Pseudo-pheochromocytoma due to obstructive sleep apnea: a case report

SUMMARY

Obstructive sleep apnea (OSA) is a condition of intermittent nocturnal upper airway obstruction. OSA increases sympathetic drive which may result in clinical and biochemical features suggestive of pheochromocytoma. We present the case of a 65-year-old male with a 2.9-cm left adrenal incidentaloma on CT, hypertension, symptoms of headache, anxiety and diaphoresis, and persistently elevated 24-h urine norepinephrine (initially 818 nmol/day (89-470)) and normetanephrine (initially 11.2 µmol/day (0.6-2.7)). He was started on prazosin and underwent left adrenalectomy. Pathology revealed an adrenal corticoadenoma with no evidence of pheochromocytoma. Over the next 2 years, urine norepinephrine and normetanephrine remained significantly elevated with no MIBG avid disease. Years later, he was diagnosed with severe OSA and treated with continuous positive airway pressure. Urine testing done once OSA was well controlled revealed complete normalization of urine norepinephrine and normetanephrine with substantial symptom improvement. It was concluded that the patient never had a pheochromocytoma but rather an adrenal adenoma with biochemistry and symptoms suggestive of pheochromocytoma due to untreated severe OSA. Pseudo-pheochromocytoma is a rare presentation of OSA and should be considered on the differential of elevated urine catecholamines and metanephrines in the right clinical setting.

LEARNING POINTS

Obstructive sleep apnea (OSA) is a common condition among adults. OSA may rarely present as pseudo-pheochromocytoma with symptoms of pallor, palpitations, perspiration, headache, or anxiety. OSA should be considered on the differential of elevated urine catecholamines and metanephrines, especially in patients with negative metaiodobenzylguanidine (MIBG) scan results.

Infantile Hypotonia: A Case of Spinal Muscular Atrophy With Respiratory Distress Type 1 Presenting As Infant Botulism

Spinal muscular atrophy with respiratory distress type 1 (SMARD 1) is a rare autosomal recessive disease characterized by distal muscular atrophy and respiratory distress. It presents between six weeks and six months of age, with an eventual requirement of respiratory support. To date, no curative treatment to attenuate or stop the clinical deterioration has been found; therefore, supportive treatment is the corner stone of management.

We report a 12-week-old infant with SMARD1 initially diagnosed and managed as a case of infant botulism secondary to a history of significant exposure to honey. SMARD1 and infant botulism all share characteristic clinical features, namely, respiratory distress, hypotonia, and autonomic dysfunction with typical onset of less than one year of age.

This case report illustrates that SMARD1, SMA Type 1, and infant botulism share common clinical features. It is important to maintain a broad differential when evaluating an infant with hypotonia, especially when there is a lack of clinical response to conventional medical interventions directed toward the working diagnosis.

A Japanese family showing high-frequency hearing loss with KCNQ4 and TECTA mutations

CONCLUSIONS

We describe a Japanese family with high-frequency sensorineural hearing loss (SNHL) harboring a c.211delC mutation in the KCNQ4 gene. Families showing progressive high-frequency SNHL should be investigated for mutations in the KCNQ4 gene.

OBJECTIVE

To determine the responsible deafness gene in a Japanese family with dominantly inherited high-frequency SNHL of unknown etiology.

METHODS

We performed hearing tests for five members of the family, and the three affected with hearing loss underwent further audiological and vestibular examinations. Genetic analysis was performed to identify any possible causative mutations, as well as analysis of detailed clinical findings to determine the phenotype.

RESULTS

The three affected subjects showed high-frequency SNHL. Extensive audiologic evaluation suggested cochlear involvement and progressive hearing loss. As for bilateral caloric testing, two of the three affected subjects showed hyporeflexia with recurrent vestibular symptoms. We identified the c.211delC mutation in the KCNQ4 gene and the c.2967C>A (p.H989Q) mutation in the TECTA gene. Based on the genotype-phenotype correlation, the c.211delC mutation in the KCNQ4 gene was associated with high-frequency SNHL in this family.

Lower motor neuron findings after upper motor neuron injury: insights from postoperative supplementary motor area syndrome

Hypertonia and hyperreflexia are classically described responses to upper motor neuron injury. However, acute hypotonia and areflexia with motor deficit are hallmark findings after many central nervous system insults such as acute stroke and spinal shock. Historic theories to explain these contradictory findings have implicated a number of potential mechanisms mostly relying on the loss of descending corticospinal input as the underlying etiology. Unfortunately, these simple descriptions consistently fail to adequately explain the pathophysiology and connectivity leading to acute hyporeflexia and delayed hyperreflexia that result from such insult. This article highlights the common observation of acute hyporeflexia after central nervous system insults and explores the underlying anatomy and physiology. Further, evidence for the underlying connectivity is presented and implicates the dominant role of supraspinal inhibitory influence originating in the supplementary motor area descending through the corticospinal tracts. Unlike traditional explanations, this theory more adequately explains the findings of postoperative supplementary motor area syndrome in which hyporeflexia motor deficit is observed acutely in the face of intact primary motor cortex connections to the spinal cord. Further, the proposed connectivity can be generalized to help explain other insults including stroke, atonic seizures, and spinal shock.