Chapter 33 Wilderness Neurology
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It is essential for practitioners in wilderness settings to have a working knowledge of neurology and to be able to diagnose and treat patients without recourse to specialist investigation, especially computed tomography and magnetic resonance imaging. Circumstances will vary depending on terrain, weather, and the availability of emergency transport (Figure 33-1, online).
FIGURE 33-1 Dr. Charles Clarke and Per Temba Sherpa treating a case of high-altitude cerebral edema at 6100 m (20,013 feet) on the British expedition of the southwest face of Mt Everest in 1975.
(Courtesy Dr. Charles Clarke.)
Preliminaries: History and Examination
Nervous system examination need not be lengthy or complex. A short neurologic examination (Box 33-1) takes less than 5 minutes. Much can be done without any special equipment; a tendon hammer can be improvised easily, and lack of an ophthalmoscope rarely makes a great difference to diagnosis and management.
BOX 33-1 Five-Part Short Neurologic Examination
Try to answer the following critical questions, using the story and examination findings:
Incidental Neurologic Conditions
Headache after Head Injury
The vast majority of headaches that occur after trauma—even those that last for several months—are not caused by serious intracranial pathology. However, subdural and extradural hematoma (see Chapter 21) must be considered in the aftermath of head injury. Both are rare in the absence of corroborating physical signs.
Wilderness Guidelines for the Diagnosis of Headache
The development of sudden headache, no matter how severe, that involves flashing lights, nausea, and vomiting is very likely to be migraine. Some migraines are devastating. Subarachnoid bleeding does not typically cause migrainous visual symptoms. In any event, in wilderness settings, management is expectant, because immediate evacuation is unlikely to be possible. Treat the patient with an analgesic (e.g., acetaminophen) and an antiemetic (e.g., metoclopramide, ondansetron). Await and expect recovery. After 12 to 24 hours, the majority of migraines will have resolved. If the patient becomes drowsy with neck stiffness, subarachnoid bleeding should be considered.
Band-like (i.e., around the head) headaches without any other clinical features and the absence of neurologic signs are distinctly unlikely to be the result of anything sinister. Again, await events.
Sinusitis, glaucoma, dental pain, and cluster headache need to be considered. With glaucoma, the eyeball will typically be painful, and vision may be altered. Sinusitis can cause severe pain that is usually well localized within and around the infected sinus. Cluster headache causes pain of exceptional severity, often at night, and is typically perceived around and behind the eye. Cluster headache, no matter how severe, tends to resolve after 4 to 6 hours.
This is a cause for concern and requires careful reevaluation for emerging physical signs. For example, in a situation that involves chronic meningitis (e.g., tuberculous meningitis), headache can precede the onset of neck stiffness and emerging signs (e.g., hemiparesis, cranial nerve lesions) by several weeks.
Epilepsy
Emergency Management of Seizures
Status Epilepticus
Status epilepticus, which is also known as status (Box 33-2), involves the occurrence of continuous seizures (two or more) without fully recovering consciousness. More than 50% of cases of status occur without a previous history of epilepsy. Status is associated with a mortality rate of 10% to 15%.
BOX 33-2
Status Epilepticus
Doses from Clarke C, Howard R, Shorvon S, et al: Neurology: A Queen Square textbook, Oxford, UK, 2009, Wiley Blackwell Publishing, p. 235.IV, Intravenously.