Normal pressure hydrocephalus (NPH)

Vignette says a 75 year old male with a history of hypertension and diabetes presents to the neurology clinic with complaints of difficulty walking, memory problems and urinary incontinence over the past year; His wife notes that he has been more forgetful recently, often misplacing items and repeating conversations, although he still recognizes family members and can performs daily tasks; He wife also notes that recently, he started urinating on himself frequently before reaching the bathroom; The patient exhibits a slow, broad-based gait with difficulty initiating step movement, and a tendency to fall forward (also known as "magnetic gait"); There are no signs of increased intracranial pressure (e.g. headache, vomiting, papilledema); Examination shows normal deep tendon reflexes with no focal neurologic deficits; CT scan of head shows enlargement of the lateral ventricles without significant cortical atrophy.; Lumbar puncture shows normal opening pressure; Diagnosis?

Diagnosis is normal pressure hydrocephalus. 

Normal pressure hydrocephalus (NPH) is a chronic dilatation of the cerebral ventricles with a normal lumbar puncture opening pressure.

Pathophysiology:- Failure of reabsorption of CSF by the arachnoid granulations.

Presents with urinary incontinence, ataxia, dementia (i.e. "wet, wobbly, and wacky").

The patient shows significant improvement in symptoms after a CSF removal of about 30-50 mL.

Diagnosis:-
1. Lumbar puncture shows normal opening pressure with large volume lumbar tap. 
2. CT scan of head shows enlargement of the lateral ventricles without significant cortical atrophy.
3. MRI shows ventricular enlargement disproportionate to cortical atrophy.

Management:- Ventriculoperitoneal (VP) shunt.

Pneumocystis jirovecii

Vignette says a 33 year old male with a known history of HIV presents to the emergency department with a 7 days history of progressive shortness of breath, dry cough and fever; His CD4 count is 90 cells/μL despite being on antiretroviral therapy (ART); Vital signs show blood pressure of 110/70 mm of Hg, pulse rate of 108 bpm, respiratory rate of 22 breaths/min, oxygen saturation of 92% in RA and temperature of 100.9 F;  Lung auscultation reveals bilateral crackles; There is no evidence of peripheral edema or lymphadenopathy; CBC shows white blood cell count of 6,000 cells/mm3 with a mild lymphopenia; Chest X-ray shows bilateral diffuse reticulonodular infiltrates and CT scan of the chest shows ground-glass opacities, especially in the perihilar regions; ABG analysis shows pH of 7.48, PaCO2 of 30 mmHg, PaO2 of 50 mmHg and HCO3- of 22mEq/L; Microscopic examination of bronchoalveolar lavage (BAL) with silver stain shows disc shaped yeast; Diagnosis?

Diagnosis is Pneumocystis jirovecii.

Pneumocystis jirovecii pneumonia is caused by Pneumocystis jirovecii.

Etiologies:-

1. AIDS (i.e. CD4 < 200 cells/μL)

2. Immunosuppressive medications (e.g. chronic glucocorticoids, immunosuppressant agents)

Presents with fever, dyspnea and dry cough.

Diagnosis:-

1. Chest x-ray shows diffuse bilateral reticulonodular infiltrates.

2. LDH is elevated.

3. Microscopic examination of BAL with silver stain shows disc shaped yeast.

Management:-

1. Trimethoprim-sulfamethoxazole + Steroids; Indications for steroids in Pneumocystis

pneumonia is A-a gradient >35 mm Hg, or PaO2 <70, or SaO2 <92% in RA.

2. ART therapy.

Patients with AIDS (i.e. CD4 <200 cells/μL) and those on chronic glucocorticoid therapy

generally receive primary prophylaxis against Pneumocystis jirovecii pneumonia with

trimethoprim-sulfamethoxazole.

Guillain-Barré Syndrome (GBS)

Vignette says a 42 year old male presents to the emergency department with a progressive weakness in his both legs along with tingling sensation in his feet over the past 4 days; He also suggests that the weakness has gradually spread upwards in past 24 hours, now affecting his arms and causing difficulty in swallowing; He states that he had developed bloody diarrhea 2 weeks back after consumption of poultry products; On examination he has bilateral lower limb weakness with MRC grade of 3/5 in both limbs along with absent deep tendon reflexes in both knees and ankles; CSF shows elevated protein with normal cell count; Electrophysiologic studies show prolonged latency, decreased motor nerve conduction velocities and amplitude; MRI of the brain and spinal cord is normal; Serology shows Campylobacter jejuni infection; Diagnosis?

Diagnosis is GBS following campylobacter infection.

Guillain-Barré Syndrome (GBS) is an autoimmune demyelinating disorder of peripheral nervous system that usually following gastrointestinal or respiratory infections; Molecular mimicry between microbe and nerve antigens; Commonly associated with Campylobacter jejuni, Mycoplasma pneumoniae, cytomegalovirus, Epstein Barr, influenza A, Zika, HIV.

Presents with bilateral symmetric progressive, ascending flaccid paralysis or weakness of limbs, decreased deep tendon reflexes and distal numbness or dysesthesias (i.e. feeling of pins and needles) of extremities.

Diagnosis:-
1. CSF shows elevated protein with normal cell count (i.e. albuminocytologic dissociation).
2. Electrophysiologic studies (EMG/NCV) show demyelination in peripheral nerves (i.e. prolonged latency, decreased motor nerve conduction velocities and amplitude).
3. MRI of the brain and spinal cord is usually normal or shows enhancement of anterior nerve roots/cauda equina.
4. Spirometry (i.e. FVC) is used to assess pulmonary function. 

Treatment:-
1. Intravenous immunoglobulin (i.e. IVIG) or Plasmapheresis is the mainstay of treatment. 
2. Supportive measures like DVT prophylaxis, Respiratory monitoring and Physical therapy.

Figure:- Guillain-Barré Syndrome