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Flashcards in Infection - Meningitis Deck (87):



What is meningism?

Triad of:

  • Headache
  • Photophobia
  • Neck rigidity




What is meningitis?


Usually inflammation of the meninges




What is the pathophysiology behind bacterial meningitis?

Inflammation of the meninges, usually result of infection

Involves at least five steps:

  • Attachment to mucosal epithelial cells
  • Transgression of the mucosal barrier
  • Survival in the blood stream
  • Entry into CSF
  • Production of overt infection in the meninges +/- brain infection (encephalitis).




What are the 3 layers of the meninges (from outermost to inner most)?


  1. Dura Mater
  2. Arachnoid Mater
  3. Pia Mater




What is normally the cause of death in meningitis?



Sepsis - not the actual meningeal inflammation




What routes do organisms reach the meninges by?

Either by:

  • Direct extension from the ears, nasopharynx, cranial injury or congenital meningeal defect
  •  Haematogenous spread.




What are the main causes of meningism?


  • Meningitis
  • Sub-arachnoid Haemorrhage
  • Malignancy
  • Autoimmune disease




When assessing neck stiffness, what key finding would indicate meningeal irritation?



Stiffness on flexion. If on rotation, more likely to be caused by cervical problem like spondylosis




What are bacterial causes of meningitis?


  • Neisseria Meningitidis
  • Streptococcus pneumoniae (pneumococcus)
  • E. coli  
  • Group B streptococci




What other conditions can mimic meningitis?


  • Cervical spondylosis
  • Cervical fusion
  • Parkinson’s disease
  • Raised ICP - esp if there is impending tonsillar herniation.
  • Acute dystonic reaction
  • Tetanus




What are viral causes of meningitis?


  • Enteroviruses
  • Echoviruses
  • Parechoviruses
  • Coxsackie A and B
  • Poliovirus
  • Mumps
  • Herpes simplex virus




What are the most common causes of bacterial meningitis in neonates (<1 month)?


  • E. Coli and other coliforms
  • Group B Strep
  • Listeria Monocytogenes




What are the most common causes of bacterial meningitis in 3 month to 6 year olds?


  • Nisseria Meningitidis
  • Streptococcus Pneumoniae
  • Haemaphilus Influenzae
  • Group A strep.
  • Staph. aureus




What are the most common causes of bacterial meningtis in those over the age of 6?


  • Neisseria Meningitidis
  • Strep. Pneumoniae




Which patient groups is listeria meningitis more common in?


  • Immunocompromised
  • Neonates
  • Over age of 50




What are symptoms seen in meningitis in adults?


  • Headache
  • Irritability
  • Stiff neck
  • Photophobia
  • Fever/Rigors
  • Altered level of consciousness
  • Vomiting





What fungi can cause meningitis?


  • Cryptococcus neoformans
  • Candida albicans




What are symptoms of meningitis in a child/neonate?



Can be vague symptoms:

  • Lethargy
  • Malaise
  • Vomiting
  • Poor feeding
  • Irritability




What ENT problems can lead to meningitis?


  • Otitis Media
  • Sinusitis




What signs can present in meningitis?

  • Pyrexia
  • Tachycardia
  • Signs of shock - cool peripheries, decreased BP
  • Cranial nerve palsies
  • Petechial Rash
  • Kernig's Sign
  • Brudzinski's Sign
  • Jolt accentuation
  • Opisthotonos




What is Brudzinski's Sign?


With the patient in the supine position, passive neck flexion results in active hip flexion and knee flexion.




What is thought to be the mechanism behind brudzinski's Sign?


Passive neck flexion results in mechanical stress on the spinal nerves and the arachnoid mater, which may be somewhat alleviated by active hip flexion and knee flexion. When the subarachnoid space is inflamed, as with meningitis, mechanical forces on the arachnoid mater result in tenderness and an attempt to alleviate pain (hip flexion, knee flexion)




What is Kernig's Sign?

With the patient lying supine with the hip flexed to 90°, the examiner attempts to passively extend the knee from 90°. Resistance to passive knee extension at less than 135° is considered a positive sign.




What is the mechanism of Kernig's Sign?


Passive extension of the knee with the hip at 90° results in mechanical stress on the spinal nerves, arachnoid mater and subarachnoid space. When the subarachnoid space is inflamed, as in meningitis, mechanical forces on the arachnoid mater result in resistance to further movement to prevent worsening discomfort.




What is jolt accentuation?


Rapid horizontal rotation of the neck (2–3 Hz) in a patient with suspected meningeal irritation results in exacerbation of pre-existing headache.

Rotational and centrifugal forces upon inflamed meninges are thought to exacerbate cephalgia when meningeal irritation is present.


What is the following?



Non-blanching petechial rash




What is photophobia?


Photophobia is light-induced ocular and/or cephalic discomfort. The patient exhibits discomfort and aversion to light stimuli, resulting in involuntary eye closure and/or gaze deviation.




What is characteristic about the petechial rash seen in certain types of meningitis?



It is non-blanching




If someone was showing signs of meningism, and had papilloedema, what would this indicate?


Unusual in meningitis and should lead one to consider an intracranial SOL (eg, brain abscess or tuberculoma).




What is opisthotonos?


Spasm of the muscles causing backward arching of the head, neck, and spine, as in severe tetanus, some kinds of meningitis, and strychnine poisoning




In meningococcal disease, how quickly do symptoms take to develop?



4-6 hours




With pneumococcal meningitis, how long does it take for symptoms to develop?



1-2 days




Which organism is the most common cause of meningitis with petechial rash?



Meningococcal meningitis




What is the mechanism behind the development of petechial rash in meningitis?



Coagulopathy caused by infection




How would you manage someone with viral meningitis?

Symptomatic control:

  • Ibuprofen/calpol - to reduce fever.




What are malignant causes of meningitis?


  • Leukaemia
  • Lymphoma
  • Breast cancer
  • Bronchial cancer




What are the earliest features of meningitis?


  • Headache
  • Leg Pains
  • Cold hands and feet
  • Abnormal skin colour




In someone with meningitis, what are signs of septic shock?

  • Cap refill > 2 seconds
  • Unusual skin colour/mottled skin
  • Tachycardia +/- hypotension
  • Respiratory symptoms or breathing difficulty
  • Leg pain
  • Cold hands/feet
  • Toxic/moribund state
  • Altered mental state/decreased conscious level
  • Poor urine output




What are features of TB meningitis?


Usually presents subacutely as meningism and low grade fever who has active extrameningeal tuberculosis

  • Lethargy
  • Chronic headache
  • Change in mentation
  • Cranial nerve palsies





What are features of fungal meningitis?

Subacute onset of symptoms

  • Low grade fever
  • Headache
  • Nausea
  • Lethargy
  • Confusion
  • Abdominal pain.

Meningism less common - can develop quickly as the condition progresses




What groups of patients does fungal meningitis occur in?



Immunocompromised - HIV positive, malignancy, organ transplant




What percentage of those with bacterial meningitis are under the age of 16?







If a newborn develops meningitis within the first 72 hours of life, what is the most likely source of infection?



Usually acquired from mother genital tract at birth





What investigations would you do if you suspected meningitis?

Look for source of infection, severity and signs of complication/organ dysfunction

  • Bloods - FBC, U+E's, CRP, LFTs, ABGs, Blood cultures, Coagulation Screening
  • Blood Glucose
  • Throat Swab
  • Urine Dipstick
  • Lumbar Puncture
  • ?CT/MRI




What extra investigations would you perform if you suspected TB to be the cause of a meningitis?


  • Chest x-ray
  • Mantoux test




What might you see on LP in someone with bacterial meningitis?


  • Turbid appearence
  • Neutrophil predominant WCC
  • Reduced glucose, decreased CSF/Serum ratio
  • Greatly increased protein
  • Increased opening pressure




What are characteristics on LP investigation for Viral meningitis?


  • Clear to turbid
  • Lymphocyte predominant WCC
  • Normal glucose
  • Moderate increased protein
  • Normal or mildly increased opening pressure




What are features of fungal/TB meningitis on LP analysis?


  • Clear/Turbid appearence
  • Lymphocyte/mixed WCC
  • Reduced glucose
  • Greatly increased protein




What are the main features of meningococcal septicaemia?


  • Fever,
  • Petechiae/purpura
  • Toxicity




What might you see on FBC when investigating for meningitis?


  • Neutrophil leucocytosis**
  • DIC - Thrombocytopaenia, abnormal clotting, increased FDP

**White cell count may be decreased in septicaemia and DIC




What are haematological features of DIC (on coagulation screening)?


  • Increased INR, APTT and thrombin time
  • Thrombocytopenia
  • Abnormal clotting factors
  • Increased FDP - D-dimer




Why might you do U+E's in someone with meningitis?



To assess for signs of kidney failure




How would you initially assess someone with suspected bacterial meningitis?


  • Airway
  • Breathing - Respiratory rate & O2 saturation
  • Circulation - Pulse; capillary refill time; urine output; blood pressure (hypotension occurs late)
  • Disability - Glasgow coma scale; focal neurological signs; seizures; papilloedema; capillary glucose

Senior review +/- Critical Care review if any Warning Signs are present




What are clinical signs of raised ICP?


  • Reduced (GCS≤8) or fluctuating level of consciousness
  • Relative Bradycardia and Hypertension
  • Focal neurological signs
  • Abnormal posture or posturing
  • Seizures
  • Unequal, dilated or poorly responsive pupils
  • Papilloedema (late sign)
  • Abnormal ‘doll’s eye’ movements




Why would you do LFTs in someone with meningitis?



Look for liver failure as part of multisystem organ failure




What might you do coagulation screening for?



Check for features of DIC




What might you see on ABG in someone with meningitis?



Lactic acidosis and increased LDH




What dose of dexamethasone would you give someone presenting with features of bacterial meningitis?



10 mg/6h IV - for 4 days




How long would you treat someone with antibiotics with confirmed meningococcal meningitis?



IV ceftriaxone - 7 days




How long would you treat someone with confirmed H. influenzae meningitis?



IV ceftriaxone - 10 days




If someone over the age of 55 presented with suspected bacterial meningitis, what antibiotic therapy would you use?



Ceftriaxone + Amoxicillin*

*Vancomycin if penicillin allergic




What are common microbiology tests performed on CSF?


  • Gram stain (and ZN if appropriate)
  • Differential cell count
  • Antigen detection test (latex agglutination)
  • Bacterial culture
  • Mycobacterial or fungal culture (if appropriate)
  • PCR for viruses (if appropriate)
  • PCR for bacteria (if appropriate)




If someone was penicillin allergic, and had bacterial meningitis, what would you treat them with?



Chloramphenicol - 12.5-25mg/kg 6hrly IV




What LP results would indicate subarachnoid haemorrhage?


  • Bloodstained CSF
  • After centrifugation - supernatant has a golden-yellow tinge due to haemoglobin breakdown and is described as xanthochromic.




How would you tell if a CSF sample is bloodstained due to subarachnoid haemorrhage or due to operator error?


If operator strikes a blood vessel -“bloody tap” - first specimen collected is more bloodstained than subsequent ones and there is no xanthochromia on centrifugation.




How would you manage suspected bacterial meningitis in the community?



Initiate antibiotic treatment as soon as meningococcal infection is suspected (within 30 minutes of arrival!):

  • Benzylpenicillin - parenteral




If someone had HSV meningoencephalitis, what would you treat them with?







What are contraindications to performing an LP?


  • Clinical/radiological signs of raised ICP
  • Shock
  • After convulsions until stabilised
  • Coagulation abnormalities
  • Local superficial infection at LP site
  • Respiratory insufficiency





Why would you consider giving ampicillin/amoxicillin plus cefotaxime to those under the age of 3 months for suspected bacterial meningitis?



To cover for listeria infection




If someone presented with suspected meningits without signs of shock, severe sepsis or signs of brain shift, how would you manage them?


  • Blood cultures
  • IV Antibiotics - Ceftriaxone - 2g/12 hrs
  • Lumbar puncture
  • Dexamethasone - 10 mg IV
  • Careful fluid management





If someone presented with suspected meningitis and signs of brain shift/increased ICP, how would you manage them?


  • Get Critical Care input
  • Secure airway, high flow oxygen
  • Take bloods inc. Blood Cultures
  • Give Ceftriaxone - 2g IV immediately after blood cultures taken
  • Dexamethasone - 10mg IV
  • Delay LP until neurological imaging - once patient is stabilised




If someone presented with supected meningitis and was showing signs of septic shock or a rapidly evolving rash, how would you manage them?


  • Get Critical Care input
  • Secure airway and give high flow oxygen
  • Fluid resuscitation
  • Blood Cultures
  • Ceftriaxone - 2g IV immediately after blood cultures
  • Delay LP




What are warning signs that you may need critical care input for managing someone with meningitis?

  • Rapidly progressive rash
  • Poor peripheral perfusion - Capillary refill time > 4 secs, oliguria or systolic BP < 90mmHg
  • Respiratory rate < 8 or >30 / min
  • Pulse rate < 40 or >140 / min
  • Acidosis pH < 7.3 or Base excess worse than -5
  • White blood cell count < 4 x 109/L
  • Lactate > 4 mmol/L
  • GCS <12 or a drop of 2 points
  • Poor response to initial fluid resus




When would you consider giving dexamethasone in bacterial meningitis?

For suspected or confirmed bacterial meningitis if lumbar puncture reveals any of the following:

  • Frankly purulent CSF
  • WBC count greater than 1000/microlitre
  • Raised WBC count + protein concentration >1 g/litre
  • Bacteria on Gram stain




What dose of ceftriaxone would you give someone with suspected bacterial meningitis?



2g IV/12hrs




How long would you treat someone with antibiotics for with confirmed pneumococcal meningitis?



IV ceftriaxone - 14 days




What antibiotics would you give for unconfirmed bacterial meningitis?


  • <3 months age - Cefotaxime + Amoxicillin/Ampicillin
  • >3 months age - Ceftriaxone




What percentage of those with meningococcal meningitis die within the first 24 hrs?







What is important to do if someone is diagnosed with meningococcal meningitis from a public health point of view?


  • Notify public health
  • Contact screening
  • Immunisation programmes
  • Prophylactic antibiotics - all household contacts




What prophylactic antibiotics can be used for prophylactic treatment of meningococcal meningitis?

Eradicate n. meningitidis from nasopharynx

  • Rifampicin
  • Ciprofloxacin





What complications can occur from bacterial meningitis?


  • Hearing loss
  • Vasculitis – can cause cranial nerve lesions
  • Cerebral Infarct
  • Subdural effusion
  • Hydrocephalus
  • Cerebral abscess
  • Seizures
  • Complications from sepsis - limb loss




Why is dexamethasone given in bacterial meningitis?



To reduce risk of long term complications - especially deafness




What would be your differential diagnosis for someone presenting with features of meningitis?


  • Malaria
  • Encephalitis
  • Septicaemia
  • Subarachnoid haemorrhage
  • Dengue fever
  • Tetanus




What antibiotics would you give for someone with fungal meningitis?


  • Amphotericin
  • Fluclonazole




What are high risk groups for neonatal GBS meningitis who may require prophylactic antibiotics?


  • Pre-term delivery
  • Prolonged period between membrane rupture and delivery
  • Previous strep infection
  • Intrapartum fever




What is a non-blanching purpuric rash a sign of?



Suggests that the patient has septicaemia, not just meningitis on its own




How would you remember the difference between brudzinskis and kernig's sign?


  • Brudzinskis - Bend the neck
  • Kernigs' - straighten the Knee