CMV in Immunocompetent Hosts

Internal Medicine Morning Report August 2009

Lindsay A. Wilson

A Herpes Virus:

A double-stranded linear DNA virus with 162 hexagonal protein capsomeres surrounded by a lipid membrane. CMV has the largest genome of the herpes viruses, ranging from 230-240 kilobase pairs.  Most closely related to HHV-6 and 7.

CMV Mononucleosis: • Most common presentation of symptomatic CMV infection in

immunocompetent adults.   • Systemic symptoms and fever predominate and signs of

enlarged cervical nodes, tonsillitis, and splenomegaly are not as commonly seen as they are in EBV.

  • Patients with CMV mononucleosis may be older and have a

longer duration of fever. • Often see mild transaminitis, which can aid in diagnosis.

 

 Transmission

• Via body fluids:  CMV has been cultured from multiple sites, including urine, blood, throat, cervix, semen, stool, tears, and breast milk.

Typical owl's eye inclusion seen on HE stain.

Prevalance of CMV Worldwide--Seroprevalence rates ranging between 40 to 100 percent of the adult population.  Studies suggest that certain groups (ie

developing countries) have a higher prevalence.

Other Presentations: Disease localized to a single organ has been described in immunocompetent hosts.  Of course, this is much less common.

GI: 

COLITIS:• Diarrhea, fever, and abdominal pain are the common

presenting symptoms. • Can be bloody diarrhea (about half of the time) and mimic

ischemic colitis.     Can also have CMV hepatitis, gastroduodenititis, gastric ulcers, cholangitis, pancreatitis.

 

CV:

Pericarditis and myocarditis have been described in immunocompetent patients with acute CMV infection. Thought to be under-diagnosed due to it's milder presentation. When it is found, it is often an incidental finding on EKG or ECHO.  

Neuro:

• Guillain-Barré syndrome:CMV-related GBS are generally younger and experience more prominent sensory deficits, respiratory insufficiency, and cranial nerve impairments.  • Encephalitis:

Symptoms can include:  motor deficits (localized weakness, paraplegia), sensory abnormalities (numbness, hypoaesthesia, paraesthesia, dysaesthesia, anaesthesia), disorientation, confusion.  • Transverse myelitis

Pulm:

Pneumonia: Occurs at a rate of approximately 0-6% in CMV infections.  Often see ground-glass appearance on CT scan.  

Renal:  Collapsing focal glomerulosclerosisInfections that Can Cause FSGS HIV, CMV, HTLV-1, parvovirus B19, polyomavirus, pulmonary TB, leishmaniasis.

Ocular:

Anterior uveitis (also called iritis) is more commonly seen in immunocompetent (versus the retinitis seen in AIDS patients). Presenting symptoms include loss or blurring of vision, as well as redness of the affected eyes.  

Gancyclovir

• The drug of choice for treatment of cytomegalovirus (CMV) disease is ganciclovir.

 • Ganciclovir is a nucleoside analogue that inhibits DNA

synthesis in the same manner as acyclovir. The major difference is that CMV does not contain a thymidine kinase.

 •  Major adverse effects of ganciclovir therapy are

neutropenia and thrombocytopenia.

CMV:  most common congenital infectionA woman who contracts CMV for the first time during pregnancy has about a 1-in-3 chance of passing the virus on to her fetus. A woman can pass CMV on to her baby at any stage of pregnancy. However, studies suggest that babies are more likely to develop serious complications when their mother is infected in the first 20 weeks of pregnancy.  Only about 1 percent of fetuses become infected when their mother has a recurrent infection. When these babies do become infected, they rarely develop any serious CMV-related problems.

 

Babies w/ CMV:

 • About 10 percent show temporary symptoms like liver or

spleen problems that eventually resolve.  • A very small percentage of babies born do suffer severe

complications: seizures, loss of hearing and vision, mental and physical disabilities, delayed development and even death.

 • Some infected children don't demonstrate any of these

symptoms for months or years after birth, or experience worse symptoms later in life after showing initially mild symptoms.

Tips for pregnant women:

Wash hands!!   Avoid secretions from small children. Healthcare workers--may want to be tested to know status; however, this is not a general recommendation.

Take home points...

Most common presentation of CMV in immunocompetent is mononucleosis-like illness.  It can have some features that may help distinguish it from EBV. CMV infection can also be localized to a single organ. CMV is an important congenital infection that is under-recognized. Monitor CBC with diff in patients on ganciclovir. It is spread via bodily fluids, so hand-washing is an important way to avoid infection. 

Works Cited

Petros I Rafailidis et al. Severe cytomegalovirus infection in apparently immunocompetent patients: a systematic review. Virol J. 2008; 5: 47. 2008 March 27. Fernandez-Ruiz M et al.  Cytomegalovirus myopericarditis and hepatitis in an immunocompetent adult: successful treatment with oral valganciclovir. 

Intern Med. 2008;47(22):1963-6. Epub 2008 Nov 17.  

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