Infectious Disease Flashcards

Question

Septic Arthritis - Critical diagnosis that cannot be missed and is a true medical emergency. Missed septic arthritis leads to severe destruction of the infected joint. - _____ is most common cause - In neonates, GBS (usually late-onset disease) and gram negatives are implicated - In children <5yo, S aureus, S pyogenes, and S pneumoniae are the most common - In >5yo, S pneumoniae diminishes as a cause. - Do not forget Neisseria gonorrhoeae in the sexually active adolescent, esp if menstruating. - Consider Salmonella septic arthritis in pts with Sickle cell disease or other hemoglobinopathies. - Neonates are more difficult to diagnose bc of the immature inflammatory and immune responses present. Therefore, neonates may present with only vague symptoms and may be lacking fever or obvious joint involvement, although pseudoparalysis (refusal to move an affected joint) is common. - Maneuvers that twist the pelvis, such as the FABER test, are painful in pts with septic arthritis of the sacroiliac joint. - Perform the FABER test (aka Patrick test “figure of 4” test) by inducing flexion of the hip and knee, with abduction and external rotation of the hip, in such a way that the ankle of the ipsilateral leg lies atop the opposite knee in a figure of 4 configuration. - Dx: - Those pts with ____, ____, ____, and ___ can be classified as being highly likely to have septic arthritis, with a chance of >96% rather than transient synovitis. - Do _______ quickly to discern the diagnosis and send the fluid for gram stain, culture, and cell count. - WBC count >50,000/uL is common with mostly PMNs. - K. kingae is difficult to isolate on typical culture media (negative synovial fluid culture), but PCR assays can improve the diagnostic yield. - Also, obtain ____ - _____of the joint is helpful in discerning the presence of fluid. MRI can also detect any accompanying osteomyelitis. - Tx: Prompt Ortho consult for decompression - <3mo: ____ and ____ - >3mo: ____ or ____

Answer 1

Septic Arthritis - Critical diagnosis that cannot be missed and is a true medical emergency. Missed septic arthritis leads to severe destruction of the infected joint. - Staph aureus is most common cause - In neonates, GBS (usually late-onset disease) and gram negatives are implicated - In children <5yo, S aureus, S pyogenes, and S pneumoniae are the most common - In >5yo, S pneumoniae diminishes as a cause. - Do not forget Neisseria gonorrhoeae in the sexually active adolescent, esp if menstruating. - Consider Salmonella septic arthritis in pts with Sickle cell disease or other hemoglobinopathies. - Neonates are more difficult to diagnose bc of the immature inflammatory and immune responses present. Therefore, neonates may present with only vague symptoms and may be lacking fever or obvious joint involvement, although pseudoparalysis (refusal to move an affected joint) is common. - Maneuvers that twist the pelvis, such as the FABER test, are painful in pts with septic arthritis of the sacroiliac joint. - Perform the FABER test (aka Patrick test “figure of 4” test) by inducing flexion of the hip and knee, with abduction and external rotation of the hip, in such a way that the ankle of the ipsilateral leg lies atop the opposite knee in a figure of 4 configuration. - Dx: - Those pts with refusal to bear weight, fever >38.5 (101.3), ESR >40mm/h, and WBC >12,000/uL can be classified as being highly likely to have septic arthritis, with a chance of >96% rather than transient synovitis. - Do joint aspiration quickly to discern the diagnosis and send the fluid for gram stain, culture, and cell count. - WBC count >50,000/uL is common with mostly PMNs. - K. kingae is difficult to isolate on typical culture media (negative synovial fluid culture), but PCR assays can improve the diagnostic yield. - Also, obtain blood cultures - MRI or US of the joint is helpful in discerning the presence of fluid. MRI can also detect any accompanying osteomyelitis. - Tx: Prompt Ortho consult for decompression - <3mo: Vancomycin and cefotaxime - >3mo: Vancomycin or cilndamycin

Answer 2

Kingella kingae - Gram negative. - Increasingly recognized as a cause of osteoarticular infections in pediatrics, such as osteomyelitis, septic arthritis, and tenosynovitis. - Indolent organism seen in patients age 6-36 months. - Pt: More subacute presentation - Entire disease course is more subacute than other causes of septic arthritis. - Afebrile presentation is classic for Kingella - K. kingae is difficult to isolate on typical culture media (negative synovial fluid culture), but PCR assays can improve the diagnostic yield. - Tx: Beta-lactam antibiotics; Penicillin, Amp-sulbactam or cephalosporin

Answer 3

Reactive arthritis - Inflammatory arthritis associated with prior infection at a site other than the affected joint, most commonly associated with GI or GU. - 1-4 weeks after GI/GU/URI infection - Pt: Triad of urethritis, conjunctivitis, arthritis (can’t pee, can’t see, can’t climb a tree) - Synovial fluid is typically sterile (No microorganisms are present) with signs of inflammation including elevated leukocyte counts. - Due to fever and the severity of the systemic symptoms, reactive arthritis can present like septic arthritis, requiring you to aspirate joint fluid. - Tx: NSAIDs

Answer 4

Sore throat + eye infection (pharyngoconjunctival fever) = Adenovirus

Answer 5

Sore throat + eye infection (pharyngoconjunctival fever) = Adenovirus

Answer 6

Human Metapneumovirus - Enveloped, SINGLE-stranded, NEGATIVE-sense RNA virus - In a pt presenting with bronchiolitis and acute otitis media, human metapneumovirus is the likely etiology. - Tx: Supportive.

Answer 7

Influenza Virus - Begins with sudden onset of nonspecific systemic symptoms including fever, malaise, and myalgias. - Most common complication of influenza is otitis media - Oseltamivir (Tamiflu) is approved for treatment of influenza A and B viruses in individuals >2 weeks of age and prophylaxis of influenza A and B viruses in individuals >1 yo. - Zanamivir (Relenza) is approved for the prophylaxis of influenza in individuals >5 years and the treatment of influenza in individuals >7 years. It is a dry powder administered by oral inhalation. It is not recommended for pts with a hx of wheezing or underlying chronic respiratory disease. - This mechanism has been linked to bronchospasm in patients with asthma as well as in individuals without airway disease. - Antiviral tx is recommended as early as possible, even > 48 hours duration of illness, for patients who are: - 1) Hospitalized with presumed influenza - 2) Confirmed or suspected influenza who have severe, complicated, or progressive illness - 3) Influenza infection of any severity in children at high risk for complications - 4) Any otherwise healthy child with influenza infection for whom a decrease in duration of clinical symptoms is felt to be warranted by his or her provider - High Risk patients who are at increased risk of complications and need treatment: - Children <5 years of age - especially those <2yo. - Children with chronic disease: pulmonary diseases (asthma, chronic lung disease), cardiovascular (except HTN alone), chronic renal disease, hepatic, hematological (including sickle cell disease), immunosuppressive disorders, HIV, metabolic disorders (including diabetes mellitus), conditions requiring long-term aspirin use, or neurologic/neurodevelopment conditions (cerebral palsy, epilepsy, stroke, intellectual disability, moderate-severe developmental delay, muscular dystrophy, spinal cord injury) - People <19yo who are receiving long-term aspirin or salicylate-containing medications (rheumatoid arthritis, Kawasaki disease) due to risk of Reye syndrome - Adults >65yo - People with immunosuppression (by medications or by HIV infection) - Women who are pregnant or postpartum within 2 weeks - American Indians/Alaska Natives - People who are extremely obese (BMI >40) - Residents of nursing homes and other chronic care facilities

Answer 8

Staph aureus - Can cause several toxin-mediated syndromes (toxic shock syndrome, staph scalded skin syndrome, staph food poisoning) - Staph aureus is the most common cause of food poisoning in the US. Typical incubation period is 2-4 hours; this short incubation period distinguishes from other organisms - MRSA: Vancomycin is DOC - Newer agents (off label): Linezolid, daptomycin, ceftaroline, tigecycline

Answer 9

Coagulase negative staph (CONS): S epidermis, S saprophyticus - S epidermidis: Usually methicillin resistant. - It is the most common cause of both catheter-related bacteremia and post-op bacteremia occurring when any foreign material is left in the body (eg prosthetics, including heart valves, joint, VP shunts) - Common “contaminant” of blood. If isolated in a child without underlying prosthetic device is usually a contaminant - Tx: Vancomycin +/- gentamicin (serious infections) +/- rifampin - S saprophytic: - UTIs in adolescent females - Tx: TMP/SMX, nitrofurantoin, cephalothin

Answer 10

Viridans streptococci are the most common cause of endocarditis in children

Answer 11

Strep pyogenes (group A strep) Strep pharyngitis - Do not test or give treatment if <3 yo - Tx: - IM Penicillin G benzathine (bicillin) once 600,000 U for <27kg or 1.2 million U for >27kg - PO amoxicillin 50mg/kg daily for 10 days - If penicillin allergic, use cephalexin, cefadroxile, or cephalosporin for 10 days - If allergic to PCN and cephalosporins, use macrolide (erythromycin, azithromycin) over clindamycin - To eradicate carrier state: clindamycin - Complications: - Rheumatic fever: Can be prevented if abx given within 9 days after onset of symptoms. Occurs only after pharyngitis - Poststrep glomerulonephritis: Occurs regardless of therapy and regardless of source (pharynx (10 days) or skin (21 days)) - Paradise criteria for tonsillectomy: - >7 in the preceding year, or - >5 in each of the preceding 2 years, or - >3 in each of the preceding 3 years

Answer 12

Enterococcus (E faecalis, E faecium) - Gram positive in short-medium chains - 3 main types of infections: UTI, abdominal infection, bacteremia/sepsis - Tx: - Ampicillin/vancomycin + gentamicin - For VRE: Linezolid or daptomycin - Resistant to cephalosporin

Answer 13

Listeria - Direct contact with milk products (goat cheese), deli meats, hot dogs, tofu, vegetables - Granulomatosis infantisepticum: Amnionitis, pneumonia, septicemia, erythematous rash with papules - Be aware of a neonate for whom the lab has identified an organism from blood or CSF as diphtheroids. Remember: Listeria is a gram+ rod and can mimic the appearance of diphtheroids. - Tx: - Mild-moderate: ampicillin - Serious/resistance: PCN/ampicillin + aminoglycoside - Listeria meningitis: High-dose PCN/ampicillin + aminoglycoside

Answer 14

Corynebacterium diphtheriae - Respiratory distress, cutaneous disease, or asymptomatic carriage - Tonsillar diphtheria: - Incubation of 1-10 days, then - Sore throat, hoarseness, LOW fever (rarely >39.4) - After 2-3 days, grey-white pharyngeal pseudomembrane - In severe disease, cervical lymphadenopathy lead to marked edema of neck, creating “bull neck” - Toxin-medicated effects: Myocarditis (strong predictor for mortality), QTc prolongation, ST-T wave changes, 1st degree heart block - Concomitant tonsillitis and ECG changes (vs strep pyogenes with onset of rheumatic fever a few weeks after tonsillitis) - Tx: - Specific equine antitoxin. - Also give close contacts erythromycin to render noncontagious and to stop production of toxin. - Give close contacts prophylaxis with oral erythromycin or IM PCN

Answer 15

Bacillus Anthracis - Large encapsulate spore-forming gram+ rod - 3 types: Cutaneous, GI, Inhalation (Woolsorter’s disease) - Cutaneous: PainLESS pruritic papule, then over 7 days evolving into a painLESS black eschar with nonpitting, painless induration and swelling - Tx: - Cutaneous: Amoxicillin or ciprofloxacin or doxycycline for 7-10 days - Inhalation and GI: 2-drug (eg ciprofloxacin + clindamycin) - CNS: 3-drug (ciprofloxacin, meropenem, linezolid)

Answer 16

Clostridium: Infant botulism - Spores are typically found in honey, corn syrup, or more commonly presumed inhalation of spores from environmental dust/soil, particularly in rural or farm areas where soil is disturbed. Outbreaks have appeared with carrot juice and cheese sauce. Highest rates are in Alaska and are due to ingestion of fermented fish. - Pt: - Starts with prodrome of constipation, then weakness and hypotonia - Lack of pupillary reflex (in contrast to SMA in which pupils are unaffected and tongue has fasciculations). Oculobulbar weakness resulting in ptosis. Absent gag reflex - Poor feeding, weak cry, difficulty swallowing, facial droop, and diminished cough, gag, swallow - Later poor head control, diminished DTR - Descending paralysis - Respiratory failure (can occur without respiratory distress) - Dx: Gold standard is to detect stool botulinum spores or toxins in the feces - Tx: Give antitoxin:Equine serum botulism antitoxin for pts >1yo, and human botulism immunoglobulin for pts <1yo.

Answer 17

Clostridium perfringes: - Food poisoning - Gas gangrene can be caused by it - Acute tx: High dose PCN G

Answer 18

Clostridium tetani: - Usually by 24h into the illness, there is marked trismus - Tx: Metronidazole for 10-14 days preferred. PCN G acceptable

Answer 19

Nocardia - Only weakly acid fast - Gram positive - Beaded, branching, filamentous - Usually starts as a lung infection in immunocompromised children - occasionally causing a thin-walled cavity lesion - Can cause brain abscesses and chronic neutrophilic meningitis - Tx: - High-dose sulfonamides or TMP/SMX. - In severely ill patients, add combinations of drugs, including amikacin + ceftriaxone or amikacin + imipenem. - 6-12 weeks for immunocompetent - 6-12 mo for immunocompromised

Answer 20

Actinomyces - Gram positive, filamentous, branching, anaerobic organisms - Most common presentation: Cervicofacial involvement caused by a dental infection or trauma - In infections of normally sterile sites, the presence of characteristically yellow “sulfur” granules that are actually clusters of organisms and inflammatory debris is typical - Tx: PCN is 1st choice

Answer 21

Neisseria Meningitidis - Tx: 3rd generation cephalosporin ceftriaxone - Recurrent meningococcal infections should prompt evaluation for complement deficiencies. Screen with total hemolytic complement activity assay - Ppx: With Rifampin for 2 days, ceftriaxone x1 (DOC in exposed pregnant woman), ciprofloxacin 500mg once in adults - Ideally within 24 hours for: - Direct exposure to patient’s oral secretions: Kissing, sharing toothbrushes or eating utensils, mouth-to-mouth resuscitation, intubation, or suctioning <24h after initiation of antimicrobial therapy - Child care/preschool contacts within previous 7 days - Slept in same dwelling within previous 7 days - Household members - Passengers directly next to index case (within 3 feet) during flights >8h within 1 week of symptom onset or <24h after start of antibiotics

Answer 22

Bordetella pertussis - 3 stages of infection: - 1) Catarral (1-2 weeks): Rhinorrhea, cough, +/- fever - 2) Paroxysmal (2-6 weeks): Cough with paroxysms, inspiratory wheeze/whoop - 3) Convalescent: Resolve gradually. Typically 6-10 weeks - Complications: seizures, encephalopathy - Labs: Lymphocyte-predominant leukocytosis - Dx: Nasal PCR testing in most appropriate in earliest stages. Nasophyarngeal culture is gold standard - Tx: - <1mo: Azithromycin (less likely to cause pyloric stenosis) - >1mo: Any macrolide- azithromycin or clarithromycin or erythromycin. If allergic, TMP/SMX - Chemoprophylaxis (same meds) for household contacts - Return to daycare when 5 day treatment is completed OR if not treated, 21 days after onset of symptoms

Answer 23

Pseudomonas Aeruginosa - Consider in osteochondritis/osteomyelitis of the foot following a nail-puncture wound (esp if through a tennis shoe), endocarditis in IV drug abusers, bacteremia in burn pts, chronic suppurative otitis media, and otitis externa - In immunocompromised hosts, might see cutaneous ecthyma gangrenosum (round, indurated, painless pustular/bullous/nodular black lesion with central ulceration with gray-black eschar surrounded by erythematous halo) - Tx: Pip-tazo, ceftazidime, cefepime, aminoglycosides, fluoroquinolones (only oral option), imipenem, meropenem

Answer 24

Salmonella | - Gram negative bacilli

Answer 25

Nontyphoidal Salmonella - Risk factor is milk bottles prepared in the same sink that family uses to wash raw chicken - Food borne (chicken, milk, eggs, produce, peanut butter). Main reservoirs are animals (birds, mammals, reptiles, amphibians) - Pt: Enteritis - Treatment generally not recommended. Antibiotics can prolong salmonella infection (HIV/AIDS, agammaglobulinemia, malignancy, Crohn’s) - However, give antibiotics for salmonella diarrhea in <3mo and older children with immunocompromising conditions - Treat invasive infections with 3rd generation cephalosporin until susceptibilities are known. TMP/SMX, ciprofloxacin - A child or staff member with nontyphoidal Salmonella enteritis should be excluded from a child care center only if symptomatic.

Answer 26

``` Salmonella Typhi (Typhoid fever) - Humans are carriers/source. Tend to seed in gallstones. ``` - Pt: Fever rising slowly (accompanied by relative bradycardia is classic!), constitutional symptoms, and abdominal pain. - Classic “rose spots” form on the trunk a week after the fever starts - Typhoid fever must be considered in the differential in any traveler returning from a resource-limited country - Labs: Commonly leukopenia - Dx: Blood, bone marrow, or bile culture. Stool often negative - Tx: Ceftriaxone is 1st line. Ampicillin, Bactrim, quinolones - Typhoid vaccine should be offered to patients traveling to endemic regions

Answer 27

Shigella - Gram negative bacilli - Highest incidence occurs in child care centers, among people living in crowded conditions or institutions, and among people living on Native American reservations. - Person-to-person transmission plays a key role (unlike Salmonella). Shigella can infect with 10-100 organisms (compared to thousands-millions for Salmonella) - Pt: - Diarrhea is typically water and voluminous and can progress to dysentery within hours or days - frequent small stools with mucus or blood accompanied by lower abdominal cramps and tenesmus. - Shigella can also cause vulvovaginitis with bloody or serosanguineous vaginal discharge. GI symptoms + vaginal symptoms = Shigella - Seizures occur with increased frequency in Shigella infection in young children; seizures are the most common neurologic symptom. - Classic scenario is an infant presenting with high fever and new-onset seizure who, while performing the LP, has a large bloody stool! - Complications: Rectal prolapse (5-8%), - Generous leukocytosis and associated bandemia is common with this infection. - Tx: - Most clinical infections are self-limited (48-72 hours) and do not require tx. - While mild cases do not require antimicrobial therapy, tx is recommended for severe disease (ie hypovolemic shock from increased losses) or immunocompromised individuals. - Empiric abx tx options for severe dx in children include azithromycin or ceftriaxone (or ciprofloxacin in adults >18yo) for 5 days.

Answer 28

Haemophilus influenzae - For meningitis: Prior to or concurrent with initiation of antibiotics, use dexamethasone 0.5mg/kg/day divided q6h for 2-4 days to decease the incidence of hearing loss and neurologic sequelae. - For pneumonia: Amoxicillin is DOC Chemoprophylaxis is important for those exposed to invasive strains of H influenzae. - Ppx: With rifampin daily for 4 days - All household members if household has - At least 1 contact <4yo incompletely immunized OR - Immunocompromised regardless of immunization - Preschool and child care center contacts when have had >2 pts with invasive Hib disease within 60 days - For index pt tx with regimen other than cefotaxime or ceftriaxone - <2yo OR - Lives in household with child <3yo who is under immunized or immunocompromised

Answer 29

Yersinia - Reservoir is wild rodents. Transmitted by fleas or direct contact - Infected from ingestion of contaminated food or water, especially undercooked or raw pork, and contact with animals. - Has been associated with preparation of chitterlings (chitins), - Pt: Febrile illness with lymphadenopathy (usually inguinal) - 1) Fever and diarrhea (often bloody in children). 20% report pharyngitis. - Pharyngitis may be an important diagnostic clue for the diarrhea’s etiology as this is not associated with other acute bacterial diarrheas - Duration of diarrhea is typically longer than the usual acute gastroenteritis, sometimes persisting up to 3 weeks. - 2) Older children and adults may develop pseudoappendicitis: RLQ pain, and elevated WBC, without evidence of appendicitis on imaging - Postinfectious complications: Reactive arthritis and erythema nodosum - Dx: Culture or serology - Tx: - No evidence that abx are of any benefit. Supportive care: Encourage oral fluids - Treatment is only indicated for pts with septicemia or those who are immunocompromised. - A fluoroquinolone, doxycycline (if >8years), and TMP-SMX would be oral drugs of choice. IV therapy would include 3rd gen cephalosporin (ceftriaxone or a fluoroquinolone) plus gentamicin. - Gentamicin or streptomycin

Answer 30

Legionella pneumophila - Found in water - Pt: Multisystem disease is the clue (diarrhea, CNS, renal, pneumonia). Similar to and often confused with Mycoplasma pneumoniae. - Triad of pneumonia, diarrhea, CNS symptoms (headache, delirium, and confusion) - CXR looks worse than exam indicates - Dx: Urine immunoassay to detect Legionella antigen - Tx: Azithromycin or quinolones

Answer 31

Klebsiella | - DOC: Meropenem. Most are resistant to ampicillin

Answer 32

Brucella - Pt: Undulant fever, weight loss, night sweats - Check for brucella in a fever of unknown workup. It should be considered in any child with prolonged fever without an obvious source, esp if there is a hx of contact with farm animals or travel to an endemic region. - Tx: - >8yo: Doxycycline for 6 weeks + aminoglycoside for 2 weeks OR doxycycline + rifampin for 6 weeks

Answer 33

``` Francisella Tularensis (Tularemia, rabbit fever) - Classic scenario is someone who handles rabbits ``` - Pt: Ulceroglandular form (myalgia, arthralgia, irregular ulcer with surrounding erythema) - Dx: Clinical. Confirm with serologic testing. - Differential includes plague, which occurs mostly in desert Southwest - Tx: Gentamicin or streptomycin for 10 days. Alternative is doxycycline.

Answer 34

Bartonella Henselae - Can cause cat scratch disease - Transmission is from flea to cat to human - Pt: >3 weeks of chronic tender regional lymphadenopathy/lymphadenitis, often in absence of systemic sx - Enlarged erythematous node (site of inoculation) - Less common: Parinaud oculoglandular syndrome (conjunctivitis with preauricular adenopathy) - Hepatosplenic CSD: Hepatomegaly, splenomegaly, micro abscesses in liver/spleen - Dx: - Clinical - PCR and serology (antibodies) to confirm - Rarely, FNA/tissue biopsy of lymph nodes to show necrotizing granulomas and see bacilli on Warthin Starry silver stain - Tx: Self-limited - Some recommend 5 days of oral azithromycin to speed up recovery

Answer 35

Pasteurella - Best known for causing infection in cat or dog bites - Pt: rapidly progressing cellulitis within 24 hours of bite, often with fever and regional lymphadenopathy - Tx: Amoxicillin/Clavulanate - Give for all cat bites and only dogs bites that are infected, involve critical area (eg face), or are deep wounds

Answer 36

Helicobacter Pylori - Pt: Dyspepsia - epigastric pain worse with eating - Alarm features: Anorexia, weight loss, recurrent vomiting, reported GI bleeding. - Dx: - Without alarm symptoms: Urea breath test or H pylori stool antigen in patients - With alarm symptoms: Upper endoscopy with biopsies - Serologic tests cannot distinguish past from current infection

Answer 37

Citrobacter - Pts with meningitis with Citrobacter growing in a blood or CSF culture immediately get a CT or MRI of the head to look for brain abscess. - Tx with 3rd generation cephalosporin or aminoglycosides

Answer 38

Rickettsiae - Causes RMSF and Q fever (Coxiella burnetii) - Cattle or Cats or Conception = Coxiella Q fever - Pt: Triad of fever, rash (distal extremities to trunk, palms, soles), and headache - Labs: Thrombocytopenia, hyponatremia, elevates in LFTs - Dx: serology or biopsy tissue staining - Tx: Doxycycline for 3 days after fever resolves, 5-10 days total

Answer 39

Ehrlichia and Anaplasma (Rocky Mountain spotless fever) - Pt: “Viral” picture of fever, headache, leukopenia - Consider with presentation of pancytopenia and tick bites - Dx: Serologic testing or culture - Tx: Doxycycline

Answer 40

Chlamydia trachomatis: GU infection, trachoma (external eye infection), neonatal pneumonia, lymphogranuloma venereum Chlamydophila pneumonia: CAP Chlamydophila psittaci - With any pneumonia associated with poultry or pigeons, esp with splenomegaly, strongly suspect C psittaci - Differential: Histoplasma also causes pneumonia and splenomegaly; it is found in bird and bat droppings

Answer 41

Anaerobes - Anaerobic infection is main concern with oral, pulmonary, or intraabdominal abscesses - Fusobacterium necrophorum is an anaerobe that causes septic thrombophlebitis of the jugular vein (Lemierre syndrome) and is more common in adolescents and young adults. - Tx: Combination of metronidazole and ceftriaxone - Tx of dental infections usually includes penicillin

Answer 42

Mycobacteria | - Acid-fast (red on a green background)

Answer 43

Nontuberculous mycobacteria - 70% of cases are caused by MAC - Pt: Most common manifestation is lymphadenitis followed by skin and soft tissue infections - Most commonly involves the submandibular lymph nodes - Dx: FNA, or I&D of the lymph node, will identify acid-fast bacilli; and, histology reveals granulomas. However, incision biopsy increases the risk of reoccurrence, formation of a fistula, and scarring, if caused by mycobacterial. - Tx: - Will not respond to 1st line antibiotics used to treat bacterial lymphadenitis, as these typically target Staph and Strep - Complete excision of involved nodes (do NOT incise the nodes). Excision of the node has been found superior to antibiotic therapy bc it has the smallest recurrence risk.

Answer 44

Mycobacterium tuberculosis - Screening - 2 methods: - Tuberculin skin test (TST) preferred for <5yo - Inteferon gamma release assays for children >5yo who have received BCG or >5yo who are unlikely to return - Positive tests - 5mm - HIV+ - Abnormal CXR with evidence consistent with TB or fibrotic changes consistent with prior TB - Close contacts with active TB - Severely immunocompromised/organ transplants - 10mm = All the rest - Homeless persons - Those with recent travel or birth in a high-prevalence region of the world - IV drug abusers who are HIV negative - Prisoners - Health care workers - Nursing home patients and staff - Diabetics and chronic renal failure patients - No risk factors and >4yo = 15mm - False negative skin tests: - 1) Too recent an exposure: It takes up to 10 weeks for TST to turn positive after exposure; if a recently exposed pt has a negative skin test, recheck 10-12 weeks after exposure. - Children <4yo who have been exposed to TB are at high risk for disseminated disease, so evaluate with a CXR and start therapy while to repeat TST. - 2) Severe disseminated (or military) TB - 3) Anergy - Positive skin test indicates that the pt has, or has had, LTBI but not necessarily active TB disease. If pt has had no previous TB workup and is asymptomatic, evaluate with an CXR - Tx: LTBI: Isoniazid for 9 months. - If INH-resistant: Rifampin for 4 months - Alternate: INH + rifapentin once weekly x12 weeks - Tx for tuberculosis: RIPE or RIP if low-chance of drug-resistant TB infection - In US, RIPE for 2 months (unless criteria for RIP are met) followed by RI for 4 months - Rifampin: orange discoloration of secretions and urine - INH: Hepatotoxicity - PZA: Nausea, vomiting, abd pain - Ethambutol: Can cause decrease in visual acuity or decreased color perception. Not hepatotoxic. - Vitamin B6 is also given to some to prevent peripheral neuropathy and mild CNS effects - Corticosteroid use if indicated in TB meningitis to reduce morbidity and mortality - Rifampin, INH, PZA are all potentially hepatotoxic. Stop the medication when ALT/AST >3x the upper limit of normal with symptoms or ALT/AST > 5x ULN without hepatitis symptoms

Answer 45

Leptospirosis - Spirochetal disease transferred by contact with animals, water, or soil. Clue: Look for contact with dog or rat urine - Most widespread zoonosis in the world - Pt: - Wide range of symptoms, from myalgia, fever, and headache to Weil disease (severe hepatitis with renal failure and hemorrhagic complications) - Conjunctival suffusion without purulent discharge and mayflies of the calf/lumbar regions. - Dx: Blood cultures are usually positive in the initial septicemia phase (days 4-7), and urine cultures are positive thereafter, but isolation of Leptospira organisms can take months! - Tx: - IV PCN G, cefotaxime/ceftriaxone, or doxycycline for severe infections - Tx milder cases with oral doxycycline (or azithromycin)

Answer 46

Lyme disease - Ticks/nymphs must be attached for at least 36 hours. Ticks are more likely to transmit after 2 or more days of feeding. If a person reports having had a tick for a few hours the previous day, provide reassurance that no tx is necessary. - Early clinical diagnosis is crucial bc treatment with appropriate PO antibiotics results in cure rates >90% and prevents late disease and sequelae. - 1) Early localized disease: Erythema chronic migrans at site of tick bite is the pathognomonic skin lesion - Dx is clinical. Do not need to check Lyme serology. Just treat! - Tx early localized dx and isolated Bell’s palsy: Oral doxycycline, amoxicillin (for <8yo), or cefuroxime for 14 days - 2) Early disseminated disease: Multiple erythema migrans, neurologic problems (aseptic meningitis, CN palsies), carditis (heart block; myocarditis can cause a rapidly alternating 1st, 2nd, or 3rd degree AV block) - 2 tiered: ELISA or immunofluorescence followed by 1st tier western blot - AV heart block of carditis OR meningitis: Oral doxycycline or IV ceftriaxone for 14 days or IV PCN G for 21-28 days - 3) Late disease: Arthritis (monoarticular or migratory) - Negative grain stain - 2 tiered - Oral agent for 28 days - Ppx: Single PO Doxycycline is used as chemoprophylaxis for those >8yo within 72 hours of a tick bite (if attached >36 hours) in an area hyperendemic for Lyme disease (at least 20% of ticks are infected with B burgdorferi). Ticks should be removed by using forceps or tweezers to pull steadily upwards from their point of attachment as close to the skin as possible. - The risk of contracting Lyme disease is low if a tick is attached for <24-36 hours; ticks should therefore be removed promptly.

Answer 47

FUNGI Cryptococcus neoformans - Dissemination more likely in T-cell deficient pts - Pt: - Immunocompetent: minimally symptomatic - Symptoms if present include low-grade fever, cough, and a pulmonary infiltrate, all of which resolve spontaneously - Cryptococcal pneumonia can form cavity lesions and peripheral “cannon ball” skin lesions. - Meningitis - Dx: CSF antigen test or CSF india ink test. Definitive dx by culturing. - Tx: - Can treat less severely ill pts with fluconazole - Meningitis: Amphotericin B and 5-FC flucytosine

Answer 48

Coccidiomycosis “Valley fever” - Systemic fungal infections endemic to southwestern US - soil fungus is native fo San Joaquin Valley (California) - Pt: Mostly Asymptomatic or self limited. Once inhaled, causes self-limited flu-like illness or illness like pneumonia. - Cutaneous abnormalities with erythema multiforme or erythema nodosum - Dx: Serology to detect IgM or IgG (EIA, serum complement fixation ab testing). Gold standard is isolation of organism via tissue culture. - Tx: - Self-limited form does not require tx - Mild-moderate disease: Oral fluconazole and itraconazole - For disseminated infections without CNS involvement: PO fluconazole or itraconazole. If do not respond, amphotericin - For CNS infections, meningitis: Fluconazole is DOC. If does not respond, consider intrathecal amphotericin B. - For severe or life threatening infections: Amphotericin B

Answer 49

Histoplasmosis - Common in endemic areas - especially seen in Mississippi and Ohio River valleys. Think of histoplasMOsis (Mississippi, Ohio) - Pt: Most are asymptomatic. Can have pneumonia and splenomegaly (similar to those seen in C psittaci infection). - CXR shows hilar adenopathy - Past infection can cause an incidental calcified granuloma (visible on CXR) - Dx: Detect antigen in urine, serum, or CSF - Tx: - No tx is indicated for acute pulmonary disease without complications - Tx chronic or severe acute disease: Use itraconazole for persistent disease >4mo or if hypoxemia occurs in the acute setting - Disseminating disease requires amphotericin B

Answer 50

Blastomycosis - Pt: - Can have purulent sputum (blastomycosis is more pyogenic than other fungal infections) - In children, dissemination is typically to bone and skin, causing crusted lesions - Sputum shows large, single, broad-based budding yeasts - Tx: - Indolent: Observe or prescribe PO intraconazole - Severe: Prescribe amphotericin B

Answer 51

Aspergillosis - Primarily occurs in pts with underlying lung diseases or immunocompromised pts - Hallmark of invasive aspergillosis is angioinvasion, with resulting thrombosis and dissemination to other organs. - Dx: Branched and septate hyphae on KOH stain is suggestive - Tx: - Voriconazole is DOC for invasive disease - Amphotericin B in neonates. - Fluconazole has no activity against Aspergillus

Answer 52

Allergic bronchopulmonary aspergillosis - Suspect in pts with asthma who have difficult-to-control or worsening asthma symptoms, are coughing up brownish mucous plugs, have recurrent infiltrates, and have peripheral eosinophilia. - Allergy causes type I (immediate; IgE-mediated) and type 3 (>4 hours out) reactions but NOT type 4 (delayed) reactions - Labs: - Elevated total blood eosinophil count (>500 cells/uL) and an elevated total serum IgE (>1,000 IU/mL) (not specific) - If there is only lung eosinophilia (no peripheral eosinophils), consider instead a chronic eosinophilic pneumonia. - ABPA panel with Aspergillus-specific IgE and IgG titers: IgG antibodies (precipitins) to Aspergillus and also specific IgE and IgG antibodies to Aspergillus on immunoassay may help pinpoint the actual etiology. - CXR and CT can show central mucus impaction and central bronchiectasis causing a “fingers in glove” appearing central infiltrate. - Dx: No single test or criteria - Most agree that pts must have asthma or cystic fibrosis, a positive skin test to Aspergillus or elevated IgE against A fumigates, and an elevated serum IgE (>1000 IU/ml) - At least 2 additional criteria should be met: - Serum antibodies to A fumigates or an elevated serum Aspergillus IgG immunoassay - Radiographic pulmonary opacities consistent with ABPA - Total eosinophil >500 in glucocorticoid-naive pt - Tx: Control inflammation with long-term systemic glucocorticoids. Itraconazole antifungal may be used.

Answer 53

Malassezia - Catheter-related infection that occurs in NICU babies who are receiving IV lipids and TPN - Clue: if the lab tells you the organism required an olive oil overlay to grow, it is M furor - Tx: Remove the catheter, stopping the lipid infusion, starting amphotericin B

Answer 54

Sporotrichosis - Gardeners tend to get it after being pricked by a rose thorn - Pt: Cutaneous, Lymphangitic, Pulmonary, Disseminated - Tx: - Cutaneous and lymphangitis: Itraconazole - Pulmonary and disseminated: Amphotericin B followed by itraconazole

Answer 55

Mucormycosis - In immunocompromised pts, pulmonary mucormycosis causes pulmonary infarcts - In diabetics, sinusitis is more common - Rhinocerebral mucormycosis starts as a black necrotic spot in the nose or paranasal sinuses and extends intracranially - Know: Both Aspergillus and Mucor can cause a necrotizing, cavitating pneumonia - Tx: - Amphotericin B and surgical debridement

Answer 56

Pneumocystic jiroveci - HIV-infected pts with low CD4 counts are at higher risk of P jiroveci pneumonia - Most significant RF for PCP in pts without HIV are steroid use and defects in cell-mediated immunity - Pt: - In pts without HIV infection, PCP can present either subacutely or as fulminant respiratory failure with fever, dry cough, tachypnea, and hypoxia - Immunocompromised: Insidious onset of fever, SOB, dry cough - CXR shows diffuse bilateral interstitial (ground glass) infiltrates but can appear normal - Labs: LDH is elevated - Dx: Demonstration of organisms - PCR assay of lower respiratory tract specimen - Methanamine silver stain to identify cysts - Mild PCP: PO TMP/SMX or atovaquone - For moderate-severe PCP: IV TMP/SMX for 21 days and add corticosteroids - IV pentamidine if the pt cannot tolerate TMP/SMX or if they have not responded after 5-7 days - Ppx indications - Beginning at 6 weeks only for infants with positive DNA PCR or RNA PCR. - No longer recommended if DNA PCR or RNA PCR at birth and >4-8 weeks are negative - HIV infected 1-5yo if CD4 <500 or CD4 <15% - HIV infected >6yo if CD4 <200 or CD4 <15% - Hx of prior PCP infection - Ppx with TMP/SMX 3x/week, monthly aerosolized pentamidine, daily oral dapsone, and IV pentamidine every 4 weeks - Primary immune deficiencies associated with impaired immunity - Acquired immune deficiencies - HIV infection with severe immunosuppression

Answer 57

PARASITES: PROTOZOA (do not cause eosinophils)

Answer 58

PARASITES: PROTOZOA (do not cause eosinophils) Toxoplasma Gondii - Cats are the definitive host bc all of the oocysts in cat feces - Dx: Diagnose active infection by finding an elevated IgM antibody - 1) Toxoplasmosis in immunocompetent host - Asymptomatic but can cause mono-like illness with nontender lymphadenopathy, night sweats, and atypical lymphs - Think of it in a pt with mononucleosis symptoms and a negative heterophiles antibody test results - Tx: - Self-limited. No treatment but if becomes immunocompromised will need prophylaxis - For healthy children who have developed chorioretinitis, severe symptoms, or have reactivated latent infection: Tx with combination of pyrimethamine, sulfadiazine, and folinic acid - 2) Toxoplasmosis during pregnancy - 3) Toxoplasmosis in the immunocompromised patient - Tends to cause CNS infection and multiple mass lesions - Tx: Pyrimethamine, sulfadiazine, leucovorin - 4) Ocular toxoplasmosis - Retinal lesions (white focal retinitis with overlying vitreous inflammation that has appearance of a “headlight in fog”) - Tx: Pyrimethamine plus sulfadiazine with leucovorin

Answer 59

Malaria - 5 species: Plasmodium falciparum, vivax, ovale, malariae, knowleski - Pt: - Uncomplicated malaria: Nonspecific febrile illness, jaundice, splenomegaly - Complicated/severe malaria (often caused by P falciparum): Cerebral malaria, renal failure, metabolic acidosis, hepatic failure, severe jaundice - Dx: Thick and thin smears of peripheral blood, usually with Giemsa stain. Finding a banana gametocyte on peripheral blood smear is diagnostic for P falciparum (contrasts from other forms of malaria in which the parasitized RBCs are often hard to find) - Tx: - Nonfalciparum P vivax, ovale, malaire: Chloroquine - Primaquine is adjunctive medication. Primaquine induces hemolytic anemia in G6PD-deficient persons, so much screen for G6PD deficiency - P falciparum Chloroquine-sensitive: Chloroquine - P falciparum Chloroquine-resistant: Atovoquone/proguanil - Ppx: - Encourage wearing protective clothing and use of DEET and picaridin-containing insect repellents for >2mo - Before arrival and after leaving: Chloroquine, mefloquine, atovaquone/proguanil, doxycycline

Answer 60

Babesia - Organism is transmitted via the Ixodes tick from rodents (as spirochete Borrelia burgdorferi) - Pt: Mild infections are generally self-limited. Hemoglobulinuria is a predominant sign. - B micro has an early trophozoite ring form similar to P falciparum. Unlike P falciparum, trophozoites of B microti produce daughter merozoites with a tetrad “Maltese cross” form - Tx: - Moderate infections: Atovoquone + azithromycin for 1-2 weeks - Severe cases: Cindamycin + quinine

Answer 61

Ameba - Dx: - For intestinal disease, examine stool for ova and parasites - Aspirate of an amebic liver abscess often shows no ameba or PMNs - diagnose with serology - Tx: - For asymptomatic infection, a luminal agent is fine: Diloxanide furoate (available only from the CDC), paromomycin, or iodoquinol - For liver abscesses or invasive colitis: Metronidazole is TOC

Answer 62

Trypanosoma - African disease is sleeping sickness - American illness, chagas disease - Acute phase: Asymptomatic or mild with nonspecific symptoms - Chronic form: Problems with heart (ranging from heart block to heart failure), GI system (esp achalasia, megaesophagus, megacolon), and occasionally CNS - Be suspicious of trypanosomiasis in a child from Mexico or from Central or South America who presents with unilateral firm edema of the eyelids (Romana sign) followed by fever, generalized lymphadenopathy, and malaise (acute phase) - Tx: Benznidazole and nifurtimox are the only drugs with proven efficacy.

Answer 63

Leishmania - 3 major clinical syndromes - 1) Cutaneous: An erythematous papule at the site of the sand fly bite slowly enlarges and becomes ulcerative. After weeks-years, the lesions scar. - 2) Mucosal - 3) Visceral - Tx: Liposomal amphotericin B

Answer 64

Ascariasis lumbricoides (Roundworm) (A scarred lumberjack with round face eats soil, leads to GI problems or Loffler problems. He needs to take ivory medicine and his name is Abe.) - Largest intestinal roundworm that infects humans - Direct ingestion of soil or soil-contaminated product - Pt: Many are silent. GI manifestations: Abdominal pain - A key to look for is migratory infiltrates or atelectasis occurring with Loffler syndrome (which usually also has a high eosinophil count) - Dx: Finding eggs or worms in the stool - Tx: Antiparasitic drugs including albendazole or ivermectin are DOCs

Answer 65

Enterobius vermicularis (Pinworms) (Abe the pirate pins pruritus perianally while drinking Scotch) - Fecal-oral route from contact with toys, bedding, clothing, toilet seats - Pt: Nocturnal perianal pruritus (pruritus ani) - Dx: Clinical. Visualize worms in the perianal region. Cellophane (Scotch) tape test performed early upon awakening. - Tx: - Pyrantel pamoate or albendazole or mebendazole - Simultaneous tx of entire household

Answer 66

Necator americanus (hookworm) (Abe the pirate eats an American nectar caught on a hook with a serpentine and a __ making him anemic.) - Pt: Microcytic anemia. Also can cause cutaneous larva migrans with erythematous raised serpentine lesion - Lab: Eosinophilia, anemia - Dx: eggs in stool - Tx: Albendazole or pyrantel pamoate. Alternate is mebendazole

Answer 67

Trichuris trichiura (whipworm) (I have a trick to whip, causing bloody stools/rectal prolapse and make me bend) - Pt: - Asymptomatic - Heavy infestations can cause diarrhea, blood-streaked stools, and rectal prolapse - Dx: Eggs in stool - Tx: Mebendazole is the TOC, with albendazole as alternate therapy

Answer 68

Trichinella spiralis (Trichinosis) - Larvae, usually found in pig - Tx: Albendazole

Answer 69

``` Wuchereia bancrofti (Filariasis) - Tx: Diethylcarbazine citrate ```

Answer 70

Strongyloides stercoralis (Strong person is strong with serpinous rash while take Ivory medicine) - The ONLY helminthic organism that replicates in the body. (Is a “strong” infection) - Pt: Often have larva current, a serpiginous itchy rash with erythematous tracks - Eosinophilia common present - Dx: Serial stool samples for larvae (NOT eggs) - Tx: Ivermectin is DOC

Answer 71

Toxocara (Taxi car with dogs with eye dx, lung dx, or pica and Abe) - Dogs and cats are the primary hosts for toxocara - The infection is acquired when children unintentionally ingest eggs that were excreted in the soil by infected puppies - Pt: - Visceral larva migrans - Ocular toxocariasis / Ocular larva migrant - Suspected in a child who presents with unilateral vision loss and retinal lesions with hx of contact with dogs - Look for this in a child with fever, hepatosplenomegaly, “migratory pneumonia” on XR, wheezing, hypergammaglobulinemia, eosinophilia - Esp consider in a child 1-4yo with hx of pica - Dx: serology using ELISA to detect antibodies IgG - Tx: Observe or treat - VLM: Albendazole; systolic corticosteroids may be considered in severe disease - OLM: Topical or systemic corticosteroids to reduce inflammation

Answer 72

Taenia solium (Pork tapeworm / cestodes) (Sisters connected by tape with seizures and cysts still eat pretzels with Abe; sun in the background) - Consider cysticercosis in a pt with new-onset seizures who is - An immigrant from Central or South America or from Mexico or - From a household with an immigrant from these areas - Tx: Praziquantel or niclosamide is usual treatment - Neurocysticercosis (ie cysts occurring in the CNS) with resulting inflammation, usually causes SEIZURES as the 1st symptom. - Head CT initially shows single or multiple cysts, which then progress to calcified granulomas - Dx: 1 absolute criterion with varying combinations of criteria - Absolute: - The presence of parasites on fundoscopic exam - presents the strongest evidence for supporting the diagnosis for neurocysticercosis - Positive histology from brain/spinal cord lesion - Cystic lesions with scolex (elongated bright nodule within a cavity) - Dx: Neuroimaging studies with serum T solium antibody tests - Tx: Albendazole is 1st choice

Answer 73

Schistosoma (Trematodes / Flukes) (Sisters drink to have cirrhosis/esophageal varicose and pretzels; Tree toad fluke) - Pt: Fever, lymphadenopathy, diarrhea, hepatosplenomegaly, urticaria, bronchospasm, marked eosinophilia - Most serious complication is cirrhosis with esophageal varices. Does not cause other stigmata seen with alcoholic cirrhosis (spiders, gynecomastia, ascites) - Tx: Praziquantel for 1 day

Answer 74

HSV - Risk of HSV transmission to neonate born to mother with PRIMARY (1st episode) genital infection at or near delivery is very high 40-45% - Risk of transmission falls if infection is acquired during 1st half of pregnancy or with recurrent herpes at term. - 3 clinical syndromes: - 1) Localized to SEM - 2) Localized CNS disease - 3) Disseminated disease in 25% of cases (liver, lungs, CNS) - Think about HSV in neonates with skin lesions, conjunctivitis, fever, elevated ALT, oozing, pneumonia, seizures, sepsis - Management - PCR test or viral culture from surface swabs collected approx 24 hours after delivery. - Tx: IV acyclovir 14 days for SEM and 21 days for CNS. Followed by 6 months of PO acyclovir

Answer 75

HSV-1 - Orofacial infections - Recurrent HSV-1 eye infection resulting in a keratitis is the most common infectious cause of blindness in industrialized nations. Presents with dendritic, branches, fluorescent-staining corneal ulcers - HSV is the most common cause of erythema multiforme, HSV-2 - Causes 75% of HSV genital infections - the rest are due to HSV-1 - HSV encephalitis has predilection for the temporal lobe, at risk for temporal lobe seizure symptoms Treatment: Acyclovir

Answer 76

Major side effect of ganciclovir is granulocytopenia

Answer 77

Measles / Rubeola = 1st Disease - Pt: 3 Cs (Cough, coryza, conjunctivitis, Koplik) that lasts 3-4 days with fever, malaise, sinus discharge, and a hacking cough - Then fever AND maculopapular rash 2-4 days after - Vitamin A deficiency results in more severe disease - including eye disease, with corneal ulcers and loss of vision. - CNS complications are common: Subacute sclerosing panencephalitis, can occur 7-10 YEARS after measles infection - Pts typically had measles at <2yo and present with dementia, myoclonus, and new-onset seizures at ~10yo (esp think in adopted children from a country in which measles vaccination is not routine.) - Pneumonia is most common cause of death - Tx: Vit A treatment for 2 days is recommended for all children with acute measles, regardless of their country of residence. Vitamin A can help prevent eye damage and blindness and reduce overall mortality, esp in individuals at risk for vitamin A deficiency - Ppx: - MMR vaccine (for immunocompetent) within 72hr of exposure - Doses given prior to 1st birthday do not count towards 2-dose series - OR immunoglobulin (for immunocompromised) within 6 days of exposure (should never give both at same time as can inactivate each other) - IG is recommended for susceptible household measures or other close contacts with measles, esp for those <12mo, pregnant without evidence of measles immunity, primary or acquired immunocompromised, >2mg/kg corticosteroids daily for >2 weeks, or in home measles is contraindicated (ie sensitivity to neomycin or gelatin or severe allergic reaction with previous MMR vaccination).

Answer 78

Rubella (German measles) = 3rd Disease - Approx 50% of pts with postnatal rubella do not have symptoms - Pt: - Prodrome: Fever, generalized tender lymphadenopathy (most commonly posterior cervical, post auricular, sub occipital). - Enanthem of Forchheimer spots that are pinpoint or slightly larger red spots (petechiae) on the soft palate in 20% of pts and can occur during the late prodrome or at the beginning of the rash appearance.

Answer 79

Erythema infectiousum = 5th disease - Path: Parvovirus B19 - Fever and rash (on cheeks usually) - Dx: Clinical diagnosis without lab confirmation is frequently wrong. Test IgM antibodies to diagnose an acute infection. - Tx: Self limited Petechial Papulopurpuric Gloves-and-Socks Syndrome (PPGSS) - Pt: Rash restricted to the extremities Aplastic crisis - Pts with chronic hemolytic anemias or AIDS can have aplastic crisis Pregnancy - Risk of intrauterine hydrops and possibly fetal loss

Answer 80

Roseola = 6th Disease - Path: Human herpes virus 6 - Pt: High spiking fever >104 3-5 days THEN rose-colored blanching maculopapular rash that occurs immediately 12-24 hours after fever abruptly resolves

Answer 81

Varicella Zoster - Incubation period for chickenpox is 10-21 days - Complications: - Most common is secondary bacterial infection (S progenies and S aureus involved). - Hepatitis with mild liver enzyme elevations is common in varicella. - Reye syndrome has resulted from aspirin use during varicella - Children have pneumonitis in 10% of cases - Thrombocytopenia can occur - Most common CNS complications are transient cerebellar ataxia and encephalitis - Management: - Airborn precautions - PO acyclvoris for 5 days if present within first 24 hours of exanthem - IV acyclovir for immunocompromised pts - Avoid aspirin bc of Reye syndrome risk - Children with varicella must be exlucded from school until all lesions are crusted. Exposed individuals are potentially contagious from day 8 after exposure to the end of the incubation period (21 days). - Pts with primary infection are most contagious 1-2 days before onset of rash. - Hospitalized pts who are exposed need to be placed in a negative-pressure isolation room with airborne precautions during the incubation period if their hospitalization falls within the time frame - specifically from 8-21 days after exposure (up to 28 days if given VZIG). - Ppx: - Indicated for: - Active case residing in same household - Active case sharing the same hospital room - Visit deemed contagious - Indoor face to face play - Intimate contact - Vaccine should be given within 3-5 days of exposure to prevent disease or lessen the severity for healthy varicella virus-nonimmune individuals >12 months - Infants as young as 6mo can receive the vaccine; however, dose <12mo does not count to 2-dose series. - Varicella immunoglobulin (VariZIG) given within 10 days of exposure can provide immunoprophylaxis to pts who cannot receive a live vaccine - Newborns of mothers w varicella infection 5 days before to 2 days after delivery - Premature infants >28 weeks exposure during hospitalization, and have non immune mothers - Premature infants <28 weeks or weight <1000g at birth who are exposed during hospitalization, regardless of their mother’s immunity to varicella - Pregnant women without evidence of varicella immunity - Infants <2 weeks of age whose mothers do not have evidence of immunity - Immunocompromised children and adults without evidence of varicella immunity, received stem cell transplant, received immunosuppressive therapy including prednisone 2mg/kg/day for >14 days - If VZIG is not available, an alternative if IVIG. - If these children have not received VZIG by day 7, consider a course of acyclovir.

Answer 82

``` Herpes Zoster (Shingles) - Most commonly zoster affects 1-2 adjacent dermatomes ``` - If shingles involves the portion of the facial nerve near the ear, Ramsay Hunt syndrome can result. - This includes the typical rash involving the affected ear and facial weakness or paralysis (Bell’s palsy) - Dx: Tzanck smear shows multinucleate giant cells, which are pathognomonic for herpes viruses. - Tx: If initiated quickly, high-dose PO acyclovir is helpful. Although it shortens the course of acute illness a little, it does NOT decrease the incidence of postherpetic neuralgia. - Amitryptyline can be helpful for postherpetic neuralgia - Note: If mother has herpes zoster, do NOT give VZIG or IVIG to newborn

Answer 83

Mumps - Pt: Prodromal period followed by 3-7 days of parotid gland swelling - Complications: Orchitis/oophoritis, meningitis (most common complication), pancreatitis - To differentiate mumps from bacterial parotitis (most commonly due to S aureus), check a gram stain of the parotid secretions. There are many WBCs and organisms in bacterial parotitis - but there are none in mumps. - Note: Another cause of enlarged parotid glands is frequent vomiting. Always consider bulimia in an adolescent with parotid gland enlargement. - Management: Supportive

Answer 84

Infectious mononucleosis (EBV infection) - Path: - EBV is shed for >6 months after an acute infection - Can be spread through oral secretions and sexual intercourse - Pt: Among young children, often asymptomatic. - Pt: Triad: Fever, pharyngitis, and cervical lymphadenopathy. - Uncommon manifestations: Palatal petechiae, bilateral upper eyelid edema, and rash (3-15% of cases). - Liver involvement is common. Liver dx tends to be mild and transient, but can occasionally be severe and long lasting, particularly in immunocompromised. - Morbilliform rash following administration of penicillin derivatives, esp amoxicillin or ampicillin - Children <4yo rarely have classic symptoms. - Most are subclinical but can present with rashes and hepatosplenomegaly. - The monospot test is rarely positive in a child <2yo of age and has ~50% sensitivity in children 2-4yo. - Life-threatening complications: - Splenic rupture - Labs: - Leukocytosis with a substantial atypical lymphocytosis (>10%; activated T cells; enlarged with abundant cytoplasm, vacuoles, and indentations of the cell membrane) - Dx: - In pts with symptoms and signs consistent with diagnosis of acute IM, detection of >10% atypical lymphocytes on peripheral blood smear, in conjunction with positive heterophile antibody test is diagnostic. - For definitive diagnosis, or for a negative monospot test, Measurement of EBV-specific antibody titers - IgM viral capsid antigen (VCA) is positive, the pt has acute primary EBV or a very recent-past EBV infection. - IgG-VCA does not help you much. - Antibodies to EBNA (Epstein-Barr nuclear antigen) develop weeks-months later; positive in convalescent or past infection. - IgG against EBV nuclear antigen (EBNA) becomes detectable 1-2 months after infection but overlaps with IgM against VCA until about 3-4 months after infection. - Management - Supportive care is mainstay of tx for acute - Affected persons should avoid contact sports and other activities during the time of splenomegaly (usually 1-3 months).

Answer 85

Bronchiolitis - Ppx Palivizumab 15mg/kg 1x/month for max 5 monthly doses - MANDATORY for - <12mo born with chronic lung dx of prematurity (born <32+0weeks required >21% O2 for at least first 28 DOL) - Preterm born <29+0 (without chronic lung disease) who are <12mo of age at the onset of the RSV season - Babies <24mo with chronic lung disease who require medical therapy (O2, chronic corticosteroid, diuretic) within 6mo of the RSV season. Monthly ppx should be administered for the remainder of the season - CAN be recommended for: - Infant <12mo with hemodynamically significant heart disease - (but NOT secundum ASD, small VSD, pulmonic stenosis, uncomplicated aortic stenosis, PDA, mild coarctation) - <24 mo who undergoes cardiac transplantation during RSV season - <12mo with either airway abnormalities or neuromuscular disorder impairing cough - <24 mo who is severely immunocompromised during RSV season

Answer 86

Influenza - Tx: - Ideally start within 48 hours of illness onset - Oseltamivir - Zanamivir is neuraminidase inhibitor administered by inhalation of a powder. Mechanism has been linked to bronchospasm in pts with asthma and in pts without airway disease - Tx is recommended as early as possible, even >48 hours duration of illness, for pts who are: - Hospitalized with presumed influenza - Confirmed or suspected influenza who have severe, complicated, or progressive illness - Influenza infection of any severity in children at high risk for complications - Any otherwise healthy children with influenza infection for whom a decrease in duration of clinical symptoms is felt to be warranted by his or her provider - High risk patients are increased risk of complications and need treatment: - Children <5yo, esp <2yo - Children with chronic disease (including asthma) - <19yo who are receiving long-term aspirin - Immunosuppression (by meds or HIV) - American Indians/Alaska natives - Extremely obese (BMI >40) - Residents of nursing homes and other chronic care facilities

Answer 87

Polio - CNS onset is characterized by septic meningitis and/or an asymmetric flaccid paralysis WITHOUT reflexes - Can cause destruction of motor neurons and thus motor weakness. Proximal muscles are usually affected more than distal muscle - descending paralysis - Tx: Supportive

Answer 88

Rabies - Pt: Acute encephalomyelitis with symptoms of initial excitation phase, especially when the affected person sees food or water (hydrophobia) - Dx: - Diagnose by finding pathognomonic Negri bodies (acidophilic inclusion bodies) in the cytoplasm of neurons - Indications for post-exposure prophylaxis: - In the case of a bite from a domesticated animal, the animal should be watched by a veterinarian for 10 days. Post-exposure prophylaxis should only be given to the pt if the animal becomes symptomatic in this 10-day period. - In the case of a bite from a wild animal (among animals known to harbor rabies, including skunks, foxes, racoons), post-exposure prophylaxis can be given to the pt if the animal was not captured. - Bats are an exception bc the pt is often unaware that a bite occurred, and bite marks from a bat are often invisible to the naked eye. The only situation in which post-exposure prophylaxis is NOT indicated is if a bite can be completely ruled out - Post exposure ppx: - Subcutaneous rabies immune globulin (RIG)- dose of 20 U/kg. Infiltrate the wound with as much RIG as you can and then administer the rest of the 20 IU/kg dose via the IM route (separate site from the vaccine) - AND rabies vaccine at 0, 3, 7, and 14 days (injected into the contralateral deltoid muscle)

Answer 89

Arboviruses - Mainly transmitted by mosquitoes or ticks - West nile virus - Most common arbovirus in the US - Most are asymptomatic - More severe neurologic disease presents similar to aseptic meningitis - CSF with pleocytosis with predominance of lymphocytes - Dx: WNV IgM serum antibodies or a positive IgM CSF antibody titer - Tx: Supportive care

Answer 90

Chikungunya fever - Day-biting mosquitoes - Pt: Symptomatic with fever and polyarthralgia - Dx: Virus-specific IgM (which may not appear until 5-7 days of symptom onset) or by PCR - Tx: Supportive

Answer 91

Hantavirus - Primary reservoir is the deer mouse - Early: Constitutional symptoms in all cases; ~50% have nausea, vomiting, diarrhea, and abdominal pain - Late: 4-10 days later, coughing, and SOB as ARDS develops - Hantavirus pulmonary syndrome (HPS): Starts with severe myalgia, fever, headache, and cough and quickly progresses to ARDS and death

Answer 92

Dengue fever - Caused by flavivirus transmitted by aides mosquitos - Pt: - Rapid onset of high fever, severe myalgia, and arthralgia (break-bone fever), retro-orbital pain, and severe headaches with nausea and vomiting, followed by macular red rash - 2nd rash resembling measles occurs later, along with an occurrence of fever “saddleback fever” - goes up, down, and up (biphasic). - 3 phrases: Febrile phase, Critical (plasma leakage) phase, and a Convalescent (reabsorption) phase - Tx: Supportive. Acetaminophen for managing fevers. During the febrile phase, pts should stay well hydrated and avoid salicylates and NSAIDs to minimize the risk of bleeding.

Answer 93

Zika virus - Flavivirus - Pt: Symptoms in 20% of people. Fever, rash, muscle and joint pain, and conjunctivitis. - Tx: No treatment

Answer 94

Ebola virus | - Tx: No effective antiviral therapy for treat Ebola. Primarily supportive

Answer 95

Hepatitis A - Transmission person to person through fecal-oral route - Screen: IgM HAV - Ppx: Preferably given within 2 weeks of exposure - Give the following prophylaxis: - All household contacts - Sexual partners - Needle-sharing persons - Day care and nursing home attendees and staff in close contact with case - NO prophylaxis warranted: School, hospital, or workplace day-to-day contact - For healthy persons 12mo-40yo: Hepatitis A vaccine is preferred - For children <12mo, immunocompromised, pts with chronic liver disease, and those allergic to vaccine: Immnoglobulin - PPX are NOT indicated for unvaccinated persons with recent HAV if exposure occurred >2 weeks prior

Answer 96

Hepatitis B - Only hepatitis virus composed of DNA - Transmission by body/blood fluids, sexual contact, and transplacentally - Pt: - Prodromal symptoms (serum sickness-like; nonspecific) occur first and commonly resolve at the time jaundice becomes apparent. - With onset of jaundice, pt typically feels better but can have liver swelling, tenderness, and cholestatic symptoms. - Associations: Likelihood of developing chronic hep B infection is inversely related to the age at which infection was acquired. 90% of infants infected at birth will develop chronic hepatitis. - Children with chronic infection are at risk for cirrhosis, hepatic failure, and hepatocellular carcinoma. - Screen: HBsAg (antigen; 1st marker detectable in serum) and IgM HBc (Ig to core; 2nd marker detectable in serum; confirms acute infection in “window”) - Anti- HBsAb (surface antibody) becomes positive 6mo after infection. Past exposure to HBV or HepB vaccine - HBeAg - infectious; marker of actively replicating virus - Chronic HBV is characterized by presence of hepatitis B surface antigen for >6 months - +HBsAg, +HBc Ab, No IgM HBc - Ppx - Exposure to +HBsAg source - Nonimmune individuals should begin age-appropriate hep B vaccination series AND receive Hep B IG (HBIG) within 24 hours of exposure - Immunized individuals should receive 1 booster dose of Hep B vaccine - Perinatal: Exposed infants should receive the hepatitis B vaccine and immunoglobulin within 12 hours of birth, followed by completion of the normal hepatitis B series (at age 0, 2, and 6 months). Serology for anti-HBs and HBsAg should be obtained at approx 3 months after the final hepatitis B vaccine, usually at 9mo. - Unknown HBsAg source - Nonimmune individuals should begin Hep B vaccination series - Immunized individuals require no further tx

Answer 97

Hepatitis C - ssRNA - RF: Perinatal transmission occurs in up to 5% of infants born to viremic mothers. Coinfection with HIV increases the risk of perinatal transmission of hepatitis C percentage to 10%. - Pt: Most without symptoms. Only 25% symptomatic - fever, malaise, fatigue, jaundice, RUQ pain - Extrahepatic disease: Small vessel vasculitis and glomerulonephritis and nephropathy, mixed cryoglobulinemia (vasculitis with palpable pupura), porphyria cutaneous tarda - Chronic form relatively benign - Long term outcomes: Cirrhosis, liver failure, hepatocellular carcinoma - Screen: Anti-HCV antibody - Infants with perinatal hepatitis C exposure should be screened for chronic HIV infection with anti-HCV antibody testing at 18 mo - Dx: - Confirm with RIBA (recombinant immunoblot assay) to exclude a false-positive test. - If RIBA+, check for active virus by ordering HCV RNA viral load (NAAT). This is necessary bc anti-HCV does not confer immunity (unlike HBV antibody). - Within 2-4 mo after an episode of hepatitis C, recheck for loss of HCV RNA to ensure it has not become chronic. - Management: - No FDA-approved antiviral therapies for children <2yo - Combinations of hepatitis C antivirals - One regimen approached in children: Peginterferon and ribavirin

Answer 98

Hepatitis D - RNA virus that requires concomitant or previously existing HBV infection to become pathogenic - Immunity to hepatitis B implies immunity to hepatitis D - Dx: Anti-HDV IgM

Answer 99

Hepatitis E - Unlike hepatitis A, it carries a very high risk for fulminant hepatitis in the 3rd trimester of pregnancy, with 20% maternal fatality rate - Think of acute hepatitis E infection in a returning traveler from an endemic area who presents with acute hepatitis and whose hepatitis A, B, and C serologies are negative.

Answer 100

HPV - Most common STI - These lesions need to raise question of sexual abuse when noted in children. - HPV 1, 2, and 5 cause plantar warts - HPV 6, 11, 16, 18, 31 are genital - HPV 6 and 11 cause >90% of genital warts - HPV 16, 18, and 31 are linked to cervical cancer - Pt: Condyloma acuminata (genital warts) - Tx: - Child abuse specialist - Watchful waiting is an appropriate 1st step in management. Slightly more than half the cases will resolve spontaneously within 5 years. - Remove symptomatic genital warts - Medical tx includes topical products (imiquimod or podophyllotoxin). With tx, warts usually resolve within 3mo.

Answer 101

Polyomaviruses: BK virus and JC virus - BKV: - Can cause asymptomatic hematuria or cystitis in healthy children. - In immunocompromised pts, is more likely to cause hemorrhagic cystitis or interstitial nephritis - JCV: - Cause of progressive multifocal leukoencephlopathy (PML) that occurs in severely immunocompromised pts

Answer 102

Prion Diseases - Kuru, Creutzfeldt-Jakob disease (CJD), new variant CJD (vCJD), Gerstmann-Straussler-Scheinker (GSS) syndrome, and fatal familial insomnia. - CJD: - Most common prion disease - Pt: Myoclonus and severe dementia. Neurologic symptoms predominate. Pts generally die within 5 months - No effective therapy - Variant CJD - Early psychiatric symptoms and late-appearing neurologic symptoms (ataxia ~6mo after infection) - Look for a young adult from England with progressive psychiatric symptoms and ataxia.

Answer 103

HIV/AIDS - Pt: - Wasting is a common presentation in children - Acute retroviral syndrome: Occurs in adolescents/adults following HIV acquisition 2-4 weeks after initial infection, before antibody testing is confirmed positive - Dx: - HIV-1/HIV-2 antigen/antibody combination assay (ELISA / enzyme-linked immunoassay)(4th generation assay) followed by Western blot. Both tests must be positive to indicate a positive result. - The preferred test for children <24mo is nucleic acid testing of unique viral genetic material, such as HIV DNA PCR assay or RNA assays (to detect viral load) in peripheral blood at 14-21 days of age. If results are negative, again at 1-2mo and 4-6mo. - Cannot use ELISA or antibody assays since child has acquired passive maternal HIV antibodies that can be detected put to 18mo. - HIV Tx: - Combination antiretroviral therapy (cART) is always recommended - include at least 3 drugs from at least 2 classes - Zidovudine - Bone marrow suppression, myopathy, macrocytosis - No problems with kidneys, lungs, or pancreatitis - Abacavir: Hypersensitivity reaction. Flu-like illness - Didanosine (ddI) and stavudine (d4t): Pancreatitis, peripheral neuropathy - Tenofovir: Nephrotoxicity - Nevirapine: Rash - Efavirenz: Teratogenic - Atazanavir: Jaundice - Indinavir: Nephrolithiasis - Ppx: - Do not give PEP for intact-skin exposure and urine-source exposures - Current recommendation is at least 3 antiretroviral drugs: emtricitabine (FTC) + tenofovir (TDF) + raltegravir (RAL) - Pregnancy: Give pregnant woman cART as well as IV ZDV during labor ant delivery. - Newborns should begin with in 12 hours of birth with zidovudine for 4-6 weeks depending on risk - Immunizations: - Do NOT give OPV to children with HIV. Also, remember that OPV is NOT given to household contacts of a person with HIV; this is secondary to potential viral shedding that may allow contraction of vaccine associated poliovirus - Give PPSV23 after 24mo of age, at least 8 weeks after last dose of PCV13 MAC is a common infection - Tx: Clarithromycin or azithromycin in combination with ethambutol is 1st line Subacute diffuse encephalitis is a common neurologic problem seen win AIDS

Answer 104

The only 3rd generation cephalosporin to have activity against pseudomonas is ceftazidime Ceftrixone has potential to cause hyperbilirubinemia in neonates by displacing bilirubin from albumin. For this reason, cefotaxime is usually used in neonates when a 3rd generation cephalosporin is needed.

Answer 105

Amphotericin B: Side effects include fever, renal failure, phlebitis, acidosis, low K and Mg Fluconazole: Main side effect are nausea and vomiting

Answer 106

LYMPH NODES - Supraclavicular nodes are NEVER normal - Clues suggestive of malignancy include hard, irregular, firm, immobile lymph nodes, nodes >2cm, and supraclavicular location. Investigate the findings further with lab work, US, CT scan, and fine needle biopsy. - Labs when evaluation lymph nodes: CBC, ESR/CRP for inflammation, LDH and uric acid for rapid cells cell turnover for malignancy, EBV, HIV, CMV, parvovirus, TB, Bartonella, CXR for mediastinal lymph node enlargement (occurs in 2/3 Hodgkin lymphoma), ultrasound, excision biopsy of largest node and send for culture (high suspicion for malignancy) (versus FNA which has high false negative and potential sinus tract formation). Red flag signs - Persistent lymphadenopathy >1cm in diameter - Presence of “B” symptoms: Fever, weigh loss >5% body weight, night sweats

Answer 107

Lymphadenitis - For age <3 mo: Most commonly Staph aureus and group A strep - Pt: Enlarged, painful lymph node often with fever - Rx: Augmentin, Keflex, Clindamycin, TMP-SMX. Follow up in 2 weeks to assess resolution of lymph nodes

Answer 108

- Viral lymphadenitis typically causes acute bilateral lymphadenopathy - Acute unilateral disease most commonly results from S pyogenes or S aureus infection - Subacute/chronic unilateral lymphadenitis is most typically caused by nontuberculous myobacteria or Bartonella henselae (cat scratch fever) - Subacute/chronic bilateral disease is usually the result of EBV or CMV. - Initial workup of cervical lymphadenitis: CBC with diff, tuberculin skin testing, serologic testing for B henselae, CMV, EBV, and HIV.

Answer 109

SEXUALLY TRANSMITTED INFECTIONS Screening - Sexually active women <25 years - Annual testing for Chlamydia trachomatis and Neisseria gonorrhoeae using a urine or vaginal swab (can be self-collected) specimen for nucleic acid amplification (NAAT) - Cervical cancer screening by cervical cytology (ie the Pap test) is recommended beginning 21yo with repeat testing q3 years until 29 years. - Exception is if pt has immune suppression or infection with HIV, in which case begin annual Pap tests at time of onset of sexual activity - Adolescents with HIV (or otherwise immunocompromised) should undergo cervical cancer screening twice within the 1st year following diagnosis of HIV infection and then, if the results are normal, annually. - Young men who have sex with men - Annual screening for HIV and syphilis - Annual screening for C trachomatis and N gonorrhoea

Answer 110

STI - Path: Neisseria gonorrhea or Chlamydia trachomatis - Pt: - Most cases are asymptomatic - When symptomatic, the most common presentation is uncomplicated urethritis or cervicitis, which may present with dysuria and discharge. - Anyone who has had sexual contact with an infected patients within 60 days of diagnosis should be tested with the same medications, even without testing - For chlamydia: Oral azithromycin 1g (or doxycycline 100mg twice daily for 7 days) - For gonorrhea: IM ceftriaxone 250mg

Answer 111

Chlamydia - 3 distinct clinical infections: - Conjunctivitis (20-50%) - Pneumonia (5-30%) - Urogenital infections - Tx - Infants with conjunctivitis or pneumonia are tx with oral erythromycin for 14 days or oral azithromycin for 3 days. - If suspected urogenital infections, empiric therapy should target both C trachomatis and Neisseria gonorrhoeae. Uncomplicated urogenital infections confirmed to be caused by C trachomatis can be tx within single dose of azithromycin 1g.

Answer 112

Disseminated Gonorrhea - Pt: - Gonococcal arthritis presents in 1 of 2 ways, with different means of diagnosis - 1) Symptoms of tenosynovitis and dermatitis in addition to fever, chills, pustular, or vesiculopustular skin lesions, polyarthralgia (eg hands, wrists, fingers), positive blood cultures (30-40%), and negative synovial fluid cultures. - 2) Suppurative monoarticular arthritis (typically knee, wrist, or ankle) without systemic symptoms, associated with positive synovial culture (45-55%) and negative blood culture. There is abrupt onset of pain and swelling - Work-up: - For DGI WITH skin lesions and polyarthralgia, always check cervical and blood cultures (do not tap the joint if there is no effusion) - For DGI WITHOUT skin lesions but with monoarticular inflamed joint, always tap the joint - Tx: (also treat presumed concomitant chlamydial infection) - Preferred: Ceftriaxone 1g IM/IV every 24 hours for 7 days (following clinical improvement, change dose to 250mg IM/day) and azithromycin 1g PO in 1 dose

Answer 113

HFMD - Coxsackie A16 virus - Pt: - A red maculopapular rash typically appears on the hands and feet and eventually becomes vesicular. - Oval-shaped papules with surrounding erythema on the buccal mucosa, oropharynx, palms, and soles. Less commonly, the palate, lips, and gums. - In contrast to HSV, coxsackievirus tends to spare the lips and gingiva. - Contrasts from herpangina in that HFMD is usually associated with lower fevers, a nonpainful papulovesicular rash on the hands, feet, arms, buttocks, and thighs; and painful vesicles on the tongue and buccal mucosa.

Answer 114

Herpangina - Enanthem caused by enteroviral infection. Most commonly caused by Coxsackievirus group A - Pt: - Tiny 1-2mm painful yellow-gray vesicles surrounded by erythematous halo occur on the posterior pharynx, involving the soft palate, uvula, and tonsillar pillars - This is in contrast to HSV, which more commonly occurs in the front of the mouth and extends out onto the lips. - Tx: Supportive.

Answer 115

Herpetic gingivostomatitis - Path: HSV type 1 primary classically causes infection of the oral mucosa, and may present as herpetic gingivostomatitis in children. - Pt: - Several days of high fever, irritability, and malaise followed by enanthem. - Numerous small vesicles on erythematous base on anterior oropharynx - Gingiva may be erythematous, inflamed - Tx: - Self-limited, will resolve in 1-2 weeks - Supportive therapy aimed at relief of pain and fever, plus management of fluid status - Antiviral therapy with oral acyclovir may be considered for those with more serious signs or symptoms, and systemic therapy should be used in immunodeficient patients. Tx is most effective when initiated in first 3 days of disease.

Answer 116

CDC STD Treatment Guidelines state that the diagnosis of genital ulcers on history and physical is inaccurate and that pt with genital, anal, or perianal ulcers should have - HSV culture or PCR testing for HSV - Serologic testing for type-specific HSV antibody - Syphilis serology and dark-field examination - HIV testing on those not known to have HIV infection - Ulcer biopsy if unresponsive to initial therapy

Answer 117

Herpes Simplex Virus - Pt: - Painful pruritic vesicular grouped lesions on an erythematous base. These vesicles spontaneously rupture to form shallow, painful ulcers - Do NOT be swayed by the presence of cervicitis and discharge and think it is something else (instead, think coinfection with gonorrhea and chlamydia). If you see grouped vesicles, particularly on an exam question, think HSV! - Dx: Cell culture and PCR are preferred HSV tests. - PCR is the most sensitive diagnostic modality. - Treat acute flares with antiviral therapy - Preferred is valacyclovir 1000mg PO BID for 7-10 days. - Chronic suppressive therapy for people who are: - Patients with >=6 recurrent episodes/year and/or severely symptomatic disease - Significant anxiety regarding recurrences

Answer 118

Syphilis (painless ulcer, painless lymph node) Primary syphilis - Pt: Painless genital ulcer (chancre) with an indurated border (highly contagious) at the site of inoculation. Secondary syphilis (A systemic disease) - Frequently presents with generalized scaly, hyperkeratotic palmar skin (pityriasis rosea-like) - Classically, the rash is “nickel and dime” lesions on the palms and soles and resolves spontaneously without treatment in 3-12 weeks. - Condyloma lata - smooth flat warts / Hypertrophic granulomatous lesions in warm moist areas (typically the vulva or anus) Latent (hidden) Syphilis - Early latent syphilis - latent syphilis where infection occurred within past 12 mo - Late latent syphilis - latent syphilis where infection occurs >12mo ago Tertiary syphilis - Presents 15-30 years later with cardiac, ophthalmic, and auditory abnormalities, as well as gummatous lesions (nonsuppurative granulomas) of the skin, bone, or viscera. Neurosyphilis - CNS disease can occur at any stage of syphilis, from primary to tertiary - Classic quiz presentation is an adolescent with sensorineural hearing loss (8th cranial nerve deafness), always think neurosyphilis. - Don’t forget about Uveitis

Answer 119

Syphilis Diagnosis - T pallidum cannot be cultured - If ulcers/lesions are present, spirochetes on Dark-field examination or direct fluorescent antibody testing of exudate/tissue is the definitive diagnosis. The test becomes positive even before the body can mount an antibody reaction, making it the most sensitive and specific test for early primary syphilis. - After early primary syphilis, a presumptive diagnosis is possible with 2 serologic tests in sequence: - Nontreponemal test: RPR (rapid plasma reagin, blood test) or VDRL (venereal disease research laboratory, ONLY done on CSF) - Treponemal tests: Positive results should be confirmed with a treponemal test: FTA-ABS (fluorescent treponemal antibody absorbed), TP-PA (T pallidum passive particle agglutination), EIAs (enzyme immunoassays), CIAs (chemiluminescence immunoassays) - For pts who receive adequate treatment, the specific treponemal tests remain positive for life; therefore, these tests are not appropriate measures of therapeutic response. - Treponemal tests are not used in the evaluation of neonates born to mothers with syphilis infection bc passive maternal transfer of antibodies would lead to positive results. - Neurosyphilis - Use of serum nontreponemal tests (RPR, VDRL) followed by treponemal tests (FTA-ABS, TPPA) is standard. - If there is evidence of treponemal infections, then obtain CSF for analysis and CSF-VDRL. - Typically, diagnosis of neurosyphilis relies on variety of clinical and lab findings: elevated CSF WBC and elevated CSF protein, with or without clinical manifestations. - After treatment: - Nontreponemal tests decrease and become nonreactive with time (3-12 mo after treatment)

Answer 120

Syphilis Treatment - Drug of choice: Parenteral Penicillin G - Is the only effective therapy for pts who have neurosyphilis, congenital syphilis, or syphilis during pregnancy; it is also recommended for HIV-infected pts. These pts must be treated with penicillin, even if desensitization for penicillin allergy is necessary. - Jarisch-Herxheimer reaction: - Acute febrile response 2-12 hours after initiation of therapy for syphilis. It is accompanied by headache, myalgia, and other symptoms within the first 24 hours after initiation of any tx for syphilis. - Tx is supportive - Treatment of primary, secondary, or early latent syphilis - IM penicillin G benzathine x 1 dose (2.4 million units - If allergic to penicillin and nonpregnant, oral doxycycline 100mg BID for 14 days is preferred or tetracycline 500mg QID for 14 days - Treatment of late latent syphilis, syphilis of unknown duration, or tertiary syphilis without CNS disease - IM penicillin G benzathine 1x/week for 3 weeks - For patients who are penicillin allergic and non-pregnant, given doxycycline 100mg BID for 28 days - If pt has neurologic or eye signs/symptoms, evidence of active tertiary syphilis, treatment failure, or HIV infection, perform a lumbar puncture to evaluate for neurosyphilis. - Neurosyphilis - IV aqueous penicillin G 3-4 million units q4 hours for 10-14 days, or - Continuous IV infusion of aqueous crystalline penicillin 18-24 million units/day for 10-14 days - If penicillin allergic, consider ceftriaxone 2g/day IM/IV for 10-14 days. However, due to cross-reactivity, some prefer skin testing and desensitization

Answer 121

Lymphogranuloma Venereum (painless ulcer, tender lymph node) - Path: C trachomatis serotypes L1, L2, or L3 - Pt: - Painless genital ulcer forms at the site of inoculation, followed by unilateral tender inguinal and/or femoral lymphadenopathy - Ulcer often goes unnoticed and commonly resolves before pt seeks treatment. - Large, hard, fixed lymph nodes in the groin above and below inguinal ligament form a groove along the ligament (“groove sign”) - Organism can cause proctocolitis in males who have sex with males. Delayed tx of LGV can lead to chronic colorectal fistulas and strictures. - Dx: - Genital and lymph node specimens are tested for C. trachomatis by culture, direct immunofluorescence, or NAAT; a complement fixation titer >1:64 is consistent with LGV - Tx: Doxycycline 100mg PO BID

Answer 122

Granuloma Inguinale (Donovanosis) (painless ulcer) - Path: Klebsiella granulomatis - Pt: - Painless, friable, progressive, beefy-red ulcerative lesion. - Dx: Identifying dark-staining Donovan bodies (intracytoplasmic inclusion bodies) on tissue crush preparation or biopsy - Tx: - Azithromycin 1g PO 1x/week or doxycycline 100mg BID or ciprofloxacin 750mg PO BID for 3 weeks or until all lesions have healed. - Use azithromycin for pregnant females.

Answer 123

Chancroid (painful ulcer, tender lymph node) - Path: Haemophilus ducreyi - Pt: - Chancroid with >1 tender inflammatory papule that within 1-2 days becomes pustular, erodes, and ulcerates into a painful (unlike syphilis), shallow, soft, friable lesion with ragged margins and a foul-smelling necrotic purulent exudate - Painful, unilateral inguinal lymphadenitis (bubo) often develops over weeks-months - Dx: Clinical basis - Tx: - Azithromycin 1g PO in 1 dose, or - Ceftriaxone 250mg IM in 1 dose, or - Ciprofloxacin 500mg PO BID for 3 days, or - Erythromycin base 500mg PO TID for 7 days - Both azithromycin and ceftriaxone can be used to treat pregnant females with chancroid.

Answer 124

SIRS: Systemic inflammatory Response Syndrome: Any 2 of - Temp >100.4 or <95.0 - RR > 20 or PaCO2<32mmHg - HR >90/min - WBC >12,000 or <4,000 Sepsis = SIRS with confirmed OR suspected infection Severe sepsis = Sepsis with organ system dysfunction (hypotension, AMS, acidosis, oliguria, ARDS, etc) Septic Shock = Severe sepsis with hypotension unresponsive to fluid resuscitation - Hypotension is a late sign of cardiovascular dysfunction and shock in pediatric patients and is not necessary to diagnose septic shock. 1) Isotonic fluids 20ml/kg via push and pull, give 3 times in 30 mins 2) Antibiotics in 1 hour - ceftriaxone 3) 100% supplemental oxygen even if O2 sat is 100%, set at the highest liter (15L for nonrebreather). 4) Intubation - not to protect the airway but to decrease metabolic demand

Answer 125

- Staph aureus infections of the CNS are unusual, but children with cyanotic congenital heart disease have an increased risk of staphylococcal brain abscesses, esp if there is endocarditis with septic emboli.

Answer 126

- If you see a child from Arkansas with a swollen lymph node and fever, think tularemia