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Biomedical subjects

N P Hirsch

Publications and source records attributed to N P Hirsch.

At least 19 recordsLinked to original sources

Status dystonicus: the syndrome and its management.

Patients with dystonic syndromes sometimes develop increasingly frequent and relentless episodes of devastating generalized dystonia which we call status dystonicus. Twelve cases of status dystonicus, of various underlying aetiologies, are presented. Possible precipitating factors were identified in only five cases: intercurrent infection (one); discontinuation of lithium (one) and tetrabenazine (one); and the introduction of clonazepam (two). Nine patients required mechanical ventilation and three others were sedated with intravenous chlormethiazole. Drug therapy used included benzhexol, tetrabenazine, pimozide, baclofen, chlorpromazine, haloperidol, carbamazepine and acetozolamide. Two patients underwent thalamotomies, one of whom improved. Two patients died, five returned to their pre-status dystonicus condition, two eventually made a full recovery and three were worse. Patients with status dystonicus should be managed on an intensive care unit as they may develop bulbar and respiratory complications which may require ventilation. Metabolic problems encountered can include rhabdomyolysis with acute renal failure. Drug therapy with benzhexol, tetrabenazine and pimozide or haloperidol may be beneficial in some cases.

Adolescent

Brainstem encephalopathy with stimulus-sensitive myoclonus leading to respiratory arrest, but with recovery: a description of two cases and review of the literature.

Two unrelated patients developed bulbar symptoms, followed within several weeks by spontaneous myoclonus and painful, generalized, stimulus-sensitive jerks triggered by unexpected noises and cutaneous stimuli. They progressed to respiratory arrest and required mechanical ventilation, but both patients subsequently made an almost full recovery. These cases stress the importance of persevering with supportive treatment despite rapid progression of this severe generalized movement disorder. The relationship of brainstem reflex myoclonus to hyperekplexia, progressive encephalomyelitis with rigidity, and the stiff-man syndrome is discussed.

Adult

Diagnosis and treatment of status epilepticus on a neurological intensive care unit.

Status epilepticus refractory to first-line therapy is associated with a high morbidity and mortality. Correct diagnosis and adequate treatment of this condition require electrographic monitoring and anaesthetic facilities available in specialist intensive care units (ICUs). We carried out an audit of 26 patients admitted to a neurological ICU with a diagnosis of status epilepticus, to identify deficiencies in diagnosis and management prior to transfer to the ICU, and examine the effectiveness of ICU management. Or transfer, only 14 (54%) were in status epilepticus; six were in drug-induced coma or were encephalopathic, and six had pseudostatus epilepticus, of whom four had been intubated. The commonest treatments prior to transfer were benzodiazepines, chlormethiazole and phenytoin; the loading dose of phenytoin was adequate in at least 7/16 cases. All those in status epilepticus on transfer had their seizures successfully controlled, but ten required general anaesthesia with thiopentone, propofol, ketamine or midazolam. Two died--one had a severe encephalitis and the other had had a cardiac arrest prior to treatment. This study highlights deficiencies in the initial diagnosis and management of status epilepticus, the role of specialist neurological intensive care, and the importance of early referral.

Adolescent

Respiratory insufficiency in neuronopathic and neuropathic disorders.

Twenty-nine patients with a neuronopathic or neuropathic disorder were referred for assessment of respiratory insufficiency between 1978 and 1994. Diagnoses included spinal muscular atrophy (6), chronic idiopathic demyelinating neuropathy (4), Vialetto-van Laere syndrome (3), hereditary motor and sensory neuropathy (3) and a miscellaneous group (5). We also describe seven patients with Guillain-Barré syndrome (GBS) who required long-term ventilatory support for over 6 months to 7 years after the initial illness. Respiratory insufficiency occurred as a consequence of respiratory muscle weakness, impaired bulbar function and restrictive lung defects. In some groups presentation was with progressive nocturnal hypoventilation culminating in acute respiratory failure. Five patients with GBS or chronic idiopathic demyelinating neuropathy were weaned from ventilatory support up to 18 months after the initial illness. The remaining 24 patients required continuous or nocturnal ventilatory support using intermittent positive-pressure ventilation (13), negative pressure ventilation (4), nasal-mask-delivered intermittent positive-pressure ventilation (4), nasal-mask-delivered continuous positive-pressure ventilation (3), mouthpiece-assisted ventilation by day (2) and rocking bed (1). None have been weaned from support after a period of ventilation ranging from one month to 10 years. Eight patients have subsequently died.

Adolescent

Nocturnal and respiratory disturbances in Steele-Richardson-Olszewski syndrome (progressive supranuclear palsy).

Respiratory and sleep disturbances may be important causes of morbidity in Steele-Richardson-Olszewski syndrome but the frequency and character of nocturnal abnormalities remains uncertain. A prospective study of 11 patients with Steele-Richardson-Olszewski syndrome and age-matched control subjects was undertaken using clinical assessments, a structured sleep questionnaire, spirometry, static maximum inspiratory and expiratory pressures and nocturnal oximetry. The mean age of the Steele-Richardson-Olszewski syndrome patients was 63.2 (52-70) years and mean disease duration was 4.0 (2-6) years. There was moderate to severe motor disability in nine and mild to moderate dementia in eight. In the patients with Steele-Richardson-Olszewski syndrome the following abnormalities contributed to sleep disturbances significantly more frequently than in normal controls: depression, dysphagia, frequent nocturnal awakenings (usually associated with urinary frequency), immobility in bed, difficulty with transfers, impaired dressing and feeding. There was profound impairment of voluntary respiratory control whilst automatic and limbic control were well maintained. Nocturnal respiratory abnormalities were not present even in the most severely disabled. In Steele-Richardson-Olszewski syndrome sleep abnormalities are common; they relate to the cognitive, pseudobulbar and extrapyramidal disturbances and may therefore be amenable to symptomatic control.

Aged

Management of mitochondrial disease on an intensive care unit.

Patients with mitochondrial disease may present to the Intensive Care Unit (ICU) with a variety of neurological and general medical disorders. Eleven patients were admitted to a neurological ICU between 1970 and 1992 because of respiratory insufficiency, status epilepticus and/or metabolic encephalopathy associated with mitochondrial disease. Respiratory impairment occurred in eight patients and was associated with nocturnal hypoventilation due to respiratory muscle weakness, aspiration due to bulbar weakness and abnormalities of central control leading to a reduced CO2 drive, irregular respiratory patterns and sleep apnoea. Seven patients received continuous respiratory support during the acute illness; three were subsequently weaned to domiciliary ventilation, and four died. Five patients had stroke-like episodes, which in two were recurrent. Four patients developed tonic-clonic grand mal epilepsy associated with myoclonic fits (2 patients), absences (2), focal fits (1) and status epilepticus (2). Encephalopathy was associated with recurrent lactic acidosis (2 patients), cardiac failure (2), hyponatraemia (2), renal abnormalities (3) and complete heart block (1). Although rare, mitochondrial disease should be considered in any patient with unexplained respiratory failure, intractable epilepsy, lactic acidosis or recurrent stroke.

Acidosis, Lactic

Management and outcome of severe Guillain-Barré syndrome.

Seventy-nine patients with Guillain-Barré syndrome admitted to a neurological intensive therapy unit (ITU) between 1985 and 1992 were studied retrospectively. The mean age was 49.8 years (range 16-86) and the time between the first neurological symptom and admission to ITU was 10.2 days (0-62). Admission was precipitated by a combination of respiratory failure requiring ventilatory support (73.4%), bulbar weakness (57.0%), autonomic features (11.4%) and general medical factors (10.1%). Specific treatments included plasma exchange (65.8%), intravenous immunoglobulin (13.9%) and methylprednisolone/placebo (12.7%). Significant complications included lower respiratory tract infections (45.6%), hyponatraemia (25.3%), dysautonomia (19.0%), urinary tract infection (12.7%) and cognitive disturbances (8.9%). Four patients (5.1%) died during the acute illness. Duration of nadir correlated with duration of ventilation, duration of ITU stay and outcomes at 3 months, 6 months and 1 year. However, time to nadir, an indicator of rapidity of deterioration, did not correlate with any outcome. The low mortality in this series of acutely ill and severely disabled patients suggests that specialized intensive therapy units continue to have an important role in the management of acutely ill patients with Guillain-Barré syndrome.

Acute Disease

Mivacurium in the myasthenic patient.

We have used mivacurium in four myasthenic patients presenting for thymectomy. Supramaximal single twitch stimulation was applied to the ulnar nerve at the wrist and the force of contraction of the adductor pollicis was measured. After an initial bolus dose of 30 micrograms kg-1 (approximately one-fifth of the normal intubating dose), we observed a mean 37.5 (SEM 5.6)% reduction in evoked twitch tension. Neuromuscular block was increased with incremental doses and maintained with repeat bolus doses of 15 micrograms kg-1 at 25% recovery. The interval between maintenance bolus doses remained constant (mean 5.9 (0.7) min). Spontaneous offset was rapid with a mean recovery index (T25-T75) of 11.9 (2.1) min. Provided anticholinesterase therapy is withheld in the immediate preoperative period, mivacurium would appear to be a safe and appropriate neuromuscular blocker in this variably sensitive group of patients. The cumulative dose required to establish full neuromuscular block varied between 60 and 90 micrograms kg-1. A maintenance infusion, commencing at 3 micrograms kg-1 min-1, is recommended, guided by neuromuscular monitoring.

Adult

Respiratory abnormalities due to craniovertebral junction compression in rheumatoid disease.

OBJECTIVE: To assess the extent and severity of respiratory insufficiency associated with severe rheumatoid atlantoaxial dislocation and its relation to compression of the neuraxis. METHODS: Twelve patients with severe atlantoaxial dislocation due to rheumatoid disease were studied. Detailed clinical, CT myelography and respiratory assessment including nocturnal oximetry, were performed on all patients. RESULTS: All patients were severely disabled by their underlying disease but none had symptoms of hypoventilation. All the patients with C1 compression had myelopathic features. Those with medullary deformation (moulding and/or stretch) had abnormal noctural oximetry whilst no significant desaturations were seen in the remaining patients. Post-operative studies showed resolution of noctural desaturations. CONCLUSION: This study suggests that clinically unsuspected respiratory insufficiency may be common in patients with severe medullary compression associated with rheumatoid atlantoaxial dislocation. It emphasises the importance of careful respiratory monitoring including nocturnal oxygen saturation in patients with major atlantoxial dislocation due to rheumatoid disease.

Aged

Sleep problems in multiple sclerosis.

Twenty-eight consecutive patients with multiple sclerosis (MS) were clinically evaluated to determine the presence of sleep-related disorders. There were 12 males and 16 females aged between 22 and 67 with disability ranging between 1.5 and 8.5 on Kurtzke extended disability status score (EDSS). Fifteen patients (54%) reported sleep-related problems. These included difficulties initiating sleep and/or frequent awakenings due to spasms or discomfort in the legs (8 patients), difficulty in initiating or maintaining sleep (3), habitual snoring (4) and nocturia (1). All-night oximetry was performed and the tracings analysed for the number of dips in oxygen saturation (SaO2) or more than 4%. Three patients showed significant sleep-related oxygen desaturation (> 5 dips of > 4% SaO2/h). Subsequent polysomnography performed in 2 of the 3 patients with significant oxygen desaturation confirmed the presence of sleep apnoea. MRI analysis of brain stem regions showed abnormalities in 20/22 cases. The 3 patients showing nocturnal oxygen desaturation had MRI brain stem lesions, but their locations were variable and their general appearance not different from that seen in the 17 without sleep apnoea. Sleep disturbance in MS is common but poorly recognised. It is usually due to leg spasms, pain, immobility, nocturia or medication. It is much less commonly associated with nocturnal respiratory insufficiency.

Adult

Failure of 3,4-diaminopyridine to reverse conduction block in inflammatory demyelinating neuropathies.

3,4-Diaminopyridine was administered to 6 patients with inflammatory demyelinating neuropathies in whom partial conduction block was demonstrable. Four had Guillain-Barré syndrome and 2 had chronic inflammatory demyelinating neuropathy. Nerve conduction studies were performed before the administration of a single oral dose of 3,4-diaminopyridine, and at regular intervals thereafter. Neither resolution of conduction block nor clinical benefit were seen.

4-Aminopyridine

Respiratory involvement in primary muscle disorders: assessment and management.

Eighty-four patients with primary disorders of muscle were referred for assessment of respiratory insufficiency between 1978 and 1991. The eventual diagnoses were: 'limb girdle syndromes' (18 patients), adult onset acid maltase deficiency (14), dystrophia myotonica (13), inflammatory disorders (10), congenital myopathies (nine), rigid spine syndromes (five), dystrophies (Duchenne (six), facioscapulohumeral (four), Becker (one)) and miscellaneous (four). Presentations were often insidious, with progressive nocturnal hypoventilation culminating in respiratory failure or arrest, recurrent respiratory tract infections, or obstructive sleep apnoea. Respiratory symptoms developed relatively early in patients with acid maltase deficiency and inflammatory disorders but parallelled the development of limb weakness in limb girdle, myotonic and congenital syndromes. Sixty-six patients received respiratory support for a median of 5 years (1-34 years) using various techniques of negative and positive pressure ventilation. Fourteen patients received short-term support for an episode of respiratory failure before being weaned, 51 required nocturnal domiciliary ventilation and one was dependent on continuous domiciliary support. Tracheostomy was performed in 32 patients and used for domiciliary nocturnal ventilation in 25. Twenty-eight patients have subsequently died.

Adult

Respiratory involvement in multiple sclerosis.

Respiratory complications occur in advanced multiple sclerosis (MS) but may also complicate acute relapses earlier in the disease. We present 19 patients with MS who developed respiratory complications at a mean of 5.9 (range 1-12) yrs after the onset of neurological symptoms. Fourteen patients developed severe respiratory insufficiency presenting with a combination of reduced forced vital capacity (FVC), hypoxaemia or hypercapnia (12 patients) and respiratory arrest (four patients). Two patients presented with apneustic breathing, one with paroxysmal hyperventilation, one with obstructive sleep apnoea and one with bulbar weakness leading to aspiration pneumonia. Respiratory muscle weakness was a major factor in 14 patients (predominantly diaphragm involvement in six), bulbar weakness in seven patients, impaired voluntary control in three and impaired automatic control in three. Twelve patients received mechanical respiratory support of whom seven have subsequently died. The methods of support used were intermittent positive pressure ventilation (nine patients), iron lung (three), cuirass (two) and rocking bed (one). Six patients were maintained on respiratory support until they died after intervals varying from 24 h to 6 yrs (mean 17.7 mths). Five patients received temporary ventilation for between 6 d and 42 d: of these four remain alive at up to 4 yrs and one died after 16 yrs. One patient remains on domiciliary nasal intermittent positive pressure ventilation (IPPV) after 1 yr.

Adolescent