General Medicine Flashcards

1
Q

Encapsulated bacteria (name 3)

A

Streptococcus pneumoniae
Haemophilus influenzae
Neisseria meningitidis

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2
Q

Risky organisms for post-splenectomy patients (other than encapsulated bacteria)

A

Malaria (+babesiosis)
E. coli + pseudomonas aeruginosa
Capnocytophagia canimorsus

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3
Q

What features suggest immunodeficiency?

A

Severe Persistent Unusual Recurrent infections.

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4
Q

Post-splenectomy management?

A

Antibiotic prophylaxis for 2y
Vax: Hib, niesseria, pneumococcus
Pt education re signs/symptoms of infections
Avoid malaria areas

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5
Q

Definition of Pyrexia of unknown origin

A

Fever >38.3 (>1 occasion) + >3w duration +no diagnosis despite >1w inpt investigations.

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6
Q

PUO subtypes

A

Classic
Nosocomial
Immunodeficient
HIV-related

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7
Q

Common causes of PUO

A

1/3-1/2 infections
1/4- neoplasms
1/10- CTD

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8
Q

Test for encapsulated bacteria?

A

Quellung reaction (capsular swelling)

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9
Q

How do we test for C. Dificile?

A

Detect toxin.

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10
Q

Appropriate tests for ?legionella

A

Detection of antigen in urine: positive early in disease but only detects serogroup 01.
Detect antibody serology: delay in diagnosis
Bronchoalveolar Lavage: invasive, low yield, but detects all stereotypes (NB special media needed)
Cultures: blood/sputum = unhelpful

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11
Q

What does CD4+ T cell count predict in HIV?

A

Current susceptibility to opportunistic infections

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12
Q

What do you measure in HIV to assess stage of disease?

A

CD4+ T cell count

Plasma HIV RNA load

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13
Q

What does plasma HIV RNA load predict?

A

The rate of decline in CD4+ T cell count.

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14
Q

CD4+ count: 600. Likely infections present?

A

No infections seen if >500

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15
Q

CD4 T cell count 200-500 likely infections?

A

HSV
VZV
Oral candida
Progressive stage of disease

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16
Q

CD4+ T cell count if pneumocystis infection?

A

CD4+ <200

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17
Q

CD4+ count if oral candida?

A

200-500

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18
Q

CD4 count when crytococcus infection

A

<200

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19
Q

Infections likely when CD4+ T cell count <200?

A
TB
Pneumococcus
Salmonella
Pneumocystis
Cryptococcus
Oesophageal candida
Toxoplasma
Cryptosporidium
Isospora
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20
Q

Infections likely when CD4+ <50?

A

Mycobacterium avium intracellulare
Progressive Multifocal Leuko-Encephalopathy
CMV

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21
Q

CD4+ cell count if HIV and CMV infection?

A

<50

22
Q

CD4 cell count if progressive multifocal leuko-encephalopathy?

A

<50

23
Q

How to diagnose HIV?

A

Screening assay: ELISA for anti-HIV antibodies and antigens
Confirmation: ELISA + RIBA (reverse line blot assay)
NB. Follow-up sample to rule out error in sample collection.

24
Q

What is successful treatment in HIV?

A

At least 10x decrease in viral load at 8w

No detectable virus (<50 copies/ml) at 4-6m.

25
Q

Features of primary infection in HIV?

A

Symptoms in >50%. 2-6w after infection for 1-2w.
Transient fall in CD4+ (<500)
Sustained rise in CD8+
(No antibody) = ‘window period’

26
Q

What stage is the pt at if CD4+ 300, and viral load is ~20k? What would you expect in the CD8+ cells?

A

Asymptomatic/progressive phase.
CD4+ slightly reduced-normal. (Impaired function)
Strong HIV-specific CD8+ CTL response.
Chronic activation of T and B cell lineages.

27
Q

Features of transition to advanced disease?

A

Increased viral replication (viral load)
Progressive decline in CD4+ count and function
Reduced CD8+ CTL response
Destruction of lymph node architecture.

28
Q

How do we measure CD4+ cell count? Causes of false results?

A

Fluoro-tagged monoclonal antibody and flow cytometry.
Most accurate if measured on day of sampling.
Refrigeration = CD4+ shedding and spuriously low count
Intercurrent illness = transient lymphopaenia
Low CD4+ count also seen in sarcoid, TB, serious bacterial infections.

29
Q

How to diagnose acromegaly?

A

GH secretion is pulsatile.

OGTT and synchronous [GH]. Expect GH to be suppressed to <2mU/l.

30
Q

How to test for adrenal failure?

A

Short synACTHen test: baseline cortisol at t=0. Give 250mcg of ACTH at 30min. Measure plasma cortisol at 60min.
Adrenal failure if <550nmol/l

31
Q

How to distinguish primary and secondary adrenal failure?

A

Long SynACTHen test: give 1mg ACTH and measure cortisol after 24h. Primary adrenal failure if <900nmol/l. (Adrenals diseased themselves and not responsive)
Secondary if >900 (atrophic adrenals have had time to recover after long period without stimulation from pituitary failure).

32
Q

How to distinguish causes of microcytic anaemia?

A

Anaemia of chronic disease: raised ferritin
Thalassaemia: normal ferritin
Fe deficient anaemia: reduced ferritin (raised TIBC, reduced serum Fe)
NB. Ferritin also raised 2o to inflammation (acute phase protein)

33
Q

Causes of raised bence-jones protein?

A

Multiple myeloma
Waldenstrom’s macroglobulinaemia
Amyloid light chain amyloidosis

34
Q

Features of Wilson’s disease:

A

Low plasma caeruloplasmin levels.
Autosomal recessive.
Defect in copper transporter (copper -> caeruloplasmin) caeruloplasmin degraded in blood.
S+S: neurological, psychiatric, iris Keizer-Fleischer rings.

35
Q

Features of Paget’s disease?

A

Impaired bone remodelling, larger new bone that is weaker and prone to fracture.
S+S: extreme bone pain, bowing, chalk-stick frx, bossing of skull, CNVIII palsy/hearing loss.
X-ray: lytic and sclerotic lesions of bones

36
Q

Biochemistry of Paget’s disease?

A

Ca, Phosphate, vit D, PTH = normal

Alk phos = raised due to increased turnover

37
Q

Features of primary hyperparathyroidism?

A

Increased PTH
Increased ALP (increased bone resorption)
Hypercalcaemia (increased Ca resorption in kidneys and by gut via activation of vit D/calcitriol)
Normal PO4 (excreted by kidneys)

38
Q

Causes of secondary hyperparathyroidism?

A

release of PTH due to low Ca due to non-parathyroid pathology e.g. CKD.

39
Q

Features of pseudohypoparathyroidism?

A

Genetic resistance to PTH. High PTH and phosphate but hypocalcaemic.

40
Q

Ca/PO4/PTH/AlkPho in osteoporosis?

A

Normal. Just reduced bone density

41
Q

18m, F. Mother concerned by brittle hair and inability to walk. 2 previous convulsions. Likely diagnosis?

A

Homocystinuria

42
Q

How to confirm a diagnosis of Cushing’s?

A

24h urinary free cortisol excretion (at least 3 separate collections)
Loss of diurnal cortisol variation (serum/saliva)
Overnight dexamethasone suppression test (1mg at 2300h, measure serum cortisol at 0900h)
Low dose dexamethasone suppression test (0.5mg every 6h for 8 doses)

43
Q

Difference between cushing’s disease and syndrome?

A

Cushing’s disease = pituitary dependent Cushing’s syndrome.

44
Q

Side effects of Rifampicin?

A
Orange secretions
Altered LFTs (hepatotoxicity)
Potent enzyme inducer
45
Q

Side effects of Isoniazid?

A
Peripheral neuropathy (prevented with Vit B6/pyridoxine)
Agranulocytosis
Myelofibrosis
Hepatitis
Enzyme inducer
46
Q

Pyrazinamide side effects?

A

Gout (due to Hyperuricaemia)

Hepatitis

47
Q

Ethambutol side effects?

A

R-G colour blindness

Altered visual acuity (check before/after)

48
Q

How do you monitor treatment of TB?

A

Direct observed therapy (2-3 times per week)
Sputum analysis for TB weekly until conversion.
Failure of treatment if blood culture positive after 2m.
Monitor for drug toxicty

49
Q

1st line tests for ?immunodeficiency in young child

A
FBC and white cell differential
IgGAM
IgE
functional antibodies
lymphocyte subsets
50
Q

1st line tests for older child with? immunodeficiency

A
FBC and white cell differential
IgGAM
IgE
functional antibodies
lymphocyte subsets
IgG subclasses
B cell maturation