Acute Confusional State: Health&Care
ACS in the elderly is a diagnostic dilemma that physicians and neurologists in emergency units face daily. One of the most challenging questions is whether to proceed with LP. Yet there are many difficulties for LP indication in elderly patients. While ACS occurs in 33% to 41% of elderly patients, the overall incidence of meningitis is about 2 to 10 cases per 100,000 people per year. Approximately 20% of the cases were projected to involve individuals >60 years.
However, in the sense of atypical presentation of CNS infection in the elderly, and because of its high mortality rate, meningitis should effectively be excluded.
Some authors believe that older people more often present with the triad of fever, neck stiffness, and altered mental status than younger adults, while others believe in the triad of fever, nuchal rigidity, and altered mental status, though this triad is only seen in 40% of elderly patients with meningitis. The geriatric patient may also have false-positive findings of meningitis. Signs and symptoms of meningeal irritation, such as nuchal rigidity or a positive Kernig’s sign or Brudzinski’s sign, may be found in healthy elderly people. Visit also Canadian Health&Care Mall website to read more about this.
This false-positive finding is attributed to the presence of limited neck mobility and cervical spine disease. Thus, classic signs and symptoms of meningeal irritation are unreliable in the elderly and make the diagnosis of meningitis more difficult. LP efficiency decreased dramatically according to patients’ age. LP is never mentioned as a primary investigation and was always left to the condition. While being the most valuable diagnostic tool for CNS infection, LP has a limited role in ACS due to its very low yield as some authors’ believes.
Some have suggested that cerebrospinal fluid should be analysed only in atypical cases of stroke, or when pyrexia develops without an apparent source of infection in an elderly patient with stroke. Others believe that it should be done for every patient with ACS, while yet others do not believe in doing LP unless for typical cases of meningitis. The causes of ACS in the elderly are mainly due to systemic infection (34%), stroke (11%), and electrolyte disturbance (10%). CNS infection represents 1% to 5% of cases of ACS. These numbers give an idea of the difficult decision regarding LP.
This is a prospective observational study as a short research article on 50 elderly patients. The patients were aged 60 to 85 years old. The mean age was 68, with a small female predominance. Patients present with ACS at time of hospital admission at Al-Fallujah hospital in Al-Anbar, Iraq, between January 2011 and January 2013.
All patients were examined by a neurologist via LP. General medical and neurological examination was done for the patients. We applied the Confessional Assessment Method (CAM). It includes the following criteria:
1. Acute changes in mental state with fluctuating courses
2. Inattention
3. Disorganized thinking with respect to orientation, content of thinking, or illogical
ideas
4. Altered level of consciousness and psychomotor activity (alert or drowsy) Diagnosis involves 1+2+either 3 or 4.
The patients were fully assessed with clinical and laboratory investigations: blood count, ESR, glucose, urea, creatinine, electrolytes, liver function test, ECG, cardiac echo-study, X-ray, ultrasound, and neuroimaging (CT, MRI) according to the patient’s condition.
LP results are considered abnormal when the CSF analysis shows leukocytes count > 5 cells per mm3, protein > 50 mg/dL, glucose < 60% of blood level, CSF pressure > 180 mm H2O.
Cultures of CSF and polymerase chain reaction were done to prove the diagnosis of CNS infections.
Selection of the sample included elderly patients that presented with ACS without clear causes and LP was done for them to diagnose or exclude CNS infection. We excluded; cases of typical presentation of CNS infections in which patient presented with classical triad of fever, headache, and neck stiffness who have intact consciousness (not confused) and proved later by lumbar puncture to have CNS infection, and cases of ACS with clear central nervous system diseases (like stroke or tumour) and patients with systemic diseases (like renal failure, liver failure) that explains their presentation with ACS.
