8 Serious Viral Infections

Question 1

Incubation period of Influenza

Answer 1

1 to 4 days

Question 2

Risk factors for severe influenza

Answer 2

Children <2 y
Adults ≥65 y
Comorbid conditions
Immunosuppression
Pregnancy
Patients <19 y receiving long-term aspirin
American Indians / Alaskan natives
Morbid obesity
Residents of nursing homes and long-term care facilities

Question 3

Most widely used neuraminidase inhibitor

Answer 3

Oseltamivir
treatment:
- 75 mg twice daily for 5 days (longer if critically ill)
chemoprophylaxis:
-75 mg OD for 1-2 weeks

Question 4

Remarks on herpes simplex infections

Answer 4

Herpes simplex infections are treatable with antiviral drugs, making early recognition of serious infection important

Question 5

The risk of HSV encephalitis in neonates is highest when?

Answer 5

When the mother acquires the infection in the 3rd trimester

Question 6

HSV resides where during latency

Answer 6

HSV-1: trigeminal ganglia
HSV-2: sacral ganglia

Question 7

Predilection of HSV encephalitis

Answer 7

Medial and inferior temporal lobes of the brain

Question 8

Primary HSV infection presents as

Answer 8

Gingivostomatitis and pharyngitis

Question 9

Recurrent HSV infection presents as

Answer 9

Herpes labialis

Question 10

Hallmark of HSV encephalitis

Answer 10

acute onset of fever and neurologic symptoms

Question 11

Imaging finding suggestive of HSV encephalitis

Answer 11

Identification of temporal lobe lesions on CT scan or MRI is strongly suggestive of HSV encephalitis

Question 12

CSF analysis of HSV encephalitis

Answer 12

CSF analysis typically shows a lymphocytic pleocytosis with the presence of RBCs

However, some patients have normal CSF parameters.

Question 13

testing modality of choice for HSV meningoecenpalitis

Answer 13

PCR of CSF

Question 14

Without treatment, HSV encephalitis has mortality of

Answer 14

> 70%

Question 15

Independent predictors of poor outcome for patients with HSV encephalitis

Answer 15

HCS ≤6
Focal lesions on CT scan
Increased patient age
Start of antiviral tx >4 days after onset of symptoms

Question 16

Remarks on treatment of HSV encephalitis

Answer 16

Because altered mental status and focal neurologic abnormalities are key features of encephalitis and because it can be clinically difficult to distinuish meningitis form encephalitis, consider adding acyclovir to empiric antibiotic therapy in patients with these neurologic findings when the diagnosis of acute bacterial meningitis is also being considered.

Question 17

Varicella zoster immune globulin is available, but its use is generally limited to

Answer 17

postexposure prophylaxis for nonimmune pregnant women and the weverely immunosuppressed

Question 18

Lesions of varicella

Answer 18

Lesions are concentrated more on the torso and face and typically crust and slough off after 1 to 2 weeks

Question 19

Remarks on immunized patients to varicella

Answer 19

Immunized patients can occasionally develop mild chickenpox

Question 20

Remarks on complications of varicella

Answer 20

1. Bacterial superinfections of skin lesions, most often with group A streptococci, can cause serious illness including necrotizing fasciitis
2. Pneumonitis can be severe and is more common in pregnant women

Question 21

Most commonly, herpes zoster affects what body area>

Answer 21

chest or face
but it can affect any dermatomal level

Question 22

Often a clue to an immunodeficient condition

Answer 22

Herpes zoster involving more than 3 dermatomes (dissemination of varicella-zoster virus)

Question 23

Remarks on treatment of varicella

Answer 23

1. Most healthy patients need only supportive care
2. Acyclovir and similar antiviral agents decrease the number of lesions and shorten the course of therapy if started within 24 hours of rash onset
3. However, the impact of traetment is modest, so it is not routinely recommended for those who are otherwise healthy

Question 24

Remarks on varcilla zoster virus

Answer 24

VZV is less sensitive to antiviral medication than herpesvirus and requires higher and more frequent dosing

Question 25

remarks on herpes zoster and antivirals

Answer 25

Antiviral agents hasten lesion resolution, reduce new lesions, reduce viral shedding, and decrease acute pain, but do not reduce the severity of postherpetic neuralgia

Question 26

Initiation of antivirals in herpes zoster

Answer 26

1. Using antiviral therapy in immunocompromised patients may reduce the risk of severe disseminated disease
2. Start antivirals within 72 hours of the onset of rash, and consider treatment at >72 hours if new vesicles are still present or developing
3. Treat immunocompromised patients regardless of the time since rash onset

Question 27

Use this for herpes zoster ophthalmicus

Answer 27

Valacyclovir

Question 28

Most infectious virus known to humans

Answer 28

Rubeola
and is communicable before symptoms begin

Question 29

Incubation period of measles

Answer 29

10 to 14 days

Question 30

Treatment of measles

Answer 30

supportive, with particular attention to ensuring adequate nutrition, especially vitamin A