Infectious Disease, Rheumatology Flashcards
Most common diagnosis for sick kids and antibiotic therapy?
Otitis media
AOM risk factors?
Younger than 6yo FH, especially if American or Australian indigenous Male Poor Cold season Smoke exposure Day care Decreased risk with breastfeeding
Respiratory epithelium histology?
Pseudostratified ciliated columnar epithelium with goblet cells
Why are infants at greater risk of AOM?
Flatter ETs = worse drainage of middle ear
AOM pathogenesis
Inflammation (due to URI, allergy, smoke) –> ET obstruction (mass, anatomy) –> Middle ear effusion (barotrauma) –> AOM –> OME (w/effusion) –> complications/resolution
Most common microbial causes
Viruses - Adeno, Influenza, Mono, Rhino, Corona, Parainfluenza, RSV
Strep pneumonia, Haemophilus, Moraxella, GABHStrep, Staph, Anaerobes
Is AOM contagious?
No, but URIs are, which may cause AOM secondarily
AOM history
PAIN, URI, Fever, Headache, Irritability/apathy;
Anorexia, vomiting, diarrhea with Adeno
Behavior changes, communication problems, plugged/popping ears, recent URI/allergy
AOM presentation and DDX
Otalgia = otitis externa, dental problems, pharyngitis
Ottorhea = otitis externa
Hearing loss = impaction, sensorineural deficits
Vertigo, nystagmus, tinnitus = ET dysfunction, labyrinthitis
Postauricular swelling = mastoiditis
Facial paralysis = Bell’s palsy
AOM physical exam findings
General = sepsis Head = craniofacial abnormalities Eyes = drainage w/H. influenzae Nose = congestion, drainage, septal deviation Neck = lymph nodes, meningeal signs Throat = Bifid uvula (cleft palate), redness, drainage - SAVE FOR LAST
AOM TM triad on otoscopy
Bulging, red, immobile
AOM TM abnormalities
Bulging, bubbles, air-fluid levels, perforation w/ottorhea, bullae, tympanosclerosis, cholesteatoma
Fever and earache associated with … ?
Pneumococcal infection
Otitis-conjunctivitis syndrome or bilateral otitis associated with … ?
Haemophilus influenzae infection
Ways to prevent chronic OM?
Educate parents - don’t smoke, breastfeed, vaccines, smaller daycare
Chemoprophylaxis
Surgery
Retracted TM indicates?
Negative pressure in middle ear
AOM diagnosis must have what three things?
Acute history of URI/congestion
Evidence of middle ear effusion - drainage, bulging TM, or abnormal tympanometry
Signs/symptoms - fever, pain
AOM treatment
Observation
If over 2yo, short course of amoxicillin preferred, macrolides or erythromycin if penicillin allergy
Should respond within 2d. Recheck by 2wk.
Recurrent OM treatments
Antibiotic prophylaxis
Image adults for masses
Surgery - myringotomy w/tympanostomy tubes
Monitor hearing, speech, language development
OME treatment
Observe unless infant
Full antibiotic course if over 3m
Surgery if high risk, chronic, or bilateral effusion - tubes, may remove adenoids if obstructing ETs
Monitor hearing, speech, language development
When are speech and language development at risk?
Infant younger than 6m Existing hearing loss or speech/language disorder Autism Developmental delay Uncorrectable visual impairment
Potential targets of HIV drugs
Integrase inhibitors
Protease inhibitors
RT inhibitors
Fusion/entry inhibitors
Clinical indications for HIV testing
TB
Syphilis
HIV-associated opportunistic diseases: Pneumocystis, Karposi’s sarcoma
Recurrent shingles
Chronic constitutional symptoms, generalized adenopathy, diarrhea, encephalopathy, thrombocytopenia
Symptoms of primary HIV infection
Non-specific flu-like symptoms w/ or w/o rash
Fever, fatigue, rash, myalgia, night sweats, low WBCs, weight loss
Mucocutaneous ulcerations, rash, abrupt onset of multiple symptoms
DDx for HIV
EBV mono, CMV, HSV, flu, hepatitis, organisms causing rash
Cryptococcus neoformans
HIV OI
Subacute meningitis w/fever, headache, malaise, occasionally encephalopathy
Treat w/ amphotericin B, then fluconazole
Consider CSF shunt if hydrocephalus does not resolve
Advanced HIV OIs (CD4 less than 50/mL)
CMV - now causes CNS disease when CD4 below 50/mL
TB - all HIV+ patients should be tested for latent TB at diagnosis, rifampin/isoniazid is well-tolerated; Systemic TB common in advanced HIV disease –> Fever, weight loss, sweats, diarrhea
Primary CNS lymphoma
Toxoplasma gondii
May reactivate when CD4 below 200/mL
Present in white matter, CSF
Headache, fever, behavioral change, lethargy, gait change, seizures
JC Virus
Asymptomatic latent infection reactivates causing CNS involvement
Potential complications of HIV treatment
Lipodystrophy - body morphology changes and metabolic complications
Premature osteopenia/-porosis
Peripheral neuropathy
Best time to start HIV treatment?
As early as possible if the patient is functional, esp. if pregnant
Give vaccines early to maximize benefits, but avoid live vaccines
Pneumocystis jirovecii
HIV OI
Gradual onset fever, dry cough, dyspnea, tachypnea
CXR may show indicative infiltrate
Bronchoscopy diagnostic
Treat w/ IV SxT; patient will typically worsen after 2-3d as fungus begins to die, IR begins
Normal stool volume and frequency
Less than 1L/d
Less than 7 BM/d
Dysentery-causing organisms
Which bowel?
Small bowel:
Salmonella
E. coli (all strains besides 0157)
Large bowel:
Campylobacter
Shigella
Entamoeba histolytica
Define pseudodiarrhea, fecal incontinence, and overflow incontinence
Rectal urgency due to anal inflammation/infection
Neuromuscular loss of anal sphincter control
Constipation in sigmoid colon causes watery stool to leak around blockage
Causes of acute diarrhea
Viral - most common, least complicated
Bacteria - severe
Protozoa - least common
Diarrhea-causing organisms with preformed toxin
Which bowel?
C. perfringens
Staph
Bacillus cereus
All small bowel
Diarrhea-causing organisms with enterotoxin
Which bowel?
Vibrio cholerae
Small bowel
Diarrhea-causing organisms with cytotoxin
Which bowel?
E. coli 0157:H7
C. diff
Large bowel
Diarrhea-causing organisms with enteroadherance
Which bowel?
Giardia lamblia
Small bowel
Diarrhea soon after cream pie/salad?
Staph
Diarrhea after rice that was left out?
Bacillus cereus
Diarrhea within enclosed space (cruise ship)?
Norovirus
Diarrhea/dysentery 1-3 days after undercooked meat?
Salmonella
Diarrhea a few days after raw vegetables or undercooked meat?
E coli 0157:H7
Diarrhea after sushi?
V. parahemolyticus
Diarrhea in child in daycare?
Rotavirus
Diarrhea associated with unsanitary conditions?
HepA
Infantile diarrhea?
Adenovirus
Diarrhea associated with unclean surface water?
Giardia
Travelers diarrhea?
ETEC
Diarrhea after antibiotic therapy?
C. diff
Diarrhea pertinent history questions
Onset Frequency Presence of blood or mucus BMs at night? Associated symptoms Exposures? Recent antibiotics?
Diarrhea pertinent physical exam findings
Vital signs/General - patient sick and near shock?
Abdominal exam - Surgical abdomen? (Rigidity, guarding, rebounding, no sounds)
Musculoskeletal - accompanying arthritis
Skin - vasculitis?
Rectal exam - blood, masses
Anal fissure may be indicative of?
Minor cause of hematochezia
Anal fistula may be indicative of?
More severe disease such as IBD
When to culture stool?
When to look for parasites/ova?
- Bacteria suspected
- Persistent diarrhea w/risk factors, dysentery, but no fecal leukocytes
Typical antibiotics for diarrhea
Flouroquinolone = G- coverage Metronidazole = C. diff coverage
When to not use anti-motility agents?
Bacterial or amoebal dysentery, inflammatory response that needs to be cleared
Prevent C. diff establishment
Influenza types
A = humans, animals, pandemics B = humans, no pandemics C = mild disease
Influenza surface proteins
Hemaglutinin and neuraminidase
Antigen drift and antigen shift
Drift = mutation causes small changes in H, N from year to year Shift = Reassortment of genes in cells co-infected with different strains causes acquisition of new H, N genes
Influenza transmission path
Need large respiratory droplets (sneezing, coughing)
Need close contact for these to be transmitted
Can’t get from contaminated surfaces, meat
Clinical influenza disease
Fever, headache, myalgia, fatigue
Followed by cough, sore throat, nasal discharge
GI symptoms NOT typical
Flu complications
Pneumonia (viral, strep, or staph)
Rhabdomyolysis
MI
Encephalitis and Reye’s syndrome (from too much aspirin) rare
Spanish flu unique features
Bacterial pneumonia most common cause of death
H5N1 bird flu unique features
Primarily children and young adults most affected with little person-to-person transmission
H3N2 swine flu
Close contact with pigs at IN state fair, with genes from H1N1 and H3N2 strain
Diagnosing flu
In season, typical symptoms usually enough
Otherwise viral culture (gold standard) or RT-PCR (higher cost)
Flu treatment
No antiviral works well, but may reduce mortality
Old rimantidine and amantidine are ineffective
Current neuraminidase inhibitors only moderately shorten course
Why must flu vaccines be changed every year?
Must anticipate antigenic drift with educated guess
Flu vaccine features
Grown in eggs
Inactivated with formaldehyde
Current is a subunit containing only H and N proteins with few side-effects
Tri- or quadrivalent
GBS now rare
Most effective in children, least effective in elderly
Lyme disease organism and vector
Borrelia burgdorferi
Deer tick
Rocky Mountain Spotted Fever organism and vector
Rickettsia rickettsii
Dog tick
Ehrlichiosis organism and vector
Ehrlichia chaffeensis
Lone star tick
Lyme disease stages
- Localized - Erythema migrans (blanching)
- Disseminated - multiple annular skin lesions, meningitis, CN7 neuritis, carditis/AV block, arthralgia
- Persistent - Oligoarticular arthritis (knee), encephalopathy, axonal (distal) polyneuropathy, acrodermatitis
DDx of CN7 palsy
Idiopathic Bell’s Palsy
HSV usually w/o rash
Herpes Zoster - vesicles in external auditory canal
Lyme disease
Testing for Lyme disease
Serologic IgM/IgG at presentation and 2-4w later
ELISA w/ Western blot verification
PCR of joint fluid in patients w/ arthritis
Treatment for Lyme disease
Doxycycline
Rickettsia rickettsii trophism
Vascular endothelial cells –> Vasculitis (increased vascular permeability, non-blanching petechial rash w/palms and soles, edema, hypovolemia, hyponatremia from disproportionate ADH response, thrombocytopenia)
Classic presentation of RMSF
Fever, rash, history of tick exposure
Flu-like symptoms
Serious RMSF symptoms
Shock from hypovolemia/-tension Respiratory failure CNS involvement Acute tubular necrosis Acute hepatitis/liver failure
RMSF labs will show what?
Thrombocytopenia, hyponatremia, azotemia (high BUN, high Cr if ATN occurs)
Fever, petechial rash on palms and soles, potential tick exposure DDx
Meningococcal disease RMSF ^^^Most important, both treated w/doxycycline, cephtriaxone^^^ Enterovirus Secondary syphilis
RMSF treatment for pregnant women
Chloramphenicol
Reasons for RMSF treatment delay
Absence of skin rash
Early presentation before severe symptoms
Presentation outside of summer months
Ehrlichiosis symptoms
Flu-like symptoms
Rash is rare
Fewer long-term complications
Ehrlichiosis lab findings
Leukopenia
Thrombocytopenia
Elevated transaminases
Ehrlichiosis treatment
Doxycycline
Malaria physical exam findings
Fever Mild hepatomegaly Palpable spleen Jaundice Rash is very unusual
Malaria lab findings
Nonspecific
Normocytic normochromic anemia
Increased ESR, CRP
Malaria drugs
Chloroquine - if in sensitive area
Doxycycline
Malarone
Mefloquine - avoid because of CNS side effects
Staphylococci (aureus, epidermidis) pathogenic proteins
S. aureus: G+, catalase- and coagulase-positive = hemolytic
S. epidermidis: Coagulase-negative, less virulent, but affects prosthetics
Risk factors for S. aureus colonization
Diabetics
HIV
Dialysis patients
Patients with skin damage (wounds, psoriasis, etc.)
PMN defects (neutropenia, chronic granulomatous disease, Chediak-Higashi syndrome)
Staph pathogenesis
Pyogenic, causes abscesses at primary and/or distant sites
Inflammatory response -> PMN infiltrate -> Macrophage and fibroblast infiltration -> Contained infection OR spread
Toxin-mediated Staph diseases
Cytotoxins
Pyrogenic toxin superantigens: Food-borne illness (enterotoxin), Staph toxic shock syndrome (produced at infection site, causes clinical toxin - USE CLINDAMYCIN to stop toxin production most effectively)
Exfoliative toxin: Staph scalded skin syndrome
Protective value of anti-Staph Abs?
None in clinical trials
PMNs are main control
Staph clinical manifestations
Skin, soft tissue infection (cellulitis, fasciitis more likely w/GABHStrep)
Bacteremia
CV infection
Sepsis, toxic shock syndrome
Bone, joint infection - osteomyelitis, septic arthritis
Pulmonary infection
Renal infarction, psoas abscess -> CVA tenderness
Rare:
Splenic abscess
Meningitis
Bacteruria - indwelling catheter
Staph bacteremia, sepsis risk factors
Intravascular catheters
MRSA colonization
Implanted prosthetics
Injection drug use
Physical exam and diagnostic evaluation of Staph in adults
Careful cardiac exam to detect new murmurs, heart failure, endocarditis
Blood cultures daily, ECG
Staph aureus bacteremia treatment in adults
Remove infection source (catheters, prosthetic)
Empiric antibiotics until sensitivity determined - vancomycin
MSSA - nafcillin q 4h/oxacillin, cefazolin more common
Follow up blood cultures daily
Therapy duration - 14d IV abx w/o complications
Enterococcus treatments
Penicillins if sensitive
Vancomycin if sensitive
MRSA drugs
Cephalosporins, fluoroquinolones, macrolides = NO EFFECT
ESBL-producing E. coli treatment
Carbapenem
Sepsis risk factors
ICU, nosocomial infection, esp. pneumonia Bacteremia Older than 65y, immunosuppression Diabetes Cancer Genetic factors
How to manage sepsis
Control airway - supplemental O2, intubation, ventilation
Establish venous access - central line
Maintain perfusion - IV fluids, vasopressors
Empiric, then targeted antibiotics
Possible surgical debridement
MRSA risk factors
Recent stay in care facility or hospital Recent antibiotic therapy HIV IV drug use Dialysis Diabetes Shared sports equipment
Septic shock progression
Systemic inflammatory response syndrome (SIRS) -> Sepsis -> Severe sepsis -> Septic shock
Common causes of antibiotic resistance spread
Antibiotic use in livestock causes spread in meat
Stay in long-term care facilities w/other sick people
NOT WASHING HANDS
Key interventions to prevent MRSA spread
Hand hygiene
Decontamination of environment, equipment
Contact precautions for infected/colonized patients
Active surveillance cultures of all people working/housed in facility
Precautions for C. diff
Gown and gloves
Hand washing
Vancomycin side effects
Renal failure, ototoxicity
Strep throat history and physical
H: Contact, sore throat, headache, fever, adenopathy
P: Exudative tonsillitis, petechiae on palate (strawberry tongue), fever, cervical adenopathy, circumoral pallor (pale around mouth)
Strep throat DDx
Viral pharyngitis
Coxsackie
Herpes
GABHStrep pyogenes
Strep throat labs
Rapid (Strep antigen - GA carb Ag) and routine throat culture
Strep throat treatment
Routine - Penicillin V (250 or 500mg b./t.i.d. for 10d) or G (1 IM dose), 10d erythromycin for patients with penicillin allergy, or 10d cephalosporins
Carrier - Pen G, clindamycin, cephalosporins, or amoxicillin; 10d penicillin w/ rifampin last 4d
Strep throat complications (5) w/cause, course, symptoms, treatment
Scarlet fever - from erythrogenic Strep exotoxin w/1-7d incubation: Fever, vomiting, headache, strep pharyngitis, chills, abdominal pain, rash first appearing in axilla/groin/neck, then generalized in 1d, followed by desquamation - Treat w/Pen 10d
Rheumatic fever - M type GABHS extracellular toxin: Carditis, migratory polyarthritis, erythema marginatum (almost looks like 2o Lyme disease), chorea, subcutaneous nodules, fever, arthralgia, high ESR/CRP, prolonged PR on EKG - Treat Strep, aspirin, steroids, bed rest, chorea w/anticonvulsants, heart failure w/bed rest, digitalis, diuretics; prevent relapse w/penicillin prophylaxis
Glomerulonephritis - GABHS infxn 1-2w prior: Hematuria (RBC casts), malaise, lethargy, abdominal/flank pain, fever, edema, oliguria, hypertension; check w/culture, serum C3, streptolysin O Abs; Treat w/Pen and for complications
Peritonsillar abscess
TSS - rare
Rheumatologic diseases
Musculoskeletal conditions, pain syndromes, autoimmune syndromes w/o musculoskeletal components
“Pain about, but not in joints”
What provides nutrients to cartilage
Synovial fluid made by the membrane (cartilage is avascular)
Cartilage molecular structure
Hyaluronic acid backbone w/ proteoglycan attached
MW may reach 300m
Synovial membrane thickness
1-3 cells thick
Pathophysiology at cartilage causes … ?
Osteoarthritis
Pathophysiology at bony end-plate causes … ?
Avascular necrosis
Pathophysiology at synovial membrane causes … ?
RA
Pathophysiology at joint space causes … ?
Gout
Pathophysiology at enthesis causes … ?
Ankylosing spondylitis
Rheumatologic history should include what?
Complete history
Time and rapidity of onset (Gout = rapid, RA = w/m, Fibromyalgia = slow)
Number of joints
Constitutional symptoms - systemic or local?
Response to therapy (Gout w/NSAIDs, FM w/exercise)
Functional status - define therapeutic end goals
Rheumatologic physical should include what?
Complete physical and joints
Palpate joints
Evaluate swelling, tenderness, limited ROM
Function
Rheumatologic labs
Useful for supporting Dx, not determining disease
CBC - assess systemic involvement, therapy contraindications
ESR, CRP - systemic inflammation?
RF, ANA - for classifying systemic polyarticular inflammatory arthritis, not diagnostic
Joint aspiration - diagnostic for crystal-induced, septic arthritis
X-ray - diagnostic in ankylosing spondylitis, osteoarthritis; follow RA progress
Rheumatologic treatments
Exercise - CV conditioning for FM, ease pain in osteoarthritis
PT, OT
NSAIDs - risks of renal insufficiency, GI bleeds, CV risk
Corticosteroids - for flares, intraarticular injections useful for non-/inflammatory arthritis, systemic for inflammatory, autoimmune
DMARDs - treat underlying immune defect
Articular symptoms shorter than 6w DDx
Crystal-induced (pseudo-/gout), septic, infectious arthritis, initial chronic presentation
Noninflammatory arthritis longer than 6w DDx
Osteoarthritis
Polyarticular arthritis DDx
RA, SLE, PsA
Pauciarticular arthritis DDx
Ankylosing spondylitis, Reiter's, PsA Juvenile RA Pseudo-/gout Septic arthritis Early polyarthritis symptoms
