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Influenza Pneumonia

Influenza with Pneumonia

Influenza pneumonia is a life-threatening complication of influenza virus infection, one of the most frequently encountered infections in clinical practice. After typical symptoms of upper respiratory tract infection and fever appear, severe respiratory decline with hypoxia and cyanosis can ensue without early recognition and appropriate therapy. Several diagnostic tests exist for prompt confirmation of influenza infection, but clinical suspicion is the key to diagnose the condition.


Presentation

Influenza is a rather common viral upper respiratory tract infection among humans. It is caused by influenza A (and less commonly B) viruses, and the pathogenesis, as well as transmission, involves several animal hosts and human-to-human spread through air droplets via inhalation, coughing, or sneezing [1] [2]. After an incubation period of a few days, constitutional symptoms of myalgia, fatigue, malaise, anorexia, fever, and a dry cough are main manifestations of influenza infection and usually last for 7-10 days [1] [3] [4]. It must be noted that the majority of infections are seen during the winter, and rarely in other parts of the year when pandemic or epidemic outbreaks occur [1] [2] [4]. In some patients, the infection is self-limiting, but numerous complications may arise, one of them being influenza pneumonia [1] [2] [3] [4] [5] [6]. It is regarded as the most severe complication and appears more frequently in the presence of various risk factors [5]. In children, concomitant cardiorespiratory illnesses (eg. asthma), diabetes mellitus, immunosuppression, long-term use of aspirin, and other diseases that increase the risk of hypertension are well-established risk factors, whereas pregnancy, chronic diseases, obesity, and residency in chronic care facilities are strongly associated with the development of influenza complications in adults and the elderly [2] [4] [5]. Influenza pneumonia represents the dissemination of the virus into the lower respiratory tract and the lung parenchyma, but secondary bacterial infections of the lungs might also be the culprit in influenza-infected patients, as the virus indirectly promotes bacterial adhesion to the respiratory epithelium [1] [2] [4] [5] [7]. For this reason, a clear distinction between primary influenza pneumonia and secondary bacterial pneumonia may be difficult to make. Nevertheless, approximately 2-5 days after the appearance of signs and symptoms typical for influenza, dyspnea, hypoxia, hemoptysis, cyanosis, and rapidly ensuing acute respiratory distress are hallmarks of influenza pneumonia [2] [3] [4] [8]. In addition, cognitive impairment, gastrointestinal complaints (diarrhea, abdominal pain) and myalgia are reported, and are sometimes the only symptoms, particularly in the elderly population [6]. In fact, pneumonia is one of the most important causes of death from this viral infection, and fatal outcomes might be seen within 24 hours [3] [5] [8] [9].

Fever
  • A 47-year-old man with a fever was highly suspected of having influenza A infection since his wife and son who lived with him had been diagnosed with influenza A.[ncbi.nlm.nih.gov]
  • After typical symptoms of upper respiratory tract infection and fever appear, severe respiratory decline with hypoxia and cyanosis can ensue without early recognition and appropriate therapy.[symptoma.com]
  • […] fatigue A cough that produces greenish or rust-colored mucus These are symptoms of viral pneumonia: Initial flulike symptoms: fever, headache, muscle aches and dry cough Worsening of symptoms after 12 to 36 hours: fever, breathlessness that may become[weather.com]
Malaise
  • After an incubation period of a few days, constitutional symptoms of myalgia, fatigue, malaise, anorexia, fever, and a dry cough are main manifestations of influenza infection and usually last for 7-10 days.[symptoma.com]
  • Symptoms include abrupt onset of fever, cough, malaise, myalgia, sore throat, and headache.[www1.health.gov.au]
  • The other symptoms, especially cough and malaise, may persist for up to 2 weeks. Unlike adults, children may present with vomiting and diarrhea.[thermofisher.com]
  • Influenza is classically characterized by an abrupt onset of headache, high-grade fever, chills, dry cough, pharyngeal irritation, myalgias, malaise, and anorexia. The fever lasts an average of 3 days (range of 2 to 8 days).[ncbi.nlm.nih.gov]
Constitutional Symptom
  • After an incubation period of a few days, constitutional symptoms of myalgia, fatigue, malaise, anorexia, fever, and a dry cough are main manifestations of influenza infection and usually last for 7-10 days.[symptoma.com]
Cough
  • Conclusions: For outpatient adults with acute cough due to suspected pneumonia, we suggest the following clinical symptoms and signs are suggestive of pneumonia: cough; dyspnea; pleural pain; sweating, fevers, or shivers; aches and pains; temperature[mayoclinic.pure.elsevier.com]
  • The Expert Cough Panel agreed on the following clinical symptoms as criteria suggestive of pneumonia in outpatient adults: cough, dyspnea, pleural pain, sweating, shivers, aches, temperature of 38 C, tachypnea, and new and localizing chest examination[clinicaladvisor.com]
  • […] more severe dry cough that produces small amounts of mucus A bluish color to the lips; this occurs in some cases These are symptoms of the flu: Headache Chills Dry cough Muscle aches (myalgia) Fever Stuffy nose Sore throat The fever usually appears on[weather.com]
  • The most frequent signs of influenza pneumonia were fever and cough. Of these children, 47% had no specific clinical signs or symptoms suggesting pneumonia.[ncbi.nlm.nih.gov]
  • Pneumonia symptoms typically involve coughing with phlegm, fever with chills, absent appetite, confusion, chest pains worsening with breathing or coughing, headaches, shortness of breath, and fatigue.[belmarrahealth.com]
Dry Cough
  • ., fever, sore throat, dry cough, arthralgias, myalgias, thrombocytopenia, relative lymphopenia, and elevated serum transaminases, some findings suggested an alternate diagnosis, e.g., leukopenia, a highly elevated erythrocyte sedimentation rate, highly[ncbi.nlm.nih.gov]
  • cough Worsening of symptoms after 12 to 36 hours: fever, breathlessness that may become extreme and a more severe dry cough that produces small amounts of mucus A bluish color to the lips; this occurs in some cases These are symptoms of the flu: Headache[weather.com]
  • After an incubation period of a few days, constitutional symptoms of myalgia, fatigue, malaise, anorexia, fever, and a dry cough are main manifestations of influenza infection and usually last for 7-10 days.[symptoma.com]
  • Infection with influenza most typically results in lung manifestations limited to dry cough and fever, and understanding how the transition to pneumonia occurs could shed light on interventions that reduce mortality.[medicalxpress.com]
  • Distinguishing between influenza and pneumonia signs and symptoms Influenza, the flu, generally comes on suddenly and it arrives with a fever, dry cough, chills and sweats, absent appetite, stuffy nose, and head-to-toe body aches.[belmarrahealth.com]
Dyspnea
  • Pure influenza viral pneumonia was observed in 94 cases, which were most frequently young adults with chief complaints of non-productive cough and dyspnea. Radiological imaging showed diffuse ground-glass opacity.[ncbi.nlm.nih.gov]
  • Conclusions: For outpatient adults with acute cough due to suspected pneumonia, we suggest the following clinical symptoms and signs are suggestive of pneumonia: cough; dyspnea; pleural pain; sweating, fevers, or shivers; aches and pains; temperature[mayoclinic.pure.elsevier.com]
  • The Expert Cough Panel agreed on the following clinical symptoms as criteria suggestive of pneumonia in outpatient adults: cough, dyspnea, pleural pain, sweating, shivers, aches, temperature of 38 C, tachypnea, and new and localizing chest examination[clinicaladvisor.com]
  • Nevertheless, approximately 2-5 days after the appearance of signs and symptoms typical for influenza, dyspnea, hypoxia, hemoptysis, cyanosis, and rapidly ensuing acute respiratory distress are hallmarks of influenza pneumonia.[symptoma.com]
  • All patients had fever, cough, dyspnea or respiratory distress, increased serum lactate dehydrogenase levels, and bilateral patchy pneumonia.[nejm.org]
Rales
  • Physical examination may demonstrate evidence of conjunctivitis, nasal discharge, hyperemic pharyngeal mucosa without exudate, cervical adenopathy, and, rarely, rales.[thermofisher.com]
  • If patients have lower respiratory tract symptoms and signs (eg, dyspnea, rales noted during lung examination), pulse oximetry to detect hypoxemia and a chest x-ray to detect pneumonia should be done.[merckmanuals.com]
  • […] alcoholism/alcoholic withdrawal, hyponatremia, unexplained metabolic acidosis, elevated lactate, cirrhosis, asplenia Major Criteria • Invasive mechanical ventilation • Septic shock requiring vasopressors Diagnostic Tests • Physical exam: º Crackles or rales[empr.com]
Tachypnea
  • Conclusions: For outpatient adults with acute cough due to suspected pneumonia, we suggest the following clinical symptoms and signs are suggestive of pneumonia: cough; dyspnea; pleural pain; sweating, fevers, or shivers; aches and pains; temperature 38 C; tachypnea[mayoclinic.pure.elsevier.com]
  • The Expert Cough Panel agreed on the following clinical symptoms as criteria suggestive of pneumonia in outpatient adults: cough, dyspnea, pleural pain, sweating, shivers, aches, temperature of 38 C, tachypnea, and new and localizing chest examination[clinicaladvisor.com]
  • This can look a lot like uncomplicated influenza; hypoxemia and tachypnea are the key distinguishing features. imaging Chest ultrasonography will usually show bilateral B-lines in a patchy distribution (e.g. one interspace will look normal, but the adjacent[emcrit.org]
Severe Clinical Course
  • In fact, younger persons are particularly at risk of severe clinical courses and death. In particular, pregnancy, although not significantly different in our series, was more frequent in patients with H1N1 (n 4 versus n 0).[erj.ersjournals.com]
  • clinical course, occasionally requiring mechanical ventilation, compared with those who present with ground-glass opacities. 7,15 All the patients described originally by Perez-Padilla et al. 5 had radiologically confirmed pneumonia with bilateral patchy[journalpulmonology.org]
Chest Pain
  • Young healthy adults without a cardiac history who have H1N1 and chest pain usually have either acute myocardial infarction or acute myocarditis.[ncbi.nlm.nih.gov]
  • If the doctor diagnoses bacterial pneumonia, treatment typically includes antibiotics and possibly other medications to help relieve coughing and chest pain.[weather.com]
  • One person died at home suddenly; the other patients' presenting symptoms were cough with bloody sputum, fever, and pleuritic chest pain. Chest films showed extensive bilateral opacities.[pulmccm.org]
  • Pneumonia symptoms typically involve coughing with phlegm, fever with chills, absent appetite, confusion, chest pains worsening with breathing or coughing, headaches, shortness of breath, and fatigue.[belmarrahealth.com]
  • The most common, similar signs and symptoms of lung cancer and pneumonia are cough, chest pain or discomfort, and shortness of breath.[emedicinehealth.com]
Tachycardia
  • With H1N1 pneumonia, clinicians should be alert for otherwise unexplained tachycardia or chest pain that may represent acute myocardial infarction or myocarditis.[ncbi.nlm.nih.gov]
  • The latter presented more frequently with fever and tachycardia.[erj.ersjournals.com]
Cyanosis
  • After typical symptoms of upper respiratory tract infection and fever appear, severe respiratory decline with hypoxia and cyanosis can ensue without early recognition and appropriate therapy.[symptoma.com]
Cardiomegaly
  • At autopsy there was cardiomegaly present but there were no signs of acute myocardial infarction or myocarditis. Pathologically, he died of severe H1N1 pneumonia and not bacterial pneumonia.[ncbi.nlm.nih.gov]

Workup

Mortality rates of influenza pneumonia are very high without early therapy, thus a detailed and comprehensive clinical, radiological, and microbiological assessment is vital in preventing the onset of respiratory decline. Firstly, physicians must obtain a complete patient history that will note the course and progression of symptoms and reveal any preexisting comorbidities that could predispose patients to a more severe form of infection. The physical examination is important in guiding the physician toward the lungs as the primary source of infection, after which both imaging studies and microbiological evaluation are necessary. Plain radiography is a valuable tool for visualizing the changes in the lung parenchyma for many infections, including influenza, and bilateral reticular or reticulonodular opacities, as well as patchy areas of consolidation (although other authors suggest that consolidation is absent) are principal features of influenza pneumonia [2] [3] [5] [9]. Unfortunately, not all patients exhibit typical X-ray findings [6]. Thus, confirmation of influenza virus as the underlying cause through microbiological testing is crucial. Several tests are available [1] [2] [5] [6]:

  • Rapid influenza diagnostic test (RIDT) - Very fast results (within 15-30 minutes), the ability to discern between influenza A and B, and very high specificity are the reasons why RIDT is quite often performed in standard practice [1] [3] [4] [5].
  • Reverse transcriptase-polymerase chain reaction (RT-PCR) - Although it is more expensive and requires advanced technical equipment, the RT-PCR test detects viral genetic material and possesses very high sensitivity and specificity rates [2] [5]. Because of its fast turnaround time (1-4 hours), it is considered to be the optimal diagnostic procedure [3] [5].
  • Viral culture - Long waiting times (several days) are the main limitation of viral cultivation in the setting of influenza pneumonia, despite the fact that the specificity rate is virtually 100%. However, newly designed tests can yield conclusive results within 1-3 days [5].
  • Serology - Detection of specific influenza antibodies is now being replaced by faster and more reliable methods for the diagnosis of influenza, and serology is often used as a retrospective analysis [5].
Pulmonary Infiltrate
  • Early diagnosis of the pulmonary infiltrates was accomplished by obtaining bronchial secretions with fiberoptic bronchoscopy and staining them with influenza-A fluorescent conjugate.[ncbi.nlm.nih.gov]
  • We have adapted a scoring system described by Opravil to grade the severity of pulmonary infiltrates in CXR: each lung is divided into four equal quadrants and each quadrant is scored on a scale of 0–3 (0: normal, 1: subtle increase interstitial markings[journalpulmonology.org]
Lymphocytopenia
  • Further study showed that hemin could regulate the immune response to IAV infection by reducing lymphocytopenia and local inflammatory cytokine increases caused by IAV infection.[ncbi.nlm.nih.gov]

Treatment

  • The range of absolute risk differences in mortality between the early treatment group and the late treatment group was 26% to 50% (pooled risk difference, 41% [CI, 29% to 54%]).[ncbi.nlm.nih.gov]

Prognosis

  • Moreover, metabolomics is a highly sensitive and specific tool for the 90-day prognosis of mortality in H1N1 pneumonia.[ncbi.nlm.nih.gov]
  • Plasma metabolomics for the diagnosis and prognosis of H1N1 influenza pneumonia. Crit. Care. 21:97 (2017)[bioanalysis-zone.com]
  • A person who has pneumonia repeatedly, may have an undiagnosed lung cancer; moreover, if a person has lung cancer and contracts pneumonia the prognosis and life expectancy is poor.[emedicinehealth.com]
  • […] been described 2 : initial chest radiographs usually show central or peripheral pulmonary ground-glass opacities (GGO) and consolidations that have a patchy or nodular appearance multizonal and bilateral peripheral opacities are associated with adverse prognosis[radiopaedia.org]

Etiology

  • Differentiation between a bacterial and viral etiology for the pulmonary infiltrates frequently presents a diagnostic dilemma. Rapid diagnosis is essential; and once established, the patient requires careful supportive therapy.[ncbi.nlm.nih.gov]
  • When pneumonia is documented, another reason for a query would be to identify the etiology of the pneumonia. Documented etiology could change the MS-DRG assignment.[hcpro.com]
  • The findings in A, B and C are quite common in diffuse alveolar damage of any etiology. Board review question #2 This image is from an autopsy of a 43 year old man with influenza A/H1N1 infection.[pathologyoutlines.com]
  • Several reports have identified methicillin-resistant Staphylococcus aureus (MRSA) as the etiologic agent for severe community acquired pneumonia (CAP) in otherwise healthy young patients with influenza [ 15 , 16 , 17 ].[link.springer.com]

Epidemiology

  • Research Article Epidemiology Sourya Shrestha 1, 2, *, Betsy Foxman 3, Daniel M.[stm.sciencemag.org]
  • BACKGROUND: Diabetes is a major public health problem and thought to be a risk factor for infectious diseases, but pertinent epidemiological evidence is limited.[ncbi.nlm.nih.gov]
  • Rohani is a professor of ecology and evolutionary biology, a professor of complex systems and a professor of epidemiology at the School of Public Health.[ns.umich.edu]
  • The recent epidemiology findings have helped to partially resolve the contribution of different pathogens.[journals.lww.com]
Sex distribution
Age distribution

Pathophysiology

  • Cytomegalovirus (CMV), mainly in people with immune system problems Smallpox virus Dengue virus The most commonly identified agents in children are respiratory syncytial virus, rhinovirus, human metapneumovirus, human bocavirus, and parainfluenza viruses. [4] Pathophysiology[en.wikipedia.org]

Prevention

  • In our case H1N1 influenza pneumonia was treated according to the published guidelines and had a mild course of disease, but nevertheless emphasis should be put on the prevention of disease applying known general infection control procedures and vaccination[ncbi.nlm.nih.gov]
  • Prevention To prevent contracting the flu people can take everyday precautions such as regularly washing their hands and avoiding those who are sick, but the best way to prevent the flu is by receiving the flu vaccination every year.[statista.com]
  • Centers for Disease Control and Prevention (CDC). Available at . Accessed: July 22, 2013. Preventing Seasonal Flu With Vaccination. Centers for Disease Control and Prevention. Available at . Accessed: August 17, 2012.[medscape.com]
  • The Centers for Disease Control and Prevention (CDC) recommends annual influenza vaccinations for everyone age 6 months or older.[news.vanderbilt.edu]

References

Article

  1. Mandell GL, Bennett JE, Dolin R. Mandel, Douglas and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, Pennsylvania: Churchill Livingstone; 2015.
  2. Murray PR, Rosenthal KS, Pfaller MA. Medical Microbiology. Seventh edition. Philadelphia: Elsevier/Saunders; 2013.
  3. Rello J, Pop-Vicas A. Clinical review: Primary influenza viral pneumonia.Crit Care. 2009;13(6):235.
  4. Taubenberger JK, Morens DM. The Pathology of Influenza Virus Infections. Annual review of pathology. 2008;3:499-522.
  5. Marzoratti L, Iannella HA, Gómez VF, Figueroa SB. Recent Advances in the Diagnosis and Treatment of Influenza Pneumonia. Curr Infect Dis Rep. 2012;14(3):275-283.
  6. Falsey AR, Walsh EE. Viral pneumonia in older adults. Clin Infect Dis. 2006;42(4):518-524.
  7. Joseph C, Togawa Y, Shindo N. Bacterial and viral infections associated with influenza. Influenza Other Respir Viruses. 2013;7(2):105-113.
  8. Rello J, Rodríguez A, Ibañez P, et al. H1N1 SEMICYUC Working Group. Intensive care adult patients with severe respiratory failure caused by Influenza A (H1N1)v in Spain. Crit Care. 2009;13:R148.
  9. Kim EA, Lee KS, Primack SL, et al. Viral pneumonias in adults: radiologic and pathologic findings. Radiographics. 2002;22 Spec No:S137-149.

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Last updated: 2019-07-11 21:20