Infectious Disease

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We live in a world of toxins and potential toxins, and thus we are often just a misstep away from a toxic exposure and its consequences. Even that which is meant to cure can kill. All substances are poisons; there is none which is not a poison. The right dose differentiates a poison and a remedy; exposure to the wrong dose of a medication (whether accidental or not) remains a common form of toxic exposure.

The line on the gums of this 30-year-old man indicates lead poisoning. The patient had been employed for 8 months at a lead smelting plant in which no occupational safety precautions had been enforced. He was admitted to the hospital with the classic symptoms and signs of lead poisoning--pain in the nape of the neck that radiated down the spine, posterior thighs, and calves to the plantar aspect of the feet; colicky panabdominal pain; anorexia; weight loss; nausea; vomiting; constipation; bone and muscle tenderness; hyperesthesia of all extremities; insomnia; irritability; generalized weakness; malaise; and dizziness.

For 2 months, a 35-year-old woman has been troubled by a bilateral pruritic eruption on her neck. The condition did not respond to a 3-week course of oral terbinafine. The patient has a history of childhood asthma; her only current medication is an oral contraceptive. She has had a cat for the past 2 years. She has not used any new shampoos or conditioners.

A 35-year-old veterinary technician who lived in south central Texas presented with a raised, warm, tender 2- to 3-cm papule on her lower leg of more than 2 weeks' duration. Topical mupirocin and oral trimethoprim/ sulfamethoxazole were prescribed, but the papule continued to enlarge and became increasingly erythematous and painful.

Q:My patient’s family appears to be genetically predisposed topulmonary fibrosis. How should I follow this patient? What earlywarning signs herald the condition, and what diagnostic tests are mostappropriate?

A persistent, 2-month-old rash under both breasts has not responded to overthe-counter antifungal creams. The 55-year-old patient now seeks medical care;she is otherwise healthy.

Infection with hepatitis C virus (HCV) was recently diagnosedin a 45-year-old man when a positive enzyme-linked immunosorbentassay was followed by a polymerase chain reaction assaythat showed a viral load of 835,000 copies/mL. The patient probablyacquired the infection when he was using intravenous heroin, a practice he quit 10 yearsago. The patient is immune to both hepatitis A and hepatitis B viruses, and there is no coinfectionwith HIV. Liver biopsy shows moderate cellular inflammation (grade 3) and bridging fibrosis(stage 3) but no evidence of cirrhosis. Iron staining shows no abnormal iron deposition in theliver. The HCV genotype is 1A.

A Thumbnail Sketch

My patient, a 33-year-old man who works with his hands, presented with a growthunder his left thumb nail (Figure).

A 56-year-old man who has type 2 diabetes presents with feverof 3 to 4 days’ duration, scrotal swelling, and a feculent odor. He has nohistory of trauma or serious illness; however, his glucose level has not beenwell controlled during the past several weeks.

The sudden onset of asymptomatic red streaks on several sites alarms a14-year-old girl. The patient is otherwise healthy; she denies any symptoms ofdepression.

This painful, eroded plaque on thedorsum of a 39-year-old man’s handhad developed over a few days from asmall, painful pustule. The patient’shistory included ulcerative colitis,which was not active when the lesionoccurred.

Delirium in older adults needs to berecognized early and managed as amedical emergency. Prompt detectionand treatment improve both shortandlong-term outcomes.1,2 Becausedelirium represents one of the nonspecificpresentations of illness in elderlypatients, the disorder can be easilyoverlooked or misdiagnosed. Misdiagnosismay occur in up to 80% of cases,but it is less likely with an interdisciplinaryapproach that includes inputfrom physicians, nurses, and familymembers.3

Guidelines for the management of community-acquired pneumonia (CAP) have been published by several medical organizations, including the British Thoracic Society, the American Thoracic Society, and the Infectious Diseases Society of America (IDSA). Do these guidelines help improve survival rates? Yes, according to a study that focused on adherence to the IDSA guidelines and outcomes for patients with severe CAP. This study also underscores the importance of providing adequate coverage for Pseudomonas aeruginosa in patients with risk factors such as chronic obstructive pulmonary disease (COPD), malignancy, or recent antibiotic treatment.

A 28-year-old man presented with chest pain, hemoptysis, and wheezing. He had a history of intermittent shortness of breath that occurred at least 3 times a year in the past 3 years; fever; and loss of appetite associated with headache, vomiting, and weakness. His medical history also included asthma, chronic gastritis, and more than 5 episodes of pneumonia since 1996. A test for hepatitis C virus (HCV) had yielded positive results.

A 66-year-old man presented with weight loss for 2 months, loss of appetite for several weeks, and abnormal chest radiographic findings. He denied chest pain, cough, fever, chills, shortness of breath, and chest trauma. He was an active smoker, with a 50-pack-year history of smok- ing, and a cocaine and alcohol abuser. His history included treatment of hypertension for 10 years and treatment of pulmonary tuberculosis 14 years previously.

High-resolution CT (HRCT) and galactomannan enzyme-linked immunosorbent assay (ELISA) are valuable in the diagnosis of invasive aspergillosis; however, both of these methods have limitations. Although the role of polymerase chain reaction (PCR) testing has not been established yet, the results of a study in the Netherlands are encouraging.

Abstract: Multidrug-resistant tuberculosis is defined as tuberculosis caused by strains that have documented in vitro resistance to isoniazid and rifampin. Treatment involves a regimen consisting of at least 4 or 5 drugs to which the infecting strain has documented susceptibility. These agents may include ethambutol, pyrazinamide, streptomycin, a fluoroquinolone, ethionamide, prothionamide, cycloserine, and para-aminosalicylic acid. In addition, an injectable agent, such as kanamycin, amikacin, or capreomycin, should be used until negative sputum cultures have been documented for at least 6 months. If the patient has severe parenchymal damage, high-grade resistance, or clinically advanced disease, also consider clofazimine, amoxicillin/clavulanate, or clarithromycin, although there is little evidence supporting their efficacy in this setting. Routine monitoring includes monthly sputum smear and culture testing, monthly assessment of renal function and electrolyte levels, and liver function tests every 3 to 6 months. (J Respir Dis. 2006;27(4):172-182)

The mother of this 3-year-old boy noticed that his smile was asymmetric when he awoke that morning. He had been seen 3 days previously for left ear discomfort, sore throat, and a low-grade fever. Otitis media was diagnosed, and amoxicillin was prescribed.