A 29-year-old man is hospitalized due to a flulike illness. His symptoms abruptly began 3 days ago with fever, rigors, malaise, headache, and myalgia. The patient has no prior health conditions and is usually very active, participating in multiple outdoor sports. Temperature is 38.9 C (102 F), blood pressure is 124/84 mm Hg, and pulse is 110/min. Physical examination shows an ill-appearing man with bilateral conjunctival suffusion. Lung and heart sounds are normal, but abdominal examination reveals mild hepatosplenomegaly. Generalized lymphadenopathy is also present. A test for influenza antigen is negative, and blood cultures in routine growth media are negative. The patient subsequently develops progressive jaundice and renal failure. Further testing detects an infection with a highly motile, corkscrew-shaped pathogen. This patient most likely acquired the infection via which of the following?

Question

A 29-year-old man is hospitalized due to a flulike illness.  His symptoms abruptly began 3 days ago with fever, rigors, malaise, headache, and myalgia.  The patient has no prior health conditions and is usually very active, participating in multiple outdoor sports.  Temperature is 38.9 C (102 F), blood pressure is 124/84 mm Hg, and pulse is 110/min.  Physical examination shows an ill-appearing man with bilateral conjunctival suffusion.  Lung and heart sounds are normal, but abdominal examination reveals mild hepatosplenomegaly.  Generalized lymphadenopathy is also present.  A test for influenza antigen is negative, and blood cultures in routine growth media are negative.  The patient subsequently develops progressive jaundice and renal failure.  Further testing detects an infection with a highly motile, corkscrew-shaped pathogen.  This patient most likely acquired the infection via which of the following?

Quizplus · Accepted Answer

Leptospirosis is a widespread, zoonotic infection caused by several species of Leptospira, a thin, highly coiled, motile spirochete that infects wild (eg, rodents) and domestic (eg, dogs, cattle) animals. Infected animals harbor the organism in the proximal renal tubule and excrete it in urine. Transmission to humans primarily occurs during outdoor recreational (eg, kayaking, freshwater swimming) or occupational activities that exposes them to water contaminated with animal urine. Most cases of leptospirosis are mild or subclinical. However, some patients develop a flu-like illness (eg, fever, rigors, myalgia, headache), lymphadenopathy, or more severe end-organ disease such as renal failure or hepatic failure (eg, jaundice, hepatomegaly). Conjunctival suffusion, redness of the conjunctiva that resembles conjunctivitis but is noninflammatory, is an important diagnostic clue. Because spirochetes do not grow well on traditional culture media, initial testing (eg, influenza antigen, blood culture) is often negative. However, specialized culture media can often identify the corkscrew-shaped organism. Most cases are self-limited and do not require treatment. (Choice A) Bats can transmit rabies to humans via a bite wound. Manifestations typically begin with flulike symptoms and progress to fever, hydrophobia, pharyngeal spasms, coma, and death. Rabies is a cylindrical, enveloped RNA virus; it is not a motile, corkscrew-shaped organism. (Choice B) Yersinia, a bacteria transmitted by animal (eg, rodent) fleas, can cause bubonic plague, which typically presents with sudden-onset, flulike symptoms followed by intense pain and regional lymphadenopathy (eg, inguinal). Yersinia grows well on traditional culture media; it appears on Gram stain as a gram-negative coccobacillus. (Choice D) Rocky Mountain spotted fever is a tickborne illness caused by the small, gram-negative bacterium Rickettsia rickettsii. Although initial symptoms are often flulike and may include conjunctivitis, most individuals develop an erythematous rash that begins on the wrists and ankles, spreads to the center of the body, and includes the palms and soles. The organism is not corkscrew-shaped. (Choice E) Tularemia is caused by the gram-negative bacterium Francisella tularensis, which frequently infects rabbits. Manifestations typically include flulike symptoms followed by lymphadenopathy and a papulo-ulcerative eschar at the site of inoculation. Educational objective: Leptospirosis is a zoonotic infection caused by the motile spirochete Leptospira. Transmission primarily occurs when humans come into contact with water contaminated with animal urine during outdoor recreational or occupational activities. Patients classically have a mild, self-limited, flulike illness but may develop more serious complications such as renal or hepatic failure. __________ References: Leptospirosis in humans. (http://www.ncbi.nlm.nih.gov/pubmed/25388133)

A 29-Year-Old Man Is Hospitalized Due to a Flulike Illness