First-Onset Hypokalemic Periodic Paralysis Following Surgery for Myxopapillary Ependymoma.

BACKGROUND: Hypokalemic periodic paralysis is a rare skeletal muscle channelopathy characterized by intermittent episodes of acute flaccid paralysis with associated hypokalemia. We present here the case of a first-onset hypokalemic periodic paralysis triggered by lumbar spinal surgery for tumor resection. CASE DESCRIPTION: A 37-year-old male without any known prior medical conditions presented with a first-onset attack of hypokalemic paralysis 1.5 days after lumbar spinal surgery for myxopapillary ependymoma. Initially, the patient presented paraparesis mimicking a spinal cord compression, and while en route for imaging there was an abrupt onset of flaccid paralysis with significant respiratory distress. The emergency blood tests revealed extreme hypokalemia with a serum potassium of 1.42 mm/L. The patient was transferred to the intensive care unit, intubated, sedated, and administered intravenous reperfusion with an infusion dose of 20 mEq/hour potassium in a solution of 5% mannitol. Following reperfusion, the patient recovered completely in 12 hours. Renal potassium hyperexcretion and hyperthyroidism were excluded by laboratory tests. The diagnosis was confirmed by genetic tests showing mutation of the CACNA1S gene. CONCLUSIONS: To the best of our knowledge, this is the first described case with the first onset triggered by a neurosurgical intervention and the second case following any kind of surgery. Neurosurgeons should consider hypokalemic periodic paralysis when encountering a rapidly evolving tetraparesis, even in an apparently healthy patient.

Hypokalemic periodic paralysis induced by thymic hyperplasia and relieved by thymectomy.

IMPORTANCE: Hypokalemic periodic paralysis is a muscle channelopathy based on mutations or predisposing variants or secondary to potassium wasting. In contrast to myasthenia gravis, an association with thymic hyperplasia has not yet been reported, to our knowledge. OBSERVATIONS: We report a male patient in his mid-20s with progressive episodes of flaccid muscle weakness, associated low serum potassium levels, and a pathologic decrement in the long exercise test. Because the familial inheritance in the family was initially unknown, thorough diagnostic tests were performed including contrast-enhanced computed tomography scan, which displayed a mass in the anterior mediastinum. The test results for autoantibodies against myasthenia gravis (acetylcholine receptor, muscle-specific tyrosine kinase, and low-density lipoprotein receptor-related protein 4) and other end plate channelopathies were negative, and test results for hypokalemia-inducing hormones (thyroid, corticotropin, and cortisol) were negative. Surgery identified a thymus of 13 × 8 × 3 cm(3). Histologic analysis was consistent with thymic hyperplasia of the follicular subtype and immunohistologic analysis showed cytokeratin 5/6 in hyperplastic epithelial cells. A 2-year follow-up revealed the postoperative absence of weakness episodes. As in 30% of familial cases, molecular genetics testing failed to identify a mutation in periodic paralysis genes. CONCLUSIONS AND RELEVANCE: Thymic hyperplasia can clinically manifest susceptibility to hypokalemic periodic paralysis. For patients with late onset or increasing weakness episodes, we recommend imaging to assess for thymic enlargement and thymectomy at thymic hyperplasia.

[Thyrotoxic hypokalemic periodic paralysis: a rare complication of a common disease]. / Paralisi periodica ipopotassiemica tireotossica: una rara complicanza di una malattia comune.

Thyrotoxic periodic paralysis (TPP) is an uncommon but potentially lethal manifestation of hyperthyroidism characterized by muscle paralysis and hypokalemia. We have reported 3 cases of TPP in male patients, which manifested with morning muscle weakness evolved into paralysis. In all patients were found severe hypokalemia, abnormalities on electrocardiogram, and Graves' hyperthyroidism. Intravenous potassium administration led to normalization of potassium levels, and resolution of neurological symptoms. In addition, beta blockers and methimazole were started. Two patients required total thyroidectomy for poor control of hyperthyroidism with antithyroid drug. In patients presenting with periodic paralysis or diffuse muscle weakness thyroid function should be investigated in order to find out the cases secondary to unknown hyperthyroidism and to start an early appropriate combined therapy. The correct management of TPP can prevent serious cardiopulmonary complications.

Surgical treatment for thyrotoxic hypokalemic periodic paralysis: case report.

Thyrotoxic hypokalemic periodic paralysis (THPP) is a rare, potentially life-threatening endocrine emergency. It is characterized by recurrent muscle weakness and hypokalemia. Because many THPP patients do not have obvious symptoms and signs of hyperthyroidism, misdiagnosis may occur. The published studies revealed that definitive therapy for THPP is control of hyperthyroidism by medical therapy, radioactive iodine or surgery, but the long-term post-operative follow-up result was not observed. We reported two cases of medically refractory THPP with recurrent paralysis of extremities and hypokalemia, and both were combined with thyroid nodules. Both patients were treated with total thyroidectomy; the pathology revealed that one is Graves' disease with thyroid papillary carcinoma, and the other is adenomatous goiter with papillary hyperplasia. No episode of periodic paralysis was noted and laboratory evaluation revealed normal potassium level during the post-operative follow up. Our experience suggests that total thyroidectomy by experienced surgeon is an appropriate and definite treatment for medically refractory THPP, especially in cases combined with thyroid nodules.

[Intravenous regional anesthesia in patients with hypokalemic periodic paralysis].

Hypokalemic periodic paralysis is a familial autosomal dominant trait. The paralytic attacks are precipitated by large carbohydrate-rich meals, cold, mental or surgical stress, infections, exercise, drugs, electrolytes and endocrine abnormalities. Death may occur from respiratory arrest, infections, aspiration or cardiac arrhythmias. Anesthesia and surgical procedures may induce an attack and complicate the perioperative patient condition. Guidelines for anesthetic management should include preventive measures i.e. reduce mental stress and carbohydrate intake and correction of electrolytes and endocrine abnormalities. During the operation, measures should include prevention of cold and monitoring of muscle relaxants and ECG. When paralysis is diagnosed, slow (50 mEq/hr) i.v. infusion of potassium is suggested, while monitoring plasma levels of potassium ECG, and facial nerve conduction. We present two patients with hypokalemic periodic paralysis who underwent uneventful orthopedic procedures under i.v. regional block.

[Thyrotoxic hypokalemic periodic paralysis. Report of three cases]. / La paralysie périodique thyréotoxique hypokaliémique. Présentation de trois cas.

AIM OF THIS STUDY: Hypokaliemic thyrotoxic periodic paralysis (HTPP) is an uncommon complication of hypothyroidism. Mostly described among Asian patients, it is rare in the other ethnic groups, in particular in caucasians people. Among the possible mechanisms, modification of potassic flows in relation to anomalies of the sodium-potassium pump were evoked. PATIENTS AND METHOD: We present the cases of three caucasians patients operated on for HTPP. These patients had all previous history of several paretic episodes. The flask paralytic attacks occurred in a brutal way or were preceded by diffuse myalgias. They reached the proximal muscles, especially in inferior limbs. No patient had any respiratory complications. These three patients underwent total thyroidectomy to treat the symptoms of HTPP. RESULTS: In the three cases, a total thyroidectomy allowed the recovery of the symptoms. After a four years average period of post-operative follow-up, no patient presented any repetition of HTPP. The hyperthyroidism is the cause of decompensation of the molecular anomaly. CONCLUSION: In our opinion, surgical treatment (total thyroidectomy) is needed in order to reduce the potential gravity of this pathology.