A 19-year-old man who recently went camping in the northeast United States presents to the student health clinic at his college with fever, headache,...
A 29-year-old woman and her husband seek your consultation for an inability to conceive. After a thorough workup, you believe the cause to be an undiagnosed infection in the woman. Examination reveals mild cervical motion tenderness; Gram stain of cervical secretions shows neutrophils but no organisms. The inability of the causal bacteria to produce what substance causes it to be an obligate intracellular parasite?
A 29-year-old woman and her husband seek your consultation for an inability to conceive. After a thorough workup, you believe the cause to be an undiagnosed...
A 24-year-old sexually active man presents with dysuria and urethral discharge. Gram stain of the discharge reveals neutrophils but no gram-negative diplococci. What is the diagnosis and treatment?
A 24-year-old sexually active man presents with dysuria and urethral discharge. Gram stain of the discharge reveals neutrophils but no gram-negative diplococci....
How does C. bumetii differ from other rickettsiae?
How does C. bumetii differ from other rickettsiae?Answer: It is transmitted by aerosols rather than an arthropod vector, is not associated with a...
What are the symptoms of Q fever?
What are the symptoms of Q fever?Answer: Self-limited flu-like illness, soaking sweats, pneumonia, and can cause hepatitis and endocarditis. Note...
What disease does C. burnetii cause? How does C. bumetii spread?
What disease does C. burnetii cause? How does C. bumetii spread?Answer: Q fever. Spreads by inhalation of endospores from placental products of ...
What class of antibiotic can be used for all rickettsial infections?
What class of antibiotic can be used for all rickettsial infections?Answer: Tetracyclines (eg, doxycycli...
What causes rickettsial pox?
What causes rickettsial pox?Answer: Rickettsia akari carried by mites that causes an initial red papule at the bite site, and eventually chickenpox-like...
What is endemic typhus, and how is it spread?
What is endemic typhus, and how is it spread?Answer: Fever, headache, rash from Rickettsia typhi (less severe than epidemic typhus) spread by rodent-fleas...
What is epidemic typhus, and how is it spread?
What is epidemic typhus, and how is it spread?Answer: Fever, headache, rash due to Rickettsia prowazekii. Transmitted at times of overcrowding (poverty,...
Where does the rash related to RMSF start? Where does it spread to?
Where does the rash related to RMSF start? Where does it spread to?Answer: On the ankles and wrists and palms and soles and then spreads to the trunk,...
What is Rocky Mountain spotted fever (RMSF)?
What is Rocky Mountain spotted fever (RMSF)?Answer: Fever, headache, conjunctival redness, and petechial rash on palms and soles due to Rickettsia...
What is the Weil-Felix reaction?
What is the Weil-Felix reaction?Answer: A test for antibodies to Proteus vulgaris antigens used to diagnose rickettsial infection based on the coincidental...
What symptoms are associated with most rickettsial infections?
What symptoms are associated with most rickettsial infections?Answer: Rash (vasculitis), high fever, severe heada...
How are rickettsiae transmitted?
How are rickettsiae transmitted?Answer: Through arthropod vectors (except Q fever, Coxiella burnetii was previously classified as a Ricketts...
What is the appropriate therapy for chlamydial neonatal conjunctivitis?
What is the appropriate therapy for chlamydial neonatal conjunctivitis?Answer: Erythromycin eye dr...
How are Chlamydia infections treated?
How are Chlamydia infections treated?Answer: Tetracycline, doxycycline, erythromycin, azithromycin, or a fluoroquinol...
How are C. pneumoniae and C. psittaci transmitted?
How are C. pneumoniae and C. psittaci transmitted?Answer: Aerosol transmiss...
What vascular changes may Chlamydia pneumoniae elicit?
What vascular changes may Chlamydia pneumoniae elicit?Answer: Intimal changes with deposition of lipid-laden macrophages, resulting in a fatty streak.Note...
What disease is caused by Chlamydia pneumoniae?
What disease is caused by Chlamydia pneumoniae?Answer: Atypical pneumonia (gradual onset of fever and nonproductive cough, eosinophilia, history...
What disease is caused by Chlamydia psittaci?
What disease is caused by Chlamydia psittaci?Answer: Psittacosis, an atypical pneumonia occurring after exposure to infected bi...
How is LGV diagnosed?
How is LGV diagnosed?Answer: Serology and PCR. In the past, a skin test using antigen, prepared from Chlamydia and known as the Frei test, was u...
What are the clinical manifestations of lymphogranuloma venereum (LGV)?
What are the clinical manifestations of lymphogranuloma venereum (LGV)?Answer: Primary: painless, self-limited genital ulcerSecondary: acute inguinal...
What type of arthritis is associated with Chlamydia?
What type of arthritis is associated with Chlamydia?Answer: Reactive arthri...
What is pelvic inflammatory disease?
What is pelvic inflammatory disease?Answer: A sequela of cervicitis due to C. trachomatis (or Neisseria gonorrhoeae) infection. Spread of the infection...
What are the most common bacterial sexually transmitted diseases?
What are the most common bacterial sexually transmitted diseases?Answer: Urethritis and cervicitis caused by C. trachoma...
Is there lifelong immunity to Chlamydia?
Is there lifelong immunity to Chlamydia?Answer: Because of the existence of multiple serotypes, there is no lifelong immunity to Chlamydia as reinfection...
Serotypes D-K?
Serotypes D-K?Answer: Nongonococcal urethritis (men) and cervicitis/PID (women), both sexually transmitted. Inclusion conjunctivitis (newborns) and...
What disease is caused by Chlamydia trachomatis serotypes A, B, C?
What disease is caused by Chlamydia trachomatis serotypes A, B, C?Answer: Trachoma, a chronic conjunctivitis that can lead to corneal scarring (most...
Can Chlamydia be visualized with Gram stain?
Can Chlamydia be visualized with Gram stain?Answer: Chlamydia Gram stains quite poorly because it is an intracellular pathog...
How is Chlamydia diagnosed in the laboratory?
How is Chlamydia diagnosed in the laboratory?Answer: Basophilic intracytoplasmic inclusion bodies within epithelial cells are visualized with Giemsa...
What is unusual about Chlamydia's cell wall? How does this influence choice of antimicrobial therapy?
What is unusual about Chlamydia's cell wall? How does this influence choice of antimicrobial therapy?Answer: It lacks muramic acid, therefore, all...
During its life cycle, Chlamydia exists in two forms, the elementary and reticulate bodies. Which one is the extracellular, infectious body and which one is the intracellular, dividing body?
During its life cycle, Chlamydia exists in two forms, the elementary and reticulate bodies. Which one is the extracellular, infectious body and which...
How are these bacteria cultured?
How are these bacteria cultured?Answer: In living cell S. Rickettsia and Chlamydia cannot be cultured on nonliving media because they need to steal...
Which bacteria are obligate intracellular parasites?
Which bacteria are obligate intracellular parasites?Answer: Chlamydia and Rickett...
An 18-year-old woman presents with 2 days of inability to close her right eye. She has a low-grade fever and rash. One month ago she went camping but has no memory of a tick bite. On examination, she has multiple erythematous skin lesions with central clearing and right-sided facial nerve palsy. What is the most likely diagnosis? Most appropriate treatment?
An 18-year-old woman presents with 2 days of inability to close her right eye. She has a low-grade fever and rash. One month ago she went camping but...
A 35-year-old man presents with impaired proprioception and locomotor ataxia. He has a history of unprotected intercourse with multiple partners. His symptoms are most likely caused by an untreated infection by what organism?
A 35-year-old man presents with impaired proprioception and locomotor ataxia. He has a history of unprotected intercourse with multiple partners. His...
A 26-year-old urban man presents to you with a painless chancre on his penis. What is the drug of choice for treatment of his disease?
A 26-year-old urban man presents to you with a painless chancre on his penis. What is the drug of choice for treatment of his disease?Answer: Treponema...
What is the treatment of Leptospira?
What is the treatment of Leptospira?Answer: Penicillin or doxycycl...
How is Leptospira transmitted?
How is Leptospira transmitted?Answer: Water contaminated with infected urine of dogs, rats, livestock, and wild anim...
What is Weil disease?
What is Weil disease?Answer: Severe leptospirosis with renal failure, hepatitis, jaundice, mental status changes, and multiorgan hemorrhageMnemonic:Organs...
What are the symptoms of each phase of leptospirosis?
What are the symptoms of each phase of leptospirosis?Answer: First (leptospiremic) phase: high spiking temperatures, headache, and severe muscle...
Why does relapsing fever relapse?
Why does relapsing fever relapse?Answer: Antigenic variation: B. recurrentis changes its surface proteins to evade the immune syst...
How is relapsing fever treated?
How is relapsing fever treated?Answer: Doxycycline or erythromy...
What are the symptoms of relapsing fever?
What are the symptoms of relapsing fever?Answer: 3- to 6-day episodes of high fever, headaches, myalgias, followed by approximately 8 afebrile days,...
What disease does Borrelia recurrentis cause?
What disease does Borrelia recurrentis cause?Answer: Relapsing fe...
How is Lyme disease treated?
How is Lyme disease treated?Answer: Doxycycline, amoxicillin (for children <8 for whom Doxy is contraindicated), or a third-generation cephalosporinMnemonic:GEt...
What are the chronic manifestations of Lyme disease?
What are the chronic manifestations of Lyme disease?Answer: Encephalopathy (impaired memory, somnolence) and migratory autoimmune arthri...
What are the manifestations of disseminated (stage 2) Lyme disease?
What are the manifestations of disseminated (stage 2) Lyme disease?Answer: Systemic: fever, malaiseNeurologic: aseptic meningitis, Bell palsy, peripheral...
What is erythema migrans (EM)?
What is erythema migrans (EM)?Answer: A red, circular, macular rash that spreads with a red advancing border and a clear central region, giving a...
What are the manifestations of primary Lyme disease?
What are the manifestations of primary Lyme disease?Answer: Erythema migrans (EM) and nonspecific flu-like sympt...
What are the stages of Lyme disease?
What are the stages of Lyme disease?Like syphilis, there are three stages:1. Primary localized stage (erythema migrans)2. Disseminated stage3. Late chronic...
During what time of year is Lyme disease most common?
During what time of year is Lyme disease most common?Answer: Sum...
Where is Lyme disease endemic?
Where is Lyme disease endemic?Answer: In the northeastern, midwestern, and northwestern United States (also endemic in Europe). Named after Lyme,...
How is Lyme disease transmitted?
How is Lyme disease transmitted?Answer: By insect vector, the Ixodes tick, from a mouse reserv...
How is B. burgdorferi visualized?
How is B. burgdorferi visualized?Answer: Borrelia burgdorferi is seen by light microscope with Giemsa or Wright stain S. Borrelia are much bigger...
What disease does Borrelia burgdorferi cause?
What disease does Borrelia burgdorferi cause?Answer: Lyme dise...
What are the clinical manifestations of the three stages of yaws?
What are the clinical manifestations of the three stages of yaws?1. Primary: a painless papule develops into a yaw (a large wart-like lesion).2. Secondary:...
What is another disease caused by another specifies of Treponemal?
What is another disease caused by another specifies of Treponemal?Answer: Treponema pertenue causes ya...
What is a Jarisch-Herxheimer reaction?
What is a Jarisch-Herxheimer reaction?Answer: Fever, malaise/headache, and myalgias that can occur at the onset of syphilis treatment due to pyrogens...
What may cause a false-positive VDRL?
What may cause a false-positive VDRL?Answer: Viral infections (Epstein-Barr virus [EBV], hepatitides), Drugs, pregnancy, Rheumatic fever, Rheumatoid...
Describe VDRL and RPR in terms of sensitivity and specificity for syphilis:
Describe VDRL and RPR in terms of sensitivity and specificity for syphilis:Answer: VDRL and RPR are highly sensitive but have low specifici...
Which serologic tests are specific for antibodies against T. pallidum and which are not? Which ones become negative with treatment?
Which serologic tests are specific for antibodies against T. pallidum and which are not? Which ones become negative with treatment?Answer: Specific:...
What serologic tests are used to screen for syphilis?
What serologic tests are used to screen for syphilis?Answer: Venereal Disease Research Laboratory (VDRL), rapid plasma reagin (RPR), the fluorescent...
What is the treatment of syphilis?
What is the treatment of syphilis?Answer: Penicillin (The particular type and dosing of the penicillin depends on the stage of the diseas...
What are the classic findings of congenital syphilis?
What are the classic findings of congenital syphilis?Answer: Snuffles (bloody nasal discharge), saddle nose, saber shins (bowing of the tibia), Hutchinson...
What is Argyll-Robertson pupil?
What is Argyll-Robertson pupil?Answer: A feature of tertiary syphilis, it is a pupil that constricts during accommodation but not in response to...
What is general paresis?
What is general paresis?Answer: A form of neurosyphilis presenting with insidious psychiatric symptoms (irritability, apathy) and progressing to...
What is tabes dorsalis?
What is tabes dorsalis?Answer: Syphilitic damage to the posterior columns and dorsal roots of the spinal cord with impairment of position and vibration...
When should you suspect neurosyphilis as the cause of a stroke?
When should you suspect neurosyphilis as the cause of a stroke?Answer: Stroke without hypertension in an individual with a history of sexually transmitted...
What are the manifestations of neurosyphilis?
What are the manifestations of neurosyphilis?Answer: Aseptic meningitis (predominantly lymphocytes in cerebrospinal fluid [CSF]), meningovascular...
How does cardiovascular syphilis manifest?
How does cardiovascular syphilis manifest?Answer: Classically a thoracic aneurysm forms in the ascending aorta or aortic arch leading to aortic insufficiency...
What are gummas?
What are gummas?Answer: Soft, non-cancerous granulomatous growths of tertiary syphi...
When does tertiary syphilis develop?
When does tertiary syphilis develop?Answer: After 6 to 40 ye...
What are the main categories of tertiary syphilis?
What are the main categories of tertiary syphilis?Answer: Gummatous syphilis, cardiovascular syphilis, and neurosyphi...
What is the natural history of latent syphilis?
What is the natural history of latent syphilis?Answer: In the first 2 years (early latent), 25% may relapse to secondary syphilis. Over many years,...
What is latent syphilis?
What is latent syphilis?Answer: Latent syphilis occurs after secondary syphilis has resolved. All patients are asymptomatic with a positive blood...
Describe the symptoms of secondary syphilis:
Describe the symptoms of secondary syphilis:Answer: The bacteremic/disseminated stage with systemic symptoms (fever, weight loss, etc), a classic...
Describe the chancre of primary syphilis:
Describe the chancre of primary syphilis:Answer: Ulcerating, painless lesion that is highly infecti...
How does primary syphilis manifest?
How does primary syphilis manifest?Answer: A painless chancre that may be accompanied by nontender swelling of regional inguinal lymph nodes (groin...
What are the stages of syphilis?
What are the stages of syphilis?Answer: Primary (3-6 weeks after initial infection), secondary (~6 weeks after resolution of primary chancre), latent...
How is syphilis transmitted?
How is syphilis transmitted?Answer: Sexually or transplacenta...
What disease does Treponema pallidum cause?
What disease does Treponema pallidum cause?Answer: Syphi...
How do you visualize spirochetes?
How do you visualize spirochetes?Answer: On dark-field microsc...
What are the main classes of spirochetes?
What are the main classes of spirochetes?Answer: Mnemonic: Borrelia, Leptospira, Treponema ...
A 29-year-old liver transplant patient presents with fever, anorexia, night sweats, weight loss, and a productive cough for 1 week. His purified protein derivative (PPD) is 3 mm and his chest x-ray (CXR) shows a right upper lobe cavitation. Sputum examination shows acid-fast branching rods. What is the most likely diagnosis?
A 29-year-old liver transplant patient presents with fever, anorexia, night sweats, weight loss, and a productive cough for 1 week. His purified protein...
A human immunodeficiency virus (HlV)-positive patient with a CD4 count of 100 was found to have a brain abscess that contained a gram-positive organism that stains weakly acid-fast. What is the organism and what is the treatment for choice?
A human immunodeficiency virus (HlV)-positive patient with a CD4 count of 100 was found to have a brain abscess that contained a gram-positive organism...
A 50-year-old alcoholic with poor dentition comes in with 1 week of chest wall pain, fevers, and chills. A lesion from the left side of his chest is draining serosanguinous fluid and laboratory analysis shows a gram-positive branching rod. What is the most likely diagnosis? What is the appropriate antibiotic therapy?
A 50-year-old alcoholic with poor dentition comes in with 1 week of chest wall pain, fevers, and chills. A lesion from the left side of his chest is draining...
A 47-year-old male patient was found to have an oral abscess that drains through a sinus tract in the skin. When the organism was cultured, it produced yellow granules. What is the organism and what is the treatment of choice?
A 47-year-old male patient was found to have an oral abscess that drains through a sinus tract in the skin. When the organism was cultured, it produced...
How can Ureaplasma urethritis be distinguished from other causes of urethritis (eg, Neisseria, Chlamydia)?
How can Ureaplasma urethritis be distinguished from other causes of urethritis (eg, Neisseria, Chlamydia)?Answer: Ureaplasma has urease, and can...
What infection is caused by Ureaplasma and how is it treated?
What infection is caused by Ureaplasma and how is it treated?Answer: Urethritis with dysuria and clear mucoid discharge. Treat with tetracycline...
Where is U. urealyticum normally found?
Where is U. urealyticum normally found?Answer: In the normal flora of the lower urinary tract of 60% of sexually active wo...
What is the prognosis of M. pneumoniae pneumonia and how is it treated?
What is the prognosis of M. pneumoniae pneumonia and how is it treated?Answer: Pneumonia is self-limiting, but macrolides or tetracyclines can shorten...
How can M. pneumoniae be cultured?
How can M. pneumoniae be cultured?Answer: On Eaton a...
Name a laboratory test for M. pneumoniae:
Name a laboratory test for M. pneumoniae:Answer: Infection leads to production of antibodies against M. pneumoniae antigens, resulting in a positive...
How is M. pneumoniae transmitted?
How is M. pneumoniae transmitted?Answer: Inhalation of respiratory dropl...
What is "walking pneumonia"?
What is "walking pneumonia"?Answer: A community-acquired pneumonia usually caused by M. pneumoniae in which the radiologic findings appear much worse...
Mycoplasma pneumoniae is the most common cause of pneumonia in what population?
Mycoplasma pneumoniae is the most common cause of pneumonia in what population?Answer: "Walking pneumonia" in teenagers and young adu...
Name two Mycoplasma species that cause disease in humans:
Name two Mycoplasma species that cause disease in humans:1. Mycoplasma pneumoniae (Eaton agent)2. Ureaplasma urealyti...
What is unique about the size of Mycoplasma?
What is unique about the size of Mycoplasma?Answer: They are the smallest free-living organisms capable of self-replicati...
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