The Journal of
Laryngology and Otology (Founded in 1887 by MORELL MACKENZIE and NORRIS WOLFENDEN)
May 19JJ Laryngeal tetany: An unusual presentation of chronic renal failure By H. A. YOUNG and I. T. FERGUSON
(Dundee) Introduction ADDUCTOR spasm of the vocal cords is recognized in children and rarely in adults as an uncommon manifestation of hypocalcaemia (Fourman and Royer, 1968) which may occur secondary to malabsorption, acute pancreatitis, inadequate diet or hypoparathyroidism (Williams and Brown, 1974). Chronic renal failure is usually accompanied by hypocalcaemia (Black, 1972) but tetany is rare and isolated laryngospasm exceptional. We present two such cases. Case Reports Case 1
A 44-year-old woman first presented to hospital as an emergency in an unrousable state. She had marked inspiratory stridor complicated by the sudden onset of deep cyanosis and apnoea. This was relieved by endotracheal intubation. Apart from glottic adductor spasm indirect laryngoscopy revealed no abnormality. There was no increase in muscular tone. Chvostek's and Trousseau's signs were negative and further examination of the central nervous system failed to reveal any abnormality. There was no known history of inhalation of a foreign body or previous laryngeal disease. On admission the following blood results were obtained: serum calcium (corrected for albumin) i-6 mmol./l. (normal range: 2 ^5-2-65 mmol./l.); 373
H. A. Young and I. T. Ferguson plasma organic phosphate 3 • 6 mmol./l. (0 • 8-1 • 55 mmol./l.); serum alkaline phosphatase 20 King Armstrong units/100 ml. (3-14 K.A. units/100 ml.); serum creatinine 1600 umol./l. (44-150 umol./l.); serum potassium 7-4 mmol./l. (3-5-5-0 mmol./l.); actual bicarbonate 8 mmol./l. (21-28 mmol./l.); arterial pH 7-00 (7 • 36-7 • 44) ; The electrocardiogram showed a prolonged Q-T. interval (0-38 seconds)— compatible with marked hypocalcaemia. Chest X-ray was normal. Laryngeal spasm secondary to the hypocalcaemia of chronic renal failure was diagnosed. Artificial ventilation and continuous peritoneal dialysis was started— intermittent (I.V.) 10 per cent calcium gluconate (total 60 ml.) and 1 -5 litres of 4-2 per cent I.V. sodium bicarbonate were given. Serum levels of calcium and phosphate approached normality (Fig. 1). Despite treatment she died 48 hours after admission following repeated episodes of ventricular fibrillation with terminal asystole. Post mortem examination revealed cardiomegaly and small fibrotic kidneys due to chronic glomerulonephritis. The parathyroid glands and larynx were normal.
Case 2 A previously fit 46-year-old man was referred to the department of Otolaryngology with a history of intermittent inspiratory difficulty, particularly at night, for one month. Each episode was of acute onset lasting several minutes and resolving spontaneously. He also gave vague history of nocturia and polydipsia for the previous six months. Following admission he experienced two episodes of apnoea and cyanosis lasting one to two minutes. Between attacks, indirect laryngoscopy showed no notable abnormality. Coarse limb muscle twitching without rigidity was observed. Trousseau's and Chvostek's signs were negative. Blood pressure was found to be 200/130 and fundoscopy revealed papilloedema with exudates and haemorrhages. X-rays of chest and soft tissues of neck were normal. Initial blood investigations showed: serum calcium 1 • 4 mmol./l. (2 • 15-2 • 65 mmol./l.) plasma inorganic phosphate 2 • 9 mmol./l. (o • 8-1 • 55 mmol./l.) serum creatinine 1500 umol./l. (44-150 umol./l.) serum alkaline phosphatase, potassium, magnesium and arterial pH,—normal. The electrocardiogram showed a prolonged Q-T. interval (0 • 36 seconds). Intermittent I.V. 10 per cent calcium gluconate (total 50 ml.) was given over 48 hours. Serum calcium fluctuated with therapy (Fig. 2) and stabilized at 1 -7-1-85 mmol./l. when taking 9 -5 g. per day of oral calcium gluconate. Renal biopsy showed chronic glomerulonephritis. He had no further episodes of laryngospasm. 374
Laryngeal tetany Case 2.
Case i. ^
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Variations in blood calcium and phosphate during therapy. P.D. = Peritoneal dialysis (Dialysate contained 3-6mEq/i calcium and no phosphate) I.V.Ca. = Intravenous calcium gluconate Conversion S.I. to traditional units: Calcium: immol/i = 4-omg/iooml Phosphate: immol/1 = 3-img/iooml
Discussion Laryngospasm in the apyrexial patient is an uncommon condition, but may be due to hypocalcaemia. When poor nutrition was commonplace, particularly with low vitamin D intake, children were frequently seen with laryngeal tetany (laryngismus stridulus). Similar episodes have been reported in adults but are usually associated with hypocalcaemia due to hypoparathyroidism (Williams and Brown, 1974). The spasm follows increased reflex excitability at the neuromuscular junctions of the recurrent laryngeal nerves. The condition is often worse during the night because of the collection of pharyngeal secretions (Jackson and Jackson, 1937). This was demonstrated in our second patient. Laryngospasm due to hypocalcaemia is usually accompanied by other features of tetany including cutaneous paraesthesiae, carpopedal spasm, bronchospasm and rarely seizures. However, our two patients with chronic renal failure 375
H. A. Young and I. T. Ferguson
]
I presented with isolated laryngospasm without any evident precipitating] factor. i While a level of less than i • I mmol./l (4-3 mg./ioo ml.) serum ionized j calcium in hypoparathyroidism usually produces tetany, patients in ] chronic renal failure (C.R.F.) with similar levels seem to have some form : of protection (Fanconi and Rose, 1958). The percentage of calcium ionization in uraemic subjects with marked acidosis (venous pH 7-30) is no j higher than in uraemic patients with a normal pH or even alkalosis. Indeed one of our patients was grossly acidotic and the other had a normal pH. The protection must be due to some factor other than acidosis (Walser, \ 1962). ; Nevertheless tetany does rarely occur in C.R.F. Sudden reversal of the acidosis by hyperventilation or the rapid administration of I.V. bicarbonate may cause a temporary decrease in the ionized fraction of calcium and thus precipitate tetany. However, this was not a factor in the two cases described. Administration of phosphate enemas in children with C.R.F. and hypocalcaemia (e.g. 'Fletchers'—10 per cent NaH 2 PO 4 and 8 per cent Na2HPO4) may result in marked hyperphosphataemia and tetany (Oxnard et al., 1974); conceivably variations in dietary phosphate produce an analoguous effect in adults. Or the cases described may have had a diminished parathyroid 'reserve' and, therefore, an inadequate response to the hypocalcaemia of C.R.F. The management of this condition should be primarily directed towards treating the hypocalcaemia and chronic renal failure. The laryngospasm which is usually intermittent should relax spontaneously without recourse to endotracheal intubation, although a wide selection of tubes should be on hand for use if necessary. Oxygen must always be available to relieve the hypoxia which may develop. Hypocalcaemia and chronic renal failure are treated by the administration of calcium and setting up of peritoneal dialysis with daily monitoring of blood levels of calcium and phosphate. After reviewing the literature we have been unable to find any reports of patients suffering from chronic renal failure presenting with laryngospasm and this is surprising since chronic renal failure is not an uncommon condition. We are not able to offer a satisfactory explanation. Nevertheless, it is important that practitioners should be aware of the association and serum calcium estimations should be performed in all cases of unexplained laryngospasm. Summary
The presenting features and subsequent management of two adult patients with chronic renal failure complicated by laryngospasm are described. Possible mechanisms to explain this uncommon phenomenon are discussed but its rarity remains unexplained. 376
Laryngeal tetany REFERENCES BLACK, D. A. K. (1972) Renal disease 3rd edition, p. 473. FANCONI, A., and ROSE, G. A. (1958) Quarterly Journal of Medicine, 27, 463. FOURMAN, P., and ROYER (1968) in Calcium Metabolism in Bone, 2nd edition, Blackwell, Oxford, p. 203. JACKSON, C, and JACKSON, C. L. (1937) The Larynx and its Diseases, p. 266, Saunders, Philadelphia. OXNARD, S. C, et al. (1974) Pediatrics, 63, 105. WALSER, M. (1962) Journal of Clinical Investigation, 41, 1459. WILLIAMS, G. T., and BROWN, M. (1974) Journal of Laryngology and Otology, 88, 369. H. A. Young, Dept. of Otolaryngology, Ninewells Hospital, Dundee, DD2 iUD.
377
Laryngology and Otology (Founded in 1887 by MORELL MACKENZIE and NORRIS WOLFENDEN)
May 19JJ Laryngeal tetany: An unusual presentation of chronic renal failure By H. A. YOUNG and I. T. FERGUSON
(Dundee) Introduction ADDUCTOR spasm of the vocal cords is recognized in children and rarely in adults as an uncommon manifestation of hypocalcaemia (Fourman and Royer, 1968) which may occur secondary to malabsorption, acute pancreatitis, inadequate diet or hypoparathyroidism (Williams and Brown, 1974). Chronic renal failure is usually accompanied by hypocalcaemia (Black, 1972) but tetany is rare and isolated laryngospasm exceptional. We present two such cases. Case Reports Case 1
A 44-year-old woman first presented to hospital as an emergency in an unrousable state. She had marked inspiratory stridor complicated by the sudden onset of deep cyanosis and apnoea. This was relieved by endotracheal intubation. Apart from glottic adductor spasm indirect laryngoscopy revealed no abnormality. There was no increase in muscular tone. Chvostek's and Trousseau's signs were negative and further examination of the central nervous system failed to reveal any abnormality. There was no known history of inhalation of a foreign body or previous laryngeal disease. On admission the following blood results were obtained: serum calcium (corrected for albumin) i-6 mmol./l. (normal range: 2 ^5-2-65 mmol./l.); 373
H. A. Young and I. T. Ferguson plasma organic phosphate 3 • 6 mmol./l. (0 • 8-1 • 55 mmol./l.); serum alkaline phosphatase 20 King Armstrong units/100 ml. (3-14 K.A. units/100 ml.); serum creatinine 1600 umol./l. (44-150 umol./l.); serum potassium 7-4 mmol./l. (3-5-5-0 mmol./l.); actual bicarbonate 8 mmol./l. (21-28 mmol./l.); arterial pH 7-00 (7 • 36-7 • 44) ; The electrocardiogram showed a prolonged Q-T. interval (0-38 seconds)— compatible with marked hypocalcaemia. Chest X-ray was normal. Laryngeal spasm secondary to the hypocalcaemia of chronic renal failure was diagnosed. Artificial ventilation and continuous peritoneal dialysis was started— intermittent (I.V.) 10 per cent calcium gluconate (total 60 ml.) and 1 -5 litres of 4-2 per cent I.V. sodium bicarbonate were given. Serum levels of calcium and phosphate approached normality (Fig. 1). Despite treatment she died 48 hours after admission following repeated episodes of ventricular fibrillation with terminal asystole. Post mortem examination revealed cardiomegaly and small fibrotic kidneys due to chronic glomerulonephritis. The parathyroid glands and larynx were normal.
Case 2 A previously fit 46-year-old man was referred to the department of Otolaryngology with a history of intermittent inspiratory difficulty, particularly at night, for one month. Each episode was of acute onset lasting several minutes and resolving spontaneously. He also gave vague history of nocturia and polydipsia for the previous six months. Following admission he experienced two episodes of apnoea and cyanosis lasting one to two minutes. Between attacks, indirect laryngoscopy showed no notable abnormality. Coarse limb muscle twitching without rigidity was observed. Trousseau's and Chvostek's signs were negative. Blood pressure was found to be 200/130 and fundoscopy revealed papilloedema with exudates and haemorrhages. X-rays of chest and soft tissues of neck were normal. Initial blood investigations showed: serum calcium 1 • 4 mmol./l. (2 • 15-2 • 65 mmol./l.) plasma inorganic phosphate 2 • 9 mmol./l. (o • 8-1 • 55 mmol./l.) serum creatinine 1500 umol./l. (44-150 umol./l.) serum alkaline phosphatase, potassium, magnesium and arterial pH,—normal. The electrocardiogram showed a prolonged Q-T. interval (0 • 36 seconds). Intermittent I.V. 10 per cent calcium gluconate (total 50 ml.) was given over 48 hours. Serum calcium fluctuated with therapy (Fig. 2) and stabilized at 1 -7-1-85 mmol./l. when taking 9 -5 g. per day of oral calcium gluconate. Renal biopsy showed chronic glomerulonephritis. He had no further episodes of laryngospasm. 374
Laryngeal tetany Case 2.
Case i. ^
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Q. CO
ORAL CALCIUM
ALC
o
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1.5
1"
DAYS FIGS, I and
2.
Variations in blood calcium and phosphate during therapy. P.D. = Peritoneal dialysis (Dialysate contained 3-6mEq/i calcium and no phosphate) I.V.Ca. = Intravenous calcium gluconate Conversion S.I. to traditional units: Calcium: immol/i = 4-omg/iooml Phosphate: immol/1 = 3-img/iooml
Discussion Laryngospasm in the apyrexial patient is an uncommon condition, but may be due to hypocalcaemia. When poor nutrition was commonplace, particularly with low vitamin D intake, children were frequently seen with laryngeal tetany (laryngismus stridulus). Similar episodes have been reported in adults but are usually associated with hypocalcaemia due to hypoparathyroidism (Williams and Brown, 1974). The spasm follows increased reflex excitability at the neuromuscular junctions of the recurrent laryngeal nerves. The condition is often worse during the night because of the collection of pharyngeal secretions (Jackson and Jackson, 1937). This was demonstrated in our second patient. Laryngospasm due to hypocalcaemia is usually accompanied by other features of tetany including cutaneous paraesthesiae, carpopedal spasm, bronchospasm and rarely seizures. However, our two patients with chronic renal failure 375
H. A. Young and I. T. Ferguson
]
I presented with isolated laryngospasm without any evident precipitating] factor. i While a level of less than i • I mmol./l (4-3 mg./ioo ml.) serum ionized j calcium in hypoparathyroidism usually produces tetany, patients in ] chronic renal failure (C.R.F.) with similar levels seem to have some form : of protection (Fanconi and Rose, 1958). The percentage of calcium ionization in uraemic subjects with marked acidosis (venous pH 7-30) is no j higher than in uraemic patients with a normal pH or even alkalosis. Indeed one of our patients was grossly acidotic and the other had a normal pH. The protection must be due to some factor other than acidosis (Walser, \ 1962). ; Nevertheless tetany does rarely occur in C.R.F. Sudden reversal of the acidosis by hyperventilation or the rapid administration of I.V. bicarbonate may cause a temporary decrease in the ionized fraction of calcium and thus precipitate tetany. However, this was not a factor in the two cases described. Administration of phosphate enemas in children with C.R.F. and hypocalcaemia (e.g. 'Fletchers'—10 per cent NaH 2 PO 4 and 8 per cent Na2HPO4) may result in marked hyperphosphataemia and tetany (Oxnard et al., 1974); conceivably variations in dietary phosphate produce an analoguous effect in adults. Or the cases described may have had a diminished parathyroid 'reserve' and, therefore, an inadequate response to the hypocalcaemia of C.R.F. The management of this condition should be primarily directed towards treating the hypocalcaemia and chronic renal failure. The laryngospasm which is usually intermittent should relax spontaneously without recourse to endotracheal intubation, although a wide selection of tubes should be on hand for use if necessary. Oxygen must always be available to relieve the hypoxia which may develop. Hypocalcaemia and chronic renal failure are treated by the administration of calcium and setting up of peritoneal dialysis with daily monitoring of blood levels of calcium and phosphate. After reviewing the literature we have been unable to find any reports of patients suffering from chronic renal failure presenting with laryngospasm and this is surprising since chronic renal failure is not an uncommon condition. We are not able to offer a satisfactory explanation. Nevertheless, it is important that practitioners should be aware of the association and serum calcium estimations should be performed in all cases of unexplained laryngospasm. Summary
The presenting features and subsequent management of two adult patients with chronic renal failure complicated by laryngospasm are described. Possible mechanisms to explain this uncommon phenomenon are discussed but its rarity remains unexplained. 376
Laryngeal tetany REFERENCES BLACK, D. A. K. (1972) Renal disease 3rd edition, p. 473. FANCONI, A., and ROSE, G. A. (1958) Quarterly Journal of Medicine, 27, 463. FOURMAN, P., and ROYER (1968) in Calcium Metabolism in Bone, 2nd edition, Blackwell, Oxford, p. 203. JACKSON, C, and JACKSON, C. L. (1937) The Larynx and its Diseases, p. 266, Saunders, Philadelphia. OXNARD, S. C, et al. (1974) Pediatrics, 63, 105. WALSER, M. (1962) Journal of Clinical Investigation, 41, 1459. WILLIAMS, G. T., and BROWN, M. (1974) Journal of Laryngology and Otology, 88, 369. H. A. Young, Dept. of Otolaryngology, Ninewells Hospital, Dundee, DD2 iUD.
377
