prostatitis

• related: ID
• tags: #note

This patient's presentation is most consistent with acute bacterial prostatitis (ABP).  Most cases are due to Gram-negative (eg, Escherichia coli, Proteus mirabilis, Klebsiella, Enterobacter) organisms.  Gram-positive (eg, Staphylococcus aureus, Streptococci, Enterococci) infections are less common and are usually due to remote in

ABPA

• related: ID, Pulmonology, aspergillosis

• patients: underlying asthma, CF
• pathogenesis: sensitization to aspergillus, intense IgE and IgG mediated immune response
• sx: recurrent exacerbations. Sx of pneumonia in asthma patient unresponsive to treatment
• dx:
  • elevated Aspergillus-specific IgE
  • elevated (eg, >417 IU/mL) t

HIV

• related: ID

HIV:

• HIV and opportunistic infections
• HIV and TB
• CNS lymphoma
• HIV exposure
• cryptococcus
• HIV and pregnancy
• HIV resistance testing
• HIV and immunization
• PrEP
• HIV testing HIV CNS lesions

HPV

• Keywords:: Step 3 ID HIV

Human papillomavirus (HPV) is a common sexually transmitted virus that causes cervical cancer. In immunocompetent women, HPV usually causes a transient infection. Immunosuppressed patients (eg, HIV infection) are unable to clear HPV and are at increased risk for persistent HPV infection that can progress to cervical dysplasia and cancer. Therefore, patients newly diagnosed

Lyme

• related:ID, post lyme disease syndrome, neuroborreliosis, tick born infections
• tags: #note

Pathogenesis

• bacteria: spirochete Borrelia burgdorferi
• tick: Ixodes scapularis "deer ticks"
• carrier: mice > deer
• time: most occur in summer

symptoms

• most patient won't recall tick bite
• early localized
• early dissemin

Medicine

• Keywords:: 000 Index
• Related: Step 3, Step 1, mksap, notes

Todos

• tolearn
• MKSAP todos
  • heart murmurs

Organ Systems

• Allergy and Immunology
• Rheumatology
• Cardiology
• Dermatology
• Endocrine
• ENT
• GI
• Hemeonc
• ID
• MSK
• Nephrology
• Urology
• Neurology
• Pulmonology
• Podiatry

Subject Areas

• General
• Biostats
• Psychiatry
• [[Geriatric

Mono

• Keywords:: Step 3 ID

• 
• Epstein-Barr virus (EBV) is the most common causative agent of IM and is transmitted via contact with oropharyngeal secretions. The diagnostic test of choice in confirming EBV IM is the heterophile antibody test, which screens for IgM antibodies called heterophile antibodies. These antibodies are produced in response to EBV infection and aggl

Tuberculosis

• related: ID, TB note 11 4, MAC, mycobacterium kansasii, rapid growsers, marinum, gordonae

This patient's clinical presentation is consistent with active pulmonary tuberculosis (TB), which is typically due to the reactivation of latent disease. Suspicion should be raised when individuals with epidemiologic risk facto

Ehrlichosis

• related: ID, tick born infections

Ehrlichiosis is a tick-borne infection caused by Ehrlichia chaffeensis and E ewingii. These bacteria are carried by ticks, including the lone star tick (Amblyomma americanum), found in the **southeastern

otitis externa

• Keywords: Step 3, Medicine, ID

This patient has acute otitis externa (OE), likely from swimming.  The most common organisms causing OE are Pseudomonas and Staphylococcus species.  Initial treatment includes thoroughly cleaning the ear canal to remove cerumen and other debris and nonsteroidal anti-inflammatory drugs for pain control.  An otos

septic arthritis

• related: MSK, ID, pediatric septic arthritis, osteomyelitis, prosthetic joint infection, notes, arthrocentesis

Causes

Septic arthritis is an infection of the synovial joint space.

Septic arthritis can occur through hematogenous spread, local extension, or direct inoculation (trauma).

• S. aureus: most common, more than 50% of cases
  • chil

Shingles

• related: ID, Ramsay Hunt

Patients with herpes zoster may transmit varicella-zoster virus (VZV) through direct contact (primarily) or aerosolized particles (rarely) to health care personnel (HCP) and other individuals. As such, the Centers for Disease Control and Prevention recommend the following precautions for hospitalized patients with herpes zoster until lesions are crusted over (i

Syphillis

• related: ID
• tags: #id

Congenital

Treponema pallidum crosses the placenta; a syphilis infection during pregnancy can result in vertical transmission, leading to adverse fetal outcomes including fetal growth restriction, intrauterine fetal demise, and congenital syphilis (eg, hepatomegaly, jaundice, rash, skeletal abnormalities).

Diagnosis

The diagnosis of primary syph

Strongyloidiasis

• related: ID

This patient from the Dominican Republic has a raised, erythematous, linear rash with significant eosinophilia, raising suspicion for strongyloidiasis.

Strongyloidiasis is caused by Strongyloides stercoralis, a roundworm endemic to tropical and subtropical regions where prevalence can approach 25%. Inoculation occurs when human skin contacts filariform larvae in soil contaminated by human feces (from an infected host).

genital ulcers

• related: ID

Patients with multiple sexual partners and substance abuse are at high risk for sexually transmitted infections. This patient has classic symptoms of primary syphilis - bilateral inguinal lymphadenopathy and a painless genital chancre. Syphilitic chancres form at the site of direct inoculation with Treponema pallidum. After exposure (3-60 days), patients develop a single papule that turns into a shallow, painless, **nonexud

prosthetic joint infection

• related: septic arthritis, MSK, ID

Prosthetic Joint Infection

HIV and TB

• related: HIV, ID, immune reconstitution inflammatory syndrome

• IRIS common in TB patients with HIV
• interferon gamma poor indicator of active TB
• might not mount response to have positive interferon gamma
• treat with rifabutin over rifampin

The timing of his presentation is consistent with the immune reconstitution inflammatory syndrome (IRIS) (median 48 days), the return

HIV and opportunistic infections

• related: ID, HIV and TB

• Candida
• TB
• PCP

Mucocutaneous Candida infections can occur in HIV-infected patients at relatively preserved CD4 cell counts. HIV-infected patients do not usually develop invasive Candida infection unless they have other risk factors, such as neutropenia. Oral candidiasis usually presents as thrush, with mucosal whitish

Helminths

• related: ID

• usually developing world with poor sanitation
• In US, usually from traveling to other areas
• Ascaris lumbricoides (roundworm), Trichuris trichiura (whipworm), and Ancylostoma duodenale (hookworm)
• Sx:
  • early: transient pulmonary: dry cough, sob
  • long term: gi, N/V, diarrhea
  • peipheral eosinophilia
  • positive FOBT
• Rx: albendazole, oral; mebendazole b

PCP

• related: ID

Pneumocystis jirovecii pneumonia:

• usually presents as a subacute illness with fever, dyspnea, and dry cough in a patient with a CD4 cell count less than 200/µL who is not receiving prophylaxis.
• Chest radiographs most often show bilateral interstitial infiltrates; cavitation or pleural effusion is unusual and suggests another diagnosis. A normal chest radiograph does not exclude the d

aspergillosis

• related: ID, ABPA

Aspergillus

• most common species: A. fumigatus, A. flavus, A. niger, and the amphotericin-resistant A. terreus.
• Aspergillus produces disease after inhalation of airborne spores (90%) and only occasionally by traumatic skin inoculation. Of all the fungi, Aspergillus is notable for the diverse settings in which it can occur and the various clinical manifestations it can produce.

Types

![](https://photos.th

clostridium difficile

• related: ID, fulminant clostridium difficile

• Possibly restrict use of clindamycin, fluoroquinolones & cephalosp

coccidioidomycosis

• related: ID

• background: dimorphic fungus, mold in environment, yeast in lung
• location: SW, California, Arizona, New Mexico, Texas, Mexico, central/south America
• epidemiology
  • endemic area: causes up to 1/3 pneumonia
  • lifetime risk of infection 3% in endemic areas
• spread: inhaled and initially lung infection
• pathogenesis: healthy person contains it with cell mediated immunity

cryptococcus

• related: ID, HIV, immune reconstitution inflammatory syndrome

• cryptococcus
• Starting HAART can cause IRIS
• Wait 5 weeks before starting HAART

Types:

• neoformans most common
• agathi: more tropical. Has decreased activity to fluconazole
• usually inhaled

Demographics

• BMT: less b/c ppx fluconazole
• alemduzumab: CD 52
• corticosteroids use
• calcin

fever of unknown origin

• related: ID

• Definition: fever of 38.3 °C (100.9 °F) or greater for 3 or more weeks that remains undiagnosed after two visits in the ambulatory setting.

• Important history: procedures, surgeries, presence of foreign bodies or implants, immunosuppression, travel, animal and other exposures (including hobbies), dietary habits, and medications (includin

immune reconstitution inflammatory syndrome

• related: ID, HIV and TB, HIV

leptospirosis

• related: ID

• risks: freshwater exposure to urine, tissues of infected animals, contaminated water/soil
• timing: weeks after exposure
• sx: uveitis, rash, conjunctival suffusion, sepsis, LAD, AKI, hepatosplenomegaly, rash, pharyngitis, meningitis, jaundice
• LP: resemble enteroviral meningitis
• Dx: CSF or urine clx
• rx: doxycycline

A 19-year-old woman is evaluated in the emergency department fo

non TB mycobacterium

• related: ID, TB meningitis, Tuberculosis

M Fortuitum

M. fortuitum is one of the rapidly growing, nontuberculous mycobacteria (NTM) capable of producing chronic, nonhealing wounds anywhere the bacteria has been introduced, including skin, soft tissue, surgical sites, and occasionally on prosthetic devices. Although M. fortuitum is not part of the differential diagnosis of acute wound

staph surgical infection

• related: ID, notes, preop shaving

• S. aureus is the most common pathogen (23%) associated with surgical site infections (SSIs)
• SSIs after CABG can be serious and devastating, with mediastinitis related to S. aureus of particular concern.
• evaluate for nasal carriage 2 weeks before surgery and decolonize if positive.
• prophylaxis: mupirocin ointment for 5

surgical intervention prevention

• related: preop shaving, ID, notes

• hyperglycemia: glucose < 180 during first 48 hours after sugery
• immunosuppression: reduce dose of agents
• tobacco: cease 30 days prior
• skin: shower night before
• hair removal: clip and not shave
• hypothermia: maintain temperature > 96.8
• hypovolemia: enure volume replacement
• incision drainage: sterile dressing 24-

asymptomatic bacteriuria

• related: ID

Asymptomatic bacteriuria:

• definition: presence of at least 10^5 CFU/mL of a uropathogen from 2 consecutive voided urine specimens in women or one specimen in men, or more than 10^2 CFU/mL of one bacterial species from a catheterized urine specimen in women or men, in all cases without local or systemic signs or symptoms of active infection.
• The prevalence of asymptomatic bact

liposomal amphotericin B

• related: ID, pharmacology

Indicated for treatment of Aspergillus species, Candida species, and/or Cryptococcus species infections refractory to amphotericin B deoxycholate, or if renal impairment or unacceptable toxicity precludes use of amphotericin B deoxycholate

Liposomal formulations have been found to have less renal toxicity than deoxycholate,and fewer infusion-related reactions. They are more expensive than amphotericin B deoxyc

BK virus

• related: ID

• After renal transplantation, patients are at risk of allograft dysfunction from a wide variety of mechanisms.
• The biopsy findings here of basophilic intranuclear inclusions are characteristic of BK-virus induced nephropathy.
• The BK virus is a polyomavirus that is well-known to cause nephritis in renal transplant recipients who are immunosuppressed, with a prevalence of about 5%.
• ==Urin

IgA deficiency

• related: Allergy and Immunology, ID

MRSA risks

• related: ID, MRSA

Empiric MRSA coverage may be included in patients with risk factors for MRSA infection (MRSA nasal colonization, recent hospitalization, recent antibiotic use, previous MRSA infection).

Malaria notes

• related: ID

This patient with recent travel to Sub-Saharan Africa has an acute-onset febrile illness, scleral icterus, mild splenomegaly, anemia, and thrombocytopenia.  This presentation is most consistent with malaria.

Plasmodium falciparum accounts for the majority of deaths from malaria, followed by Plasmodium vivax.  Many of the clinical sympt

Pasteurella

• related: ID, cat bite

abscesses

• related: ID

Abscess vs cellulitis

bartonella

• related: ID

This patient has cervical and preauricular adenopathy as well as unilateral conjunctivitis. Given the history of kitten exposure, she most likely has oculoglandular syndrome (Parinaud syndrome), a specific manifestation of cat-scratch disease (CSD). CSD is caused by infection due to Bartonella henselae, a small gram-negative rod carried by cats, especially kittens. Human transmission most commonly occ

cat bite

• related: ID
• tags:

• Cat bites are more likely than dog bites to cause infection because of cats' sharp, narrow teeth
• Infections are caused by organisms from the animal's mouth flora and the host's skin flora. This flora comprises a mix of anaerobic and aerobic organisms, including streptococci, staphylococci, and Bacteroides, Fusobacterium, _Por

chlamydia psittaci

• related: ID

Chlamydia psittaci is the causative agent of psittacosis, which typically presents as pneumonia associated with abrupt onset of fever, severe headache, and dry cough. This organism is associated with inhalation of dried bird droppings, so bird owners or breeders and poultry farmers are at particularly high risk for this infection.

coxiella burnetti

• related: ID

Q fever

• pathogenesis: inhalation or aerosolized bodily fluid from infected animals
• occuptation risk: zoonotic organisms, farm animals
• sx
  • pulmonary infection from subclinical to severe
  • fever, myalgia, headache
• treatment: doxycycline

fever in travelers

• related: ID

The differential diagnosis for fever in a returning traveler depends on geographic epidemiology and is often divided into 3 categories (with some overlap):

• Early incubation period (<10 days) infections include typhoid fever, dengue fever, chikungunya, influenza, and legionellosis
• Medium incubation period (1-3 weeks) infections include malaria, typhoid fever, leptospirosis, schistosomiasis, and r

foodborne illnesses

• related: ID

Foodborne disease

ricketsia

• related: ID

Rocky Mountain spotted fever (RMSF) is a tick-borne illness caused by Rickettsia rickettsii. The classic triad of symptoms includes fever, headache, and rash. Early nonspecific manifestations (eg, fever, nausea, myalgias, arthralgias) are followed by the development of erythematous macules on the **wr

shigella

• related: ID

EHEC vs Shigella

EHEC infection occurs after exposure to infected animals (eg, farms, petting zoos) or ingestion of undercooked beef. Shigella sonnei causes bloody diarrhea and abdominal cramps. However, affected patients are commonly febrile, and animal exposure is not typical as it is usually contracted through contaminated food or water.

Antimicrobials should be avoided as they may i

Zika

• related: ID, dengue, chikungunya

Arboviruses are spread by arthropod vectors. Mosquitoes spread most travel-related arboviral diseases. Some arboviruses, such as yellow fever, are endemic throughout the tropics, and several countries require proof of vaccination before allowing entry by travelers. Other viruses, such as Japanese encephalitis, have more restricted geographic areas. The dengue fever, chikungunya, and Zika arboviruses are all spread by _A

MSSA vanc vs cefazolin

• related: ID

For MSSA, cefazolin/penicillin is better medication compared to vancomycin

HIV and immunization

• related: ID

Numerous immunizations are recommended for all persons with HIV, starting with the 13-valent pneumococcal conjugate and 23-valent pneumococcal polysaccharide vaccines, respectively, at least 8 weeks apart; a 23-valent polysaccharide vaccine booster is also recommended after 5 years. Patients who are not already immune or infected with HBV should receive the hepatitis B vaccine series. Influenza, tetan

histoplasmosis

• related: ID

Histoplasma capsulatum is responsible for one of the most common endemic mycoses in the world. Acquired by inhalation of airborne conidia, this organism primarily produces asymptomatic pulmonary infection. It is distributed along the ==Missi

plasmodium

• related: ID

This pregnant woman has contracted Plasmodium falciparum malaria after visiting a part of the world where malaria is endemic. Her clinical presentation and peripheral blood smear showing many parasitized erythrocytes demonstrating signet ring forms, together with the absence of trophozoites and schizonts, are typical for infection with P. falciparum. Of returning travelers with acute and potentially life-threatening febrile diseases, _P.

salmonella

• related: ID

This patient most likely has typhoid fever, also known as enteric fever, caused by either of the typhoidal Salmonella strains, S. typhi or S. paratyphi. Infection is transmitted by ingestion of food or water contaminated by feces. In resource-poor areas, organisms may be spread in community food or, more frequently, by water. In developed countries, transmission is chiefly by food

yersinia

• related: ID

Primary pneumonic plague occurs after Yersinia pestis exposure through infectious aerosols and person-to-person transmission through respiratory droplets, which are likely scenarios for bioterrorism. Patients with suspected pneumonic plague require droplet precautions.

Bubonic plague is characterized by lymphadenopathy (buboes), fever, rigors, and headache. Chest radiographs are nonspecific. Gra

PrEP

• related: ID

• Pre-exposure prophylaxis (PrEP) with antiretroviral medication is recommended in select persons at high risk for exposure to HIV to reduce the risk of infection.
• A two-drug combination of tenofovir disoproxil fumarate and emtricitabine, taken once daily, is FDA approved for HIV PrEP; it has been shown to be effective in reducing infection in persons at high risk.

anthrax

• related: ID

• Cause: Bacillus anthracis spores ([Figure 15][1] panel A and [Figure 15][2] panel B). Spores may be spread by aerosolization or in the mail, with infection following inhalation. Infection may also occur by cutaneous contact, with a characteristic black eschar forming ([Figure 15][3] panel C), or by ingestion. Person-to-person transmission does not occur.
• Sx:

cryptosporidium

• related: ID

Cryptosporidium species can infect humans and other mammals. Infection occurs through consumption of fecally contaminated water or food or through close person-to-person or animal-to-person transmission. Municipal water supplies and swimming pools can be a source of infection because the thick-walled oocysts are chlorine resistant and can evade filtration. This parasite is highly infectious; ingestion of fewer than 50 oocysts may resul

cyclospora

• related: ID

Cyclospora infections are typically acquired after consumption of food or water that is fecally contaminated with Cyclospora oocysts. In the United States, most of these infections have been traced to imported fresh produce from tropical areas or have occurred in persons who have traveled to areas of endemicity. The incubation period is approximately 1 week. Infected patients typically report watery diarrhea, decreased appetite, weight lo

MAC

• related: Tuberculosis, ID, Pulmonology
• tags: #pulmonology

Overview

• new bronchiectasis, nodules: females, no smoking hx.

  • indolent, fatigue, malaise, dry cough,
  • 2 AFB sputum
  • bronchoscopy: 1 specimen

• can also be fibrocavitary : older males, smoking hx

  • cavitation
  • can mimick TB

Mycobacterium avium complex (MAC) is a group of free-living nontuberculous mycobacteria that are ubiquitous in the environment.  Human

transplant infection

• related: ID

MRSA

• related: ID

Bacteremia

• VIRSTE criteria
• MEC A gene for MRSA vs MSSA
• Mec C gene for staph

Pneumonia

• related: Pulmonology, ID, pneumonia vaccine, legionella pneumonia
• tags: #pulmonology

Symptoms

• cough, purulent sputum, pleuritic chest pain, dyspnea, chillls, fever, night sweats, weight loss
• hemoptysis: necrotizing infections, lung abscess, TB, Gm neg pneumonia
• Elderly: less immune response. More nonrespiratory response. Confusion, weakness, lethargy, falling, decreased PO intake

Pathogenesis

• Common bugs: strep, H. flu, myco

tick born infections

• related: ID

• Lyme
• ehrlichosis

microbes by organs

• related: ID
• tags: #note

• brain: usually gram positives
• mouth: gm+, strep viridans, anaerobes
• throat: anaerobes
• lung: GPC, GNR
• heart: GPC 98% of the time
• belly: GNR, anaerobes, few strep
• UTI: GNR
• bones: feet: microbials
  • sacrum: GNR, anaerobes

acinetobacter

• related: ID
• tags: #note

Do not switch from Unasyn to Augmentin for Acinetobacter as Sulbactam is the active antibiotic that treats the bacteria

Bioterrorism

• related: ID
• tags: #id

Introduction

Unusually severe illness, rapid increase in disease incidence, atypical clinical presentation, and uncommon geographic, temporal, or demographic clustering of disease outbreaks suggest a bioterrorism attack. Bioterrorism agents are classified (Table 39) according to ease of dissemination, mortality rate, potential for public panic and so

Central Nervous System Infections

• related: ID
• tags: #id

Meningitis

A positive Gram stain result for bacteria or yeast is seen in only 5% of patients with community-acquired meningitis. Meningitis with a negative Gram stain result is a diagnostic and management challenge because the differential diagnosis includes urgent treatable causes, such as bacterial or fungal meningitis. Bacterial cultures of cerebrospinal fluid (CSF) or blood are needed for antimic

Community-Acquired Pneumonia

• related: ID
• tags: #id

Epidemiology

Community-acquired pneumonia (CAP) is a leading cause of infection and hospitalization in the United States, associated with more than $10 billion annually in health care expenditures. The spectrum of illness due to CAP ranges from mild disease, with approximately 50% of patients managed in the ambulatory setting, to fatal infections. Rates of hospitalization increase with advanced age; the i

Fever of Unknown Origin MKSAP

• related: ID
• tags: #id

Introduction

The classic definition of fever of unknown origin (FUO) has changed over time (including removing the requirement for in-hospital evaluation), and three categories have been added: health care–associated, neutropenic, and HIV-associated (Table 37). Diagnostic advances have revealed a spectrum of diseases causing FUO, wit

Fungal Infections

• related: ID
• tags: #id

The incidence of fungal infection is increasing because of the increased recognition of these infections and an increase in the population at risk worldwide. According to a recent analysis by the Prospective Antifungal Therapy Alliance, the most commonly encountered infections in North America were caused by Candida species (73%) followed by Aspergillus species (14.8%), other yeast (such as Cryptococcus species; 6

HIV-AIDS

• related: ID
• tags: #id

HIV is a retrovirus that infects CD4 lymphocytes, among other cell types. Depletion of CD4 T-helper cells results in impairment of cell-mediated immunity and increasing risk for opportunistic infections. This chapter will focus on HIV-1. Infection with HIV-2 primarily occurs in parts of Africa and remains rare in the United States; HIV-2 generally is a less progressive disease with less immunocompromise and lower risk of opportu

Health Care–Associated Infections

• related: ID
• tags: #id

Epidemiology

Health care–associated infections (HCAI) have been linked to indwelling medical devices, prosthetic devices and materials, surgery, invasive procedures, transmission of organisms between patients and health care personnel, and environmental factors. Four percent of hospitalized patients acquire at least one HCAI, costing the U.S. health care system an estimated $28 billion to $45 billion

Infections in Transplant Recipients

• related: ID
• tags: #id

Introduction

Despite improvements in immunosuppression and antimicrobial therapy, infection remains a significant cause of morbidity and mortality after solid organ transplantation (SOT) and hematopoietic stem cell transplantation (HSCT). Infection is the most common cause of death in the first year after SOT. Additionally, the interaction of the immune system and infection goes both ways; although

Infectious Gastrointestinal Syndromes

• related: ID
• tags: #id

Overview

Diarrhea, defined as three or more unformed stools daily or a quantity greater than 250 grams daily, is a major public health concern. Diarrhea lasting less than 14 days is considered acute, 14 to 30 days is persistent, and longer than 30 days is chronic. Acute infectious diarrheal presentations include acute gastroenteritis, with associated fever, nausea, vomiting, flatulence, tenesmus,

Mycobacterium tuberculosis Infection

• related: ID
• tags: #id

Epidemiology

Tuberculosis is one of the oldest and most prevalent infectious diseases in the world. It remains one of the most common causes of death from an infectious disease worldwide. Although rates of Mycobacterium tuberculosis infection remain relatively low in North America, approximately one third of the world's population is infected with the bacteria. As of 2015, approximately 10 milli

Nontuberculous Mycobacterial Infections

• related: ID
• tags: #id

Nontuberculous mycobacteria (NTM) comprise species other than Mycobacterium tuberculosis complex and Mycobacterium leprae. NTM are often divided into slow and rapid growers (Table 25). These organisms are found in surface water, soil, domestic and wild animals, milk, and food products. Additionally, they can be colonizers,

Osteomyelitis MKSAP

• related: ID
• tags: #id

Osteomyelitis occurs as a result of hematogenous dissemination or contiguous spread of bacteria. Hematogenous osteomyelitis in adults most commonly affects vertebral bodies, although involvement of other sites has been described, particularly in persons who inject drugs. Contiguous-spread osteomyelitis may arise from direct contamination (fracture, joint replacement, orthopedic implant), wounds (pressure sores, diabet

Primary Immunodeficiencies

• related: ID
• tags: #id

Introduction

Primary immunodeficiency disorders often present during childhood, but milder heritable forms may not manifest until adulthood. Primary immunodeficiency should be considered when patients present with frequent infections or infections with unusual organisms. The specific microbiology is often a clue to which arm of the immune system is affected (**[Table 38](https://mksap18.acponline.org/app/to

Prion Diseases of the Central Nervous System

• related: ID
• tags: #id

Prions cause rare but relentlessly progressive and rapidly fatal neurodegenerative diseases characterized by dementia and ataxia. The cause of disease is an abnormally folded prion protein. In humans, prion diseases occur by three mechanisms: sporadic (spontaneous), familial (genetic), and acquired (infectious or transmissible). In patients of any age presenting with otherwise unexplained rapi

Sexually Transmitted Infections

• related: ID
• tags: #id

Introduction

Sexually transmitted infections (STIs) occur most commonly in adolescents, young adults, and men who have sex with men (MSM), but STIs affect all demographics. Most infections are asymptomatic, so it is imperative that a detailed sexual history, including sexual practices, be obtained to understand individual risk. STI risk factors include a new partner, more than one current partner, a pa

Skin and Soft Tissue Infections

• related: ID
• tags: #id

Introduction

Skin infections usually result from epidermal compromise that allows skin colonizers such as Staphylococcus aureus and Streptococcus pyogenes to become pathogenic. Predisposing conditions include vascular disease, immunodeficiency, neuropathy, previous cellulitis, obesity, skin trauma, tinea pedis, and lymphedema. Infections can be characterized by anatomic involvement and presence or

Stewardship and Emerging Resistance

• related: ID
• tags: #id

Introduction

Emergence of antibiotic resistance is potentiated by all antibiotic use. Careful antibiotic use is essential to preserving the armamentarium. Among outpatient visits, 12.6% are associated with antibiotic prescriptions, and 30% of those prescriptions are considered inappropriate. Most prescriptions are for acute respiratory infections (usually caused by viruses) and asymptomatic bacteri

Tick-Borne Diseases

• related: ID
• tags: #id

Lyme Disease

Lyme disease is the most common vector-borne infection in the United States. More than 30,000 new infections are reported annually, which likely represent only 10% of actual infections. More than 95% of infections in the United States occur in the northeastern, mid-Atlantic, and upper Midwest regions (Figure 5). These areas are e

Travel Medicine

• related: ID
• tags: #id

Introduction

Pretravel consultation should occur no less than 4 to 6 weeks before departure. Regularly updated information by country is available on the Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) websites (http://www.cdc.gov/travel and http://www.who.int/ith). Travel-related illnesses (mostly febrile, diarrheal, respiratory, and cutaneous infections) are reported in 20% t

Urinary Tract Infections

• related: ID
• tags: #id

Epidemiology and Microbiology

Community-acquired urinary tract infections (UTIs) account for approximately 8 million ambulatory visits and 1 million hospitalizations each year in the United States, making them one of the most common infections for which an antibiotic is prescribed in clinical practice. Another 1 million nosocomial UTIs are diagnosed annually, primarily indwelling urinary catheter–associated U

Viral Infections

• related: ID
• tags: #id

Influenza Viruses

Overview

Three types of influenza viruses primarily infect humans: A, B, and C. Influenza A viruses are divided into subtypes based on two surface proteins, hemagglutinin (H) and neuraminidase (N). Influenza A viruses can infect animals and humans and produce epidemics and pandemics. Influenza B viruses only affect humans and cause yearly epidemics but not pandemics. Influenza C causes mild ill

culture negative endocarditis

• related: ID
• tags: #id

This patient has multiple findings to suggest subacute infective endocarditis (ie, fatigue, low-grade fevers, splenic infarcts, m

Schistosomiasis

• related: ID
• tags: #id

This young man with terminal hematuria (blood at the end of micturition) has a history of extensive travel to a schistosomiasis-endemic area; his laboratory studies are notable for eosinophilia, hematuria, and leukocyturia without bacteriuria or glomerular casts.  These findings are consistent with Schistosoma haematobium infection.  In contr

antibiotic prophylaxis for secondary prevention of rheumatic fever

• related: ID
• tags: #id

This patient's childhood history of a febrile illness with movement disorder (chorea) is consistent with previous rheumatic fever complicated by persistent valvular disease (mitral stenosis).  Rheumatic fever occurs as a complication of group A beta-hemolytic Streptococcus (GAS) phary

treat fever in asplenic patients seriously

• related: ID
• tags: #id

Asplenic patients are at increased risk of infection from encapsulated organisms such as Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis.  Overwhelming infection in asplenic patients is rare but rapidly fatal if not recognized and treated aggressively at an early stage.  On presentation, the patient may have mild symptoms and not appear toxic, but the infecti

sexually transmitted proctitis

• related: ID
• tags: #id

This patient’s presentation of tenesmus, purulent discharge, and small-volume stools containing blood is consistent with proctitis.  Proctitis has multiple causes, including ulcerative colitis, radiation treatment, and infections.  Given this patient’s history, a sexually transmitted infection is most likely.  Neisseria gonorrhoeae

candida infections

• related: Pulmonology, ID
• tags: #pulmonology

Lung

Bronchial tree colonization with Candida species is common in critically ill patients receiving mechanical ventilation, but primary Candida pneumonia and invasive disease are rare.  Candida pneumonia is usually not due to aspiration of oropharyngeal secretions but rather to hematogenous spread from disseminated candidiasis (eg, osteomyelitis, septic arthritis, or endocar

HIV CNS lesions

• related: ID
• tags: #id

Toxoplasma gondii infection in AIDS usually presents in patients with CD4 cell counts less than 100/µL. Because it is a reactivation disease, patients are usually serology positive. Clinical presentation includes headache, fever, and focal neurologic deficits. Imaging by CT or MRI (which is more sensitive) rev

acute rheumatic fever

• related: ID, antibiotic prophylaxis for secondary prevention of rheumatic fever
• tags: #id

This patient's history (recent emigration) and presentation with fever, arthralgias, migratory arthritis, subcutaneous nodules, mitral regurgitation murmur, and elevated erythrocyte sedimentation rate (ESR) are suggestive of acute rheumatic fever (ARF).  Rheumatic fever o

herpes zoster ophthalmicus require ophtho consult

• related: ID
• tags: #id

This patient presents with headache, malaise, fever, and a skin rash, all highly suggestive of herpes zoster.  The vesicular, crusty skin eruption on her forehead also involves the eyelids, with evidence of edema and drooping.  She is at risk of developing herpes zoster ophthalmicus (HZO).  HZO is a serious, vision

Medicine

• Related: Step 1, mksap, notes

Todos

• tolearn

Organ Systems

• Allergy and Immunology
• Rheumatology
• Cardiology
• Dermatology
• Endocrine
• ENT
• GI
• Hemeonc
• ID
• MSK
• Nephrology
• Urology
• Neurology
• Pulmonology
• Podiatry

Subject Areas

• General
• Biostats
• Psychiatry
• Geriatrics
• OBGYN
• Pediatric
• [