Infectious Disease ER CAQ 2022 Questions and Answers
Which of the following meets criteria for a diagnosis of systemic inflammatory response syndrome
... [Show More] (SIRS)?
Heart rate > 80 and respiratory rate > 16
Heart rate > 90
Heart rate > 90 and temperature > 100.4°F
Temperature > 100.4°F and WBC > 10,000 - Correct Answer ( C )
Explanation:
The SIRS criteria is part of the sepsis syndrome spectrum of diseases. 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.
Question: What is the definition of Sepsis Criteria? - Answer: The presence of SIRS + a suspected or confirmed source of infection.
Sepsis Syndromes
SIRS: 2 or more of the followingT >38° or <36°HR > 90 bpmRR > 20 bpm or PCO2 < 32 mmHgWBC > 12,000 or < 4000
Sepsis: SIRS + infection
Severe sepsis: sepsis + organ dysfunction
Septic shock: sepsis + refractory hypotension
A 26-year-old woman presents to the ED after finding a tick attached to her right flank. She believes it has been there since she went hiking four days prior. On exam, you notice a red annular rash on her right flank with mild central clearing. A urine beta-hCG test is positive. Her last menstrual period was six weeks prior to this visit. What antibiotic prescription should this patient receive?
Amoxicillin, 14 days
Doxycycline, 7 days
Erythromycin, 7 days
Trimethoprim-sulfamethoxazole, 14 days - Correct Answer ( A )
Explanation:
This patient has a history and physical exam consistent with Lyme disease. Her rash is classic for erythema migrans, seen in 60%-80% of those with Lyme disease, usually in the first several days after a tick bite. This first stage of Lyme disease needs to be treated before it progresses to more serious symptoms affecting the neurological and cardiovascular systems. The presence of erythema migrans requires she be treated with a 14-day course of amoxicillin.
Question: How long should a deer tick be attached before prophylactic treatment to prevent Lyme disease is recommended? - Answer: Typically, longer than 36 hours.
Lyme Disease
Patient with a history of being in the woods hiking or camping
Complaining of:Stage I: erythema migrans (pathognomonic), viral-like syndrome (fever, fatigue, malaise, myalgia, headache)Stage II: myocarditis, bilateral Bell palsyStage III: chronic arthritis, chronic encephalopathy
PE will show slightly raised red lesion with central clearing, erythema migrans (bull's-eye) rash
Most commonly caused by Borrelia burgdorferi carried by Ixodes tick
Treatment is doxycycline, children - amoxicillin or doxycycline (if used for < 21 days), pregnant - amoxicillin
Comments: Bilateral facial nerve palsy is virtually pathognomonic for Lyme disease
A 73-year-old woman with an indwelling Foley catheter is sent for evaluation from the nursing home because of fever. Which of the following is a criterion for systemic inflammatory response syndrome (SIRS)?
Heart rate 86
Lactic acid 4 mg/dL
Respiratory rate 22
Temperature 37.9°CCorrect Answer ( C ) - Explanation:
Systemic inflammatory response syndrome (SIRS) is the systemic inflammatory response syndrome occurring most commonly in response to an infection. SIRS plus a source of infection is the definition of sepsis. Sepsis is an increasingly common cause of ED visits and the tenth leading cause of death in the US. In response to the infectious insult, the host's body activates a number of inflammatory cascades as part of the host response. As patients become sicker, severe sepsis develops with the presence of organ dysfunction in the setting of an infection. The respiratory rate of 22 above fulfills one of the SIRS criteria.
Question: What is the definition of septic shock? - Answer: Sepsis with hypotension not responsive to fluids.
An 18-year-old college student with a history of HIV (CD4+ 250) presents to the ED with headache, fever, and stiff neck for two days. He thought he had a cold and has been taking acetaminophen without relief of his headache. Vital signs are T 102.38°F (39.1°C), BP 100/50 mm Hg, HR 140 bpm, and RR 30/min. He is sleepy but arousable. On exam, you place the patient's right hip and knee into a flexed position and then proceed to extend the knee. The patient winces when the knee is just beyond 90 degrees of flexion. You also note petechiae on his trunk and extremities with one small area on his right forearm that looks like a purple patch with a gray necrotic center. Which of the following is the most likely diagnosis?
Cryptococcal meningitis
Herpes encephalitis
Meningococcemia
Pneumococcal meningitis
Toxoplasmosis - Correct Answer ( C )
Explanation:
This patient has meningococcemia, a disease caused by Neisseria meningitidis. The clinical presentation ranges from a mild febrile illness to fulminant disease progressing to death within hours. Patients with meningococcal meningitis may present similarly to patients with meningitis of other origins with headache, photophobia, vomiting, fever, and signs of meningeal inflammation. Petechiae generally appear on the extremities and may progress to involve almost any body surface. Macular lesions may progress to purpura and ecchymoses in fulminant meningococcemia (purpura fulminans). The patient in this scenario exhibits a positive Kernig sign, representing meningeal irritation, and has a purpuric lesion on his right forearm characterized by a gray necrotic center surrounded by a purple ring. Morbidity and mortality are high in meningococcemia but reduced with prompt recognition and immediate initiation of antibiotic therapy. Ceftriaxone and vancomycin are acceptable first-line agents.
Patients with HIV are prone to the same infections as a non-HIV infected individual, in addition to opportunistic infections. The best predictor of immunologic susceptibility to opportunistic infection is the CD4 cell count, with counts below 200 associated with increased risk. Cryptococcal meningitis (A) occurs in 10% of patients with HIV infection, but most commonly in those with CD4 cell counts less than 100 cell/µL. Headache and fever commonly occur, but there are no cutaneous manifestations. Treatment includes amphotericin B plus 5-flucytosine. HSV encephalitis (B) is associated with fever, headache, and focal neurologic signs, often localized to the temporal lobe. The patient may complain of a bad odor not perceived by anyone else (temporal lobe hallucination). Treatment includes acyclovir. Pneumococcal meningitis (D) is caused by Streptococcus pneumoniae, the most common cause of meningitis in adults. Symptoms are similar to meningococcal meningitis but do not progress to purpura fulminans. Treatment is also similar with ceftriaxone and vancomycin. Toxoplasma gondii (E) infection is the most common cause of focal intracranial mass lesions in patients with HIV infection. It is associated with fever, headache, and seizures. It is not associated with skin lesions. Treatment includes pyrimethamine plus sulfadiazine.
Question: What is the most common complication of meningococcemia? - Answer: Myocarditis with congestive heart failure or conduction abnormalities.
A 33-year-old cattle farmer presets with a rash to his lower left arm as seen above. What treatment is indicated?
Cephalexin
Ciprofloxacin
Topical bacitracin
Topical corticosteroids - Correct Answer ( B )
Explanation:
This patient presents with cutaneous anthrax requiring treatment with ciprofloxacin. Anthrax is caused by the bacteria Bacillus anthracis, a gram-positive, spore forming bacteria, and can manifest in a number of forms including cutaneous, gastrointestinal and pulmonary. Cutaneous anthrax commonly presents in animal product laborers but can also be the result of exposure to weaponized anthrax. Initially, the disease manifests as a small papule at the site of inoculation. This papule becomes erythematous with a central vesicle of bulla. This bulla then transforms into a hemorrhagic and necrotic lesion usually seen as a central black eschar. There is also regional adenitis accompanying the cutaneous lesion. The mortality associated with untreated cutaneous anthrax is high; roughly 20%. However, treatment reduces the mortality to 1%. Initiation of antibiotics does not change the local course of disease but prevents dissemination and death. Ciprofloxacin is the appropriate treatment for this form of the disease. An alternative to ciprofloxacin in cases of uncomplicated cutaneous anthrax is doxycycline.
Question: Which form of anthrax (cutaneous, gastrointestinal, pulmonary) is the most lethal? - Answer: Pulmonary anthrax is the most lethal form of anthrax.
Which of the following tick-borne illnesses is most associated with skin ulcers and lymphadenopathy?
Babesiosis
Colorado tick fever
Lyme disease
Tularemia - Correct Answer ( D )
Explanation:
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). Each of these diseases begins with non-specific viral-syndrome like symptoms including fever, myalgias, arthralgias and headache. Clinicians may be alerted to the presence of a tick-borne illness if a history of exposure (hiking in the woods, tick bite) are elicited. However, up to 50% of patients with a tick-borne illness do not recall a tick bite. Additionally, if labs are obtained, there are some common findings that would differentiate from a viral illness. Thrombocytopenia is often seen in RMSF, ehrlichiosis, tularemia and babesiosis. A mild elevation in hepatic transaminases is associated with RMSF, Lyme disease, ehrlichiosis, tularemia and babesiosis. Tularemia is associated with ulceroglandular disease.
Question: What is the recommended treatment for Tularemia? - Answer: Streptomycin.
7-year-old girl presents with the rash seen above. Her mother states it appeared seven days after hiking through the woods near their home in New Jersey. She has no known drug allergies. Which of the following is the most appropriate treatment for this patient?
Ampicillin
Azithromycin
Cephalexin
Doxycycline - Correct Answer ( D )
Explanation:
Lyme disease is the most common vectorborne disease in the United States. It is a tickborne illness caused by the spirochete Borrelia burgdorferi. The early phase of the disease results in the characteristic rash seen above, erythema migrans. Prompt treatment of early disease can shorten the duration of symptoms and prevent progression to later stages of disease. Previously it was recommended that pregnant or lactating women and children younger than 8 years of age should receive amoxicillin. This is still a viable alternative in patients that cannot tolerate doxycycline. Doxycycline, a tetracyline, may be used for all patient populations and can be recommended if the treatment length is less than 21 days in pregnant patients and children. Advanced or severe disease should be treated with intravenous ceftriaxone or penicillin.
Question: What other antibiotic can be used to treat Lyme disease in a pregnant patient? - Answer: Cefuroxime axetil, a second-generation oral cephalopsporin.
37-year-old man presents to the ED after he crashed his dirt bike going over a jump. You note a 5 cm wound to his right leg with a significant amount of dirt and debris. He does not think he has had a tetanus vaccine in the past as his mother is against vaccines. Which of the following is the most appropriate management?
Tetanus immunoglobulin
Tetanus immunoglobulin and metronidazole
Tetanus immunoglobulin and tetanus vaccine
Tetanus vaccine - Correct Answer ( C )
Explanation:
This patient is at risk for tetanus. Tetanus is caused by Clostridium tetani, which is an anaerobic, motile, spore-forming, Gram-positive rod that is found in soil, dust, and feces and is resistant to heat and chemicals. Greater than 70% of cases of tetanus are caused by wounds, including post-operative infections. The incubation time for tetanus is generally three days to two weeks. Signs and symptoms of tetanus include weakness, myalgias, dysphagia, hydrophobia, and drooling. Patients may also exhibit trismus, risus sardonicus (facial muscle spasms), and generalized severe muscular spasms. Death is commonly secondary to laryngeal or respiratory spasm leading to respiratory failure and arrest. Patients may also exhibit autonomic dysfunction. There is no effect on mental status. Tetanus is a clinical diagnosis. Management of tetanus is first supportive and includes minimizing stimuli and administering benzodiazepines and narcotics for the spasms. Intubation and nondepolarizing neuromuscular blockade may be necessary. These patients should be admitted to an ICU for further care. To eliminate toxin production, the wound should be cleaned and debrided and metronidazole given. Additionally, tetanus immunoglobulin (TIG) should also be given as this may shorten the course and reduce the severity of the disease. TIG is safe in pregnancy. TIG is not needed if the primary series of vaccines was completed (3 or more tetanus toxoid vaccinations). Tetanus immunization should be considered for all wounds in the ED. If the wound is dirty, administer Td if > 5 years since last booster. If the wound is clean, administer Td if > 10 years since last booster. If the patient is allergic to Td, administer TIG and consider prophylactic antibiotics. Tetanus immunoglobulin is needed for dirty wounds as well if the patient did not complete the primary series of vaccines.
Tetanus immunoglobulin (A) should be given as it is a dirty wound and the patient is not vaccinated; however, he also needs a diploid tetanus vaccine given that he has not been vaccinated previously. Tetanus immunoglobulin and metronidazole (B) would be indicated if the patient had signs and symptoms of active tetanus in order to neutralize the toxin as well as treat the disease process. Tetanus vaccine (D) should be given as he has not been vaccinated previously and has a dirty wound. He should also be given TIG for the same reasons in combination with the diploid vaccine.
Question: What classic diffuse spasm pattern is associated with tetanus and hallmarked by arching of the back? - Answer: Opisthotonus.
A 37-year-old man with a history of human immunodeficiency virus with a previous CD4+ count of 90 cells/µL presents to the emergency department feeling poorly with a mild headache, neck pain with stiffness and nausea. He has not been compliant with his medications. Physical examination shows vital signs of HR 97, BP 133/70, RR 16, T 99.0℉. The patient has noticeable meningismus. Head CT performed is unremarkable. Lumbar puncture is performed during the workup. Opening pressure is 40 cm H2O and results show WBC 75 cells/µL with 20% PMNs, glucose 24 mg/dL, protein 290 mg/dL and negative gram stain. What further cerebrospinal fluid analysis should be performed to confirm the most likely diagnosis in this patient?
Acid-fast bacilli test
Herpes simplex virus PCR
India ink stain
Venereal Disease Research Laboratory test - Correct Answer ( C )
Explanation:
Patients who are immunocompromised with entities such as AIDS are at increased risk for serious infections including meningitis. This is particularly true in patients with a CD4+ count less than 200 cells/µL. Cryptococcus neoformans is the most common cause of meningitis in patients with AIDS and ultimately affects 10% of patients with AIDS. As with other opportunistic infections, HAART has dramatically decreased the incidence of cryptococcal meningitis. However, it remains a leading cause of mortality for people with HIV infection. It usually affects patients with a CD4+ count below 100 cells/µL. A lumbar puncture is diagnostic; elevated opening pressures are typical and evidence of encapsulated yeast forms on staining of the cerebrospinal fluid with India ink can be found. Other CSF findings include elevated protein, low glucose and moderately elevated WBC but less than 500 cells/µL.
Cryptococcus neoformans
Patient will be HIV (+)
Complaining of headache, fever, stiff neck, photophobia, vomiting
Labs will show CD4 < 100
Diagnosis is made by India ink stain of CSF (round encapsulated yeast), Cryptococcal antigen (CrAg) - CSF or serum
Treatment is amphotericin B (fungicidal), flucytosine (fungicidal), fluconazole (fungistatic)
Question: What is the first-line therapy for patients diagnosed with cryptococcal meningitis? - Answer: Amphotericin B.
23-year-old man who has unprotected, receptive anal intercourse presents to the ED with two weeks of worsening rectal pain and dyschezia. On exam, he has numerous ulcers in the anorectal area and a crop of grouped vesicles containing clear fluid on an erythematous base. The surrounding skin shows no sign of cellulitis or abscess. Which of the following is the most appropriate next step?
Refer the patient to a surgeon for operative intervention
Send a serology test
Send a Tzanck smear
Treat with acyclovir - Correct Answer ( D )
Explanation:
This patient is suffering from herpes simplex proctitis, a sexually transmitted infection. Diagnosis is clinical. Patients present with a painful vesicular rash on an erythematous base. Constitutional symptoms and lymphadenopathy are common. Treatment with antivirals shortens the duration of illness, decreases viral shedding, and improves constitutional symptoms. Commonly used antivirals include acyclovir, valacyclovir, and famciclovir.
Referral to a surgeon (A) may be needed in cases of Condylomata acuminata, but for herpes proctitis, primary management involves antiviral therapy. Serology (B) can also be sent, but a significant proportion of the adult population will be seropositive with no history of disease, making results less useful in confirming the diagnosis. If the diagnosis is unclear, a Tzanck smear (C) can be sent after puncturing a vesicle and collecting fluid. However, a negative result does not rule out herpes.
Question: How long after symptoms cease do patients with genital herpes stop shedding virus? - Answer: It is suspected that patients with a history of herpes can shed virus continuously, whether symptoms are present or not.
What is the most likely cause of a patient presenting with bilateral facial nerve palsy?
Borrelia burgdorferi
Herpes simplex virus
Leukemia
Mycoplasma pneumoniae - Correct Answer ( A )
Explanation:
Bell's palsy is a paralysis of the peripheral seventh nerve. Clinically, one is able to distinguish a peripheral from central cause of facial motor weakness by involvement of the forehead in a peripheral palsy. The forehead receives bilateral innervation centrally and a stroke syndrome will not interfere with upper facial strength because of the contralateral innervation. In Bell's palsy, the seventh nerve is affected after leaving the brainstem and weakness is seen on the entire face. Bilateral Bell's palsy occurs simultaneously very rarely. Borrelia burgdorferi is the causative organism of Lyme disease and Lyme is one of the few causes of bilateral Bell's palsy. Other causes include Guillan-barre syndrome, sarcoidosis, meningitis, or bilateral neurofibromas.
Question: What syndrome causes a vesicular rash in or around the ear canal, facial paralysis and hearing loss? - Answer: Ramsay hunt syndrome caused by zoster.
51-year-old diabetic man presents with perineal pain and fever. Physical examination reveals crepitus along the scrotum and left inner thigh. Which of the following is the best next step in management?
Clindamycin, vancomycin, ciprofloxacin plus surgical consultation
Hyperbaric oxygen therapy
Immediate operative debridement followed by antibiotics
Urologic consultation plus broad-spectrum oral antibiotics - Correct Answer ( A )
Explanation:
Gas gangrene requires prompt diagnosis and early aggressive management to improve mortality and morbidity. Clindamycin, vancomycin, ciprofloxacin plus surgical consultation are appropriate and sufficient for patients with gas gangrene. It can be caused by Clostridium organisms (i.e. clostridial myonecrosis) or from polymicrobial deep soft tissue infection from wounds or other damage to soft tissue. Clostridium perfringens is the most common organism implicated in gas gangrene. Diabetic patients or patients with immune compromise who present with a perineal necrotizing soft tissue infection have Fournier's gangrene. Patients with gas gangrene typically appear toxic and may report pain out of proportion to examination findings. Crepitus may also be palpated in the affected area, which indicates the presence of subcutaneous emphysema. Plain radiography may reveal subcutaneous gas produced by gas-forming bacteria. In addition to parenteral antibiotics and early surgical debridement, hyperbaric oxygen therapy may be considered for necrotizing soft tissue infections as it causes suppression of growth of anaerobic organisms.
Necrotizing Fasciitis
Type 1: polymicrobial
Type 2: Group A streptococcal infection
Pain out of proportion to exam
Systemic signs of infection
Cellulitis turns dusky blue with bullae/vesicles
Radiograph: subcutaenous emphyesma
Emergent surgical debridement
Question: True or false: Piperacillin-tazobactam provides poor coverage for anaerobic bacteria. - Answer: False.
Necrotizing Fasciitis
Type 1: polymicrobial
Type 2: Group A streptococcal infection [Show Less]