Diarrhoea In A Transplant Patient Flashcards
What is CMV?
- Cytomegalovirus (CMV) is a member of the herpesvirus family. Infection is worldwide and usually asymptomatic.
- CMV may cause a mononucleosis infection in healthy individuals but can cause severe illness in congenital infection and in an immunocompromised host.
What is the most disease manifestation of CMV?
GI disease
What is the most serious complication of CMV infection?
Pneumonia.
Rare manifestations include retinitis and encephalitis.
Disease course of CMV
o After initial infection, human CMV remains in a persistent state within the host. Immunity against the virus controls replication, although intermittent viral shedding can still take place in the immunocompetent person.
o Complications are therefore mainly seen if the immune system is immature, or is suppressed by drug treatment or co-infection with other pathogens.
o Clinically significant CMV disease frequently develops in patients immunocompromised as a result of HIV, solid organ transplantation and bone-marrow transplantation.
o Primary CMV infection of the immunocompromised host may cause disease in almost every organ of the body - e.g., pneumonia, hepatitis, encephalitis, colitis, uveitis, retinitis and neuropathy.
Which infections is possible in immune competent hosts?
- In adolescence and early adulthood, primary infection is also usually asymptomatic but may cause a mild flu-like illness.
- CMV may also produce a mononucleosis syndrome similar to Epstein-Barr virus (causing a febrile illness with splenomegaly, impaired liver function and abnormal lymphocytes in the blood) but without characteristic pharyngitis and lymphadenopathy.
What are the complications of CMV infection?
o Guillain-Barré syndrome. o Meningoencephalitis. o Pericarditis. o Myocarditis. o Thrombocytopenia. o Haemolytic anaemia. o Gastrointestinal ulceration (upper and lower gastrointestinal tract).
Why are solid organ recipients susceptible to CMV infection?
- Solid organ transplant recipients are particularly susceptible to CMV-related disease due to the immunosuppression necessary to prevent organ rejection. Patients receiving T-cell depleting therapies are at the highest risk.
- The major risk factor for CMV pneumonia is a CMV-seronegative transplant recipient receiving a CMV-seropositive organ.
What should be offered to CMV-seronegative recipients who received a seropositive organ?
- All organ donors and recipients should be screened for CMV status, either before or at the time of transplantation.
- CMV-seronegative recipients who receive a solid organ transplant from a donor who is seropositive should be offered prophylaxis against primary infection, using oral valganciclovir, oral valaciclovir or intravenous ganciclovir.
Patients with CMV disease should receive intravenous ganciclovir or oral valganciclovir until the resolution of symptoms and for a minimum of 14 days. Foscarnet and cidofovir are second-line therapeutic options - unless ganciclovir resistance has been demonstrated.
If possible, a reduction in immunosuppression should be considered.
After treatment doses have been administered, an additional 1-3 months of appropriate prophylaxis should be considered to minimise the risk of recurrent infection.
What is the most common manifestation of CMV disease in patients who are HIV positive?
- CMV can cause very serious infection in HIV-positive people.
- Retinitis is the most common manifestation of CMV disease in patients who are HIV-positive.
- It presents with decreased visual acuity, floaters and loss of visual fields on one side.
- Ganciclovir has been used to treat retinitis but it only slows the progression of the disease.
The optimal treatment is using ganciclovir implants in the vitreous, accompanied by intravenous ganciclovir therapy.
What is the investigations for CMV disease?
- PCR is the fastest and most sensitive method to detect CMV in blood and tissue samples.
- CMV can be detected by culture, serology, antigen assays, PCR and cytopathology.
Management of CMV
- Immunocompetent patients usually require no treatment other than general advice to increase fluids and treat fever.
- However, patients with immunodeficiency require intensive antiviral treatment. The drug of choice for treatment of CMV disease is intravenous ganciclovir, although valganciclovir may be used for CMV treatment in selected cases.
What is infectious mononucleosis?
Infectious mononucleosis (IM) is usually a self-limiting infection, most often caused by Epstein-Barr virus (EBV), which is a human herpes virus.
However, approximately 10% of those with IM are not acutely infected with EBV and many of these have symptoms attributable to cytomegalovirus (CMV) infection
What is the presentation of infectious mononucleosis?
Most patients have few, if any, symptoms (most adults show serological evidence of previous EBV infection):
o Low-grade fever, fatigue and prolonged malaise. Fatigue and malaise may persist for several months after the acute infection has resolved.
o Sore throat; tonsillar enlargement is common, classically exudative and may be massive; palatal petechiae and uvular oedema.
o Fine macular non-pruritic rash, which rapidly disappears.
o Transient bilateral upper lid oedema.
o Lymphadenopathy, especially neck glands.
o Nausea and anorexia.
o Arthralgias and myalgias occur but are less common than in other viral infectious diseases and are rarely severe.
o Other symptoms include cough, chest pain and photophobia.
o Older adults and elderly patients often have few throat symptoms or signs and have little or no lymphadenopathy.
What are the later signs of infectious mononucleosis?
o Mild hepatomegaly and splenomegaly (splenic enlargement returns to normal or near normal usually within three weeks after the clinical presentation) with tenderness over the spleen.
o Jaundice occurs in fewer than 10% of young adults but in as many as 30% of infected elderly patients.
What are the differentials of infectious mononucleosis?
- Group A streptococcal pharyngitis.
- Kawasaki disease
- Lymphoma
- TB
