IMMUNOLOGIC DISORDERS/INFECTIOUS DISEASE Flashcards
What are the most common presenting symptoms of meningitis
Headache, fever, AMS, sensorial disturbances, neck and back stiffness, positive Kernig and Brudzinski signs, cerebrospinal fluid abnormalities
Spinal fluid analysis of purulent meningitis (bacterial)
200-20,000 polymorphonuclear neutrophils, low glucose (<45), high protein (>50), opening pressure markedly elevated (norm is 70-180)
Spinal fluid analysis of granulomatous meningitis (mycobacterial, fungal)
100-1000 mostly lymphoctyes, low glucose <45, high protein >50, opening pressure moderately elevated (norm is 70-180)
Spinal fluid analysis of spirochetal meningitis
100-1000 mostly lymphoctyes, normal glucose (45-85), high protein >50, normal to slightly elevated opening pressure (norm 70-180)
Spinal fluid analysis of aseptic meningitis, viral meningitis, or meningoencephalitis
25-2000 mostly lymphoctyes, normal or low glucose, high protein >50, slightly elevated opening pressure
Spinal fluid analysis of “neighborhood reaction”
variably increased cells, normal glucose, normal or high protein, variable opening pressure
purulent meningitis diagnosis
Gram positive smear (in 60-90% of cases) or gram positive culture (in 90% of cases) of cerebrospinal fluid
chronic meningitis diagnosis
gram positive culture or serologic testing: cryptococcosis, coccidioidomycosis, syphilis, lyme disease
Clinical manifestations of bacterial meningitis
fever, headache, neck stiffness, AMS, lethargy, nausea, vomiting, photophobia, seizures, coma, stupor, rash (petechial associated with meningococcal infection, purpura fulminans), myalgia, unilateral cranial nerve abnormality, papilledema, dilated nonreactive pupils, posturing, kernigs sign, brudzinski sign
Management of bacterial meningitis
- HandP, stat labs a 2 sets of blood cultures
- Lumbar Puncture
- Empiric therapy with IV antibiotics if: patient has purulent CSF at time of lumbar puncture, is asplenic, or has signs of DIC/sepsis pending gram stain and culture results
**don’t delay therapy if you can’t get culture
Neonate (under 1 month old) empiric therapy for meningitis
Vanco plus gentamycin plus cefotaxime or cetfiraxone
Meningitis empiric therapy for children (over 1 month old)
Vanco plus ceftriaxone or cefotaxime
Meningitis empiric therapy for adults and those over 50 years old
Vanco plus ceftriaxone or cefotaxime
Over 50 add ampicillin to cover Listeria
Meningitis empiric therapy for immunocompromised patients
Vanco plus ampicillin plus cefepime or meropenem to cover Pseudomonas
Corticosteroid tx for meningitis
Dexamethasone 10 mg IV q 6h for 4 days
Symptoms of bacterial endocarditis
Fever, Chills, Weakness, Dyspnea, Sweats, Anorexia, Weight loss, Malaise, Cough, Skin lesions, Stroke, N/V, Headache, Myalgia/arthralgia, Edema, Chest pain, Abd pain, Delirium/coma, Hemoptysis, Back pain
Physical findings of bacterial endocarditis
Fever, Heart murmur, Changing murmur, New murmur, Embolic phenomenon, Skin manifestations, Osler nodes, Splinter hemorrhages, Petechiae, Janeway lesion, Splenomegaly, Septic complications (e.g. pneumonia, meningitis), Mycotic aneurysms, Clubbing, Retinal lesion, Signs of renal failure
Empiric tx of bacterial endocarditis
Vancomycin 1G Q12H IV plus
Ceftriaxone 2G Q24H
Antibiotic therapy for a patient diagnosed with uncomplicated pneumonia caused by S. pneumoniae
Uncomplicated cases caused by penicillin-susceptible strains may be treated on an outpatient basis with amoxicillin 750 mg BID x 7-10 days. PCN allergic alternatives are azithromycin; clarithromycin; doxycycline; levofloxacin; moxifloxacin
Antibiotic therapy for a hospitalized patient diagnosed with pneumonia caused by S. pneumoniae
- PCN G 2 million IV Q4H or
- Ceftriaxone 1G IV Q24H (for strains that are not highly pcn-resistant) or
- Vancomycin (for those with serious PCN allergy or strain that is highly pcn-resistant) - alternatively the resp fluoroquinolone levofloxacin 750 mg
Most common sites for nosocomial infections
- Urinary Tract Infections usually associated with Foley catheters or urologic procedures
- bloodstream infections, most commonly from indwelling catheters but also from secondary sites, such as surgical wounds, abscesses, pneumonia
- GU tract
- GI tract
- Pneumonia in intubated patients or those with altered level of consciousness
- surgical wound infections
- MRSA infections
- CDIFF
Malarial prophylaxis when traveling to a country without drug-resistant parasites
- Bed nets treated with permethrin insecticides, indoor spraying of insecticides
- Chemoprophylaxis with chloroquine
Management of Vancomycin-Resistant Enterococci (VRE)
-For rectal or stool colonization, therapy not recommended
-In symptomatic patient, If VRE strains are known to be susceptible, potential therapeutic agents include:
Linezolid
Daptomycin
Quinupristin-dalfopristin (Synercid)- only effective for E.Faecium strains
3 negative stool cultures obtained at weekly intervals to remove a pt from contact precautions
Prevention of Vancomycin-Resistant Enterococci (VRE)
Hand Hygiene, contact isolation technique, and cleaning contaminated objects with standard hospital disinfectants
Antibiotic management of pyelonephritis
- Ampicillin and an Aminoglycoside are initiated prior to obtaining sensitivity results
- Can also use ceftriaxone, cipro, levofloxacin. Zosyn, meropenem or imipenem in toxic patients.
- IV abx are continued for 24 hours after fever resolves, and oral anbx are then given to complete a 14 days course of therapy.
- Follow up urine cultures are mandatory following completion of treatment
What is osteomyelitis
Osteomyelitis is an acute or chronic infection of the bone secondary to the hematogenous or contiguous source of infection or direct traumatic inoculation, which is usually bacterial
Essentials of diagnosis for osteomyelitis
- Fever and chills associated with pain and tenderness of involved bone.
- Dx usually requires cx of bone bx.
- ESR often extremely high (>100 mm/h)
- Xrays early in the course are typically negative
Clinical findings of Hematogenous Osteomyelitis
-resulting from bacteremia as a disease associated with sickle cell disease, injection drug users, diabetes mellitus, or older adults.
-present with sudden onset of high fever, chills, and pain and tenderness of the involved bone.
caused most often by salmonellae; S aureus is the second most common cause
- Osteomyelitis in injection drug users develops most commonly in the spine. Although in this setting S aureus is most common, gram-negative infections, especially P aeruginosa and Serratia species, are also frequent pathogens.
- Can lead to rapid progression to epidural abscess-fever, pain, and sensory/motor loss
Older patient common sites of Hematogenous Osteomyelitis
thoracic & lumbar
Risk factors: DM, IV catheters, and urinary catheters
Osteo from a contiguous focus of infection: source
- Prosthetic joint replacement, pressure injury (formerly called pressure ulcer), neurosurgery, and trauma most frequently cause soft tissue infections that can spread to bone.
- S aureus and Staphylococcus epidermidis are the most common -Polymicrobial infections are common.
Osteo from a contiguous focus of infection: signs and symptoms
- localized signs of inflammation are evident, but high fever and other signs of toxicity are usually absent.
- Septic arthritis and cellulitis can also spread to bone.
Osteomyelitis associated w/vascular insufficiency: who does it affect the most
DM pts w/ vascular insufficiency are susceptible to developing a very challenging form of osteomyelitis.
Osteomyelitis associated w/vascular insufficiency: sites
- foot and ankle
- Originates from ulcer or other break down of skin (may appear disarmingly unimpressive)
Osteomyelitis associated w/vascular insufficiency: signs and symptoms
- Absent or muted bone pain d/t neuropathy
- Afebrile
- Two of the best bedside clues- ability to easily advance a sterile probe through a skin ulcer and a ulcer area larger than 2 cm.
Labs for osteomyelitis
- ↑ESR & CRP (can be useful parameters to follow during course of therapy)
- Blood cultures
Osteomyelitis xray
- est dx but can be falsely negative initially
- Early xray- may include soft tissue swelling, loss of tissue planes, and periarticular demineralization of bone.
- 2wks after onset of sx- erosion of bone and alteration of cancellous bone appear, followed by periostitis.
Osteomyelitis MRI
most sensitive- demonstrates extent of soft tissue involvement
Osteomyelitis CT
only do if pts has contraindication to MRI
Osteomyelitis PET scan
high accuracy (similar to MRI) useful in pts with metallic implants
Osteomyelitis Radionuclide bone scan
most valuable when osteo is suspected but no site is obvious. May also detect multifocal sites of infection
Osteomyelitis ultrasound
dx effusions w/in joints and extra-articular soft tissue fluid collections but NOT in detecting bone infections.
Osteomyelitis Bone marrow biopsy
- Identify organism=abx therapy (aerobic & anaerobic & fungi)
- Is required EXCEPT in those with hematogenous osteo, who have +blood cx
- Cultures from overlying ulcers, wounds, or fistulas are unreliable
Treatment/management of osteomyelitis
- Debridement of necrotic bone and prolonged abx
- Vertebral body and epidural abscess=urgent neurosurgical decompression
- PO quinolones (ciprofloxacin) 6-8 wks; for S aureus= cipro + rifampin
- Hyperbaric oxygen therapy- chronic osteo
- Wound-assisted vacuum device-help would closure
- Immobilization of affected bone (plaster, traction) if bone is unstable
Challenges to treating osteomyelitis
Inadequate treatment of bone infections results in chronicity of infection, and this possibility is increased by delaying diagnosis and treatment.
Extension to adjacent bone or joints may complicate acute osteomyelitis.
Recurrence of bone infections often results in anemia of chronic disease, a markedly elevated ESR, weight loss, weakness and, rarely, amyloidosis or nephrotic syndrome.
Pseudoepitheliomatous hyperplasia, squamous cell carcinoma, or fibrosarcoma may occasionally arise in persistently infected tissues.
Antibiotic management of intra-abdominal infections
Zosyn, or ertapenem
Aseptic Meningitis
-More benign and self-limited syndrome than purulent meningitis- is caused principally by viruses, especially herpes simplex virus and enterovirus group (coxsackieviruses and echoviruses)
-Infectious mono may be accompanied by aseptic meningitis; leptospiral infection also in
aseptic group
-Also occurs during secondary syphilis and disseminated Lyme dz
-Prior to MMR vaccine, mumps was most common cause of viral meningitis
-Drug-induced aseptic meningitis reported w/ NSAIDS, sulfonamides, certain monoclonal
antibodies
