Neurologic Complications of Organ Transplantation Workup

Updated: Apr 09, 2019
  • Author: Jasvinder Chawla, MD, MBA; Chief Editor: Stephen A Berman, MD, PhD, MBA  more...
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Laboratory Studies

See the list below:

  • Cerebrospinal fluid (CSF) studies: CSF analysis is essential in investigations of neurologic complications and possible opportunistic CNS infections in transplant recipients who are immunosuppressed.

    • Cell count and differential, protein, glucose

    • Microbiology - Gram stain, Ziehl-Nielsen acid-fast stain, India ink, and bacterial, viral, fungal, and mycobacterial cultures

    • Molecular studies - Polymerase chain reaction (PCR) for herpes simplex virus (HSV), varicella-zoster virus (VZV), cytomegalovirus (CMV), EBV, human herpesvirus 6 (HHV-6), hepatitis E (HEV), measles virus, BK/JC virus, West Nile virus (WNV), and mycobacteria; PCR for EBV in patients with suspected PTLD

    • Immunology studies - Cryptococcal antigen, toxoplasma titers, syphilis tests (ie, microhemagglutination treponemal test [MHA-TP], fluorescent treponemal antibody absorbed test [FTA-ABS], venereal disease research laboratory [VDRL]), viral antibody titers (ie, HSV, VZV, HHV-6, EBV, CMV, WNV), histoplasma and mucor titers, and histoplasma and aspergillus antigens

    • Pathology - CSF cytology and flow cytometry, which are helpful in evaluation of possible PTLD

  • Other tests: Neurologic complications of transplantation mostly stem from underlying disorders that led to transplant, transplant procedures, and immunosuppression, and a variety of laboratory tests are helpful in establishing the cause of these complications.

    • Complete blood cell count and differential

    • Electrolytes, blood urea nitrogen, creatinine, magnesium, calcium and glucose, liver function tests, ammonia level, and thyroid-stimulating hormone (TSH) helpful in investigations of altered consciousness

    • Vitamins B-1, B-6, B-12, E, folic acid, homocysteine, and metyhlmalonic acid because many transplant recipients develop nutritional deficiencies

    • Urinalysis, urine cryptococcal antigen, and urine, blood, and sputum cultures because systemic infection may cause septic encephalopathy

    • Drug levels (note that neurotoxicity may occur even within therapeutic ranges of drug levels)

      • Immunosuppressive medications (eg, tacrolimus, cyclosporine)

      • Other medications (eg, phenytoin, valproate)

    • Creatine kinase (CK) is helpful in evaluation of toxic or inflammatory myopathy (may be within the reference range in critical illness myopathy after 2 wk)


Imaging Studies

See the list below:

  • Neuroimaging studies have a significant role in evaluation of neurologic posttransplant complications because they can provide important evidence on focal or diffuse nervous system injury.

  • CT scanning of the head is helpful when MRI is not immediately available, and it is sensitive for detection of intracranial hemorrhage. Cranial CT scanning may also confirm whether proceeding with lumbar puncture is safe. CT scanning of the sinuses can be used to evaluate opportunistic fungal sinus infections that may extend to the CNS.

  • Cranial MRI with and without gadolinium contrast is an essential diagnostic tool in the evaluation of transplant recipients with impaired consciousness or with focal findings. Cranial MRI findings may determine further diagnostic steps and possible therapeutic interventions. Diffusion-weighted imaging (DWI) and fluid-attenuated inversion-recovery (FLAIR) sequence images should be included in a standard protocol.

  • Magnetic resonance venography (MRV) is helpful in evaluation of possible cerebral venous sinus thrombosis.

  • MRI of the spine with and without contrast is helpful in the evaluation of epidural abscesses and other causes of myelopathy and radiculopathy.


Other Tests

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  • EEG is indispensable in the evaluation of possible seizures and impairment of consciousness. It is necessary for establishing the diagnosis of nonconvulsive status epilepticus, and findings are crucial for differentiating metabolic encephalopathy from complex partial seizures. Certain features of EEG, including generalized slowing, are suggestive of metabolic encephalopathy, and triphasic waves are highly suggestive of uremic and hepatic encephalopathy. Prolonged continuous monitoring may be needed in patients with refractory seizures to titrate therapy.

  • Nerve conduction and electromyography studies (NCS/EMG) are very helpful in evaluation of focal weakness and possible perioperative neuropathies, critical illness myopathy/polyneuropathy, and other neuromuscular disorders. Studies in ICU setting may be technically limited. In patients with indwelling catheters, electrical safety risks of proximal nerve stimulation should be assessed. Needle electromyography may be limited in patients with coagulopathy. Direct muscle needle stimulation may be helpful to demonstrate inexcitability of muscle in critical illness myopathy.

  • Echocardiography (transthoracic or transesophageal) is used to determine the presence of intracardiac clots and nonbacterial thrombotic or infective endocarditis.



See the list below:

  • Lumbar puncture may be indicated if it can be performed safely. It is indispensable in evaluation of possible opportunistic CNS infections.

  • Nerve and muscle biopsy is rarely used in transplant patients. It is helpful to document lymphoproliferative disorders involving nerve or muscle. Muscle biopsy (needle or open) may be helpful to document critical illness myopathy.{Imagenum2:2122992