ID Illness Scripts Flashcards
K Pneumoniae
most infections are due to “classical” K. pneumoniae, although can become MDR/XDR.
Invasive Klebsiella Syndrome: mostly Southeast Asia (ddx melioidosis): primary liver abscesses w/o biliary tract disease, metastatic infection including endogenous endophthalmitis, brain (abscess, suppurative meningitis/ventriculitis), necrotizing fasciitis, pneumonia, bone (osteomyelitis, epidural/paraspinal abscess).
Increased risk w/ diabetes. Invasiveness due to hypermucoviscosity/hypervirulent phenotype causing widely metastatic infection like S. aureus.
K. pneumoniae most common cause of endogenous endophthalmitis in SE Asia vs. Staph/Strep, Candida in U.S./West.
Inducible AmpC Resistance
HECK
Hafnia alvei, Enterobacter cloacae, Citrobacter freundii (not C. koseri), Klebsiella aerogenes, Yersinia
Carbapenem preferred, Cefepime reasonable if MIC ≤ 2, Can use non-beta lactams (FQ/macrobid/bactrim, fosfo only if E. coli); avoid ceftriaxone/pip-tazo
M Bovis
Main cause of TB in cattle, deer, other mammals; often acquired through cow exposure, consumption of unpasteurized dairy (→ scrofula, GI and extrapulmonary sxs common), vs. after intravesical BCG therapy.
Manifestations indistinguishable from MTb.
Intravesical complications can be early (<3 mo: fever, sweats, weight loss, hepatitis, pneumonitis) or late (»3 mo: symptoms typically more GU-localized, but can disseminate and present as miliary disease or delayed-onset sepsis especially after immunosuppression/compromise, often involves lungs + liver + bone + other typical disseminated granulomatous features). Intrinsically resistant to pyrazinamide.
Infectious Transverse Myelitis
Herpesviruses (HSV, VZV, CMV, rarely EBV)
Syphilis
TB
HIV
HTLV1
Schistosomaiasis
Toxocara
Ascaris
Autoimmune/Autoinflammatory:
NMO
Sjogrens
SLE
APLS
MS
ADEM
Neuro-behcet
Neurosarcoid
Other
Neoplastic/Paraneoplastic
Radiation induced
Anaplasma phagocytophilum
targets neutrophils, obligate intracellular GNR, more common than HME.
HGA can be found both internationally and locally in the Northeastern, mid-Atlantic, Midwest, and Northwestern United States. The vector for transmission includes the Ixodes ticks, which are also responsible for carrying B. burgdorferi, B. microti, and other tick-borne encephalitis viruses. Coinfection is very common due to shared vectors.
Ehrlichia chaffeensis
targets monocytes, less common than HGA. South/eastern/mid-Atlantic US. Transmitted via white-tailed deer & lone star tick.
Meningitis/meningoencephalitis with CSF pleocytosis seen in 60% of cases.
Cranial nerve palsies are a rare manifestation of HME.
E. ewingii also targets neutrophils → human granulocytic ehrlichiosis (HGE)
Borrelia borgderferi
(Lyme) - tickborne; normal CBC/CMP
Skin (erythema migrans, lasts < 2 weeks)
Neurologic (CN palsies, polyradiculitis, lymphocytic meningoencephalitis over weeks)
Cardiac (AV block, rarely myocarditis over weeks)
Joint (arthralgia/arthritis in 30% over months)
Treponema pallidum
anaerobic (lung involvement uncommon)
1° (<3 wk): localized chancre on genitals, pharynx, anus
2° (wks-months): fever, myalgia, adenopathy, skin (rash, alopecia), GI (hepatitis, luminal enteritis/colitis/proctitis - IBD mimic), renal (membranous nephropathy, MPGN, tubular disease, vasculitis), neuro (meningitis, stroke), ocular (uveitis), oto (unilateral hearing loss, vertigo, tinnitus)
3° (1-30 yr): aortitis, gummas (skin/bone granuloma), CNS (meningitis/cranial neuropathies, vascular/strokes, general paresis/dementia/psychosis/dysarthria, tabes dorsalis/ataxia)
Note neurosyphilis and ocular/oto complications can happen at any time, and neuro manifestations earlier in HIV+
Leptospira
Zoonotic infection (dogs/urine), global distribution but common in tropics
Lung: pneumonia, bilateral GGO, DAH
Kidney: acute tubulointerstitial nephritis (pyuria, non-oliguric AKI often hypokalemic)
Liver: cholestatic liver injury, can have extreme hyperbilirubinemia & jaundice
Muscle: myalgia (calves/low back), rhabdomyolysis
Heme: deep thrombocytopenia
Head: conjunctival suffusion, bitemporal headache w/ photophobia/retro-orbital pain, +/- CNS,
GI sxs
Weil disease = impaired hepatic & renal function, complications: myocarditis, neurological
Ddx - Severe lepto may mimic HLH; (pulm-renal ID ddx: hanta, legionella, consider HLH, Sjogren/Scleroderma)
(bacterial rhabdo ddx: GPC, listeria/legionella/lepto, mycoplasma, salmonella, tularemia)
Brucella
(melitensis/sheep, suis/pigs, abortus/cattle, canis/dogs)
Gram-negative intracellular coccobacilli, from unpasteurized dairy, undercooked meat, livestock.
Endemic: Middle East, Central Asia, Africa, Central/South America.
Lymphatic spread → disseminated granulomatous infection involving:
Skin
Bone / joint / spine (Pedro Pons sign = erosion of the anterior superior aspect of lumbar vertebrae with osteophytosis, a/w Brucella spondylodiscitis – predilection for lower L-spine vs. TB spondylitis predilection for mid/lower T-spine, & more likely to cause paravertebral abscesses.)
Liver/spleen/marrow/lymphadenopathy
CNS
Eyes
Epididymo-orchitis
Endocarditis (rare, but most common cause of death)
Bartonella
B. henselae - cats → Cat Scratch Disease
Neuroretinitis: acute unilateral progressive painless central vision loss with “macular star” on fundoscopy (ddx: syphilis, ocular TB, toxoplasma, viral (HSV, CMV, VZV), non-infectious (sarcoid)). Can cause secondary HLH. In HIV+ patients can cause IRIS, bacillary angiomatosis.
B. quintana - homeless, head/body lice. In HIV+ patients can cause IRIS, bacillary angiomatosis.
B. bacilliformis - Peru/Ecuador/Colombia/south Florida - Carrion’s disease / Oroya Fever. Biphasic illness: Initial phase (Oroya Fever) x 2-4 weeks involving fever, hepatomegaly, LAD; parasitizes RBCs causing intravascular hemolytic anemia & thrombocytopenia, rarely neurobartonellosis. Complications: secondary infections (salmonella, PJP, toxo, histo, lepto, malaria, others), MAHA/AIHA/HLH, cardiovascular (acute HF/cardiogenic shock, pericardial effusion/tamponade, myocarditis). Chronic phase 2-8 weeks after recovery from acute phase → nodular skin lesions (verruga peruana).
Legionella
returning travelers at risk
Fever with relative bradycardia (Faget sign)
Lung: “summer pneumonia”
GI: diarrhea, abdominal symptoms, mild liver enzyme elevation
Heme: thrombocytopenia
Renal: AKI/AIN (like lepto), hyponatremia
Muscle/rhabdomyolysis (ddx bacteria: lepto, listeria, legionella, mycoplasma, tularemia, salmonella)
Note testing only catches one serotype
Francisella tularensis
tularemia, vectors: rabbits/rodents, ticks, fleas, lice
Ulceroglandular / oculoglandular
Pneumonic
Typhoidal (systemic febrile illness similar to salmonella, can cause rhabdomyolysis)
Coxiella burnetii
rickettsia-like agent acquired from inhalation of contaminated aerosols from goats/cattle/sheep, cats; or ingestion of contaminated animal products; mammals shed Coxiella in urine, feces, milk, and birth products
Lung: Flu-like illness, pneumonia (more common in summer)
Liver: Granulomatous hepatitis
Cardiac: Culture-negative endocarditis
Salmonella
(typhi/paratyphi vs. non-typhoidal)
Sig. disseminated infection with non-typhoidal salmonella requires immunocompromise
GI illness
Endovascular infection, infectious aortitis, mycotic aneurysm, endocarditis
Bone/joint infection (osteomyelitis, septic arthritis)
Muscle involvement/rhabdomyolysis (bacterial ddx GPC, listeria/lepto/legionella, mycoplasma, salmonella, tularemia)
