Onion bulb appearance on nerve biopsy is seen in –
Correct Answer: CIDP
Description: chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) has been used to identify patients with a chronically progressive or relapsing symmetric sensorimotor disorder with cytoalbuminologic dissociation and interstitial and perivascular endoneurial infiltration by lymphocytes and macrophages. It can be considered the chronic equivalent of acute inflammatory demyelinating polyradiculoneuropathy, the most common form of Guillain-Barre syndrome. Signs and symptoms CIDP typically stas insidiously and evolves slowly, in either a slowly progressive or a relapsing manner, with paial or complete recovery between recurrences; periods of worsening and improvement usually last weeks or months. Most expes consider the necessary duration of symptoms to be greater than 8 weeks for the diagnosis of CIDP to be made. Symptoms repoed include the following: Preceding infection (infrequent) Initial limb weakness, both proximal and distal Sensory symptoms (eg, tingling and numbness of hands and feet) Motor symptoms (usually predominant) In about 16% of patients, a relatively acute or subacute onset of symptoms In children, usually a more precipitous onset of symptoms Symptoms of autonomic system dysfunction (eg, ohostatic dizziness) Peinent physical findings are limited to the nervous system, except when the condition is associated with other diseases. Such findings may include the following. Signs of cranial nerve (CN) involvement (eg, facial muscle paralysis or diplopia) Gait abnormalities Motor deficits (eg, symmetric weakness of both proximal and distal muscles in upper and lower extremities) Diminished or absent deep tendon reflexes Sensory deficits (typically in stocking-glove distribution) Impaired coordination Diagnosis Laboratory studies that may be helpful include the following: Cerebrospinal fluid analysis: Elevated protein levels are common (80% of patients); 10% of patients also have mild lymphocytic pleocytosis and increased gamma globulin Complete blood count (CBC), erythrocyte sedimentation rate (ESR), antinuclear antibody (ANA) level, biochemistry profile, and serum and urine immunoelectrophoresis (to exclude associated systemic disorders) In ceain instances, genetic testing Other tests and procedures that may be warranted are as follows: MRI of the spine with gadolinium enhancement Electromyography (EMG) is a critical test to determine whether the disorder is truly a peripheral neuropathy and whether the neuropathy is demyelinating Peripheral (sural) nerve biopsy (see the image below): This is considered when the diagnosis is not completely clear, when other causes cannot be excluded, or when profound axonal involvement is observed on EMG; biopsy was once commonly recommended for most patients before immunosuppressive therapy, but current guidelines no longer recommend it Electron micrograph of the peripheral nerve of a patient with chronic inflammatory demyelinating polyradiculoneuropathy. Note "onion bulb" formation in the myelin sheath of the nerve fibers due to continuous demyelination and remyelination. Ref: Medscape
Category:
Pathology
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