Essential Notes for Medical and Surgical Finals

Kaji Sritharan, Jonathan Rohrer, Alan Rankin, Sachi Sivananthan

• Publisher: CRC Press
• Year: 2021
• ISBN:
  9780429533532
• Edition: 1
• Topic: Medicina
• Subtopic: Teoría, práctica y referencia médicas

Covering both medicine and surgery, this book is the essential revision companion for all medical students and a valuable source of knowledge for junior doctors at all stages of their training. It is useful both in the early preparatory phase of revision as well as for last minute cramming, and for use on the wards. This book divides the medical and surgical curricula into over twenty key sections and concisely covers the relevant information for each, including definitions, aetiology, key clinical features, investigations, and management. Examinations for undergraduate medical students and at postgraduate level can take a number of forms, including multiple choice and extended matching questions, single best answers, short notes, vivas and OSCEs. The book provides the necessary information to tackle all these exam formats successfully, as well as to manage each topic competently should it arise in clinical practice. Compact and user-friendly, this book is the ideal revision tool.

Medicine

1
Neurology

1.1. Neurological examination

1.2. Epilepsy

1.3. Dementia

1.4. Acute confusional state (delirium)

1.5. The unconscious patient

1.6. Head injury

1.7. Brain tumours

1.8. Cerebrovascular disease

1.9. Headache

1.10. Meningitis and encephalitis

1.11. Movement disorders

1.12. Speech disorders

1.13. Multiple sclerosis

1.14. Cerebellar disease

1.15. Dizziness

1.16. Cranial nerve disorders

1.17. Disorders of the spine

1.18. Anterior horn cell, nerve root and plexus disease

1.19. Peripheral neuropathies (polyneuropathies)

1.20. Single nerve lesions (mononeuropathies)

1.21. Neuromuscular junction disorders

1.22. Muscle disorders

1.23. Investigations

1.1. Neurological examination

The key to neurological diagnosis is pattern recognition, and there are a limited number of patterns that you need to know. Neurological exami na tion and diagnosis is sometimes seen as difficult because emphasis is placed on lots of different individual diseases rather than patterns of disease.

Patients with weakness will fall into one (rarely two) of four syndromes represent ing the stages in the motor pathway from the cortex to the muscle: upper motor neurone (UMN), lower motor neurone (LMN), neuromuscular junction (NMJ), and muscle. You should be aware of the classical features for each of these syndromes.

TABLE 1.1 Patterns of Motor Disorder

	UMN	LMN	NMJ	MUSCLE
Inspection	Nil	Wasting	Nil	Wasting
		Fasciculations
Tone	Increased	Normal/decreased	Normal	Normal/decreased
Weakness (pattern)	Pyramidal	See below	Proximal (fatiguable)	Proximal
Reflexes	Increased Extensor plantars	Decreased/absent	Normal	Normal/decreased

• ‘Pyramidal’ weakness is the pattern seen in UMN syndromes: in the upper limb extensors are weaker than flexors; in the lower limb flexors are weaker than extensors.
• Remember that the UMN synapses with the LMN in the anterior horn of the spinal cord – this will help you remember that in motor neurone disease, a disease of the anterior horn cells, there may be both UMN and LMN signs (although this is not the true explanation!)
• It is useful to think of the LMN as consisting of three parts: the root, the plexus and the nerve. Patterns of weakness then depend on which part is affected. In a polyneuropathy or ‘peripheral neuropathy’ there is commonly distal weakness.

The two main sensory tracts are the spinothalamic tract (pain and tem perature) and the dorsal columns (proprioception and vibration). Touch is carried via both. When considering patterns of sensory loss, think about the sensory pathway as it comes in from the periphery to the brain.

Patterns of sensory disorder

• Peripheral neuropathies: ‘glove and stocking’ distal sensory loss
• Individual nerves: sensory loss over area which nerve supplies
• Plexus or root: sensory loss over dermatome that root supplies
• Spinal cord disease – commonly produces a sensory ‘level’, may:
  • affect all modalities (whole cord)
  • affect vibration/proprioception only (posterior cord)
  • affect pain/temperature only (anterior cord)
  • produce dissociated loss, i.e. vibration/proprioception one limb and pain/temperature in the opposite limb (half cord, i.e. Brown-Séquard syndrome)
• Thalamus, internal capsule, sensory cortex: hemisensory loss

The other patterns to learn are those of patients with either a cerebellar syndrome or an extrapyramidal/parkinsonian syndrome who will not have true weakness or sensory disturbance. (See sections 11 and 14).

1.2. Epilepsy

This is the tendency to have recurrent seizures. Seizures are caused by abnormal electrical activity in the brain and can be divided into two broad groups:

• Generalised (Tonic-clonic, Absence, Myoclonic).
• Partial (Simple, Complex, Secondary generalised).

Tonic-clonic (‘grand mal’) seizures

Has no warning. In the tonic phase, the patient’s limbs become stiff and there is loss of consciousness. Within a minute, the clonic phase starts with convulsive movements of the limbs. Breathing is irregular; there may be tongue biting and/or urinary incontinence. Following the seizure, there may be a ‘post-ictal’ period lasting hours where the patient feels fatigued, confused and may have a headache.

Absence (‘petit mal’) seizures

Mainly affects children. Occur without warning and consist of short-lived episodes of unawareness (normally lasting <30 s), during which the patient will look as though they are staring and remain still. The patient returns to normal immediately after the episode.

Complex partial seizures

Like other partial seizures these affect only part of the brain (i.e. are focal), but awareness is altered. Features of temporal lobe seizures include déjà vu, a rising sensation in the epigastrium, olfactory hallucinations, amnesia, and repetitive and stereotyped movements of the limbs or mouth.

INVESTIGATIONS

• Diagnosis relies on a good witness history. Examination is generally normal.
• Electroencephalogram (EEG) (interictal EEG is normal in » 50% of cases; if EEG is repeated or sleep EEG performed only » 10% will be normal) and brain CT/MRI.

MANAGEMENT

• Drug therapy: normally started after two clearly described unprovoked seizures. Most patients can be controlled on monotherapy:
  • generalised tonic-clonic: first line treatment = valproate, carbamazepine, lamotrigine
  • partial: first line treatment = carbamazepine, lamotrigine, valproate.

Status epilepticus

ABC, check glucose, IV access, specific management is lorazepam initially, followed by fosphenytoin or phenytoin if required. If still ongoing treat as refractory – admit to ITU, treat with an agent such as propofol. Further management is supportive.

• General advice to patients.
  • Safety measures: take care when bathing/swimming, avoid dangerous sports.
  • Driving regulations for unprovoked seizures: the pa...