UWorld Test 5/27/2014 - Micro Flashcards
What causes lymphogranuloma venereum? What is the ppt? Tx?
Chlamydia trachomatis serotypes L1,L2, L3. initiall - small painless ulcer on gentials. After some time=>painful swollen inguinal nodes that rupture/ulcerate “buboes”. Tx: doxycycline
What is diagnosed with “scotch tape test?” Occurs frequently in? Tx?
Enterobius vermicularis (pinworm) - most common helminthic infection. Occurs frequently in school aged children. Tx: bendazole. Pyrantel pamoate for pregnant women.
PID is most commonly caused by?
Chlamydia and Neisseria G. PD => ectopic pregnancies in 50% of causes
Most common cause of E. Coli bacteriemia is?
UTI
What is the most common cause of gram negative sepsis?
E Coli
What is the most common cause of septic arthritis in sexually active young people?
N Gonorrhea
Freshwater contact with dysuria and blood in urine- think??
Schistosomiasis.
What is the host of schistosomaias? What is the treatment?
Snail host. Infectious larvae (cercariae) penetrate human skin. S japonicum and manoson =L liver and spleen granulomas, fibrosis and inflammation. Chronic infection with S haematobium => urinary problems => sq cell carcinoma of the bladder (painless hematuria). Tx: Praziquentel
What is the major virulence factor for strep pyogenes
Protein M. Inhibits phagocytosis and activation of complement. Cytotoxic for neutrophils and mediator of bacterial attachement.
What is the most important virulence factor for uropathogenic E Coli?
Fimbraie/ Pilus - especially P-1 pilus.
Recurrence of genetial herpes is prevented by?
Daily dose of acyclovir, famciclovir or valacyclovir after first episode
Anal squamous cell carcinoma is a/w which virus?
HPV 16, 18, 31 and 33. Also cervical squamous cell carcinoma. HIV positive males have higher risk for infection
What is the most common cause of viral hemorrhagic cystitis (hematuria and dysuria) outbreaks in children?
Adenovirus
Acutre rheumatic fever follows what kind of infection vs acute streptococcal glomeruloneprhitis?
ARF: streptococcal pharyngitis, ASGN: streptococcal pharyngitis and skin infection (impetigo)
What are the common organisms that cause 1) urethritis 2) cystitis 3) pyeloneprhtiis
1) C. Trachomatis and N. Gonorrhae 2) Cystitis: E Coli, s. saprophyticus (half of UTIs in sexually active young women), Proteus, Klebsiella, Enterococci. 3) same as cystitis
What are the sw of 1) urethritis 2) cystitis 3) pyelonephritis
1) pain or burning sensation with urination, urgency of frequent urination 2) asymptomatic or symptomatic. Suprapublic tenderness and pain with frequent urination 3) flank pain, CVA tenderness fever, chills, hematuria wth casts
What labwork is done to dx 1) urethrtisi 2) cystitis and 3) pyeloneprhtiis?
1) UA: +WBCs 2) UA and Micro: + leukocyte esterase, + nitrites, + bacteria, + WBC, +RBC occasionally 3) UA and Micro: same as cystitis but also WBC casts indicatd renal based pyruia. CBC: elevated WBC
What is the toxic component of LPS? What does it do?
Lipid A. Causes activation of macrophages leading to widespread release of IL-1 and TNF-alpha causing signs of sepsis and shock.
Know difference between bacterial vaginosis, trichomoniasis and candida vulvovaginitis
Look at UWorld picture
What are the histologic characteristics of aspergillosis
Septate, acute angle branching.
Aspergillosis causes/effects?
Invasive aspergillosis - commonly affects the lungs forms lung granulomas, hemoptysis. Has predilection for blood vessels - causes tissue infarcts, aspergillomas (fungal balls in old cavities), Allergic bronchopulmonary aspergillosis (ABPA)
What is cultured on cysteine-tellurite agar?
C. Diptheriae.
PDA is a/w what congenital microbial infection?
Rubella
What is the classic triad for congenital rubella? What vaccine is recommended? What is pregnant mom’s presentation? Reg child/person ppt?
PDA (cardiorespiratory problems), cataracts, deafness. Blueberry muffin rash. Mom - rash, lymphadenopathy, artrhtitis. Child/adults ppt: fever, post-auricular lymphadenopathy, arthralgias, fine rash.
What is the tx of choice for uncomplciated malaria in “ - “ sensitive areas?. What drug is added for P vivax/ovale. Why
Chloroquine. Primaquine is added to prevent recurrence/get ride of hypnozoites
Intranuclear inclusions + gingivostomatitis (swollen gums with ulcerative lesions) is what infection?
HSV-1. Intranuclear lesions = Cowdry A inclusions.
What does HBV do for HDV?
HBsAg needs to coat HDAg of hepatitis D before it can infect hepatocytes and multipy.
What causes malignant otitis externa in diabetics? How does it present?
Pseudomonas aeruginosa. Exqusite ear pain and drainage, granulation tissue is often seen witin the ear canal.
Which virus acquires its envelope from the host cell nuclear membrane?
Herpes viruses.
What does CMV cause?
Negative monospot mononucleosis, congenital infection, pneumonia, retininits.
Facial pain + black necrotic eschar + serum ketones is suggestive of?
Infection with mucor/rhizopus.
Which hepatitis virus infects pregnant women?
Hepatitis E
Hemophilius influenza type B is what kind of vaccine
Cell wall polysaccharide that is conjugated to toxoid from either diptheria or tetanus
What is the most common cause of bacterial meningitis in adults of all ages?
Strep pneumoniae. Leading cause of MOPS 1) meningitis 2) otitits media 3) pneumonia and 4) sinusitis
Bacterial meningitis causes what changes in CSF?
Increased neutrophils, increased proteins decreased glucose.
What is strep pneum’s major virulence factor for crying out loud don’t’ get this wrong again
Capsule. Quellung reaction - when antibodies are added, the capsule swells.
What is the clinical ppt of legionella? Labs?
Atypical pneumonia = high fever, watery diarrhea, cns symptoms like confusion, severe pneumonia. Gram sputum stain shows many neutrophils but no organisms. Labs show HYPONATREMIA. TX WITH macrolides or quinolone
Describe the pathogenicity of Shigella.
Most important pathogenic mechanism is invasion of the mucosa. Invades mucosa => enters M cells in Peyer’s patches => escapes phagosomes => infects surrounding cells => releases shiga toxin. Produces host inflammatory response => diarrhea.
What is the cutaneous necrotic disease a/w pseudonomas?
Ecthyema Gangrenosum. a/w pseudomonas bacteremia and septicemia. Found in immunocompromised patients, burns/indwelling catheters. Bacteria invades perivascularly, releases exotoxins that cause vascular destruction and resultant insufficiency of blood flow to patches of skin tat become necrotic.
Which medications are strongly a/w redistrubtion of fat from extremities to abdominal viscera and adipose tissues of the thorax, posterior neck and supraclavicular regions?
HIV-1 protease inhibitors and glucocorticoids
What drug do you prescribe for oral candidiaseis in patients without advanced immunodeficiency?
Nystatin - polyene antifungal - binds to ergosterol and makes pores. Not absorbed from GI tract - swish and swallow agent
What is the primary collagen in scars?
Type 1 Collagen
Deletions in the long arm of chromosome 22 are a/w
Facial, palatal malformations as well as DiGeorge Syndrome
What is the toxicity of TCAs
Sedation, alpha 1 block effects like orthostatic hypotension, atropine like effect (anticholinergic like dry mucosa, tachycardia, urinary retnetion). Amitriptyline (3rd TCAs) have more anticholinergic effects than secondary ones. TriC’s - convulsions, coma, cardiotoxicity, respiratory depression and hyperrexia. confusion and hallucinations in elderly
What drugs have antimuscarinic effects
Atropine, TCAs, H1 receptor antagonists, neuroleptics and antiparkinson drugs
