ACUTE MEDICAL EMERGENCIES - PART 5 ppt

● causing postural hypotension (e.g. diuretics, antihypertensives, antidepressants, levodopa preparations, etc.). Assessment The paroxysmal nature of the problem means that you are likely to see the patient between episodes of collapse, when primary assessment is likely to reveal no major problems. Secondary assessment with a careful history and physical examination will provide the diagnosis in the majority of patients. History It is important to obtain a history from a witness, in addition to the patient, where possible. The circumstances of the collapse may be relevant, e.g. cough or micturition syncope. Vasovagal syncope is usually associated with a hot environment or stressful, emotional situations. Collapse associated with head turning may indicate carotid sinus hypersensitivity. Episodes associated with exertion suggest mechanical limitation of cardiac output (aortic stenosis, HOCM) or an exercise induced arrhythmia. Symptoms on prolonged standing suggest postural hypotension or vasovagal syncope. Ask specifically about cardiovascular symptoms (palpitations, chest pain, breath- lessness) and neurological symptoms (headache, weakness/parasthesiae, autonomic dysfunction). The importance of an accurate drug history cannot be over- emphasised. A family history of syncope or sudden death may be relevant. The distinction between epilepsy and syncope can be difficult. A witnessed tonic– clonic convulsion associated with tongue biting and incontinence is obviously helpful in making a diagnosis, but the story may not always be so clear. ● A patient with syncope will usually report symptoms of light headedness, nausea, sweating or blurring of vision before consciousness is lost. In contrast, a generalised tonic–clonic seizure will usually have minimal prodromal symptoms. ● With syncope the duration of unconsciousness will be shorter than epilepsy (seconds versus minutes) and the recovery will be more rapid, without the usual drowsy, con- fused postictal period. ● Brief twitching may be seen with an episode of syncope but this will usually be very transient. ● Pallor may be seen before the collapse.This is common with syncope, although it may be seen with epilepsy. Examination Assess the pulse rate, rhythm, and character. Measure the lying and standing blood pressure. A fall in systolic blood pressure of 20 mm Hg after two minutes standing is significant. Examine the precordium for evidence of structural heart disease, especially aortic stenosis or other causes of outflow obstruction. Listen for carotid bruits. A thorough neurological assessment is essential. Look for patterns of signs including upper motor neurone lesions, extrapyramidal pathology, cerebellar features, brain stem signs or evidence of peripheral neuropathy. Investigations Further investigations will be guided by the history and clinical findings. Key point The distinction between epilepsy and syncope is important. A careful history from the patient and witnesses will clarify the situation in the majority of cases ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH 178 12-AcuteMed-12-cpp 28/9/2000 4:20 pm Page 178 (a) Cardiological ● 12 lead ECG. All patients with recurrent collapse need an ECG. It may reveal evidence of ischaemia, left ventricular hypertrophy or conduction abnormalities. ● 24-hour ECG monitoring may be useful if there is a suspicion of paroxysmal rhythm disturbances, even though 12 lead ECG may be normal. ● Echocardiography is invaluable if either left ventricular outflow obstruction is suspected or left ventricular function is impaired. ● Exercise testing may be useful when collapse is associated with exertion (providing left ventricular outflow obstruction has been excluded). It may reveal ischaemia, hypotension or an arrhythmia. (b) Neurological ● Electroencephalogram (EEG) is of little value in the assessment of patients with recurrent collapse. It may be helpful in confirming a diagnosis of epilepsy, when this is suspected clinically, but it is not indicated routinely in the assessment of syncope. ● CT/MRI scanning is not required unless there are focal neurological signs or there has been a witnessed seizure. ● Carotid or transcranial doppler ultrasonography is rarely helpful. It should only be considered in the presence of bruits, a palpaple discrepancy between carotid pulses or when the history suggests either carotid or vertebrobasilar insuffi- ciency. (c) Laboratory tests ● Laboratory tests have a poor yield unless there is clinical suspicion of an abnor- mality. However, it is worth checking glucose, urea and electrolytes and haemo- globin. ● Rarely the clinical features may indicate either Addison’s disease (adrenocortical failure) or phaeochromocytoma; therefore a short Synacthen® test or 24-hour urine collection for dopamine degradation products (adrenocortical) may be needed. (d) Other investigations ● Carotid sinus massage. This is contra-indicated: (i) in the presence of carotid bruits or cerebrovascular disease (ii) if there is a history of ventricular arrhythmias or recent myocardial infarction. Providing there are no contraindications, place the patient in the supine position and monitor ECG and blood pressure. The right carotid artery is massaged longitudi- nally, with the neck slightly extended, for a maximum of five seconds. If the response is negative there should be a 30 second interval before the left carotid artery is massaged (maximum five seconds). A positive cardioinhibitory response is defined as a sinus pause of three seconds or more. A positive vasodepressor response is defined as a fall in systolic blood pressure of more than 50 mm Hg. ● Tilt testing Tilt testing is useful in the further assessment of unexplained recurrent syncope after conclusion of other cardiac causes including arrhythmias. Briefly: Key point Bilateral carotid massage must never be attempted THE COLLAPSED PATIENT 179 12-AcuteMed-12-cpp 28/9/2000 4:20 pm Page 179 (i) Baseline pulse and blood pressure recordings are measured with the patient lying supine for 30 minutes. (ii) The patient is tilted to 60–75º for up to 45 minutes and asked to report any symptoms. (iii) A positive result is a cardioinhibitory response and/or a vasodepressor response in association with symptoms. (iv) If a positive response occurs, the patient is immediately returned to the hori- zontal position. Other measures may be used to increase the sensitivity of the test. SPECIFIC CONDITIONS Status epilepticus Status epilepticus is defined as either a single seizure lasting for 30 minutes or repeated seizures between which there is incomplete recovery of consciousness. However, seizures lasting more than 5 minutes can indicate impending status epilepticus.This may be pre- vented by immediate treatment. A working definition is therefore: continuous seizures lasting at least 5 minutes, or, two or more discrete seizures betwen which there is incomplete recovery of conciousness. Primary assessment and resuscitation – specific summary for epilepsy management. A – Maintain patency/initially with nasopharyngeal airway Give oxygen (FiO 2 = 0·85) Do not attempt to insert oral airway/intubate while jaw is clenched Early liaison with anaesthetist B – Pulse oximeter C – Establish IV access Monitor ECG D – IV diazepam 10 mg over 2–5 minutes Check glucose IV thiamine (250 mg over 10 minutes) if history of chronic alcohol abuse Look for head trauma E – Check temperature Look for purpura (meningococcal septicaemia) Respiratory depression and hypotension may occur after IV diazemuls. Give 2 mg up to a maximum of 20 mg per minute. If control is not achieved, phenytoin 15 mg/kg IV Key point Generalised convulsive status epilepticus is a common and serious medical emergency. There is a significant risk of permanent brain damage and death from cardiorespiratory failure (5–10% mortality in those admitted to an intensive care unit) Key point With both carotid sinus massage and tilt testing full resuscitation facilities must be available immediately ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH 180 12-AcuteMed-12-cpp 28/9/2000 4:20 pm Page 180 should be given with ECG monitoring (reduce dose if patient previously on phenytoin). The infusion rate should not exceed 50 mg/min because of the risk of cardiac arrhythmias. Further doses up to a total of 30 mg/kg may be given if seizures persist.Then main- tenance doses of 100 mg IV should be given every 6–8 hours. Phenytoin has the advantage of suppressing seizures without causing cortical or respiratory depression. See Chapter 11 for alternative drugs e.g. lorazepam and fosphenytoin. If seizures continue, the patient should be anaesthetised and ventilated. Cerebral function monitoring is very useful in this situation. Anaesthesia and ventilation should continue until 12–24 hours after the last seizure. Secondary assessment A history from a relative is important. Are there any symptoms to suggest tumour, meningitis, head injury? Ask about alcohol consumption. If the patient is a known epileptic, ask about current drug regime, compliance or any recent changes in drug therapy. Physical examination will include a careful neurological assessment, looking particularly for evidence of meningeal irritation, raised intracranial pressure and focal neurological deficits. Arrhythmia Bradycardia Bradycardia may be diagnosed on 24-hour ECG monitoring but it is important to doc- ument associated symptoms. Review the patient’s medications and stop those which may cause bradycardia. In the presence of sino-atrial node disease, pacing may be considered if pauses greater than three seconds are documented. With atrioventicular node dysfunction, pacing should be considered for second degree or third degree heart block, in the absence of a reversible cause (drugs or ischaemia). Tachycardia Supraventricular tachycardia including atrial fibrillation, for example, often cause palpitations and dizziness but rarely present with syncope. Ventricular tachycardia is more likely to cause syncope. The Wolff–Parkinson–White syndrome and the prolonged QT syndrome should be considered in patients with recurrent syncope. The type of tachycardia will determine the treatment. This comprises antiarrhythmic drug therapy, occasionally an antitachycardia pacemaker/defibrillator or radio-ablation. Transient rhythm abnormalities are increasingly common with increasing age, for example, short runs of atrial fibrillation and sinus bradycardia occur at night. Do not treat unless there is clear evidence that these arrhythmias are associated with symptoms or predispose to further pathology, for example, paroxysmal atrial fibrillation and stroke. Vasovagal syncope The mechanism of collapse in vasovagal syncope and the assessment of patients by tilt testing has been described. Treatment is not always satisfactory. β blockers may be used to inhibit the initial sympathetic activation in vasovagal syncope.With a positive cardioinhibitory response to tilt testing, disopyramide may be useful (to block the vagal outflow) or dual chamber pacing may be necessary. With a predominant vasodepressor response, ephedrine, dihydroergotamine or fludrocortisone have been tried with variable success. THE COLLAPSED PATIENT 181 12-AcuteMed-12-cpp 28/9/2000 4:20 pm Page 181 Carotid sinus hypersensitivity Hypersensitivity of the carotid artery baroreceptors can cause bradycardia and/or vasodilatation due to vagal activation.The patient complains of dizziness or syncope associated with head turning or the wearing of a tight collar. Diagnosis is by carotid sinus massage as described previously. A positive cardioinhibitory response to this technique responds well to cardiac pacing. As with vasovagal syncope, a vasodepressor response is more difficult to treat. Postural hypotension Postural hypotension is associated with: ● hypovolaemia (dehydration, haemorrhage, diuretics) ● drugs ● autonomic failure (diabetes mellitus, Parkinson’s disease, old age). It is difficult to treat patients who have postural hypotension offering correct intravas- cular volume and rationalising the drug therapy as much as possible. They should be advised to stand up slowly and to avoid prolonged standing. Graduated elastic stockings may reduce venous pooling. Fludrocortisone increases salt and water retention and is occasionally helpful. Left ventricular outflow obstruction Advanced aortic stenosis may cause exertional dizziness and syncope because cardiac output is reduced. Such symptoms indicate urgent assessment with a view to aortic valve replacement. Hypertrophic obstructive cardiomyopathy (HOCM) is associated with restricted cardiac output during stress.Treatment is with negatively inotropic drugs ( β blockers, vera- pamil) to reduce the outflow tract gradient. Dual chamber pacing or surgery may be needed in more advanced cases. SUMMARY Recurrent collapse is common. ● It can be associated with life threatening underlying pathology and can cause serious injury. ● History and physical examination provide a likely diagnosis in the majority of patients. ● Further investigation will be guided by clinical judgement and by the frequency and severity of the symptoms. Following stroke: ● patients in atrial fibrillation should be immediately anticoagulated; ● hypertension must be aggressively treated if diastolic blood pressure is greater than 90 mm Hg; ● a normal CT brain scan excludes cerebral thrombosis. In transient collapse: loss of consciousness is an uncommon feature of transient ischaemic attack; ● prodromal symptoms of light headedness, nausea, and sweating suggest syncope rather than epilepsy as a cause of collapse; ● a sinus pause of three seconds or more with carotid sinus massage is significant. ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH 182 12-AcuteMed-12-cpp 28/9/2000 4:20 pm Page 182 TIME OUT 12.1 a. Define “stroke”. b. Describe your immediate management of a patient with a suspected transient ischaemic attack. THE COLLAPSED PATIENT 183 12-AcuteMed-12-cpp 28/9/2000 4:20 pm Page 183 This Page Intentionally Left Blank CHAPTER 13 The overdose patient OBJECTIVES After reading this chapter you will be able to: ● describe how the structured approach can be applied to patients who have taken an overdose ● discuss the diagnostic clues that are available in the primary assessment ● understand the use of various measures that can be used to eliminate drugs from the body ● describe some specific treatments for overdose. INTRODUCTION The management of overdose is one of the most challenging aspects of emergency medical care. In the absence of a clear history (for example, in the unconscious patient) the diagnosis can be difficult. Furthermore, many patients are reluctant to cooperate during their initial assessment. The pharmacological effects of the substances taken in overdose may be significant, necessitating emergency intervention to limit morbidity and mortality. The majority of cases are as a result of deliberate self harm; however, accidental overdose is also common, especially in the paediatric population. More alarmingly, a minority of patients may present with non-accidental overdose (both deliberate poison- ing and Munchausen by proxy). Care should also be taken to recognise iatrogenic overdose, which is more common in the elderly, those on multiple medications and in patients with long-standing health problems such as chronic renal failure. The presentation is generally variable; some patients may self refer with a full history whilst others may attend with symptoms such as unusual behaviour, decreased conscious level, fits and those related to an arrhythmia. Whatever the presentation, medical care should follow the structured approach discussed in Chapter 3 – with primary assessment and resuscitation preceding a secondary assessment, emergency treatment, and definitive care. Psychiatric assessment is often necessary in this group of patients but should only take place once the above medical assessment is complete. 185 Reading: 20 minutes 13-AcuteMed-13-cpp 28/9/2000 4:22 pm Page 185 PRIMARY ASSESSMENT AND RESUSCITATION Airway The simple question, “Are you all right?” will allow the examining doctor to establish whether the patient is conscious, has good laryngeal function, and an adequate vital capacity. As discussed in Chapter 3, a failure to answer this question should lead to the use of a simple airway opening manoeuvre and an assessment of breathing. Endotracheal intubation is required in the unconscious patient, to provide airway pro- tection and facilitate gastric lavage (if appropriate). Breathing Since a number of agents taken in overdose (particularly narcotics) can produce respiratory depression it is very important to look for adequate breathing. The rate, depth, and work of breathing should be assessed. If there are any signs of inadequacy, breathing should be supported using a bag–valve–mask device with added oxygen. Even in the patient who appears to be breathing adequately, oxygen should be given until it is deemed unnecessary. Circulation Pulse rate, cardiac rhythm, blood pressure, and adequacy of peripheral perfusion should be assessed. Inadequate circulation is generally caused by hypotension or arrhythmia. Hypotension is commonly caused by a relative hypovolaemia secondary to peripheral vasodilatation and will respond to fluid resuscitation.The cause of cardiac dysrhythmias differs from those seen in ischaemic heart disease, and requires a different approach to management. Dysrhythmias are often surprisingly well tolerated. If treatment becomes necessary cardioversion is preferable to antiarrhythmic drugs, as potential drug interac- tions can be avoided. Intravenous access should be established at this stage, providing an opportunity to take blood samples for relevant investigations. Diagnostic clues from the primary assessment may provide a pointer towards the specific drug or drugs ingested. These are listed in Table 13.1. Disability Assess disability in the standard manner using either the AVPU or Glasgow Coma Scale (see Chapter 3) and measure the pupillary size and responses. These latter observations can be helpful in establishing a diagnosis if the agent that has been taken is unknown. Many drugs, e.g. paracetamol, can cause rapid hypoglycaemia. As this has protean manifestations always check a serum glucose concentration. Exposure Full exposure is necessary, looking for both marking and rashes. It is very important to assess temperature at this stage since a number of drugs can alter thermoregulatory mechanisms, e.g. phenothiazines. Once patients have been fully exposed and the required examination has been completed, cover immediately; as many will lose heat rapidly in this situation. ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH 186 13-AcuteMed-13-cpp 28/9/2000 4:22 pm Page 186 Table 13.1 Diagnostic clues from the primary assessment By the end of the primary assessment, the minimum essential monitoring should include pulse oximetry and continuous ECG trace. The respiratory rate, pulse, blood pressure, Glasgow Coma Score, temperature and glucose concentration should have been documented.These observations need to be repeated on a regular basis in order to monitor the patient’s condition and response to treatment. LETHALITY ASSESSMENT At the end of the primary assessment it is important to assess the potential lethality of the overdose. This requires knowledge of the substance, the time it was taken and the dose. Corraborative evidence may need to be sought from other sources, such as family mem- bers or paramedic staff, to establish this information. Regional poisons centres will provide advice on specific treatment. If the nature of the overdose is unknown then a high potential lethality should be assumed. IMMEDIATE MANAGEMENT Drug elimination If the drug overdose is assessed as having a potentially high lethality or if the exact nature of the overdose is unknown, use measures designed to reduce drug levels. Sign Drug B Tachypnoea Aspirin Bradypnoea Opiates CNS depressants C Tachycardia Antidepressants sympathomimetics amphetamines cocaine Bradycardia β Blockers digoxin clonidine Hypertension Amphetamines cocaine D Small pupils Opioids cholinesterase inhibitors Large pupils Tricyclic antidepressants anticholinergics antihistamines ephedrine amphetamines cocaine Coma barbiturates tricyclic antidepressants opiates benzodiazepines ethanol E Hypothermia tricyclic antidepressants barbiturates phenothiazines Hyperthermia amphetamines cocaine THE OVERDOSE PATIENT 187 13-AcuteMed-13-cpp 28/9/2000 4:22 pm Page 187 [...]... with headache and extracranial signs; some examples are listed in the box Causes of headache with pericranial signs Acute sinusitis Cervical spondylosis Giant cell arteritis Acute glaucoma Daily Daily Monthly Annually 199 ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH Acute sinusitis This acute infection commonly causes frontal and/or maxillary sinusitis However, it may extend to involve the ethmoid... pregnancy) infarction (e.g bowel, spleen) 211 ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH Major causes of abdominal pain Intraabdominal Non-specific abdominal pain Daily Gastroenteritis Daily Acute appendicitis Daily Acute cholecystitis and gall bladder disease Weekly Peptic ulcer disease Weekly Intestinal obstruction Weekly Pseudoobstruction Monthly Acute pancreatitis Monthly Perforated viscus... ophthalmologist is required 203 ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH Figure 14.3 The mechanism of acute closed angle glaucoma Key points Subacute glaucoma occurs with mild, transient episodes of intraocular hypertension The patient may describe “coloured haloes around lights” especially at night This should be regarded as a danger signal indicating an imminent acute attack Coloured haloes... combined with obtaining further information and a more comprehensive examination The relevant secondary assessment features are summarised in the box 1 95 ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH Most patients presenting with a headache will have a non-immediately life threatening condition.Thus, in the secondary assessment the doctor has time to take a full history A new headache, or one different... tiredness Often unremarkable 2 05 ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH Key points Important discriminating factors in a patient with a tension headache: ● headache starts each morning and increases in severity throughout the day ● vomiting does not occur ● visual disturbances do not occur Migraine This common condition affects approximately 20% of women and 15% of men who usually present... Subarachnoid haemorrhage Always consider this condition for any patient with an unexplained headache of acute onset Please see Chapter 11 for further information 207 ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH Giant cell arteritis The differential diagnosis of a sudden headache, in any patient over the age of 50 years, includes giant cell arteritis as described earlier in this chapter Cluster headache... there is traction, inflammation or distension of these structures, in particular, the dura, blood vessels, and nerves A throbbing headache is non-specific because it is common to many intracranial conditions Similarly the site of pain is nonspecific, but it can provide clues to underlying pathology as outlined below 193 ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH ● Frontal – ipsilateral forehead... HEADACHE SUMMARY Headache of acute onset accounts for less than 2 .5% of new emergency attendances Of these, 15% will have an immediately life threatening condition These need to be identified and treated in the primary assessment Some of the remaining patients will have sinister pathology The characteristics of headache that suggest a serious underlying cause are: ● ● ● ● ● new onset acute onset progressive... producing narrowing or occlusion of the vessel lumen The onset of the arteritis may be acute, but the symptoms are present for many months before the diagnosis is made Thus, a high degree of suspicion is needed Most patients have clinical features related to the arteries involved, i.e mainly those originat201 ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH ing from the aortic arch.Therefore, symptoms and... usually stable and acute cord compression is rare (the exception is an acute disc prolapse) Assessment for spinal surgery is advocated, as it may be possible to prevent further neurological compromise Giant cell arteritis (cranial arteritis, temporal arteritis, and granulomatous arteritis) This condition predominantly affects large/medium sized arteries It is rare before the age of 50 and commonly affects . (sentinel) bleed hours or days before a major subarachnoid haemorrhage ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH 196 14-AcuteMed-14-cpp 28/9/2000 4:24 pm Page 196 HEADACHE WITH PAPILLOEDEMA. three seconds or more with carotid sinus massage is significant. ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH 182 12-AcuteMed-12-cpp 28/9/2000 4:20 pm Page 182 TIME OUT 12.1 a. Define “stroke”. b patients but should only take place once the above medical assessment is complete. 1 85 Reading: 20 minutes 13-AcuteMed-13-cpp 28/9/2000 4:22 pm Page 1 85 PRIMARY ASSESSMENT AND RESUSCITATION Airway The