What are the key components of a physical examination in a patient suspected of having bacterial meningitis, particularly one with a potential for increased intracranial pressure and possible immunocompromised conditions?

Physical Examination in Suspected Bacterial Meningitis with Increased Intracranial Pressure

The physical examination must immediately identify contraindications to lumbar puncture and signs of increased intracranial pressure, as these findings mandate CT imaging before LP and require immediate empiric antibiotics without waiting for diagnostic confirmation. 1

Critical Assessment for Increased Intracranial Pressure

Assess level of consciousness using Glasgow Coma Scale (GCS):

• GCS ≤12 (or drop of >2 points) is a contraindication to immediate lumbar puncture 1
• GCS ≤10 specifically requires CT scan before LP in bacterial meningitis 1
• Some guidelines suggest GCS <9 or fluctuating >2 as the threshold 1
• Altered mental status is present in the majority of bacterial meningitis cases (median GCS 11) 2

Examine for focal neurological signs:

• Focal neurological deficits (excluding cranial neuropathies alone) mandate CT before LP 1
• Unequal, dilated, or poorly responsive pupils indicate increased ICP 1
• Abnormal "doll's eye" movements suggest brainstem involvement 1

Assess for abnormal posturing:

• Decerebrate or decorticate posturing is an absolute contraindication to immediate LP 1, 3
• This indicates severe increased intracranial pressure requiring immediate intervention 3

Examine for papilledema:

• Papilledema is a direct indicator of raised intracranial pressure and mandates imaging before LP 1

Classic Meningitis Signs

Assess for meningismus and fever:

• Fever is present in 74% of bacterial meningitis cases 2
• Stiff neck (nuchal rigidity) occurs in 74% of cases 2
• Headache is present in 84% of cases 2
• However, these signs may be scarce in children, elderly patients, and in meningococcal disease 4

Seizure Assessment

Document seizure activity:

• New onset seizures are a contraindication to immediate LP 1
• Patients should be stabilized after seizures before considering LP 1
• Frequent or uncontrolled seizures require critical care referral 1

Cardiovascular and Hemodynamic Assessment

Examine for signs of septic shock:

• Relative bradycardia with hypertension (Cushing's triad) suggests increased ICP 1
• Delayed capillary refill time and dusky or cold extremities indicate impaired perfusion 1
• Cardiovascular instability requires critical care involvement 1
• Systemic shock is a contraindication to immediate LP 1

Assess for meningococcal septicemia:

• Rapidly evolving or extensive purpuric rash mandates immediate antibiotics and critical care referral 1
• Evidence of limb ischemia requires intensive care involvement 1

Respiratory Assessment

Evaluate respiratory status:

• Respiratory compromise or insufficiency is a contraindication to LP 1
• Hypoxia requires critical care referral 1

Immunocompromised Status Indicators

Identify immunocompromising conditions:

• Known severe immunocompromise (e.g., advanced HIV) may require imaging before LP even without other contraindications 1
• Immunocompromised patients may have atypical presentations 5

Coagulation Assessment

Examine for bleeding risk:

• Check for signs of coagulopathy (petechiae, ecchymoses, bleeding) 1
• Patients on anticoagulation therapy require special consideration before LP 1
• Platelet count <100 × 10⁹/L is a contraindication to LP (some suggest <50 × 10⁹/L may be acceptable with hematology consultation) 1

Local Examination

Inspect lumbar puncture site:

• Local skin infection at the LP site is an absolute contraindication 1

Critical Decision Algorithm

If ANY of the following are present, obtain blood cultures and start empiric antibiotics IMMEDIATELY before imaging or LP:

• GCS ≤12 or drop >2 points 1
• Focal neurological signs 1
• Papilledema 1
• Abnormal posturing 1, 3
• Recent seizures 1
• Rapidly evolving purpuric rash 1
• Hemodynamic instability 1
• Respiratory compromise 1

The key pitfall is delaying antibiotic therapy while waiting for diagnostic procedures—this increases mortality and morbidity. 1, 3, 2, 6