key: cord-0695142-ytq7y25m
authors: Aliyeva, Gulnara Davud
title: Chapter 8 Infectious Disease Emergencies
date: 2022-12-31
journal: Rapid Response Situations
DOI: 10.1016/b978-0-323-83375-2.00008-5
sha: c42b3698a5925cca3f5d59df41aaaeabe84627c2
doc_id: 695142
cord_uid: ytq7y25m

COVID-19 has added new relevance to the relationship between the world’s public health and infectious diseases and makes timely the topic of this chapter, that is, infectious disease emergencies. When patients have infectious diseases and present in-hospital with life-threatening symptoms (e.g., septic shock), prompt response is crucial to saving their lives. This chapter approaches rapid response activation from the perspective of five infectious disease emergencies: sepsis and septic shock, acute hypoxemic respiratory failure due to severe pneumonia, hypovolemic shock due to acute infectious diarrheal illness, acute respiratory failure due to influenza virus infection, and acute respiratory failure due to COVID-19 (coronavirus disease of 2019) pneumonia. The highly detailed information (e.g., predisposing conditions, initial measures to take, diagnostic work-ups, and treatment) is presented in a fashion that immediately puts pertinent information at the fingertips of those who need it.

Acute Hypoxemic Respiratory failure Due to Severe Pneumonia Presentation Community-acquired pneumonia (CAP) is one of the most common infectious diseases. The American Thoracic Society (ATS) and Infectious Diseases Society of America (IDSA) 2019 guidelines recommend to abandon the healthcare-associated pneumonia category and place emphasis on local epidemiology and validated risk factors to determine the need for MRSA or P. aeruginosa coverage. 1 This section will cover severe CAP. According to ATS/IDSA 2019 guidelines, the definition of severe pneumonia includes either one major criterion or three or more minor criteria.

Minor criteria: ■ Respiratory rate > 30 breaths/min ■ PaO 2 /FIO 2 ratio < 250 ■ Multilobar infiltrates ■ Confusion/disorientation ■ Uremia (blood urea nitrogen level > 20 mg/dL) ■ Leukopenia (white blood cell count < 4000 cells/μL) ■ Thrombocytopenia (platelet count < 100,000/μL) ■ Hypothermia (core temperature < 36°C) ■ Hypotension requiring aggressive fluid resuscitation Major criteria: ■ Septic shock with need for vasopressors ■ Respiratory failure requiring mechanical ventilation 1

Progressively worsening tachypnea, use of accessory respiratory muscles, cyanosis, tachycardia/ bradycardia, hypotension, altered mental status. Hypovolemic Shock Due to Acute Infectious Diarrheal Illness Presentation Acute infectious diarrheal illness is common in adults. The most common etiology is viral gastroenteritis. Other etiology can be bacterial or parasitic. The most common bacterial causes of acute diarrhea in the United States are Salmonella, Campylobacter, Shigella, and Shiga toxinproducing Escherichia coli (STEC). 1 Elderly patients, patients residing in nursing homes, and recently hospitalized patients are at high risk for acute infectious diarrheal illness. Recent use of antibiotics and recent sick contacts are other risk factors.

Acute diarrheal illness is classified as noninflammatory and inflammatory syndromes. Noninflammatory syndrome is milder and is characterized by intestinal secretion without disruption in intestinal mucosa. Inflammatory syndrome is characterized by disruption of intestinal mucosa resulting in tissue invasion and tissue damage and generally leads to more severe disease. 2 Examples of pathogens causing noninflammatory syndrome include enterotoxigenic E. coli, Bacillus cereus, Rotavirus, Norovirus, and Staphylococcus aureus. Examples of pathogens causing inflammatory syndrome include STEC, Salmonella, Shigella, and Clostridium difficile. Symptoms of inflammatory diarrheal illness include fever, tenesmus, and grossly bloody stools. 2 Patients with severe GI loss of fluids can develop hypovolemia with decreased tissue perfusion. Elderly patients are at higher risk. Symptoms of severe dehydration include thirst, dizziness, decreased urinary output, and altered mental status. On examination, these patients will have a generally ill appearance, dry mucous membranes, tachycardia, and hypotension.

Progressively worsening tachycardia, hypotension, altered mental status. DIAGNOSTIC WORK-UP 1. Labs: CBC with differential (leukocytosis/leukopenia, eosinophilia in parasitic infections, bandemia (especially due to Shigella), anemia, thrombocytopenia), CMP (electrolytes, renal function), procalcitonin (elevated in bacterial and fungal infection), and lactic acid.

Order fecal occult blood test.

higher specificity and sensitivity compared to fecal leukocytes. 2 

turnaround time compared to stool cultures; however, "reflex stool cultures" are needed for taxonomic classification and susceptibility 3 ; stool studies are recommended in the following situations: ■ Severe dehydration ■ Sepsis ■ Fever ■ Grossly bloody stool ■ Symptoms last > 3-7 days ■ Immunocompromised patients ■ Inflammatory diarrhea ■ Inflammatory bowel disease ■ Nosocomial diarrhea (onset after more than 3 days in the hospital, antibiotic use within 3 months) ■ Patients older than 65years with significant comorbidities 4 

■ Diarrhea lasting > 7 days ■ Immunocompromised patients ■ Diarrhea associated with infants in daycare ■ Diarrhea associated with travel to mountainous regions ■ Diarrhea in patients with AIDS or men who have sex with men ■ Community waterborne outbreaks ■ Bloody diarrhea with few fecal leukocytes 5 6. Patients with acquired immune deficiency syndrome (AIDS) with persistent diarrhea should undergo additional testing for organisms such as Cryptosporidium, Cyclospora, Cystoisospora, Microsporidia, Mycobacterium avium complex, and Cytomegalovirus. 6 7. Test for C. difficile in symptomatic patients with new-onset ≥ 3 unformed stools in 24 h with: ■ History of diarrhea following antimicrobial use (within last 3 months) ■ Healthcare-associated diarrhea ■ Persistent diarrhea without an etiology and without recognized risk factors 6 8. A single diarrheal stool specimen is recommended for detection of toxin or a toxigenic C. difficile strain (e.g., nucleic acid amplification testing); multiple specimens do not increase yield 6 ; use rectal swab in patients with ileus. 9. Order blood cultures in febrile patients. 10. Imaging (ultrasonography, computed tomography, or magnetic resonance imaging) may detect small bowel/colonic wall circumferential thickening, intra-abdominal free air, and toxic megacolon. 6 TREATMENT 1. Isotonic IV fluids such as normal saline or lactated Ringer's solution are recommended in severe dehydration, shock, ileus, or altered mental status; 1-2 L IV bolus is given initially, with close monitoring of vital signs, urinary output, and mental status.

Antimicrobial therapy for people with infections attributed to STEC O157 and other STEC that produce Shiga toxin 2 (or if the toxin genotype is unknown) should be avoided. 6 3. Empiric antimicrobial therapy while waiting for the results of diagnostic work-up is recommended for the following patients with severe illness: ■ Immunocompromised patients 

Presentation Influenza is a common highly contagious airborne viral illness. It has seasonal activity and causes significant morbidity and mortality, especially in elderly patients and patients with chronic comorbidities. Three types of influenza viruses cause infection in humans: influenza A, B, and C. Influenza A infects multiple species, including humans, equines, swine, and birds. As Influenza A is more susceptible to antigenic variation, it contributes more to major pandemics. 1 Common symptoms include chills related to fever, sweating, myalgias, malaise, sore throat, nasal discharge, cough, and headache. Some patients may have nausea, vomiting, and diarrhea. Symptoms usually continue for 2-8 days. 1 In severe pneumonia, patient will steadily deteriorate with development of dyspnea, tachypnea, and hypoxia. According to the 2010 guidelines of the World Health Organization (WHO), 2 severe influenza is defined as having at least one of the following clinical presentations: ■ Dyspnea, tachypnea, or hypoxia ■ Radiological signs of lower respiratory tract disease ■ Central nervous system involvement (e.g., encephalopathy, encephalitis) ■ Severe dehydration ■ Acute renal failure ■ Septic shock ■ Exacerbation of underlying chronic disease, including asthma, chronic obstructive pulmonary disease (COPD), chronic hepatic or renal insufficiency, diabetes mellitus, or cardiovascular conditions ■ Any other influenza-related condition or clinical presentation requiring hospital admission

Progressively worsening tachypnea, dyspnea, hypoxia, altered mental status.

Acute Respiratory failure Due to cOVID-19 (coronavirus Disease of 2019) Pneumonia

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly contagious respiratory disease that can spread in aerosols. Mean incubation period is 5 days; however, it can range from 2 days to 2 weeks. 1 The disease ranges from asymptomatic to severe illness with acute respiratory failure, multiorgan failure, and death. Initial symptoms may include fever, chills, sore throat, nasal congestion, cough, shortness of breath, loss of taste and smell, headache, nausea, vomiting, and diarrhea. Severe cases are mostly reported in patients older than 55 years with significant comorbidities, including obesity. 1 In this chapter we will only address management of severe (RR > 30 breaths/min, severe respiratory distress or SpO 2 < 90%) and critical (presence of ARDS, respiratory failure requiring ventilation, sepsis or septic shock) COVID-19.

Varying estimates of sepsis mortality using death certificates and administrative codes -United States

Update in sepsis guidelines: what is really new? Trauma Surg Acute Care Open

The third international consensus definitions for sepsis and septic shock (sepsis-3)

Assessment of clinical criteria for sepsis: for the third international consensus definitions for sepsis and septic shock (sepsis-3)

Surviving Sepsis Campaign: international guidelines for management of sepsis and septic shock: 2016

Vasopressors and Inotropes in Treatment of Acute Hypotensive States and Shock: Adult Dose and Selected Characteristics

Acute respiratory distress syndrome: diagnosis and management

Diagnosis and treatment of adults with community-acquired pneumonia. An official clinical practice guideline of the American Thoracic Society and Infectious Diseases Society of America

Preliminary FoodNet data on the incidence of infection with pathogens transmitted commonly through food-10 states

Acute diarrhea in adults

Derivation and validation of guidelines for stool cultures for enteropathogenic bacteria other than Clostridium difficile in hospitalized adults

Inappropriate testing for diarrheal diseases in the hospital

Infectious Disease Society of America clinical practice guideline for the diagnosis and management of infectious diarrhea

Influenza: diagnosis and treatment

Severe influenza treatment guideline

Clinical practice guidelines by Infectious Diseases Society of America: 2018 update on diagnosis, treatment, chemoprophylaxis and institutional outbreak management of seasonal influenza

Severe Influenza. Internet Book of Critical Care (IBCC)

Mechanical ventilation in an airborne epidemic

Ventilator management strategies for adults with acute respiratory distress syndrome

SARS-CoV-2 test (viral nucleic acid or antigen detection test). 1 2. Other labs include CBC (leukopenia, lymphopenia)

PT, aPTT); inflammatory markers such as CRP, LDH, ferritin, D-dimer, fibrinogen, and IL-6 (if elevated, associated with increased risk of ARDS and death) 2, 3 ; ABG; and BNP (BNP < 100 pg/mL in a patient with hypoxia and bilateral pulmonary infiltrates supports ARDS

Order chest X-ray: bilateral consolidation and diffuse ground-glass opacities with highest severity around days 10-12 following the onset of symptoms

Consider chest CT scan: ground-glass and fine reticular opacities with mostly peripheral distribution and vascular thickening

Order compression Doppler ultrasound (US) of extremities when DVT is suspected

Order chest CTA in patients with elevated D-dimer to rule out pulmonary embolism

Coronavirus Disease 2019 (COVID-19). Emedicine.medscape

Poor prognostic biochemical markers predicting fatalities caused by COVID-19: a retrospective observational study from a developing country

Can inflammatory markers predict the successful extubation in patients with COVID-19?

Acute Respiratory Distress Syndrome (ARDS). Emedicine.medscape

Prone positioning in awake, nonintubated patients with COVID-19 hypoxemic respiratory failure

Comparison of two fluid-management strategies in acute lung injury

Surviving sepsis campaign guidelines on the management of adults with coronavirus disease 2019 (COVID-19) in the ICU: first update

Ventilator Management Strategies for Adults With Acute Respiratory Distress Syndrome

1. Maintain continuous pulse oximetry.

Administer supplemental oxygen to maintain SpO 2 > 90% or PaO 2 > 60-65 mmHg; transition to high flow oxygen when patient requires high flow rates. , and procalcitonin (elevated in superimposed bacterial or fungal infection). 6. Order chest X-ray: clear lungs or minimal bilateral symmetrical interstitial infiltrates in early disease; bilateral patchy infiltrates later in the course of illness; in superimposed bacterial pneumonia, chest X-ray will demonstrate nonsegmental homogeneous consolidation involving one, or less commonly, multiple lobes. 3 7. CT scan of chest will show multifocal ground glass opacities; lobar consolidation will suggest superimposed bacterial pneumonia.

As patients with severe influenza are at high risk of developing acute respiratory distress syndrome (ARDS), use IV fluids cautiously.

Start antiviral treatment as soon as possible (most effective if started within 48 h of symptom onset) for hospitalized patients regardless of illness duration: ■ Oseltamivir 75 mg orally twice daily for 5 days; adjust dose to renal function ■ Peramivir 600 mg IV single dose (for patients who are unable to take oseltamivir orally); adjust dose to renal function ■ Zanamivir 10 mg inhalation twice daily for 5 days (contraindicated in intubated patients, not recommended in patients with asthma or COPD) 4 3. If clinical course remains severe, duration of the antiviral treatment can be extended until clinical improvement. 2 4. Investigate and empirically treat bacterial co-infection, for example, bacterial pneumonia in the following patients: ■ Patients presenting initially with severe influenza (extensive pneumonia, respiratory failure, hypotension, fever) ■ Patients who deteriorate after initial improvement, particularly those treated with antivirals ■ Patients who fail to improve after 3-5 days of antiviral treatment 4 DIAGNOSTIC WORK-UP TREATMENT 1. Prone positioning for awake spontaneously breathing patient is associated with improved oxygenation and a lower rate of intubation, 5 however, overall evidence is insufficient, awaiting the results of ongoing RCT's. 2. High flow nasal cannula will deliver heated humidified oxygen through large-bore nasal prongs; oxygen flow rate can be titrated up to 50-60 L/min to maintain SpO 2 of 88%-95%; this mode is associated with improved patient comfort as it allows patient to talk, eat, and move around. 4 3. As patients with severe COVID-19 pneumonia are at high risk for ARDS, a fluidconservative strategy is preferred (improved oxygenation index, lower lung injury score, and increase in ventilator-free days); closely monitor urine output; consider diuretic to maintain low normal fluid balance. 6