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PANCE Topic List: Infectious Disease

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What is SIRS?
SIRS often represents the body's host response to an infection. Although research has found that SIRS criteria alone does not predict an increased mortality, it should prompt continued investigation for an underlying pathology. The presence of organ dysfunction and shock, however are significant predictors of adverse outcomes and should be fully addressed. Sepsis is the tenth most common cause of death in the US.
What are the 4 parameters of the SIRS critera?
Temp
WBC
Heart rate
Respiratory rate
What is the MC cause of fungal meningitis?
Cryptococcus neoformans - a yeast
Risk factors for cryptococcus infection?
Hodgkin's lymphoma
Steroids
HIV
Clinical features of cryptococcus infection?
Can cause meningitis or pulmonary infection
What are lab findings with cryptococcus?
CSF will show: Low glucose, high protein, high lymphocytes
India ink prep is used
Latex agglutination titer
Treatment for cryptococcus?
Amphotericin B plus flucytosine for meningitis
Fluconazole for pulmonary disease
What causes coccidiomyocosis infection?
Coccidioides immitis
Clinical features of coccidiomyocosis infection?
Found in Southwest US
Pulmonary symptoms with arthralgias
CXR can be normal or show single or multiple areas of airspace consolidation which progress to the formation of nodules or cavities
Treatment of coccidiomyocosis infection?
Fluconazole or itraconazole
Amphotericin B
What organism causes Histoplasmosis?
Histoplasma capsulatum - a dimorphic fungi
How is histoplasmosis spread?
Bird dropping and bat exposure
Endemic to Mississippi and Ohio river valleys
Clinical features of Histoplasmosis?
Most patients are asymptomatic
Can be severe disseminated disease (if immunocompromised)
What is the MC CXR abnormality with Histoplasmosis?
Solitary pulmonary calcification. "BB sized calcifiecations". Cavitation is rare, but hilar and mediastinal adenopathy is seen frequently.
Miliary pattern
Diagnosis of Histoplasmosis?
Culture - gold standard (but takes a lot of time)
Fungal staining - quicker but less sensitive
Urine antigen test
Treatment for Histoplasmosis?
Amphotericin B - if severe
Itraconazole - if moderate
What is Rheumatic fever?
A systemic immune response occurring usually 2-3 weeks following a beta hemolytic strep pharyngitis. Most commonly affects the heart, joints, skin, and CNS. Children from 5-15 are MC affected.
How do you establish diagnosis of Rheumatic fever?
Jones criteria
Need 2 major criteria or 1 major with 2 minor + positive throat cultures or ASO titer
Labs for Rheumatic fever/heart disease?
Strep test
ASO titer
Tx for Rheumatic fever?
Strict bed rest
IM PCN. Erythromycin if patient is PCN allergic
Salicylates
Steroids
Prophylaxis - Benzathine PCN every 4 weeks
What organism causes botulism?
Clostridium botulinum - an aneorobic spore forming bacillus found in the soil which may be packed in foods (canned goods, honey)
What is the mechanism of action of the botulinum toxin?
Inhibits the release of acetylcholine at the neuromuscular junction
Clinical findings of botulism?
Initially visual changes (diplopia, loss of accommodation) 12-36 hours after exposure
Ptosis
Impaired EOM
Fixed, dilated pupils
Cranial nerve palsies
Dysphonia
Dysphagia
N/V
Respiratory paralysis if untreated
FLOPPY BABY
Diagnostic lab for botulism?
Antiserum after mouse inoculation with the patient's serum
Tx for botulism?
Botulinum antitoxin though the CDC
Intubation if there is respiratory failure
IV nutritional support for dysphagia
What causes Diphtheria?
Infection caused by Corynebacterium diphtheriae which is transmitted via respiratory secretions. It produces an exotoxin that causes myocarditis and neuropathy
What are clinical features of diphtheria?
Rhinorrhea
Upper airway and bronchial obstruction
Gray membrane which covers the tonsils and pharynx with mild sore throat, fever, and malaise <--- MC presentation
Myocarditis
Tx for diphtheria?
Horse serum antitoxin which is obtained from the CDC
Removal of gray membrane via laryngoscopy
PCN or erythromycin
Isolation - need three negative cultures to be documented before released
Contacts should be treated
What organism causes Tetanus?
Clostridium tetani - ubiquitous in soil and its spores germinate in wounds where the bacteria produce a neurotoxin (tetanospasmin)
What is the MOA of tetanus spores?
It interferes with neurotransmission at spinal synapses of inhibitor neurons. The result is uncontrolled spasms and exaggerated reflexes
Who is at risk for tetanus?
Anyone with a puncture wound
Kids
Elderly
Immigrants
IVDU
Clinical features of tetanus?
Incubation is 5-15 weeks
Pain and tingling at the site of inoculation followed by spasticity of the muscles nearby
Jaw and neck stiffness
Dysphagia and irritiablity
Hyperreflexia and muscle spasms develop, especially in the jaw (trismus) and face
Painful tonic convulsions if untreated
Tx of tetanus?
Tetanus immune globulin given IM with a full course of tetanus toxoid once patient recovers
Bed rest, sedation, mechanical vent
PCN
When should tetanus prophylaxis be administered for routine wound management?
If the wound is dirty and tetanus immunization has been more than 5 years
What causes Salmonellosis?
Infection due to Salmonella enterica - gram-negative bacterium. Transmitted by ingestion of contaminated food or water. Three patterns.
What are the three patterns of salmonellosis? Which is the most common form?
Enteric fever (typhoid fever)
Gastroenteritis <----most common
Bacteremia <---common in immunosuppressed
What are clinical features of gastroenteritis due to Salmonella?
MC cause of food poisoning
Incubation period is 8-48 hours after ingestion of contaminated food or drink
Fever, N/V, abdominal cramping, BLOODY DIARRHEA lasts for 3-5 days.
What are typical kinds of foods that contain Salmonella?
Raw meat or poultry
Fresh produce - bean sprouts, tomatoes, lettuce, melons
What are signs of inflammatory diarrhea?
Blood or mucus in the stool, severe abdominal pain and fever
How do you diagnose gastroenteritis due to Salmonella?
Stool culture
How do you treat gastroenteritis due to Salmonella?
Self-limiting disease
Supportive care - fluids
Antibiotics are indicated in immunocompromised and children
What antibiotics can be used for Salmonella?
Cipro, Bactrim, Ampicillin
What is Shigellosis?
AKA Dysentery. Caused by Shigella sonnei, Shigella flexneri, Shigella dysenteriae which are aerobic, gram-negative bacilli that are primarily transmitted person to person by the fecal-oral route or by ingestion of contaminated food or water. Children in daycare settings or crowded living conditions are MC affected.
What are clinical features of Dysentery?
Onset is days after ingestion
Abrupt diarrhea, lower abdominal cramps, and tenesmus
Fever, chills, anorexia, HA, malaise
WATERY LOOSE stools mixed with BLOOD and MUCUS
The characteristic bloody diarrhea appears after the fever subsides.
Diagnostic studies for Dysentery?
Stool is positive for leukocytes and RBCs
Culture is positive for Shigella
Sigmoidoscopy reveals inflamed, engorged mucosa, punctate lesions, or ulcers
Tx for Dysentery?
Fluid replacement
Antibiotics: Fluoroquinolones, Bactrim or Azithromycin
What is Campylobacter jejuni?
Bacteria transmitted via ingestion of fecally-contaminated food and water. Incubation is 1-7 days.
Clinical features of Campylobacter infection?
Common in SE Asia
Low fever
Abdominal cramping
Diarrhea that is initially watery, but may become bloody.
Mimics appendicitis or intussusception
Treatment of Campylobacter?
Mild and self-limiting
Can do fluoroquinolones or azithromycin
What is the MC cause of traveler's diarrhea?
Enterotoxigenic Escherichia coli
Clinical features of Enterotoxigenic Escherichia coli?
Transmission is through the fecal-oral route
Countries in Asia, Africa, Latin America and parts of the Middle East are high risk destinations.
Abrupt onset of crampy abdominal pain and WATERY DIARRHEA
Treatment of Enterotoxigenic Escherichia coli?
Fluids
Cipro for 3 days
Loperamide
Clinical features of Enterohemorrhagic E.Coli (O157:H7)?
Produces Shigella-like toxins that are cytotoxic to the intestinal vascular endothelium
BLOODY diarrhea, abdominal cramping, and low-grade fever.
What organism causes Cholera?
Vibrio cholerae
What is the mechanism of action of vibrio cholerae?
It produces a toxin that activates adenylyl cyclase in the intestinal epithelial cells of the small intestine which causes hyypersecretion of water and Cl and then MASSIVE diarrhea
Clinical features of Cholera?
Sudden onset of severe RICE WATER DIARRHEA - gray turbid and without odor blood or pus
Dehydration
Hypotension
Electrolyte imbalance
Death results from hypovolemia
Diagnostic studies for Cholera?
Stool culture
Serum agglutination tests
Treatment for cholera?
Replacement of fluids and electrolytes
Oral rehydration with water, salt, and sugar in mild cases. Severe requires IVF
Antibiotics for the severely ill or those with comorbidities (Tetracycline, ampicillin, chloramphenicol, TMP-SMX, and fluoroquinolones)
Prevention (clean water and food, vaccine is available)
What is Giardia?
Giardia duodenalis (also known as G. lamblia or G. intestinalis) is a protozoan parasite capable of causing sporadic or epidemic diarrheal illness. It is the MC intestinal parasite in the US. and is associated with ingestion of contaminated water from streams or wells.
Clinical features of Giardia
Diarrhea - 90 percent
Malaise - 86 percent
Foul-smelling and fatty stools (STEATORRHEA) - 75 percent
Abdominal cramps and bloating - 71 percent
Flatulence - 75 percent
Nausea - 69 percent
Weight loss - 66 percent
Vomiting - 23 percent
Fever - 15 percent
Constipation - 13 percent
Urticaria - 10 percent
Treatment for Giardia?
Metronidazole
Atypical mycobacterial disease
mycobacterial
Helminth infestations
Parasite
Malaria
Parasite. There are four known types of malaria: Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae. Although P. vivax is the most common form, P. falciparum leads to the most virulent disease, causing most cases of severe malaria and most malaria-related deaths. Because of its ubiquitous presence in much of the world, malaria should be considered in any patient with severe fevers and chills who reports recent travel to an endemic region. Classically, malaria begins with a flu-like prodrome that progresses to cyclical episodes of chills followed by fever, each lasting about two hours. These episodes recur every three days with P. vivax and P. ovale and every four days for P. falciparum and P. malariae. These episodes are associated with a hemolytic anemia, as identified in this patient by scleral icterus, low hemoglobin, elevated LDH, and indirect bilirubin. Identifying Plasmodial parasites on Giemsa-stained thick and thin smears makes the definitive diagnosis. Malaria

P. falciparum (deadliest), P. ovale, P. vivax, P. malariae
P. ovale, P. vivax: hepatic phase
Anopheles mosquito
Immigrant, traveler
Irregular fevers, diaphoresis
P. falciparum: cerebral malaria, Blackwater fever
Uncomplicated, no resistance areas Rx: chloroquine
Complicated, P. falciparum rx: quinidine + doxycycline
Toxoplasmosis
Parasite. This patient presents with toxoplasmosis encephalitis and should be treated with pyrimethamine and sulfadiazine. Toxoplasmosis is a parasitic disease caused by Toxoplasma gondii. Cats are the primary reservoir for human infection. Infection is mild in healthy patients and will often present with flu like symptoms. However, in those with immunocompromise including HIV/AIDS, the disease can be more severe and be complicated by encephalitis. Encephalitis from toxoplasmosis presents with headache, nausea, vomiting, fever, altered mental status, focal neurologic deficitis and seizure activity. In any patient with a history of HIV and a new seizure, a CT scan of the head should be obtained. Although the disease more commonly affects patients with AIDS, it can also be seen in patients with HIV. The diagnosis of toxoplasmosis encephalitis can be made based on the findings with a contrast CT scan. CT scan will reveal multiple ring-enhancing lesions in 70-80% of cases. The treatment of toxoplasmosis encephalitis is with pyrimethamine and sulfadiazine. Folinic acid should be supplemented as well.
Pinworms (enterobiasis)
Parasite. Transmission via ingestion of Enterobius vermicularis eggs
Nocturnal pruritus ani
Dx: tape test
The treatment is with single-dose mebendazole (or albendazole), an oral anthelmintic
How does Lyme disease clinically present?
Macule/papule at bug bite site
3-21 days later, enlarges forming annular lesion with distinct red borders and partial central clearing "ERYTHEMA MIGRANS" TARGET like
Associated Sx: chills, fever, myalgia, headache, lymphadenopathy, weakness
What is Lyme disease?
Tickborne illness caused by the spirochete Borrelia Burgdorferi. Most common in the mid-atlantic, northeast, and northcentral US. 3 Stages of disease
Syphilis
Spirochete. Syphilis is caused by the spirochete Treponema pallidum. Transmission occurs during exposure of moist skin to an infected area as the organism does not survive on dry surfaces. Syphilis progresses through three stages of illness. Primary syphilis is characterized by the chancre shown in the picture above. The lesion occurs at the site of exposure and begins as an erythematous papule that ultimately ulcerates. The ulcer has raised edges, sharply demarcated borders and a clean base. Left untreated, the chancre resolves after 2-6 weeks. Bilateral painless inguinal adenopathy is sometimes present. Secondary syphilis develops 5-8 weeks after resolution of the chancre. Most commonly, this stage involves a diffuse total body rash beginning on the trunk and spreading distally, often involving the palms and soles. During this stage, condylomata lata may develop (broad-based papules in the perineal area). Syphilis then enters a latent period, which can last for years in immunocompetent patients and then manifest most commonly affecting the cardiac or nervous systems. The treatment of primary syphilis is penicillin G benzathine 2.4 million units IM.
What are clinical features of each stage of Lyme disease?
Stage I: erythema migrans (pathognomonic), viral-like syndrome
Stage II (4 weeks): arthritis, myocarditis, bilateral Bell's palsy
Stage III: chronic arthritis, chronic encephalopathy
How do you diagnose Lyme disease?
B. burgdorferi antibody test <---best test
Western blot is confirmatory test
50% of patients can have a negative titer in the first few weeks therefore early diagnosis of Lyme disease should be based on clinical symptoms
What are complications from Lyme disease?
MSK disease - arthritis
CNS and PNS manifestations - subacute encephalopathy, paresthesias, ataxia, bladder dysfunction
Acrodermatitis chronicum atrophicans - bluish-red discoloration of distal extremities (Seen in Europe)
Tx of Lyme disease?
Doxy <----DOC
2nd line: Amoxicillin, Ceftriaxone (in pregnant pts and children)
Symptomatic tx: NSAIDs
Education on prevention
What is a Jarisch-Herxheimer reaction?
The onset of fever, myalgias, headache, tachycardia and tachypnea after initiation of antibacterial treatment of a spirochete illness.
What is Rocky Mountain Spotted Fever (RMSF)?
Caused by the spirochete Rickettsia rickettsii. Cause by wood tick. Most common in the southeastern US
Tularemia
The major tick-borne diseases include Rocky Mountain spotted fever (RMSF), Lyme disease, ehrlichiosis, babesiosis and tularemia. Tularemia is caused by Francisella tularensis and is transmitted to humans either by tick bites or handling of infected animals (rabbits and rodents). It is associated with Ulcer at site, lymphadenopathy, conjunctivitis, pneumonia. Dx is clinical. Tx is Streptomycin
Clinical features of RMSF?
Sx occur 2-14 days after exposure
High fever, chills
HA
N/V
Myalgias
Restlessness/insomnia
Irritability
Flushed face, conjunctiva is injected
Macules-->maculopapules--->petechiae develop on wrists and ankles then spread to extremities/trunk
RASH ON PALMS AND SOLES!
Complications from RMSF?
Cardio - myocarditis, AV blocks, dysrhythmias
Neuro - encephalomyelitis, meningitis, cerebral thrombovasculitis
Skin - vasculitis, ecchymosis and ulcerations
Diagnostic studies for RMSF?
indirect immunofluorescence assay (IFA) is test of choice
CBC - leukocytosis, thrombocytopenia
BMP - hyponatremia
UA - proteinuria, hematuria
CSF analysis - pleocytosis, hypoglycorrhachia
Antibody titers are positive in 2nd week
Tx for RMSF?
Doxy
CMV
...
What is the best way to remove a tick?
Although many techniques have been described over the years for removing a tick, the correct method is to use tweezers or forceps, grab the tick's head as close to the skin as possible, and gently pull upward. The goal is to avoid crushing or tearing the tick's head or body because this can induce regurgitation of infectious contents or leave behind its body parts, a possible nidus for infection or a granulomatous reaction.
HIV
...
What characteristic disease does the Epstein-Barr virus cause?
Mononucleosis AKA "Kissing disease" because transmitted through saliva. Incubation period is several weeks. EBV is human herpes virus 4
Clinical features of Mono?
Incubation period of several weeks
FATIGUE
Fever, sore throat
Oral lesions (exudative pharyngitis, tonsillitis, gingivitis, soft palate petechiae)
POSTERIOR cervical lymphadenopathy
SPLENOMEGALY (50% of cases)
Complications from Mono?
Secondary bacterial pharyngitis
Splenic rupture
Pericarditis
Myocarditis
Aseptic meningitis
Transverse myelitis
Encephalitis
How do you diagnose Mono?
Clinical presentation
Monospot (Heterophile antibody test)
CBC - Early granulocytopenia followed by lymphocytic leukocytosis (classic finding)
ATYPICAL LYMPHOCYTES appear as larger cells that stain darker and are vaculolated
EBV IgM antibodies
How do you treat Mono?
Symptomatic treatment - antipyretics, anti-inflammatories, antivirals
Avoid contact sports with splenomegaly for 1 month
Steroids
Counsel if abx are given - rash will develop
What is Influenza?
Caused by orthomyxovirus and transmitted through droplet nuclei. Occurs in epidemics and pandemics in the fall and winter. There are three strains: A, B, C. A is more capable of causing disease.
Clinical findings of influenza?
18-72 hour incubation period
ABRUPT fever, chills, malaise, muscle aches, substernal chest pain, HA, nasal congestion, nausea.
Associated coryza, dry cough, photophobia, eye pain, sore throat, pharyngeal injection, flushed face.
May be wheezes and rhonchi.
Who is most at risk for complications from influenza?
Elderly
Chronically ill
What is Reye syndrome?
Fatty liver with encephalopathy that may develop 2-3 weeks after influenza or varicella infection, especially if ASA is taken. Rarely occurs in patients over 18.
Diagnostic studies for the Flu?
Viral cultures taken from throat or nasal mucosa. Takes 3-7 days to return.
Rapid flu serology - 50-70% sensitive, 95% specific. Results are most accurate in the first few days.
CXR will show bilateral diffuse infiltrates
Tx for flu?
Supportive care ----> rest, analgesics, fluids, cough suppressants
Neuraminidase inhibitors: Oseltamivir (Tamiflu), Zanamivir inhalation (Relenza). Must be given within 48 hours of onset. Note that resistance to Tamiflu is on the rise.
Prognosis is good. Most recover in 1-7 days.
Prevention of Flu?
Trivalent or quadravalent vaccine yearly.
Should be given Sep-Nov
Especially recommended for people >65
FluMist nasal spray is recommended for patients 2-49 but is live
Immunity occurs 2 weeks after receiving the vaccination
Contraindications to the flu vaccine?
Sensitivity to eggs
Acute febrile illness
Thrombocytopenia
Complications from flu shot?
Tenderness, redness, soreness
Myalgia and fever are rare
What are the 6 exanthems (rash-causing diseases)?
Measles (Rubeola)
Scarlet fever
German measles (Rubella)
Filatov-Dukes disease
Fifth disease (Erythema Infectiosum)
Roseola
Rabies
Raccoons > bats > skunks
< 50% of cases due to bats have a documented bite
Viral prodrome (HA, fever, rhinorrhea, pharyngitis)
Encephalitis
Hallucinations, ataxia, seizure
Aerophobia
Hydrophobia, agitation, spasms
Hypersalivation
Coma, death
PEP: wound care (scrubbing), Ig at wound site, vaccination
What are clinical features of Measles?
AKA Rubeola
3 C's: Cough, Coryza (cold-like symptoms), Conjunctivitis
4 day fevers
KOPLIK's SPOTS- small red oral lesions with blue-white centers on buccal mucosa that appear before the rash
Macular-papular rash on the head which spreads to the body over 3 days
How do you treat Measles?
Supportive care - Measles is self-limiting (lasts 7-10 days)
What is a rare complication of Measles?
Subacute sclerosing panencephalitis (SSP) - fatal encephalitis that occurs years after initial infection
What is Scarlet fever?
AKA "SCARLETINA". Most commonly affects children between 5 and 12 years of age. Caused by GAS which release erythrogenic exotoxin.
What are clinical features of Scarlet fever?
Classic symptoms: FINE SANDPAPER rash in groin, axilla with DESQUAMATION (peeling) after 3-4 days.
Strep symptoms: Pharyngitis, fever
Bright red tongue with a "STRAWBERRY" appearance
rabi
The question as to which patient requires human rabies immune globulin and human rabies vaccine after exposure to a potentially rabid animal is common in emergency medicine. Even though there was no clear bite or abrasion, the Advisory Committee on Immunization Practices (ACIP) recommends postexposure prophylaxis with immune globulin and vaccine for unvaccinated patients who have been in close proximity to bats, even if there is no sign of injury or damage to the skin, including waking up and finding a bat in the room. In an unvaccinated individual, this means human rabies vaccine and immune globulin given at the time of presentation.
How do you treat Scarlet fever?
PCN VK or Amoxicillin
What is German Measles?
AKA "RUBELLA"
Symptoms last 2-3 days
Half of patients with Rubella are asymptomatic
What are clinical features of German Measles?
Rash that starts on the face and spreads to the rest of the body (less intense than measles)
Low grade fever
Postauricular and occipital adenopathy
Aching joints, especially among young women.
FORCHEIMER spots (fleeting small, red spots on the soft palate) - can also be seen with measles and scarlet fever.
How do you diagnose Rubella?
Usually a clinical diagnosis
Can do paired sera - get a blood sample now and then in a week. This is usually done in immunocompromised patients.
How do you treat Rubella?
Symptomatic treatment
Dengue fever
Dengue fever is an RNA virus transmitted to humans by infected mosquitos in the tropical regions of South East Asia, Mexico, Central America, Africa and the Caribbean. Children younger than 15-years-old have increased severity and mortality. Associated morbidity and mortality is secondary to hemorrhage from thrombocytopenia, platelet dysfunction or disseminated intravascular coagulation. Symptoms include abrupt onset of high fever, retro-orbital pain, headache, myalgias, arthralgias, mucosal bleeding and petechiae. Associated fatigue, nausea, vomiting and abdominal pain are common. Laboratory testing commonly reveals thrombocytopenia, leukopenia, elevated liver transaminases and elevated hematocrit. Supportive care is the treatment of choice. Confirmatory testing is rarely obtained but can be obtained by sending serum for reverse transcriptase-PCR of dengue virus or ELISA dengue IgM.
What is Erythema Infectiousum?
AKA 5th disease
Caused by Human Parvovirus B19
What are clinical features of Erythema Infectiosum?
Mild flu like illness
NONFEBRILE
Rash at 10-17 days (not contagious with rash)
SLAPPED CHEEKS
LACEY rash on arms and legs
Arthralgias in older patient
Can cause fetal death in 1st trimester
Cat Bite
Most commonly caused by Pasteurella multocida
Treatment is irrigate, leave wound open, amoxicillin - clavulanate
Complications: Osteomyelitis, Tenosynovitis
Treatment for Erythema Infectiosum?
Symptomatic treatment
What is Roseola?
AKA Exanthem Subitum
Caused by human herpesvirus 6 (HHV-6)
Occurs in infants ages 6 months - 3 yo
What are clinical features of Roseola?
High, abrupt FEVER--->febrile seizures. Fever lasts 3-7 days and ends abruptly
Rash on face, neck, arms, legs (pinkish-red flat or raised rash which turn white when touched)
Defervescence (fever goes away) occurs before rash appears
Treatment for Roseola?
Symptomatic treatment