Case of the Month #5

Colin McAdam

A previously well 76-year-old male presents to ED having been found on the floor at home by a relative. Collateral history reveals ‘flu-like’ symptoms and headache within the last week.

On arrival he is soiled, agitated and combative with a GCS of 9/15 (E2 V2 M5). There are no obvious localising neurological signs. Pupils are equal and reactive. Temperature is 39.0.A basic delirium screen in ED is negative (urine dip and chest x-ray). As you continue assessing the patient, he has a short-lived generalised tonic-clonic seizure.

  1. What is your differential diagnoses?
  2. How would you investigate further?

The patient is subsequently intubated and ventilated and a CT head is requested. A CNS cause for the presentation is suspected. Intravenous Ceftriaxone and Aciclovir are administered pending further investigations; the salient results are shown below.

Bloods

  • FBC: Hb 135 g/dl, WCC 17.4, Plt 405
  • U&E: Urea 8.5, Cr 95, Na 130, K 4.5, CK 905
  • Coag: Normal Limits

Imaging

  • CT – head and neck – nil acute
  • CXR – clear

CSF Results

  • Turbid in appearance
  • Cell Count 1200 cells/mm3 (95% Polymorphs)
  • Protein 0.6g/l
  • Glucose 2.1 (Serum 7.6)
  • Gram Stain – Gram +ve diplococci

The presumptive diagnosis at this point was Pneumococcal Meningitis. Treatment with broad-spectrum antibiotics and antivirals was continued, and dexamethasone was added. The patient spent 10 days in critical care and a further 22 days in hospital. He was left with significant speech and balance disorders as a result of his meningitis and was eventually discharged to a rehab facility.

Pneumococcal Meningitis

Pneumococcal (Strep. Pneumonia) meningitis is one of the most common causes of bacterial meningitis in the adult population. The mortality rate is quoted as up to 30% (worse in the immunocompromised and the elderly). Morbidity from the disease is high with a significant number of local complications such as seizures, arterial/venous accidents, hydrocephalus and hearing/balance disorders.

General Management

Assessment:

  • ABCDE approach
  • Identify abnormal neurology
  • Treat seizures as normal
  • Invasive ventilation for those with low GCS, uncontrolled seizures or another indication. (PPE for intubation if suspected meningococcal disease).

Investigations

Bloods:

  • FBC/U&E/LFT/Glucose
  • Coagulation (Contraindications to LP/DIC Screen)
  • Blood Cultures

Chest X-Ray/Urine Dip (as part of initial infection/delirium work up)

Specific Imaging:

  • CT Head
  • MRI – not first line
  • EEG – if ongoing seizure activity/ NCSE suspected

Lumbar Puncture (perform as son as possible):

  • Microscopy and Cell Count
  • Culture
  • Protein/Glucose
  • Specific Viral Screens (HSV + Others)
  • Autoimmune (if suspected)
  • Opening Pressure

Treatment

Antibiotics:

  • Cephalosporin (Ceftriaxone often first line due to CNS penetration)
  • Consider deescalation as cultures become available
  • Prolonged (>10 days) course often required

Antivirals:

  • Usually Aciclovir initially 10mg/kg IV TDS
  • Up to 14-21 days in HSV encephalitis
  • Other viral causes may require alternative antivirals

Steroids:

  • Dexamethasone 10mg IV QDS
  • Mortality reduction in Pneumococcal Meningitis only
  • Reduction in incidence of hearing loss and other neurological sequalae in all bacterial meningitis.

Autoimmune:

  • Immunosuppression mainstay
  • Early specialist involvement

Supportive Care:

  • Optimise Cerebral Perfusion
  • DVT Prophylaxis

Specific Complications:

  • Refractory Status Epilepticus/NCSE
  • Raised ICP – Routine ICP monitoring is not recommended
  • Cerebrovascular Accident
  • Venous Sinus Thrombosis
  • Hearing/Visual Defects

Public Health Considerations:

All cases of meningitis should be notified to the local public health authority.

Take home messages

  • Consider CNS infection in cases of collapse, especially if imaging normal
  • Perform a lumbar puncture early if CNS infection is suspected
  • Steroids have a role in meningo-encephalitis
  • Monitor for the complications of meningo-encephalitis
  • Consider PPE if intubating and bacterial meningitis is considered

Further reading

McGill F, Heyderman RS, Michael BD, et al. The UK joint specialist societies guideline on the diagnosis and management of acute meningitis and meningococcal sepsis in immunocompetent adults [published correction appears in J Infect. 2016 Jun;72 (6):768-769]. J Infect. 2016;72(4):405‐438.