Bug

Other Bacteria Bug Mycobacterium tuberculosis Clinical Buzz Words Homeless man presents with wasting and fever. -He has a cough with bloody sputum with night sweats -CXR – cavitations. Air fluid levels in the apex of his left lung Dz Tuberculosis Pathophys Primary TB: aerosol droplets  deposits in lower lobes  phgaocytosed  mycolic acid cell wall allows intracellular survival and prolif -T-cells wall off and destroy infected Mac  caseating granuloma  fibrosis and calcification with a few dormant bugs  Ghon complex (calcified tubercules and hilar lymph nodes) -Spread to other sties via lymph/blood  extrapulmonary tubercles Secondary TB: weakened T-cell response  reactivation of pulmonary tubercles in apex  macs respond  large caseous granulomas  cavitations  disseminate to other sites via lymph/blood and destroy tissue (bone, meninges(Miliary TB) Dx Acid fast stain of sputum PPD test DTH rxn in active or preivous infection Ghon complex on CXR Tx RIPES – rifampin, INH, pyrazinamide, ethambutol, streptomycin For 12-18 months Prophylaxis: INH BCG vaccine: live attenuated vaccine for cell mediated immunity Mycobacterium Mexican immigrant has thickened cheeks and leprae deformed nose Tuberculoid leprosy Lepromatous leprosy Nasal discharge  grow in low temp (skin, limbs)  infect cells of nerve sheaths  variable course, depends on host immune response Tuberculoid leprosy: strong immune rxn forms a granuloma  localized damage to superficial nerves and skin  thickened nerves, 1 or 2 anesthetized lesions that are hypopigmented and hairless Leprosy: weak immune rxn alls spreading infection  inf damage, especially to cooler skin, nerves, testes  sensory loss  numb regions that are vulnerable to injury  loss of eyebrows, saddle nose deformity, leonine fascies (thick cheeks), infertility Skin nerve biopsy: granulomas or acid fast-bacteria Lepronin skin test + indicates the tuberculoid form Lepronin skin test – indicates the lepromatous form Dapsone,+ rifampin +clofazamine combination Can develop DTH immune response or IC deposition. Treat DTH with prednisone and IC with thalidomide Other Bacteria Bug Leptospira interrogans Clinical Buzz Words Farmer has a 1 wk hx of flu with photophobia -severe headache, cough, myaligia -conjunctival suffusion and macular rash -elevated serum bilirubin, alk phos, AT’s, creatine phospho kinase -gives penicillin G immediately and a spirochete is seen in blood Dz Leptospirosis Weil’s syndrome (icterohemorrhagic fever) Jaundice Hemorrhage Meningitis Tissue necrosis Pathophys Carried by rodents, dogs, fish, birds  humans via water or food contaminated with these animals urine or pooh. Abrasion in mucosa lets the spirochete in  systemic spread to liver, kidney, and CNS [jaundice, hemorrahage, tissue necrosis, aseptic meningitis, death if severe] Phase 1: host immune re flu like symptoms, photophobia  resolves in a week Phase 2: host immune re  rise in antileptosira IgM with mild or severe damage Mild dz:  aseptic meningitis Severe dz:  Weil’s dz – vasculitis with hemorrhagia. Renal failure, liver damage and jaundice Dx Serology Spirochete Aerobic “ice tong” appearance Tx Ampicillin Prophylax: doxycycline Drugs are only effective if given during phase 1 Less than 100 cases a yr in the US Mycoplasma pneumoniae Young woman at an army base has cold sx. Malaise, chills, sore throat, dry cough. -CXR – interstitial infiltrate that is more severe than expected -labs – erythrocyte agglutination when incubated at 4 degrees -she is given erythromycin Tracheobronchitis Walking Pneumonia (Atypical pneumonia) Human to human  respiratory droplets  cytoadhesin p1 adheres to respiratory epithelium and inhibit ciliary motion  inflammation  tracheobronchitis, aytpical pneumonia Less frequently… B cell makes AB that autoreact with brain, heart and erythrocytes (IgM cold agglutinins)  anemia and systemic manifestations (e.g. arthritis) Commonly infects young ppl (6-20 yo) in close quarters CXR worse than expected is a classic finding (mild symptoms, but a serious looking CXR) Serology Erythromycin Tetracycline m. pneumoniae is very difficult to culture or visualize (it is the smallest prokaryote) - Fried eggs on culture with Eaton’s agar Other Bacteria Bug Chlamydia trachomatis Clinical Buzz Words Woman compalins of vaginal discharge and RUQ abdominal pain. Pt is promiscuous. Pelvic exam shows cervical motion pain. Discharge has lots of PMN’s, but no Gram stain bugs. Dz Serovars D-K Urethritis, PID, Neonatal pneumonia, Neonatal conjunctivits A-C Trachoma L1-L3 Lymphogranuloma venerum Complications Fitz-hugh-curtis; Reiter’s Syn Pathophys Elementary body  Reticulate body  Inclusion body Elementary body – small and survives outside the cell. This is the infectious form Reticulate body – enlarged, reproductive elementary body. Elementary body gets into a phagosome, it prevents lysosome fusion, then get’s bigger and multiplies Inclusion body – phagosome that is packed with reticulate bodies Trachoma – keratoconjunctivitis  blindness Reticulate bodies stop multiplying, revert back to Elementary bodies, lyse the host cell and then infect more cells Dx Visualize intracellular inclusions Iodine stain + Giemsa stain + Serology Intracellular growth – use cell lines to culture Tx Azithromycin Tetracyclines + Ceftriaxone Oral Erythromycin for babies of infected mothers Prophylactic erythromycin eye drops Chlamydia pneumoniae 22 yo student has nonproductive cough, fever and sore throat. -CXR – diffuse interstitial infiltrate -Sputum gram stain shows many PMN’s, giemsa stain reveals intracytoplasmic inclusion in epithelial -pt is given doxy 10 yr old boy in VA has rash, fever, severe headache. Started several days ago. He went hiking a week ago. -rash began on palms and soles, spreading to trunk -conjunctiva are red -proteinuria -given tetracycline and dx is confirmed by weilfelix test -Atypical pneumoniae c. pneumoniae typically infects young adults -community aquired  bug gets into URT epithelium  phago  lympho infiltrate  local pulm edema, necrosis and hemorrhage -remember the EB, RB life cycle Giemsa stain shows intracytoplasmic inclusions -serology Antibiotics that can go intracellular, e.g. doxycycline Rickettsia rickettsii Rocky Mountain Spotted Fever -fever, malaise, maculopapular rash on palms and soles Dogs, rodents  wood or dog tick  human  infect and prolif inside endothelial cell  inflame endothelial lining of small blood vessels  hemorrhage/microthombi  maculopapular rash on palms and soles If not treated… Widespread necrotic vasculitis  renal and cardiac damage  death Obligate intracellular parasites and replicate freely in cyto Actue history, skin biopsy, serology + Weil Felix test Antibiotics that can go intracellTetracycline, doxy Chloramphenicol -South-central and mid-Atlantic states. -Incidence increase in warm seasons Other Bacteria Bug Coxiella burnetii (a Rickettsia) Borrelia burgdorferi Clinical Buzz Words Cattle farmer presents with mild cough and fever. The fever began abruptly several days ago. -Occupational exposure to cattle is telling -Pt is given tetracycline -dx confirmed by serology and negative weil-felix test A 14 yr old boy presents with arthralgia -history of playing is grassy fields where ticks are known to live -had a large red, circular rash that was kind of like a donut shape several weeks ago - Dz Atypical pneumonia Q fever Pathophys Cattle, sheep, goats  bug shed in animal products  survive as a spore  inhalation  mild atypical pneumonia Can lead to hepatits and chronic endocarditis Dx Serology Cultre in cells Negative weil-felix test Tx Doxycycline or Chloramphenicol Lyme dz Tick that lives on an infected rodent bites human (has to be attached for 24 hrs to transmit the spirochete) 1 Stage: flu like symptoms with Erythema migrans 2 Stage: spirochetes that seeded joints, heart, and meninges cause artthralgias, cardiomyopathy, and meningitis 3 Stage: chronic arthritis and progressive CNS disease rd nd st Clinical H&P Labs are to be as confirmatory, not Dx itself -PCR DNA analysis - Culturing takes too long Amoxicillin Cefuroxime axetil Ceftriaxone Doxycycline Notes Causes of atypical pneumonia (in decreasing order of prevalence) 1. mycoplasma pneumoniae 2. chlamydia pneumoniae 3. legionella pneumophilia 4. Virus a. Influenza virus b. RSV c. Adenovirus Sexually Transmitted Disease Bacterial 1. Chlamydia trachomatis – PID, Neonatal conjunctivitis, Trachoma LGV, 2. Neisseria gonorrhea – PID, arthritis 3. Treponema pallidum – syphilis 4. Ureaplasma urealyticum – non-specific STD si/sx, postpartum complications 5. Haemophylis ducreyi – chancroid Fungal/Protozoal 1. Candida albicans – yeast infection 2. Trichomonas vaginalis – trichomoniasis Viral 1. Human papillomavirus – condyloma acuminata (genital warts) 2. Herpes simplex virus – genital tract lesions 3. HIV - AIDS 4. CMV – danger to breast feeding babies of mothers with concurrent primary exposure to CMV