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International Journal of Urology (2015) 22, 239
doi: 10.1111/iju.12653
Letter to the Editor Sneezing induced by bladder fullness We have long recognized that sneezing can occur in response to non-rhinological triggers. Up to a quarter of the population will sneeze in response to looking at sunlight, a response that is heritable and termed the photic sneeze reflex.1 In 2008, I reported on a number of individuals who sneeze in response to sexual ideation or orgasm, a phenomenon that is now well recognized.2 Sneezing can also occur in response to a full stomach.3 A mechanism of “parasympathetic summation” could be the explanation underlying all of these unusual triggers of sneezing, whereby activation of the parasympathetic nervous system in extra-nasal locations causes inadvertent parasympathetic stimulation of nasal secretions, which in turn triggers a sneeze.1,2 I have now been contacted by a man aged 68 years reporting sneezing induced by bladder fullness. In the past decade, he has come to recognize that when he develops watery rhinorrhoea and sneezing, it signifies that his bladder is becoming full. If he does not immediately empty his bladder, he will then develop normal conscious sensation of bladder fullness; but in addition, his rhinorrhoea becomes persistent, and his sneezing repetitive. His sneezing and rhinorrhoea are immediately and reliably relieved on micturition. He has not identified any conditions that modify this response, and he denies other urological, rhinological or neurological symptoms, or other unusual triggers of sneezing. He does not find this symptom troublesome, and has not sought medical advice or treatment, nor has he undergone medical investigation. The control of micturition remains incompletely understood, but specialized “ramp neurons” within the micturition center in the pons (Barrington’s nucleus) are thought to be central regulators.4 Ramp neurons show tonic firing activity, which is associated with relaxation of the detrusor muscle of the bladder. However, as the bladder fills, stretch receptors in the bladder wall signal distension to the micturition center, causing a rapid increase in the firing rate and intensity of ramp neurones.5 The increased firing activates central parasympathetic neurones, which communicate through the pelvic splanchnic nerves
© 2014 The Japanese Urological Association
(sacral outflow) to cause contraction of the detrusor muscle. This activity leads to pressure to void, although micturition might be delayed by voluntary contraction of the urethral sphincter. On voiding, activity in pontine ramp neurones returns to baseline tonic activity, parasympathetic activity is diminished and the bladder relaxes. Summation of parasympathetic activity to the detrusor muscle and to the nasal glands could explain the novel phenomenon in this individual of sneezing induced by bladder fullness. Under this hypothesis, as the bladder fills there will be a commensurate increase in central parasympathetic neuronal firing to the detrusor muscle. This is matched by parasympathetic activity to the nasal glands, causing nasal secretions, and triggering sneezing. The sneezing continues and increases as the bladder continues to distend, until voiding, when parasympathetic activity desists. Mahmood F Bhutta D.Phil., F.R.C.S. UCL Ear Institute (University College of London), London, UK [email protected]
Conflict of interest None declared.
References 1 Whitman BW, Packer RJ. The photic sneeze reflex: literature review and discussion. Neurology 1993; 43: 868–71. 2 Bhutta MF, Maxwell H. Sneezing induced by sexual ideation or orgasm: an under-reported phenomenon. J. R. Soc. Med. 2008; 101: 587–91. 3 Forrai G, Antal J, Balogh A. Sneezy twins. Acta Paediatr. Hung. 1985; 26: 323–6. 4 Fowler CJ, Griffiths D, de Groat WC. The neural control of micturition. Nat. Rev. Neurosci. 2008; 9: 453–66. 5 Sasaki M. Role of Barrington’s nucleus in micturition. J. Comp. Neurol. 2005; 493: 21–6.
239
Copyright of International Journal of Urology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
International Journal of Urology (2015) 22, 239
doi: 10.1111/iju.12653
Letter to the Editor Sneezing induced by bladder fullness We have long recognized that sneezing can occur in response to non-rhinological triggers. Up to a quarter of the population will sneeze in response to looking at sunlight, a response that is heritable and termed the photic sneeze reflex.1 In 2008, I reported on a number of individuals who sneeze in response to sexual ideation or orgasm, a phenomenon that is now well recognized.2 Sneezing can also occur in response to a full stomach.3 A mechanism of “parasympathetic summation” could be the explanation underlying all of these unusual triggers of sneezing, whereby activation of the parasympathetic nervous system in extra-nasal locations causes inadvertent parasympathetic stimulation of nasal secretions, which in turn triggers a sneeze.1,2 I have now been contacted by a man aged 68 years reporting sneezing induced by bladder fullness. In the past decade, he has come to recognize that when he develops watery rhinorrhoea and sneezing, it signifies that his bladder is becoming full. If he does not immediately empty his bladder, he will then develop normal conscious sensation of bladder fullness; but in addition, his rhinorrhoea becomes persistent, and his sneezing repetitive. His sneezing and rhinorrhoea are immediately and reliably relieved on micturition. He has not identified any conditions that modify this response, and he denies other urological, rhinological or neurological symptoms, or other unusual triggers of sneezing. He does not find this symptom troublesome, and has not sought medical advice or treatment, nor has he undergone medical investigation. The control of micturition remains incompletely understood, but specialized “ramp neurons” within the micturition center in the pons (Barrington’s nucleus) are thought to be central regulators.4 Ramp neurons show tonic firing activity, which is associated with relaxation of the detrusor muscle of the bladder. However, as the bladder fills, stretch receptors in the bladder wall signal distension to the micturition center, causing a rapid increase in the firing rate and intensity of ramp neurones.5 The increased firing activates central parasympathetic neurones, which communicate through the pelvic splanchnic nerves
© 2014 The Japanese Urological Association
(sacral outflow) to cause contraction of the detrusor muscle. This activity leads to pressure to void, although micturition might be delayed by voluntary contraction of the urethral sphincter. On voiding, activity in pontine ramp neurones returns to baseline tonic activity, parasympathetic activity is diminished and the bladder relaxes. Summation of parasympathetic activity to the detrusor muscle and to the nasal glands could explain the novel phenomenon in this individual of sneezing induced by bladder fullness. Under this hypothesis, as the bladder fills there will be a commensurate increase in central parasympathetic neuronal firing to the detrusor muscle. This is matched by parasympathetic activity to the nasal glands, causing nasal secretions, and triggering sneezing. The sneezing continues and increases as the bladder continues to distend, until voiding, when parasympathetic activity desists. Mahmood F Bhutta D.Phil., F.R.C.S. UCL Ear Institute (University College of London), London, UK [email protected]
Conflict of interest None declared.
References 1 Whitman BW, Packer RJ. The photic sneeze reflex: literature review and discussion. Neurology 1993; 43: 868–71. 2 Bhutta MF, Maxwell H. Sneezing induced by sexual ideation or orgasm: an under-reported phenomenon. J. R. Soc. Med. 2008; 101: 587–91. 3 Forrai G, Antal J, Balogh A. Sneezy twins. Acta Paediatr. Hung. 1985; 26: 323–6. 4 Fowler CJ, Griffiths D, de Groat WC. The neural control of micturition. Nat. Rev. Neurosci. 2008; 9: 453–66. 5 Sasaki M. Role of Barrington’s nucleus in micturition. J. Comp. Neurol. 2005; 493: 21–6.
239
Copyright of International Journal of Urology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
