The disease is of long duration; to connect, therefore, the symptoms which occur in its later stages with those which mark its commencement, requires a continuance of observation of the same case, or at least a correct history of its symptoms, even for several years.
JAMES PARKINSON (1755–1824), AN ESSAY ON THE SHAKING PALSY
In general practice there are many neurological problems that present a diagnostic dilemma, with some being true masquerades for the non-neurologist. This applies particularly to various seizure disorders, spaceoccupying lesions in the cerebrum and the cerebellum, demyelinating disorders, motor neurone disorders and peripheral neuropathies.
The most common pitfall that occurs with neurological disorders is misdiagnosis, and the most common reason for misdiagnosis is an inadequate history. Failure to appreciate the neurological meaning of points elicited during the history is another reason for misdiagnosis.
Some very important neurological disorders are presented in this section: Parkinson disease, which is common and can be easily misdiagnosed, especially when the classic ‘pill rolling’ tremor is absent or mild; multiple sclerosis (MS), because it is difficult to diagnose initially; and acute idiopathic demyelinating polyneuropathy (Guillain–Barré syndrome), because it can be rapidly fatal if misdiagnosed. MS can masquerade as almost anything—‘If you don’t know what it is, think of MS.’
Another brain teaser for the family doctor is to diagnose accurately the various types of epilepsy. The most commonly misdiagnosed seizure disorders are complex partial seizures or atypical generalised tonic–clonic seizures (see CHAPTER 54).1 Even more difficult is the differentiation of real seizures from pseudo- or non-epileptic seizures. As a rule neurological conditions should be referred early for specialist management.
The onset of diplopia (double vision) in adults is often acute, very distressing and invariably easy to diagnose. It is invariably binocular, which usually results from extraocular muscular imbalance or weakness. The type of binocular diplopia—vertical, horizontal or oblique—provides clues in identifying the affected muscle. Monocular diplopia is double vision that occurs in one eye when the other is covered. It arises from the eye itself.
The diagnostic strategy model is outlined in TABLE 33.1.
Table 33.1Diplopia: diagnostic strategy model ||Download (.pdf) Table 33.1 Diplopia: diagnostic strategy model
Ocular nerve palsy (3, 4, 6)–various causes
Drug effect, e.g. alcohol, benzodiazepines
Eye disorder, e.g. cataract, refractive error, cornea
Serious disorders not to be missed
Involving 3, 4 or 6 cranial nerves
Facial bone trauma/head injury
Pitfalls (often missed)
Any orbital infiltration
Cavernous sinus thrombosis
Seven masquerades checklist
Drugs, e.g. sedatives, opioids, alcohol
Is the patient trying ...