Weakness

1.10 Weakness

Presentation
An older patient comes to the emergency department or is brought by family, complaining of "weakness," or an inability to carry on his usual activities or care for himself.
What to do:



Work at obtaining as much history as possible. Speak to available family members or friends, as well as the patient, and ask for details. Is the patient weak before certain activities? (suggestive of depression). Is the weakness located in the limb girdles (suggestive of polymyalgia rheumatica or myopathy). Is the weakness mostly in the distal muscles? (neuropathy). Is the weakness brought out by repetitive actions? (myasthenia gravis). Is the weakness unilateral with slurring of speech or confusion? (cerebrovascular accident).



Obtain a thorough medical history and physical examination, including a review of systems (headaches, weight loss, cold intolerance, appetite, bowel habits), strength of all muscle groups (graded on a scale of 1-5), deep tendon reflexes, and neurological status. Order a head CT is there is an unexplained change in mental status or if there are abnormal neurologic findings.



Obtain a spectrum of laboratory tests which will be available within the next 2 hours, including pulse oximetry, chest x ray, electrocardiogram, urinalysis, blood counts, glucose, BUN, and electrolytes which may disclose hypoxia, anemia, infection, diabetes, uremia, polymyalgia rheumatica, hyponatremia and hypokalemia, all of which are common causes of "weakness." (Testing for serum phosphate and calcium are also valuable, if available stat.)



If no etiology for weakness can be found, probe the patient, family, and friends once again for any hidden agenda, and if none is found, reassure them about all the serious illnesses which have been ruled out. At this time, discharge the patient and make arrangements for definite followup.
What not to do:



Do not order any laboratory tests the results of which you will not see. Your best strategy is to stick to tests which will return while the patient is in the emergency department, and defer any long investigations to the followup physician. Laboratory results which are never seen or acted upon are worse than none at all.



Do not insist upon making the diagnosis in the emergency department in every case. In this clinical situation, your role in the ED is to rule out acutely life-threatening conditions, and then make arrangements for further evaluations elsewhere.
Discussion
Approach the patient with "weakness" with an open mind and be prepared to take some time with the evaluation. Demonstrable localized weakness usually points to a specific neuromuscular etiology, while generalized weakness is the presenting complaint for a multitude of ills. In young patients, weakness may be a sign of psychological depression while in older patients, inaddition to depression, it may be the first sign of a subdural hematoma, pneumonia, urinary tract infection, diabetes, dehydration, malnutrition, heart failure, or cancer. It is important to exclude the Guillain-Barre syndrome as one of the critical, life-threatening etiologies to weakness. The pattern is not always an ascending paralysis or weakness, but usually does depress deep tendon reflexes. Botulism is another condition that must be excluded by history or observation. Patients who are suffering from these sorts of neuro-muscular weakness get into danger when they can't breathe. Pulmonary function studies like pulse oximetry, capnography, blood gases, peak flow or vital capacity can be helpful in selecting patients who might be close to severe respiratory embarrassment.