Influenza Pathophysiology and Management Quiz

Respiratory Viruses

• Influenza A, B, and C: Influenza viruses spread through respiratory droplets, affecting both upper and lower respiratory tracts.
• Influenza A: Risk factors include chronic lung disease, cardiac disease, and pregnancy. Incubation period is 1-4 days. Accounts for 5-15% of childhood respiratory illness.
• Influenza B: Incubation period is 3-10 days, and this virus accounts for 5% of lower respiratory infections in children. It is a common cause of severe pharyngitis in children.
• Influenza C: This virus causes less severe illness than A and B.
• Adenovirus: Spread through respiratory droplets. Can affect respiratory, eye, and gastrointestinal tracts. Incubation period is 3-10 days.
• Symptoms (mild): Fever, myalgias, dry cough, rhinorrhea, conjunctivitis, headache, and cervical lymphadenopathy (LAD).
• Symptoms (severe): Shortness of breath (SOB), tachycardia, hypotension, and need for respiratory support.
• Complications: Pneumonia, otitis media, gastroenteritis, secondary bacterial pneumonia, acute respiratory distress syndrome (ARDS), myositis, myocarditis, and multi-organ failure.
• Diagnosis: Rapid antigen tests (15-20 minutes), PCR (24 hours), and viral culture (3-7 days). Chest X-rays may show infiltrates in the lungs.
• Treatment/Management: Supportive care. Medications like oseltamivir (Tamiflu), zanamivir, peramivir, amantadine, or rimantadine may be used if within 72 hours of symptom onset. Amantadine and rimantadine are effective only against influenza A.
• Prevention: Seasonal influenza vaccines.

COVID-19

• Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): Spreads through respiratory droplets. Affects many organ systems. Incubation period is 2-14 days (average 5).
• Risk Factors: Older adults (50-64) are at higher risk of death.
• Symptoms (mild): Dry cough, sore throat, anosmia (loss of smell), dysgeusia (loss of taste), rhinorrhea, myalgias, and fever.
• Symptoms (severe): Dyspnea, chest pain, hemoptysis (coughing up blood), crackles (rales) in the lungs, respiratory insufficiency, pneumonia, ARDS, cardiac injury, arrhythmia, septic shock, liver dysfunction, and acute kidney injury.
• Complications: Pulmonary fibrosis, COVID bronchitis, and co-infections. Other issues include venous/arterial thrombosis, multi-organ failure, and pulmonary fibrosis.
• Diagnosis: Rapid antigen tests, PCR, complete blood count (CBC), comprehensive metabolic panel (CMP), coagulation panel, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), lactate, procalcitonin, D-dimer, and chest X-rays.
• Treatment/Management: Supportive care. Antivirals, including remdesivir, nirmatrelvir/ritonavir (Paxlovid), molnupiravir, and convalescent plasma, may be used. Steroids are used in severe cases only.
• Prevention: Vaccination is important.

Measles

• Rubeola Virus: Spreads through respiratory droplets. Causes immunosuppression and hypersensitivity. Incubation is 2–3 weeks.
• Risk Factors: History of no vaccinations.
• Symptoms (prodrome): Cough, coryza (runny nose), conjunctivitis (red or inflamed eyes), high fever, and photophobia (sensitivity to light).
• Symptoms (disease): A maculopapular rash (red blotches) that develops behind the ears and spreads to the entire body. Symptoms include koplik spots (small white spots on the inside of the cheeks), bronchopneumonia, pneumonitis, encephalitis, encephalomyelitis, otitis media, cervical adenitis, diarrhea, and subacute sclerosing panencephalitis. Transmission is highly contagious throughout this process.
• Diagnosis: PCR testing, confirmation in blood serum after 3 days of rash. Positive tests must be reported to the CDC.
• Treatment/Management: Supportive care. High-dose Vitamin A injections may be effective in children. Ribavirin is used in specific cases.
• Prevention: MMR vaccine, given at 12 months and 4 years.

Mumps

• Paramyxovirus: Spreads via respiratory droplets. Can affect parotid glands, testes, and epididymis. Incubation period is 14–21 days; infectiousness is 2 days before and 5 days after the onset of swelling in the glands.

• Risk Factors: History of no vaccinations.

• Symptoms (prodrome): Fever, severe headache, arthralgia (joint pain), and anorexia (lack of appetite).

• Symptoms (disease): Fever, headache, anorexia, testicular tenderness, testicular swelling (orchitis), which may lead to sterility, and aseptic meningitis.

• Complications: Orchitis (inflammation of the testes), potentially leading to sterility.

• Diagnosis: PCR. Positive PCR results should be reported to the CDC. Testicular ultrasound if there are concerns.

• Treatment/Management: Supportive care. Testicular support in those with orchitis.

Rubella (German Measles)

• RNA Togavirus: Transmission is via respiratory droplets. Incubation is 14-21 days, contagious 5 days before rash and 5 days after.
• Risk Factors: History of no vaccinations.
• Symptoms (prodrome): Fever, cough, conjunctivitis, malaise, and postauricular and occipital lymphadenopathy.
• Symptoms (Disease): A maculopapular rash that starts on the face and rapidly spreads to the entire body. Common issues are arthralgias (joint pain) and arthritis. Maternal rubella during pregnancy can cause congenital manifestations in the fetus.
• Diagnosis: PCR on oral secretions or urine, Rubella IgM serum tests are important for pregnant women. Results must be reported to the CDC.
• Treatment/Management: Supportive care.

Poliomyelitis

• Enterovirus: Spread through the fecal-oral route. Incubation period typically is 2–6 days and many are asymptomatic. Polio has been eliminated from most of the world but some regions still struggle with its persistence.
• Risk Factors: History of no vaccinations.
• Symptoms (mild): Fever, myalgias, sore throat, and headache for 2-6 days in most cases.
• Symptoms (severe): Recurring fever, severe myalgias, headache, nuchal rigidity (stiff neck), nausea, and vomiting. 1-2% of infected can have severe myalgias, loss of reflexes, or an asymmetrical paralysis (more likely in lower limbs).
• Complications: Permanent damage to anterior horn cells leading to paralysis (e.g., respiratory muscle paralysis), pharyngeal dysfunction, bowel issues, bladder dysfunction, and death.
• Diagnosis: PCR of throat and stool; rarely spinal fluid.
• Treatment/Management: Supportive care.

Herpes Viruses

• Herpes Simplex Virus 1 (HSV-1) and HSV-2: Skin-to-skin transmission with latent periods. Reactivation is caused by sunlight, stress, illness, trauma, or fatigue.
• Symptoms (gingivostomatitis): Vesicles (blister-like sores) on an erythematous base on the inside of the mouth.
• Symptoms (herpetic whitlow): Vesicles on the finger.
• Symptoms (herpes gladiatorum): Vesicles on other parts of the body: often seen in wrestlers.
• Symptoms (keratitis): Eye pain, conjunctivitis, and dendritic lesions on cornea.
• Diagnosis: The diagnosis can be made clinically; PCR and Tzanck smear are used. Tzanck smears reveal giant, multinucleated cells
• Treatment/Management: Antivirals (acyclovir, famciclovir, or valacyclovir). Pain management is needed. Don't drain herpetic whitlows.

Herpes Simplex Virus 2 (HSV-2)

• Human Herpes Virus 2 (HHV-2): Skin-to-skin transmission with latent periods. Reactivation is caused by sunlight, stress, illness, trauma, or fatigue.
• Symptoms: Vesicles on an erythematous base on the genitals.
• Diagnosis: Clinical diagnosis, and confirmation via PCR and Tzanck smear. Tzanck smears reveal giant, multinucleated cells
• Treatment/Management: Antivirals (acyclovir, famciclovir, or valacyclovir).

Varicella-Zoster Virus (Chickenpox and Shingles)

• Human Herpes Virus 3 (HHV-3): Spread by respiratory droplets or contact. Incubation is 10–21 days; contagious until crusting.
• Symptoms (chickenpox): Symptoms of chicken pox include fever, malaise, pharyngitis, loss of appetite, headache. Vesicles/blisters are scattered across the body, initially red macules, developing to clear pruritic vesicles on an erythematous base. These eventually become pustules, then crust over 5–6 days.
• Symptoms (shingles): Reactivation leads to pain, vesicles in one dermatome. This can result in post-herpetic neuralgia or complications like ophthalmicus.
• Diagnosis: Clinical presentation, PCR, viral cultures, and Tzanck smears. A Tzanck smear will show multinucleated cells..
• Treatment/Management: Antivirals (acyclovir, valacyclovir, or famciclovir) if within 72 hours of onset. Pain management is needed.

Epstein-Barr Virus (Infectious Mononucleosis)

• Human Herpes Virus 4 (HHV-4): Spread through saliva or respiratory droplets; lifetime prevalence is high.
• Symptoms: Malaise, headache, low-grade fever. Exudative tonsillitis/pharyngitis, uvular edema/erythema, halitosis, petechiae at junction of hard/soft palate. This can present as the "worst strep you've ever had". Rash, and hepatosplenomegaly are also common.
• Diagnosis: Monospot (heterophile antibody test) and EBV specific antibody tests. Lymphocytic leukocytosis (atypical lymphocytes), and splenic ultrasound if splenomegaly is suspected.
• Treatment/Management: Supportive care. Avoid contact sports to minimize risk of splenic rupture.

Cytomegalovirus (CMV)

• Human Herpes Virus 5 (HHV-5): Transmission by respiratory droplets/saliva/other bodily fluids.
• Primary Inf.: May not cause any obvious symptoms; after initial infection, the virus remains latent.
• Reactivation: Often associated with immunosuppression - presents as diarrhea, abdominal pain, fever, bloody stools, retinitis, dysphagia, and pneumonitis.
• Congenital CMV is transmission of the virus from mother to child, causing variety of issues for the child.
• Diagnosis: PCR, serology (antigen or antibody tests), and tissue biopsies for specific issues.
• Treatment/Management: Ganciclovir for reactivation or congenital CMV.

Erythema Infectiosum (Fifth Disease)

• Parvovirus B19: Spread via respiratory droplets/saliva; inc. period is 5–10 days, occurs in winter-early summer.
• Symptoms: Edematous/erythematous plaques on the cheeks ("slapped cheeks"). Erythematous lacy eruption on the trunk and extremities follows. Common in children. Noteable symptoms are join pain.
• Diagnosis: Clinical diagnosis, CBC, IgG & IgM antibodies.
• Treatment/Management: Supportive care.

Human Papillomavirus (HPV)

• DNA virus: Spread through skin-to-skin contact.
• Symptoms: Warts (soft, skin-colored, fleshy papules) in the genital regions (can be enlarged/cauliflower-like). Common in men and women.
• Diagnosis: Acetic acid test, PCR, HPV serotyping, and colposcopy for visualization. Biopsy to confirm.
• Treatment/Management: Supportive care for many that resolve spontaneously. Some cases may require removal via cryotherapy, electrocauterization (LEEP), or topical therapy.

Rabies

• Rhabdoviridae Family: Transmitted through animal bites, most often from bats. Incubation period is 1–6 months, and can range in symptoms. Prodrome may be pain/paresthesia, fever, malaise, headache, nausea, or vomiting. Symptoms range from more subtle to more severe and life threatening issues.
• Encephalic symptoms: Once symptoms develop, survival is rare; death often occurs in 7–10 days with confusion, agitation, bizarre behavior, hallucinations, insomnia, or death. Other issues are hydrophobia, laryngeal spasms, diaphragm spasms, ascending paralysis, alteration of mental status (AMS).
• Diagnosis: Animal testing and human testing. Animal testing includes keeping animals in quarantine; testing sick/dead animals; doing autopsies on animals when necessary. Human testing includes fluorescent antibody test with skin biopsy and antibody testing. Quantitative RT-PCR of saliva or CSF, which tests for the presence of the virus in specific body fluids.
• Treatment/Management: Wound care (scrub with solution, pressure irrigation). Post-exposure prophylaxis with human rabies immune globulin (HRIG) and rabies vaccine (Immunovax or RabAvert).

HIV/AIDS

• Human Immunodeficiency Virus (HIV): Spread through bodily fluids.

Test your knowledge on the pathophysiology, symptoms, diagnosis, and management of influenza. This quiz covers various important aspects, including complications, population at risk, and appropriate treatments. Challenge yourself to see how well you understand this respiratory illness.