Solid organ transplant complications

Cytomegalovirus is a ubiquitous herpesvirus that is usually asymptomatic or causes a heterophile-negative mononucleosis-like illness in healthy hosts, but reactivates to cause retinitis, colitis, pneumonitis, or encephalitis in transplant recipients and patients with AIDS; treatment is systemic ganciclovir or valganciclovir, with foscarnet and cidofovir reserved for resistance or intolerance.

Pneumocystis jirovecii pneumonia is a subacute, often hypoxic pneumonia in patients with CD4 counts below 200/mcL or comparable immunosuppression, diagnosed by organism visualization on induced sputum or bronchoalveolar lavage and treated with 21 days of high-dose trimethoprim-sulfamethoxazole plus adjunctive steroids when hypoxic.

Kaposi sarcoma is a human herpesvirus 8-associated vascular malignancy that presents as violaceous macules, papules, plaques, or tumors of the skin, mouth, gastrointestinal tract, or lungs, most often in HIV-associated, transplant-related, or classic elderly disease. Diagnosis is confirmed by biopsy. Every patient with HIV-associated Kaposi sarcoma starts or optimizes antiretroviral therapy, with liposomal doxorubicin 20 mg/m2 intravenously every 21 days added for extensive or visceral disease.

Graft-versus-host disease is a complication of allogeneic hematopoietic stem cell transplantation in which donor T cells attack recipient tissues, classically the skin, liver, and gut in the acute form and multi-organ fibrosis in the chronic form. Diagnosis is clinical, supported by biopsy, and management is prophylaxis with a calcineurin inhibitor plus methotrexate and treatment with corticosteroids, escalating to agents such as ruxolitinib for steroid-refractory disease.

Acute kidney injury is a sudden rise in serum creatinine or fall in urine output from prerenal, intrinsic, or postrenal causes, defined and staged by KDIGO criteria. Management targets the underlying cause, corrects volume and electrolyte derangements, and escalates to renal replacement therapy for refractory hyperkalemia, acidosis, volume overload, or uremia.

Invasive aspergillosis is an angioinvasive mold infection of neutropenic and immunosuppressed hosts that begins in the respiratory tract and disseminates hematogenously, diagnosed with CT, galactomannan, and biopsy, and treated first-line with voriconazole.

Non-Hodgkin lymphoma is a heterogeneous group of B-cell (about 85%) and T-cell lymphoid malignancies that spread noncontiguously and often involve extranodal sites, ranging from indolent follicular lymphoma to aggressive diffuse large B-cell lymphoma to highly aggressive Burkitt lymphoma. Diagnosis requires excisional or core biopsy with flow cytometry and cytogenetics, Ann Arbor staging with PET-CT, and treatment is subtype-specific, from observation to R-CHOP to intensive Burkitt regimens with aggressive tumor lysis and CNS prophylaxis.

Urinary tract infection spans uncomplicated cystitis, presenting with dysuria, frequency, and suprapubic pain, through pyelonephritis, presenting with fever, flank pain, and costovertebral angle tenderness, most often from ascending Escherichia coli. Uncomplicated cystitis is treated empirically without culture using nitrofurantoin, trimethoprim-sulfamethoxazole, or fosfomycin, while pyelonephritis requires a pre-treatment urine culture and empiric fluoroquinolone or cephalosporin therapy, escalated to hospitalization and broader parenteral coverage for hemodynamic instability, obstruction, or failure to improve.