Colchicine Induced Neuromyopathy in a Patient with Normal Renal Function

A 69-year-old male on colchicine 0.6 mg twice a day for more than a year developed subacute onset of painless proximal muscle weakness with significant elevation of creatine phosphokinase (CPK) levels. He also experienced numbness and tingling in the extremities. Nerve conduction studies revealed a mild axonal neuropathy affecting the arms and legs while needle electromyography was unremarkable. He refused a muscle biopsy. After withdrawal of colchicine, muscle strength and serum CPK levels returned to normal over a period of 4 months. Neuromyopathy is a well documented side effect of colchicine, and impaired renal function has been the major risk factor in previously reported cases. In our patient, neurological toxicity occurred in the presence of normal renal function. The neuromyopathy is generally reversible on withdrawal of the drug. Colchicine is to be used with caution in patients with impaired renal function, and even if kidney function is normal, muscle strength must be monitored and serum CPK levels checked if myopathy is suspected.

Periodic lateralized epileptiform discharges after complex partial status epilepticus associated with increased focal cerebral blood flow

Periodic lateralized epileptiform discharges (PLEDs) are typically associated with encephalitis, cerebral abscess, cerebral infarct, and status epilepticus. There is considerable debate as to whether this pattern is ictal or interictal when seen in association with status epilepticus. We present a patient with complex partial status epilepticus who developed PLEDs and remained comatose despite optimal drug therapy. Technetium 99m single-photon emission computed tomography (SPECT) showed hyperperfusion that resolved with further aggressive antiepileptic drug therapy, indicating that this pattern may indeed be ictal. Further studies are needed to define the significance of PLEDs in patients with status epilepticus. The role of SPECT in differentiating PLEDs as an interictal or ictal pattern also requires further study.

Central pontine myelinolysis

Central pontine myelinolysis (CPM), a neurologic disorder caused most frequently by rapid correction of hyponatremia, is characterized by demyelination that affects the central portion of the base of the pons. There are no inflammatory changes, and blood vessels are normal. Clinical features usually reflect damage to the descending motor tracts and include spastic tetraparesis, pseudobulbar paralysis, and the locked-in syndrome. Magnetic resonance imaging of the brain, the imaging procedure of choice, shows an area of prolonged T1 and T2 relaxation in the central pons, which may have a characteristic shape. Recovery varies, ranging from no improvement to substantial improvement. To avoid CPM, correction of serum sodium in patients with hyponatremia should not exceed 12 mEq/24 h. We describe a case of CPM in a hyponatremic patient who presented with a cerebellar syndrome with no pyramidal tract involvement and in whom the rate of correction of serum sodium was within the recommended limits.

Fluorouracil-induced neurotoxicity

OBJECTIVE

To report a case of acute neurologic adverse effects related to fluorouracil administration and to review the neurotoxicity of this agent.

CASE SUMMARY

A 73-year-old white man with a history of esophageal carcinoma was treated with fluorouracil 1,500 mg iv daily for four days. After completing treatment, he presented with sudden onset of confusion, cognitive disturbances, a cerebellar syndrome, and repeated seizures. A magnetic resonance image of the brain showed no structural abnormalities, and cerebrospinal fluid examination was normal; none of the other laboratory tests provided an explanation for his symptoms. The patient was treated with anticonvulsants, and the cognitive changes resolved in 72 hours. The cerebellar signs, however, did not resolve completely and persisted when the patient was examined two weeks after discharge.

DISCUSSION

Fluorouracil can cause both acute and delayed neurotoxicity. Acute neurotoxicity manifests as encephalopathy or as cerebellar syndrome; seizures, as seen in our patient, have rarely been reported. Acute neurotoxicity due to fluorouracil is dose related and generally self-limiting. Various mechanisms for such toxicity have been postulated, and treatment with thiamine has been recommended. Delayed neurotoxicity has been reported when fluorouracil was given in combination with levamisole; this form of subacute multifocal leukoencephalopathy is immune mediated and responds to treatment with corticosteroids.

CONCLUSIONS

Clinicians should be aware of the adverse neurologic effects of fluorouracil and should include them in the differential diagnosis when patients receiving the drug present with neurologic problems.

Seizures in lung transplant recipients

PURPOSE

We wished to assess organ transplant recipients, who incur a significant risk for seizures.

METHOD

We reviewed 85 lung transplants performed in 81 patients at the University of North Carolina hospitals between 1991 and 1994. All patients were reviewed for age, reason for transplant, detailed description of seizures, neurological examination, medications, and laboratory results, including cyclosporine level, EEG, and brain imaging.

RESULTS

Eighteen of 81 (22%) patients experienced seizures. Patients aged < 25 years had the greatest risk of seizures and 15 of the 18 patients had cystic fibrosis. Sixteen of the 18 (89%) patients, by history, had partial-onset seizures. Eleven of the 18 (61%) patients had seizures < or = 10 days after initiation of intravenous methylprednisolone for allograft rejection. Two patients had seizures associated with sustained hypertension: 1 of these patients was simultaneously being treated for rejection. Four patients had strokes (1 before transplant) and seizures. Two patients were receiving imipenem. Magnetic resonance imaging (MRI) of the brain demonstrated areas of increased T2 signal in 8 of 9 patients.

CONCLUSIONS

Our findings demonstrate multiple etiologies for seizures in our transplant recipients. However, we believe that patients, especially those aged < 25 years, being treated with intravenous methylprednisolone for rejection may be at increased risk of seizures. We hypothesize that the focal loss of blood-brain barrier (BBB) may play a significant role in the development of partial seizures in lung transplant recipients.

The effects of selenium on the emergence of aflatoxin B1-induced enzyme-altered foci in rat liver

The effects of selenium on the emergence of aflatoxin B1 (AFB1)-induced enzyme-altered foci were studied in male Sprague-Dawley rats. Animals were fed a selenium-deficient diet and supplemented with 5.0, 2.0, and 0.2, or 0 ppm selenium in drinking water for 3 weeks prior to initiation with 2.0 mumol/kg AFB1. After a 1-week period of selenium normalization, the animals were placed on a diet of ordinary rat chow, and were administered a promoting regimen of 500 ppm phenobarbital in drinking water for 1 week, after which time each rat received a two-thirds partial hepatectomy. The promoting regimen of phenobarbital in tap water was then reduced to 100 ppm and continued for 7 weeks. Subsequently, the rats were sacrificed, their livers excised, and fresh frozen sections prepared and stained histochemically to demonstrate areas of gamma-glutamyl transpeptidase (GGT) activity. Selenium supplementation was observed to diminish the induction of GGT-positive foci, especially at the 5.0-ppm level. These data suggest that selenium is able to protect against the hepatocarcinogenic effects of AFB1 in the rat, and that the enzyme-altered foci bioassay may be a useful technique in assessing the interaction of selenium on the process of hepatocarcinogenesis.

Surgical approach to the rostral cranial fossa by radical transfrontal craniotomy in the dog

To overcome the problems of restricted visibility and surgical mobility, as well as those posed by anatomical features oif the canine subfrontal sinus region and associated dura mater, aggravated by hazards of infection from potentially infected frontal sinuses, of uncontrollable haemorrhage and post-operative brain compression, a radical approach was devised, combining invasion of the frontal sinus with a lateral rostrotentorial craniotomy. This offers adequate surgical manoeuvring space, excellent visualisation of the rostral cranial fossa and its contents, proper asepsis, minimal haemorrhage and no untoward after-effects. The technique lends itself to diverse neurosurgical applications in the rostral cranial fossa of the dog. Particulars of instrumentation, and pre-operative, operative and post-operative procedures, done on 3 Beagles with excellent results, are described.