additional test was done which revealed the cause of his problem. I What’s your diagnosis? Dr. Salit is an associate professor, University of Toronto, and a staff member, division of infectious diseases, University Health Network, Toronto General Hospital, Toronto, Ontario. See page 40 for the answer The Canadian Journal of Diagnosis / August 2003 37 What’s Your Diagnosis ? Answer: West Nile virus This patient’s predominant symptoms included an initial febrile illness followed by a tremor. There was some unsteadiness of gait and subtle confusion. Because of the large number of cases of West Nile virus infection occurring in Ontario, the patient’s blood was sent for arbovirus serology. Antibody titres to both St. Louis encephalitis and West Nile virus were 1:≥ 640 at one month and four months after the onset of his illness. Cross-reactions can occur among arboviruses, such as St. Louis encephalitis, Dengue fever, West Nile virus, Powassan encephalitis, Yellow fever, and Japanese encephalitis, but West Nile was geographically most likely. Share your cases with us! Our mailing address: 955 boul. St-Jean, Suite 306 Pointe Claire, Quebec H9R 5K3 Our fax number: (514) 695-8554 Our e-mail address: [email protected] More on West Nile virus In 2002, there was a 65-fold increase in the number of West Nile virus cases in the U.S. Similarly, during 2002, West Nile virus activity was detected in birds and mosquitoes in many areas of southern Ontario. During August and September 2002, there were many patients admitted to hospital with neurologic disorders which www.stacommunications.com www.stacommunications.com Mai 2003 LA REVUE DE FORMATION MÉDICALE CONTINUE Volume 18, numéro 5 Volume 19, No. 5 May 2003 May 2003 Volume 20, Number 5 Articles May 2003 33 Volume 15, Number 5 In this issue: Focus on CME at 81 Queen’s 92 The Constant Urge to Go: The Overactive Bladder Marshall Godwin, MD, BMedSc, MSc, FCFP 63 99 Picking the Perfect Pill: Choosing Oral Contraceptives How Can We Fight Insulin Resistance in PCOS? 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Manipulating Hormones: Keeping Up The Pace Dr Harold Dion 97 115 1 21 Androgen Suppression in Prostate Cancer Patients 5 questions et réponses sur l’herpès génital Dr Karl Weiss, Dre Élaine Martel et Dr Benoit Monfette Update on Sexually Transmitted Infections Managing Cellulitis, Erysipelas, & more Articles 88 Departments R. Hugh Gorwill, MD, FRCSC 80 La fibromyalgie What’s New in Dementia? Thomas Woods; Dr. James Leone; Dr. Beate Hanson; and Dr. Mohit Bhandari Susan Chamberlain, MD, FRCSC 71 75 Dr. Vincent Woo University 49 The Limiting Factor: Hypoglycemia & Diabetes ! New Check out our FAQ FAQ department. This month— Obstructive Sleep Apnea, Hypoglycemia & Diabetes, Dementia, and Ankle Problems, on page 43. New Contest ! Win Win aa Palm Palm Pilot Pilot see see page page 71 47 Médi-test En collaboration avec l’Université Laval Concours: gagnez une caméra numérique ECG of the Month In association with the University of Ottawa Heart Institute 21 Frequently Asked Questions Voir page 71 New! Table 2 turned out to be West Nile encephalitis. Patients admitted to hospital with West Nile virus had the most severe forms of the disease. The main symptoms of those hospitalized for West Nile virus and the prevalence of those symptoms are listed in Table 2. The neurologic dysfunction with West Nile virus usually starts several days after the onset of systemic symptoms, such as fevers and myalgias. Most patients with severe West Nile virus neurologic disease are over age 50 and about half have significant underlying disease. The mortality rate is almost 20% and survivors very frequently have chronic and persistent neurologic deficits. Neurologic manifestations of West Nile and their prevalence Symptom Prevalence • Decreased level of consciousness 75% • Neuromuscular weakness 40% • Dysphagia 34% • Ataxia 30% • Dysarthria 17% • Vertigo 14% • Intention tremor 13% Some of the most severe neuromuscular manifestations include coma and flaccid quadriparesis. What happened to Peter? The patient presented here had a milder form of West Nile virus encephalitis, which did improve over the ensuing months. In fact, after six months he was essentially normal. Without a high index of suspicion, many other cases of milder forms of West Nile virus encephalitis have probably occurred and have not been recognized. Dx 3