Pediatric emergency medicine trisk 1035

diagnosis of primary EBV infection which has reduced the risk of PTLD to less
than 3% in the liver transplant population, and less than 10% in the heart
transplant population.
Imaging via CT scan can help screen for enlarged lymph nodes, solid tumors,
and other findings concerning for neoplasia. If found, and if accessible, biopsy of
the disease site is the diagnostic step of choice. A PET-CT may help detect occult
disease. Treatment typically includes minimization or discontinuation of
immunosuppression as a first step, to allow the body to resume control of the
proliferating B cells. Directed therapies with chemotherapeutic regimens
including rituximab, cyclophosphamide, and prednisone may then be added. If
high EBV load is detected, an antiviral agent is typically added as adjunct
therapy.

Clinical Considerations
Clinical Recognition
Suspicion for PTLD should arise in the setting of a child with a prior EBV
infection and an increasing viral load as measured by EBV polymerase chain
reaction (PCR). Other presentations include progressive and unremitting
gastrointestinal findings (e.g., chronic diarrhea, bloody stool, abdominal pain,
anorexia, weight loss), pulmonary symptoms (e.g., chronic cough, shortness of
breath), or vague systemic malaise (e.g., fever, feeling unwell, weight loss).
Children may be asymptomatic. Lymphoproliferative disease can occur in any
location, and screening must include the graft (though lesions are rarely
intracardiac), lungs, brain, intestine, spleen, liver, lymph nodes, and bone marrow.
Clinical Assessment
Common clinical examination findings may include fever, lymphadenopathy
(especially cervical, submandibular, and axillary), sinusitis, tonsillar enlargement,
and splenomegaly. Initial assessments should target the primary symptomatology:
if diarrhea is present, stool should be collected and sent for usual infectious
pathogens plus occult (or gross) blood; if respiratory symptoms are present, chest
radiograph is indicated; palpable masses or obstructive symptoms require CT

imaging. All of this must be performed with the advice and participation of the
transplant team.
The diagnosis of PTLD is rarely made in the ED. It usually requires a
combination of imaging, analysis of tissues (e.g., lymph node, tonsil, liver) for
evidence of EBV-transformed B cells and quantitative EBV PCR from blood
confirming viral replication. With that said, investigations can be initiated in the


ED. Blood can be sent for EBV PCR if this condition is suspected. Specific T-cell
studies are used to determine the clonality of the lymphoproliferation and thereby
to determine the appropriate therapy, which can range from reduction of
immunosuppression and antiviral therapy to specific cytotoxic chemotherapeutic
agents. In many cases, the PTLD responds to discontinuation of
immunosuppressive medications without ensuing allograft rejection. Acute,
urgent management should focus on the primary symptom constellation and
resultant clinical compromise.

VASCULAR COMPLICATIONS
CLINICAL PEARLS AND PITFALLS
Vascular complications in liver transplant patients can occur in any of
the three vascular anastomoses: hepatic artery, portal vein, and hepatic
vein.
Early hepatic artery thrombosis (HAT) is a surgical emergency as it can
lead to graft failure and may require retransplantation.
Portal vein complications include portal vein thrombosis (PVT) or
stenosis and typically present with signs of portal hypertension.
Cardiac transplant recipients do not typically present de novo with
postsurgical vascular issues.

LIVER TRANSPLANTATION

Vascular complications can occur in any of the three vascular anastomoses:
hepatic artery, portal vein, and hepatic vein. Vascular thrombosis remains the
most common cause of early postoperative allograft loss.

Hepatic Artery Thrombosis
HAT occurs most often within the first few days following transplantation with a
reported incidence between 3% and 10%. HAT can present with a variable
clinical picture from mild abnormalities in transaminases and lactate
dehydrogenase to fulminant allograft failure. With graft ischemia, patients may
also present with signs of biliary obstruction secondary to associated biliary
pathology, or even systemic sepsis. Early identification of HAT is key and allows
for potential salvage of the hepatic allograft via thrombectomy or possible hepatic
artery reconstruction. Ultrasound with Doppler is the initial screening modality of
choice and is >90% sensitive at detecting early HAT, but confirmation with CT,


MRI, or angiogram is necessary. Acute HAT with allograft failure is a surgical
emergency and requires immediate listing for retransplantation. While awaiting
transplant, biliary stenting or percutaneous draining may be indicated to manage
the biliary complications associated with HAT.
Late HAT may be asymptomatic or present with progressive biliary stenosis
and as such, total bilirubin, alkaline phosphatase, and GGT levels may be
elevated. With late HAT, arterial collaterals may develop and if there is adequate
hepatic blood flow whether through these collaterals or via compensation by the
portal vein, then treatment may not be required. Imaging with ultrasound
followed by CT or angiogram may help to map the hepatic vasculature and
collaterals. Treatment options of HAT remain fairly limited as anticoagulation and
thrombolysis are not typically effective. Surgical reconstruction is typically
contraindicated as disruption of the collateral supply can precipitate hepatic
ischemia with resultant parenchymal necrosis. Most cases of HAT ultimately

require retransplantation.


TABLE 125.3
OVERVIEW OF COMPLICATIONS OF SOLID ORGAN
TRANSPLANTATION

Portal Vein Complications
Portal vein complications include abnormalities in portal flow or portal vein
obstruction from either portal vein stenosis or PVT. Portal vein obstructions occur
in approximately 10% of pediatric liver transplant recipients. Most cases are
symptomatic with portal venous obstruction ultimately resulting in portal
hypertension. Examination findings might include splenomegaly, ascites, caput
medusae, or esophageal varices. Clubbing has been described in advanced cases
of PVT. In severe cases, portal vein obstruction may lead to graft loss. PVT may
also be clinically silent or provide only subtle clues, especially if collateral
formation has occurred. For children with collaterals or who develop spontaneous
splenorenal shunts, subtle neurologic or behavioral changes may be seen as
mesenteric blood becomes diverted around the liver.
LFTs are largely unremarkable in patients with PVT. Transaminases and LDH
levels are usually only slightly elevated, and bilirubin, alkaline phosphatase, and