QuestionSBA
QuestionChoice
Migraine can cause a headache with classical photophobia and significant nausea and vomiting. Alcohol can also act as a trigger for migraines. However, if this were a migraine, it would usually have resolved within 24 hours, but more rarely can persist for up to 72 hours. The headache would usually be noted as being unilateral and pulsatile in nature. Migraines are not usually associated with significant neck stiffness or infective symptoms
33485
c
Migraine
QuestionChoice
A gastrointestinalgastrointestinal infection could cause significant vomiting and infective symptoms of fever and rigors; however, this would usually also be associated with some accompanying abdominal pain or diarrhoea. It would be uncommon for this condition to present with headache as the primary symptom
33487
e
Severe dehydration secondary to gastro-enteritis
QuestionChoice
Student populations are one of the higher risk groups for bacterial meningitis, and it is vital to always consider this diagnosis in patients of this cohort presenting with headache or vomiting so as not to miss a potentially fatal infection. This patient has several key signs of meningitis, including headache, photophobia, vomiting and neck stiffness, as well as symptoms that sound like fevers and rigors overnight. Neisseria meningitidis is the classical organism causing meningitis in student populations
33483
a
Meningitis
QuestionChoice
SAH can also cause a severe headache with photophobia, vomiting and neck stiffness. However, in SAH, you may expect a history of more sudden onset "thunderclap" headache, with the severity of the pain being the primary symptom, with patients often describing it as the "worst pain I've ever felt". This diagnosis would also not explain the notable infective sounding symptoms of fevers and rigors overnight. Additionally, in this population, meningitis would be a more common cause of these symptoms
33484
b
Subarachnoid haemorrhage (SAH)
QuestionChoice
Though it does happen, it would be rare for a simple hangover to cause severe enough symptoms for a patient to present to the hospital. Additionally, it would be rare for this to be causing such severe symptoms for more than 24 hours with no improvement. A hangover would not cause infective symptoms. Neck stiffness is quite a specific symptom that should point you towards significant central nervous system pathology (indicating inflammation of the meninges)
33486
d
Hangover
Concept
Chapter
# Summary
 
Meningitis is a potentially life-threatening condition characterised by the inflammation of the meninges, the membranes enveloping the brain and spinal cord. Its causes span from infectious agents, such as bacteria, viruses, fungi, and parasites, to non-infective causes like malignancy and certain medications. Symptoms are often non-specific, necessitating accurate differential diagnoses and prompt investigations. Timely management, including empirical antibiotics and targeted therapy post-identification of causative agent, is crucial to mitigate complications and improve patient outcomes. 
 
 
# Definition
 
 
Meningitis is an inflammation of the meninges, which are composed of three layers: the dura mater, arachnoid mater, and pia mater. This inflammation may arise from both infective and non-infective aetiologies. 
 
 
# Epidemiology
 
 
Bacterial meningitis, while not the most common form of meningitis, is particularly significant due to its high morbidity and mortality rates. 
 
Viral meningitis, predominantly caused by enteroviruses, is more common but typically less severe. Fungal and parasitic causes are relatively rare, except in immunosuppressed individuals. 
 
In the United States, the annual incidence of bacterial meningitis is approximately 1.38 cases/100,000 population with a case fatality rate of 14.3%.

# Aetiology
 
 
Infective causes of meningitis include:
 
 
 - Bacterial: **Streptococcus pneumoniae (most common bacterial cause),** Neisseria meningitidis, Haemophilus influenzae, Listeria monocytogenes, among others.
 - Viral: **Enteroviruses are overall most common** (Echoviruses, Coxsackie viruses A and B, poliovirus), herpes viruses (HSV2, HSV1), Paramyxovirus, measles and rubella viruses, Varicella Zoster Virus, Arboviruses, Rabies virus.
 - Fungal: Particularly Cryptococcus neoformans, mainly affecting the immunosuppressed population.
 - Parasitic: Amoeba (Acanthamoeba), Toxoplasma gondii.
 
 
Non-infective causes of meningitis encompass:
 
 
 - Malignancies such as leukaemia, lymphoma, and other tumours
 - Chemical meningitis
 - Certain drugs, including NSAIDs and trimethoprim
 - Systemic inflammatory diseases such as sarcoidosis, systemic lupus erythematosus, Behcet's disease.
 
 
# Signs and Symptoms
 
 
The cardinal features of meningitis include:
 
 
- Headache
- Fever
- Neck stiffness
- Photophobia
- Nausea and vomiting
- Focal neurology
- Seizures
- Reduced conscious level
- Features of overwhelming sepsis, such as non-blanching petechial rash indicative of impending Disseminated Intravascular Coagulation (DIC). 
 
Specific signs suggestive of meningeal irritation (and therefore not specific to meningitis) include:
 
 
1. **Kernig's sign:** Kernig's sign is a test performed to evaluate the presence of meningeal irritation and stiffness in the hamstrings and lower back. To perform this test, the patient is positioned lying on their back with the hip and knee flexed at 90 degrees. The examiner then attempts to extend the patient's knee. If the patient experiences pain and resistance to knee extension, especially when attempting to straighten the leg, it is considered a positive Kernig's sign. This sign suggests meningeal irritation or inflammation.
 
 
2. **Brudzinski's sign:** Brudzinski's sign is another manoeuvre used to assess for meningeal irritation. This test involves passive neck flexion, where the examiner gently flexes the patient's neck forward toward the chest while the patient is lying on their back. If the patient involuntarily flexes their hips and knees in response to neck flexion, it is considered a positive Brudzinski's sign. This involuntary movement indicates irritation of the meninges.
 
 
 
 
# Differential Diagnosis
 
The key differentials for meningitis often present with overlapping symptoms. These include:
 
 
- **Encephalitis**: Headache, fever, altered consciousness, seizures, focal neurological signs, behaviour changes.
- **Subarachnoid hemorrhage**: Sudden severe headache, nausea and vomiting, neck stiffness, altered consciousness, seizures.
- **Brain abscess**: Headache, fever, nausea and vomiting, focal neurological deficits, seizures, altered mental status.
- **Sinusitis**: Headache, fever, facial pain, nasal congestion.
- **Migraine**: Recurrent headaches, often unilateral and throbbing, accompanied by nausea/vomiting, photophobia, phonophobia.
 
 
# Investigations
 
 
Diagnostic investigations for suspected meningitis include:
 
 
 - Blood tests: Full Blood Count, Urea and Electrolytes, Clotting, Glucose, PCT
 - Arterial Blood Gas
 - Blood cultures
 - Bacterial throat swab for meningococcus
 - PCR for meningococcus & pneumococcus
 - HIV test
 - Imaging: CT Head if there are signs of raised intracranial pressure (ICP)
 - Lumbar puncture for Cerebrospinal Fluid (CSF) analysis, once confirmed there are no signs of raised ICP.
 
 
## CSF Findings 
 
 
Analysis of the cerebrospinal fluid in acute meningitis can provide important clues as to the underlying aetiology. Once establishing that it is safe to do so, a CSF sample should be taken via lumbar puncture and the opening pressure should be measured.
 
 
This can be examined macroscopically, and then sent for haematology, biochemistry, and microbiological microscopy, culture and sensitivities, as well as PCR.
 
|                           | **Appearance**                      | **Predominant cell type**                          | **Culture**                                             | **Protein** | **Glucose** |
|---------------------------|-------------------------------------|---------------------------------------------------|--------------------------------------------------------|-------------|-------------|
| **Bacterial meningitis**   | Clear or turbid                    | **Polymorphonuclear** cells (i.e. neutrophils)     | Positive                                                | Raised      | **Reduced** |
| **Aseptic (viral) meningitis** | Clear or slightly turbid            | **Lymphocytes**                                    | Negative                                                | Raised      | **Normal**  |
| **Tuberculous meningitis** | Clear or slightly turbid ± fibrin web | **Lymphocytes** + polymorphonuclear cells         | Negative gram stain; acid-fast bacilli positive (auramine staining) | Raised      | **Reduced** |

 
N.b. Cryptococcal meningitis may give any of the above results, so should be considered as a differential in any HIV or immunocompromised patient. Classically the opening pressure is very high, and this is a poor prognostic sign. If suspected, request cryptococcal antigen or India Ink staining.
 
 
# Management
 
 
- Empirical antibiotic therapy for suspected bacterial meningitis typically includes 2g of IV ceftriaxone twice daily to ensure CNS penetration, with IV amoxicillin added in patients at age extremes for listeria coverage.
- In primary care, IM benzylpenicillin or ceftriaxone should be given while awaiting urgent transfer to hospital, especially if meningococcal disease is suspected.
- Dexamethasone should be given if bacterial meningitis is strongly suspected in the absence of a rash
	- This has been shown to reduce neurological sequelae in bacterial meningitis but not meningococcal meningitis
- In cases of suspected viral encephalitis, IV aciclovir should also be administered. For patients allergic to penicillin, alternatives such as chloramphenicol may be used. 
- It's important to note that any empirical antibiotic regimen should be adjusted based on culture results when available.
 
 **Additional notes**
 
Close contacts of the patient should receive prophylactic antibiotics. This will be guided by specialists but may be a single dose of oral ciprofloxacin, or rifampicin.
 
Bacterial meningitis is a notifiable disease and any suspected cases should be reported to the local health protection team.
 
 
# Complications
 
 
Meningitis may lead to severe complications if not promptly treated, such as:
 
 - Septic shock
 - Disseminated Intravascular Coagulation
 - Coma
 - Subdural effusions
 - Syndrome of inappropriate antidiuretic hormone secretion
 - Seizures
 - Delayed complications: Hearing loss, cranial nerve dysfunction, hydrocephalus, intellectual deficits, ataxia, blindness
 - Death
 
 
# NICE guidelines
 
 [NICE CKS: Meningitis - bacterial meningitis and meningococcal disease](https://cks.nice.org.uk/topics/meningitis-bacterial-meningitis-meningococcal-disease/)
 
 [NICE: meningitis (bacterial) and meningococcal disease: recognition, diagnosis and management](https://www.nice.org.uk/guidance/ng240/resources/meningitis-bacterial-and-meningococcal-disease-recognition-diagnosis-and-management-pdf-66143949881029)
 
# References
 
 [BNF: Ciprofloxacin](https://bnf.nice.org.uk/drugs/ciprofloxacin/)
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Picture
The typical appearance of a petechial rash.
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Petechiae - free.jpeg
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2683
Meningitis
Topic
34
Neurology
6697
An 18-year-old female student presents to the emergency department on a Monday morning with 24 hours of severe headache and vomiting.

On Saturday, she went on a night out clubbing, and when she woke up on Sunday morning, she felt extremely unwell with headache, photophobia, nausea and vomiting. This has persisted, and she feels no better this morning. Her neck is also feeling stiff and painful - she wonders if this may be due to her excessive vomiting over the past 24 hours. Overnight she also reports waking up very sweaty and shaky.

What is the most likely diagnosis?
a