ID Flashcards
Botulism definition, sx, dx, tx
Clostridium botulinum
PATHO: neurotoxin inhibits acetylcholine release at the neuromuscular junction, leading to weakness, flaccid paralysis, & respiratory arrest
Transmission: canned foods (adults), wound, honey (infants)
sx
Prodromal GI sxs (N/V/D, abdominal pain)
8 D’s
*diplopia, dysphagia, dry mouth
*dilated, fixed pupils
*dysarthria, dysphonia
*descending decreased muscle strength
*decreased DTRs
- floppy baby syndrome
dx: Toxin assays from stool, wound, or serum
tx
Foodborne:
*antitoxin
Wound:
*antitoxin + PCN G
Esophagitis definition, sx, dx, tx
Candida albicans
AIDS-DEFINING ILLNESS!!!
sx: Substernal odynophagia, GERD, epigastric pain, N/V
dx
KOH smear: budding yeast & pseudohyphae
Endoscopy: white linear plaques/erosions
tx: PO fluconazole
Oropharyngeal (Thrush) definition, sx, dx, tx
Candida albicans
sx
Friable white plaques (+/- leave erythema if scraped)
*bleed when scraped
dx
KOH smear: budding yeast & pseudohyphae
tx: nystatin swish & swallow
Intertrigo definition, sx, dx, tx
Candida albicans
Cutaneous infection MC in moist, macerated areas
sx
Pruritic rash – beefy red erythema w/ distinct, scalloped borders & satellite lesions
dx
KOH smear: budding yeast & pseudohyphae
tx
*topical clotrimazole, ketoconazole, miconazole
Fungemia, Endocarditis definition, sx, dx, tx
Candida albicans
Seen in immunocompromised pts
+/- indwelling catheters
dx
KOH smear: budding yeast & pseudohyphae
tx
*IV amphotericin B
Severe 🡪 capsofungin
Gonorrhea definition, sx, dx, tx
Neisseria gonorrhea
MC infects urethra, cervix, anal canal, conjunctiva, or pharynx
sx
*most women are asymptomatic
Sxs: mucopurulent discharge, vulvar itching/burning
*MC complication is salpingitis
dx
Nucleic acid amplification test
Gram stain: gram (-) diplococci
tx
Ceftriaxone 500mg IM OR cefixime (400mg PO)
Tx for chlamydia: doxy OR azithromycin
Chlamydia Definition, sx, dx, tx
*MC reported STI in US
Chlamydia trachomatis, gram (-) rod
*in pregnancy test of cure required after 3-4wks followed by repeat testing of gonorrhea & chlamydia 3mo later
*most women are asymptomatic
Sxs: mucopurulent discharge, hypertrophic cervical inflammation
dx
Nucleic acid amplification test
Culture
UA – will reveal pyuria w/ no organisms on gram stain
tx
Azithromycin (1g PO) OR doxycycline (100mg BID x7d)
Tx for gonorrhea: ceftriaxone OR cefixime
Trichomoniasis definition, sx, dx, tx
Trichomonas vaginalis: flagellated protozoan
35% of vaginitis
Incubation period – 4-28 days
sx
*Purulent, malodorous, thin vaginal discharge – green/yellow, frothy < 10%
*Burning, pruritus, dysuria, frequency and dyspareunia
*Postcoital bleeding
PE:
*Erythematous vulva and vaginal walls (mucosa)
*Thin (snot like) discharge
*Strawberry (punctuated) cervix (< 2 %)
dx
Wet prep – mobile flagellated organism (trichomonads) & many leukocytes
Trichomonas rapid test – antigen test
Nucleic acid amplification test
Culture
tx
Metronidazole (2g once or 500mg BID x7d)
OR
Tinidazole (2g once)
*Avoid ETOH on metronidazole – disulfiram rxn
Cryptococcosis definition, sx, dx, tx
Etiology: Cryptococcus neoformans
Transmission: inhalation of pigeon & bird droppings
AIDS-DEFINING ILLNESS!!
sx
Meningoencephalitis: MCC of fungal meningitis
*HA, neck stiffness, N/V, photophobia
Pulmonary: pneumonia
*cough, pleuritic chest pain, dyspnea
*nodules, abscesses, pleural effusions
dx
Lumbar puncture: fungal CSF pattern
*↑ WBCs (lymphocytes)
*decreased glucose
*↑ protein
ELISA 🡪 cryptococcal antigen
India ink staining 🡪 encapsulated yeast
tx
Meningoencephalitis:
*amphotericin B + flucytosine x2wks THEN
*PO fluconazole x10wks
Pneumonia if immunocompetent:
*fluconazole or itraconazole x3-6mo
HIV prophylaxis: fluconazole if CD4+ <100
Cytomegalovirus (HHV 5) definition, sx, dx, tx
CMV – HHV 5 transmitted via body fluids or vertical transmission
CMV is present in most people (70% in the US) w/ clinical disease primarily in immunocompromised pts
sx
Primary infection: mostly asymptomatic
*if symptomatic, sxs are similar to mono (fever, cough, myalgia, arthralgias) except it is usually w/o sore throat or LAD
Reactivation: seen MC in immunocompromised pts (HIV, long-term steroid use, chemo, post-transplant)
*colitis (MC): diarrhea, fever, abdominal pain, bloody stools
*retinitis: decreased visual acuity w/ floaters (MC seen when CD4 count is ≤50)
*esophagitis: odynophagia w/ large superficial ulcers on upper endoscopy
dx
Fundoscopy: hemorrhage w/ yellow-white soft exudates
Serologies: antigen tests, IgM, IgG titers
PCR
Labs: lymphocytes w/ atypical lymphocytosis
Bx of tissues: owl’s eye appearance
*epithelial cells w/ enlarged nuclei surrounded by clear zone & cytoplasmic inclusions
tx
Reactivation: ganciclovir first line
Primary disease: supportive tx
HIV prophylaxis:
*valganciclovir if CD4 is ≤50
Diphtheria definition, sx, dx, tx
Corynebacterium diphtheriae (gram +)
Transmission: inhalation of respiratory secretions
Vaccine: DTaP
*2, 4, 6mo of age
*15-18mo
*4-6yrs
*Tdap booster at 11-12yrs
sx
Tonsillopharyngitis or laryngitis
*sore throat, fever, malaise, nasopharyngeal sxs
Myocarditis: arrythmias or heart failure
PE:
*pseudomembrane: friable, gray to white membrane on the pharynx that bleeds if scraped
*cervical LAD: bull neck
dx: Clinical dx w/ culture confirmation
tx
*antitoxin + erythromycin or PCN
*respiratory droplet isolation
Endocarditis: PCN + aminoglycoside
Prophylaxis for close contacts:
*erythromycin x7-10d
*PCN benzathine G x1 dose
Epstein-Barr Virus (Mononucleosis) – HHV4 definition, sx, dx, tx
Infection due to EBV characterized by fever, LAD, & tonsillar pharyngitis
PATHO: EBV infects B cells
Transmission: saliva (known as the kissing disease) esp. ages 15-25
sx
*fever, LAD (esp. posterior cervical)
*tonsillar pharyngitis (may be exudative)
+/- petechiae on hard palate
+/- fatigue, HA, malaise
PE:
*splenomegaly
*rash – seen in ~5% esp. if given ampicillin
dx
Heterophile antibody (Monospot)
Rapid viral capsid antigen test; ↑ LFTs
Peripheral smear: lymphocytosis >5% w/ >10% atypical lymphocytes
tx
Supportive
- rest
- analgesics (acetaminophen, NSAIDs)
- antipyretics
Steroids ONLY if:
- airway obstruction d/t LAD
- hemolytic anemia
- severe thrombocytopenia
AVOID TRAUMA & CONTACT SPORTS 3-4WKS IF SPLENOMEGALY TO PREVENT RUPTURE
Herpes Simplex Virus (HSV) definition, sx, dx, tx
HSV-1: oral lesions (tongue, lips), cold sores; “above the waist”
Transmission: oral secretions
Infections: herpes labialis (cold sores), gingivostomatitis, pharyngotonsillitis, herpetic whitlow, herpetic gladiatorum, keratitis, conjunctivitis, blepharitis, aseptic meningitis, encephalitis
HSV-2: genital lesions (vulva, vagina, cervix, glans, prepuce, penile shaft); “below the waist”
Transmission: STD
Infections: genital herpes, neonatal herpes
sx
Primary Infection: systemic sxs, longer, greater risk of complications
Recurrent Infection: milder, shorter, systemic sxs rare
Prodrome: burning, tingling, pain, pruritis
SXS: grouped vesicles on an erythematous base, ulcerations, same stage of development
Systemic s/sxs: fever, malaise, myalgias, LAD, HA (primary infection)
Primary HSV-1: gingivostomatitis (peds), pharyngotonsillitis (adults)
Herpes Labialis (Cold Sores): recurrent HSV-1
Herpetic Whitlow: herpes of the finger
Herpes Gladiatorum: body herpes (wrestlers)
Keratitis: pain, blurry vision, discharge; MCC of blindness; DENDRITIC LESIONS
Conjunctivitis/Blepharitis: vesicles on lid margin, chemosis, eyelid edema, tearing
CNS: aseptic meningitis, encephalitis
Primary Genital Herpes: painful grouped genital vesicles, ulcers/erosions, dysuria, fever, inguinal LAD, HA *HSV-2
Recurrent Genital Herpes: small vesicles, systemic sxs infrequent *HSV-2
Immunocompromised: HSV-1 (esophagitis, pneumonia, hepatitis); HSV-2 (hepatitis)
DIAGNOSTICS: viral cultures, PCR, direct fluorescence antibody, type-specific serology, Tzank (multinucleated giant cells)
tx
Orolabial: acyclovir ointment, Abreva (OTC), penciclovir cream
Primary Genital Herpes:
*acyclovir 400mg TID x7-10d
*famciclovir: 250mg TID x7-10d
*valacyclovir: 1g BID x10d
Recurrent Genital Herpes:
*acyclovir 400mg TID x5d
*famciclovir: 125mg BID x5d
*valacyclovir: 500mg BID x3d
Recurrent Orolabial:
*valacyclovir, famciclovir x1d
Histoplasmosis definition, sx, dx, tx
Histoplasma capsulatum
Transmission: inhalation of moist soil containing bird & bat feces in the Mississippi & Ohio river valleys
Risk Factors: immunocompromised states
*AIDS-DEFINING ILLNESS esp. if CD4+ is ≤100 cells/µL
sx
*asymptomatic (most pts) – flu-like illness if symptomatic
*pneumonia (atypical)
-fever, nonproductive cough, myalgias (can mimic TB)
Dissemination (if immunocompromised)
*hepatosplenomegaly, fever, oropharyngeal ulcers, bloody diarrhea, adrenal insufficiency
dx
Labs: ↑ alk phos & LDH; pancytopenia
CXR: pulmonary infiltrates, hilar or mediastinal LAD
Antigen testing: PCR (sputum) or urine
Cultures: most specific
*blood cultures + if disseminated/HIV
tx
Asymptomatic: no tx required
Mild-moderate disease:
*itraconazole first line
Severe:
*amphotericin B
Human Immunodeficiency Virus (HIV) definition, sx, dx, tx
HIV: retrovirus (changes viral RNA into DNA via reverse transcriptase)
HIV-1 (MC), HIV-2
sx
Acute Seroconversion:
*flu-like or mono-like sxs: fever, fatigue, myalgias
Opportunistic Infections:
*oral & esophageal candidiasis MC seen
*CMV infection (proctitis, hepatitis)
*PCP pneumonia
*cryptosporidiosis
AIDS: CD4 count <200cells/µL
*recurrent severe & potentially life-threatening infections or opportunistic malignancies
-AIDS-associated encephalopathy/dementia
-HIV wasting (chronic diarrhea, weight loss)
dx
Dx of suspected early infection: combo antigen/antibody immunoassay + HIV viral load testing (PT-PCR)
(-) immunoassay, (+) virologic tests:
*suggests early HIV
(+) immunoassay, (+) virologic tests:
*early or established infection
ELISA 🡪 western blot
HIV RNA viral load
*can be (+) in window period
tx
Regimens:
*NNRTI + 2 NRTIs
*PI + 2 NRTIs
*INTI + 2 NRTI’s
Opportunistic Infection Prophylaxis
CD4+ 500-200: TB, Kaposi Sarcoma, thrush, lymphoma, zoster
*isoniazid
CD4+ <200: PJP, Histoplasmosis
*Bactrim, itraconazole
CD4+ <100: Toxoplasmosis, Cryptococcus
*Bactrim, Fluconazole
CD4+ <50: MAC, CMV retinitis
*Valganciclovir
NRTIs MOA
MOA: inhibits viral replication by interfering w/ HIV viral RNA-dependent DNA polymerase
Zidovudine
Emtricitabine
Abacavir
Lamivudine
Didanosine
Zalcitabine
Stavudine
Tenofovir
NNRTIs MOA
Efavirenz
Delavirdine
Etravirine
MOA: inhibits viral replication by interfering w/ HIV viral RNA-dependent DNA polymerase
Protease Inhibitors MOA
Atazanavir
Darunavir
Lopinavir & Ritonavir
Nelfinavir
MOA: inhibits HIV protease leading to production of noninfectious, immature HIV particles
Influenza definition, sx, dx, tx
Orthomyxovirus, influenza A/B/C
Transmission: primarily via airborne respiratory secretions (sneezing, coughing, talking, breathing), contaminated objects
Increased risk:
*age > 65yrs, pregnancy, immunocompromised
*MC seen in children, but >65yrs at highest risk for complications
Complications: pneumonia, respiratory failure, death, meningitis, myocarditis, encephalitis, rhabdomyolysis, kidney failure
sx
ABRUPT ONSET
*HA
*fever, chills
*malaise
*URI sxs
*pharyngitis
*pneumonia
*myalgias: legs & lumbosacral areas
dx
Rapid influenza nasal swab
Viral culture
CXR (pneumonia): bilateral diffuse infiltrates
tx
Mild disease, healthy:
*supportive: acetaminophen, rest, fluids
Oseltamivir (Tamiflu)
*>65yrs, CVD, pulmonary disease, immunosuppression, chronic liver disease, hemoglobinopathies, pregnant/2wks postpartum
Prevention: influenza vaccine
*ADRs: fever, myalgia, irritability
*CI: severe egg allergy, previous reaction GB within 6wks of previous vaccine, high fever, infants <6mo
Lyme Disease definition, sx, dx, tx
Borrelia burgdoferi
Transmission: Ixodes scapularis (deer tick)
MC in northeast states
sx
Early localized (3-32d after bite): erythema migrans (red annular lesion w/ central clearing), fever, malaise, HA, myalgias, arthralgias
Early disseminated (3-10wks after bite): multiple erythema migrans lesions, CN palsies (esp. 7, lasts 2-8wks then resolves), fatigue, myalgia, HA, occasionally meningitis (stiff neck) or carditis (AV block)
Late disseminated (months-yrs after bite): monoarticular arthritis of large joint (knee in >90%), CNS involvement including chronic demyelinating encephalitis, polyneuritis, memory problems (rare in children)
dx
EIA, if ⊕ ⇢ western blot to confirm
⊕ = 2/3 IgM bands, 5/10 IgG bands
*IgM peaks @3-6wks, IgG weeks-months later
LP (meningitis): 10-150 WBC/mm3, <10% segmented neutrophils, ⇡ protein, normal glucose
EKG: heart block (pts w/ disseminated)
Joint aspiration: WBC 25,000-80,000/mm3 & ⊕ Lyme PCR of joint fluid
tx
Early localized: doxycycline x14-21d
Early disseminated: doxycycline x21d
*peds: cefuroxime (preferred), erythromycin
Carditis w/ severe/symptomatic AV block:
*ceftriaxone x14-21d
Late disseminated: doxycycline x21-28d
Arthritis unresponsive to PO therapy:
*IV ceftriaxone x28d
Jarisch-Herxheimer Reaction: transient fever, HA, myalgias after therapy is started
Rocky Mountain Spotted Fever definition, sx, dx, tx
Rickettsia rickettsia
Transmission: dog tick (Dermacentor variabilis), wood tick (Dermacentor andersonii), Lone star tick (A. americanum)
Incubation: 2-14d
Duration: typically 1-2wks
sx
Early: high fever, myalgia, HA (w/ photophobia), V/D, abdominal pain
RASH (2-6d after fever onset): begins on ankles/wrists 🡪 trunk (within hours) & palms/soles
*initially blanching, erythematous, macular
*becomes petechial then hemorrhagic
Other organ systems: vascular leak causing edema, hypovolemia, & hypotension; conjunctivitis, splenomegaly, pneumonitis, meningitis, confusion
dx
Clinical: fever + rash + hx of tick exposure
Labs (vasculitis): thrombocytopenia, ⇣ Na, mild leukopenia, proteinuria, mildly abnormal LFTs, hypoalbuminemia, hematuria
CSF pleocytosis common
Serology: indirect fluorescent or latex agglutination antibody (not ⊕ until 7-10d after onset); PCR from whole blood/skin biopsies (⊕ 1st week of illness)
tx
SUPPORTIVE; anticipate complications (hypotension, thrombocytopenia, DIC, hypoalbuminemia, hyponatremia)
DOXYCYCLINE x7-10d; alt – chloramphenicol
*continue until pt is afebrile x3d
Pertussis (Whooping Cough) definition, sx, dx, tx
Bordetella pertussis (gram -)
Transmission: respiratory droplets
Vaccine: DTaP
*2, 4, 6mo
*15-18mo
*4-6yrs
sx
Catarrhal phase: URI sxs lasting 1-2wks; poor feeding/sleeping
*most contagious
Paroxysmal phase: severe paroxysmal coughing fits w/ inspiratory whooping sound after cough fits
*may have post-coughing emesis
*often lasts 2-4wks
Convalescent phase: resolution of the cough (100d)
dx
*nasopharyngeal swab culture
*lymphocytosis common
*consider in adults w/ cough >2wks, pts <2yo
tx
Supportive:
*oxygenation, nebulizers, mechanical ventilation
Antibiotics:
*azithromycin, erythromycin
Complications: pneumonia
*Tdap in pregnancy @27-36wks
Enterobiasis *pinworm definition, sx, dx, tx
Enterobius vermicularis (pinworm)
MC helminthic infection in US
Transmission: fecal-oral (school-aged children)
sx
*perianal itching, esp. nocturnal
Severe 🡪 abdominal pain, N/V
dx
(+) scotch tape test or pinworm paddle test
*eggs under microscope
tx
*Albendazole, Mebendazole, or Pyrantel
*Pyrantel preferred in pregnancy
Ascariasis *roundworm definition, sx, dx, tx
Ascaris lumbricoides
MC intestinal helminth worldwide
Transmission: ingestion of food/water contaminated w/ Ascaris eggs
sx
Small worm load: asymptomatic
Larger load: vague abdominal sxs
*anorexia, N/V, abdominal discomfort
High load:
*intestinal obstruction MC
*hepatic or biliary manifestations
dx
Stool ova & parasites
Eosinophilia
tx
*Albendazole or Mebendazole
*Pyrantel if pregnant
Trichinosis *roundworm definition, sx, dx, tx
Trichinella spiralis
Transmission: raw or undercooked meat (esp. pork, wild boar, or bear)
sx
GI phase: abdominal pain, N/V/D
Muscle phase:
*myositis: muscle pain, tenderness, swelling, high fever
*eye: palpebral or circumorbital edema
*subungual splinter hemorrhages
Cardiac: myocarditis (due to eosinophilia)
CNS: encephalitis or meningitis
Pulmonary: pneumonia
dx
Serologies
Eosinophilia
↑ CK & LDH (due to muscle involvement)
tx
Mild cases: symptomatic treatment
*analgesia, antipyretics
CNS, cardiac, or pulmonary
*Albendazole or Mebendazole + steroids
Hookworm defintion, sx, dx, tx
Ancylostoma duodenale or Necator americanus
Transmission: human fecal contamination of soil, favorable soil conditions for larvae growth, & contact of human skin w/ contaminated soil
sx
Phase 1 (skin): pruritic erythematous maculopapular rash
*at site of larvae entry (feet/ankles)
Phase 2 (transpulmonary): usually asymptomatic
*mild cough or pharyngeal irritation
*Loeffler Syndrome: pulm sxs + ↑ IgE + eosinophilia
*rare
Phase 3 (GI): N/V/D, mid-epigastric pain (esp. postprandial) mimicking peptic ulcers
Phase 4 (chronic nutritional impairment):
*lacerate capillaries 🡪 daily loss of blood, iron, & albumin
dx
Stool examination
Eosinophilia, ↑ IgE
Chronic blood loss: iron deficiency anemia
+ guaiac
tx
*Albendazole or Mebendazole
*Pyrantel in pregnancy
Supportive: iron supplementation, multivitamins
Malaria definition, sx, dx, tx
Plasmodium spp. (falciparum most dangerous)
Transmission: female Anopheles mosquito
sx
*cyclical fever (chills 🡪 fever 🡪 diaphoresis 🡪 repeat)
*HA, fatigue, myalgias, GI sxs, splenomegaly (typically >4d of sxs)
P. falciparum:
*cerebral malaria (AMS, delirium, seizures, coma)
*blackwater fever = severe hemolysis + hemoglobinuria (dark urine) + renal failure
dx
Geisma-stained blood smear
Leukopenia, hemolytic anemia, thrombocytopenia
tx
*Chloroquine
*mefloquine for chloroquine-resistant
Rabies defintion, sx, dx, tx
Rhabdovirus infection of the CNS
Transmission: infected saliva from rabid animal bites (bats, racoons, skunks, foxes)
sx
Prodrome: pain, paresthesias, itching at the initial site of the bite
CNS phase:
*hydrophobia (painful laryngospasm w/ water)
*aerophobia (sensitive to air currents)
*hypersalivation (foaming at the mouth)
Respiratory phase: respiratory muscle paralysis (death)
dx
Immunofluorescence: Negri bodies
tx
No effective management once sxs occur (most pts do not survive)
*coma induction, amantadine, ribavirin
POST EXPOSURE FIRST EPISODE: HDCV (rabies vaccine)
*immunocompetent: days 0, 3, 7, 14 + rabies IG
*immunocompromised: add day 28
Typhoid (Enteric) Fever definition, sx, dx, tx
Diarrheal illness caused by Salmonella typhi
Transmission:
*fecal-oral, contaminated food or water
*hx of travel to areas where sanitation is poor (South-Central Asia)
PATHO: crosses intestinal epithelium barrier through M cells overlying the lymphoid follicles of Peyer’s patches
*may colonize the gallbladder in chronic carriers
sx
*HA, intractable fever, chills
*abdominal pain
*”pea soup” green diarrhea, non-bloody
*malaise, anorexia
PE:
*fever w/ relative bradycardia
*Rose spots (faint pink or salmon-colored macular rash from trunk to extremities)
*hepatosplenomegaly, GI bleeding (later stages)
dx
Culture of stool &/or blood
tx
Oral rehydration & electrolyte replacement
Abx:
*FQs (ciprofloxacin, ofloxacin)
Nontyphoidal Salmonella definition, sx, dx, tx
S. enteriditis, typhimurium
MC cause of foodborne disease
Sources: poultry, eggs, milk products, reptiles (turtles)
sx
*N/V, fever, abdominal cramping
*”pea soup” brown-green diarrhea
*malaise, HA
dx: Stool cultures
tx
Oral rehydration & electrolyte replacement
Abx in severe disease: FQs
Shigellosis definition, sx, dx, tx
Gram (-) rods: Shigella sonnei (MC in US)
S. flexneri, S. dysenteriae (enterotoxin)
Children <5 in daycare at highest risk
Transmission: fecal-oral
HIGHLY VIRULENT
sx
*lower abdominal pain, abdominal cramps
*high fever, tenesmus, chills, anorexia, HA, malaise
*explosive watery diarrhea 🡪 mucoid & bloody
Neuro manifestations: febrile seizures
dx
Stool cultures: + fecal WBCs & RBCs
CBC: leukemoid reaction (>50,000)
Sigmoidoscopy: punctate areas of ulceration
tx
Oral rehydration & electrolyte replacement
AVOID ANTI-MOTILITY DRUGS
Abx if severe: ciprofloxacin, azithromycin, ceftriaxone
Syphilis definition, sx, dx, tx
Treponema pallidum
Transmission: direct contact of a mucocutaneous lesion (sexual activity)
Associated w/ risk-taking behavior such as IVDU, 3wk incubation period
sx
Primary:
*chancre: painless ulcer at or near the inoculation site w/ raised indurated edges; heals spontaneously within 3-4wks
*non-tender regional LAD near the chancre site
Secondary: sxs may occur a few wks-6mo after initial sxs
*maculopapular rash, palms/soles
*condyloma lata: wart-like, moist lesions involving the mucous membranes & other moist areas
*systemic sxs: fever, LAD, arthritis, meningitis, HA, hepatitis, alopecia
Tertiary: may occur from 1->20yrs after initial infection
*gumma: noncancerous granulomas on skin & body tissues
*neurosyphilis: HA, meningitis, dementia, vision/hearing loss, incontinence
-tabes dorsalis: demyelination of posterior columns leading
to ataxia, areflexia, burning pain, weakness
*Argyll-Robertson pupil: small, irregular pupil that constricts w/ accommodation but is not reactive to light
*cardiovascular: aortitis, aortic regurgitation, aortic aneurysms
dx
Nontreponemal tests (screening):
*RPR, VRDL
Treponemal testing (confirmatory):
*FTA-ABS
Darkfield microscopy: allows for direct visualization of T. pallidum from chancre or condyloma lata
*Lyme disease can cause false +
tx
Early (primary, secondary):
*PCN G benzathine 2.4mil units IM x1dose
Late (tertiary or late latent):
*PCN G benzathine 2.4mil units IM once weekly x3wks
Neurosyphilis:
*IV PCN G 3-4mil units every 4hrs x10-14d
*all pts should be reexamined clinically & serologically at 6mo & 12mo after tx
Tetanus (Gram +) definition, sx, dx, tx
Clostridium tetani
Transmission: spores from soil
Neurotoxin (tetanospasmin) block neuron inhibition (ach) 🡪 severe muscle spasm
sx
*Early: local muscle spasms, neck/jaw stiffness, trismus
*Later: drooling, risus sardonicus (facial contraction)
*increased DTR
dx
ELISA 🡪 anti-toxoplasma IgG antibodies
Neuroimaging (MRI > CT): multiple ring-enhancing lesions
tx
*sulfadiazine + pyrimethamine (w/ folinic acid to prevent folic acid depletion)
Prophylaxis:
*TMP-SMX when CD4+ count ≤100
Varicella Zoster Virus (HHV-3) definition, sx, dx, tx
VZV causes 2 clinically distinct diseases:
*Primary: varicella (chickenpox)
*Reactivation: herpes zoster (shingles)
Transmission: aerosolized droplets, direct contact w/ vesicular fluid
Incubation: 14-21d; asymptomatic
Travels retrograde to trigeminal ganglion & dorsal root ganglia where it can remain dormant in a latent state for many years; later, if immune system weakens (aging, stress, immunosuppressive therapy), virus can be reactivated & travel anterograde through sensory nerve to skin (herpes zoster/shingles)
*HHV-3 virus
sx
Varicella (chickenpox): “dew drops on a rose petal”
Prodrome: fever, malaise, anorexia, pharyngitis; rash appears 24h later
Rash: *appears in successive crops over several days
*starts as macules, rapidly become papules, then vesicles; can develop pustular component followed by formation of crusted papules; crusts fall off within 1-2wks; leave temporary area of hypopigmentation
*lesions in different stages of development, PRURITIC!!!
Herpes zoster (shingles):
Prodrome: pain, itching, or tingling in area where rash will develop
Rash: single stripe of vesicles (single dermatome); don’t cross midline
*usually resolves within 1mo, but pain can last >90d 🡪 postherpetic neuralgia
Zoster Ophthalmicus: involves ophthalmic division of trigeminal nerve; 5
*eye pain, redness, swelling + fever + painful vesicular rash
Zoster Oticus (Ramsay-Hunt Syndrome): involves facial nerve (8)
*otalgia; lesions on ear, auditory canal, & TM; facial palsy, hearing loss
dx
Clinical
PCR: viral DNA; confirmatory
Blood tests: IgM antibodies
Tzanck smear:
*multinucleated giant cells
Zoster Ophthalmicus:
*dendritic lesions on slit lamp if keratoconjunctivitis is present
tx
Varicella (chickenpox): resolves in 1wk; develop immunity
*healthy children <12yo: supportive (ASPIRIN 🡪 REYE)
*≥13y & unvaccinated, immunocompromised: antivirals
PO acyclovir, valacyclovir, famciclovir
*varicella-zoster immune globulin (VZIG)
Herpes zoster (shingles): rash usually resolves in 1mo
*acyclovir, valacyclovir, famciclovir within 72h to prevent postherpetic neuralgia
Zoster Ophthalmicus: PO antivirals, can add acyclovir ophthalmic
Ramsay-Hunt: PO acyclovir, corticosteroids
Postherpetic Neuralgia: gabapentin, TCAs, topical lidocaine gel, capsaicin
Vaccines: varicella @12-15mo, second dose 4-6y; recombinant zoster vaccine (RZV) in pts >50y, 2 doses 2-6mo apart
Mycobacterium Avium Complex (MAC) definition, sx, dx, tx
Mycobacterium avium & intracellulare, etc.
Transmission: present in soil & water (not person to person)
Risk Factors:
*sxs seen in pts w/ underlying pulmonary disease (e.g., bronchiectasis, COPD)
*immunocompromised pts (e.g., HIV w/ CD4+ count ≤50cells/µL)
*sxs rarely occur in immunocompetent pts w/o underlying lung disease
sx
Pulmonary: presents similar to TB
*cough, chest pain, fever, weight loss
*upper lobe infiltrates & cavities
Disseminated: MC seen w/ HIV
*fever of unknown origin (MC)
*sweating, weight loss, fatigue, diarrhea
*dyspnea, RUQ pain, hepatosplenomegaly
Lymphadenitis in children:
*cervical, submandibular, maxillary
dx: Acid fast bacillus staining & culture
tx
*clarithromycin + ethambutol + a rifamycin (rifabutin or rifampin)
*life-threatening disease: above + parenteral aminoglycoside
Second line:
*ethambutol + a rifamycin + aminoglycoside
Surgical excision of infected lymph nodes is curative in 90% of pts w/ lymphadenitis
Prophylaxis in HIV:
*clarithromycin or azithromycin if CD4+ count ≤50cells/µL
