Miscellaneous Flashcards
Carpal tunnel syndrome - definition
- Most common entrapment neuropathy (prevalence about 1 in 25)
- compression of the median nerve in the carpal tunnel. Typical symptoms include numbness and tingling mainly in the thumb/index/middle and half of ring finger, aching and pain in the anterior wrist and forearm, and clumsiness in the hand.
- raised pressure within the carpal tunnel and ischaemia of the median nerve
CTS - clinical features
- RF: ge over 30 years, female sex, high BMI
- numbness of hand(s) (Dominant hand is usually the first and worst affected)
- night-time worsening (Waking up with paraesthesias/ pain in hand/wrist, and shaking the hand to relieve)
- numbness in median nerve distribution (Should be sparing of thenar eminence and ulnar/radial area)
Components of the carpal tunnel
- flexor digitorum profundus (four tendons)
- flexor digitorum superficialis (four tendons)
- flexor pollicis longus (one tendon)
- Median nerve
CTS - investigations
- EMG = focal slowing of conduction velocity in the median sensory nerves across the carpal tunnel
- negative Hoffman’s sign (flick middle finger, watch for flexion of index/ thumb = UMN lesion) can distinguish
from degenerative cervical myelopathy as CTS is LMN
CTS - management
- Wrist splints worn every night for 1 month.
- Activities that particularly provoke symptoms should be limited or modified.
- consider NSAIDs for pain
- corticosteroid injection
- surgical decompression (flexor retinaculum division)
Meningitis - viral
Viral meningitis is the most common cause of aseptic meningitis. Causative agents include human enteroviruses (most commonly), HSV, mumps, arboviruses such as West Nile, HIV, and (rarely) influenza. However, it is typically self-limiting without serious sequelae.
Viral meningitis - features
- RF: infants and young children, older people, young adults, and exposure to insect vectors, unvaccinated for mumps headache nausea and vomiting photophobia neck stiffness fever
Meningitis - bacterial
Bacterial meningitis is rare but serious. Streptococcus pneumoniae , Haemophilus influenzae type b (Hib), and Neisseria meningitidis are the predominant causative pathogens in both adults and children.
Bacterial meningitis - risk factors
- age ≤5 years or ≥65 years
- crowding, exposure to pathogens
- non-immunised infants
- immunodeficiency, asplenia or hyposplenia
- cranial anatomical defects
- ventriculoperitoneal shunt
- cancer
- HIV/AIDS
- cochlear implants
- sickle cell disease
Bacterial meningitis - features
headache neck stiffness (+ nuchal rigidity - resistance to passive neck flexion fever altered mental status, confusion photophobia vomiting seizures infants: hypothermia, irritability, lethargy, poor feedings, apnoea, high-pitched cry
Meningitis - what signs could be seen O/E?
- rash (in both but more common in viral)
More common in bacterial:
- Kernig’s sign (severe stiffness of the hamstrings causes an inability to straighten the leg when the hip is flexed to 90 degrees)
- Brudzinski’s sign (Severe neck stiffness causes a patient’s hips and knees to flex when the neck is flexed)
Bacterial meningitis - investigations
- LP for CSF count = CSF pleocytosis, with WBC count >10⁹/L, predominance of polymorphonuclear leukocytes aka NEUTROPHILS
- CSF protein = usually elevated (>0.5 g/L).
- CSF glucose: low = is <45 mg/dL (2.5 mmol/L), or <40% of simultaneously measured serum glucose
- CSF gram stain reveals organism in 80% cases
- CSF culture
- antigen detection in CSF (eg Neisseria meningitidis)
- blood culture
- FBC = leukocytosis, anaemia, thrombocytopenia
- serum CRP = high
- serum electrolytes, glucose = acidosis, low Ca/Mg, or hyper/hypoglycaemia
- coagulation profile (PT, INR, activated PTT, fibrinogen, fibrin degradation products) = evidence of DIC (prolonged thrombin time, elevated fibrin degradation products or D-dimer, low fibrinogen or antithrombin)
- CT head = normal or raised ICP
Viral meningitis - investigations
- CSF microscopy = WBC count >5 cells/mm^3. Lymphocytosis
- CSF gram stain and culture both negative
- CSF protein normal or mildly elevated
- CSF glucose usually normal
- CT/MRI head = normal or raised ICP. exclude brain abscess and encephalitis (HSV-1 encephalitis normally causes lesions in temporal lobe)
Meningitis - initial management
- LP usually performed before antibiotic administration
- If the patient is very ill, is immunocompromised, or has received prior Abx, empirical antibiotic Tx is justified
- need to cover group B streptococci, Listeria , and coliforms
- local protocols and guidelines should be consulted for selection of antibiotic therapy
- 1st line Abx normally Cefotaxime IV
- adjunct dexamethasone (evidence that reduces hearing loss and neurological sequelae) - reduce ICP
- A diagnosis of viral meningitis will allow antibiotics to be stopped
- Amoxicillin (or ampicillin) if listeria is suspected
- Aciclovir - pts with confusion/meningoencephalitis (need to cover for HSV and VZV)
- elderly: combine vancomycin + ceftriaxone + ampicillin
Meningitis managment- confirmed viral aetiology
For all pathogens except HSV, varicella zoster, CMV:
- supportive care: adequate hydration, antipyretics for fever, anti-emetics if vomiting, analgesia for headaches
- HSV or varicella zoster = aciclovir or valaciclovir + supportive care
- CMV = ganciclovir or valganciclovir + supportive
- recurrent viral meningitis (Mollaret’s meningitis, commonly due to HSV-2): consider antiviral
