Passmed MRCP Flashcards
The most common causes of a sudden painless loss of vision are as follows:
The most common causes of a sudden painless loss of vision are as follows:
ischaemic/vascular (e.g. thrombosis, embolism, temporal arteritis etc). This includes recognised syndromes e.g. occlusion of central retinal vein and occlusion of central retinal artery
vitreous haemorrhage
retinal detachment
retinal migraine
Central retinal vein occlusion
incidence increases with age, more common than arterial occlusion
causes: glaucoma, polycythaemia, hypertension
severe retinal haemorrhages are usually seen on fundoscopy
Central retinal artery occlusion
due to thromboembolism (from atherosclerosis) or arteritis (e.g. temporal arteritis)
features include afferent pupillary defect, ‘cherry red’ spot on a pale retina
Central retinal vein occlusion
sudden painless loss of vision, severe retinal haemorrhages on fundoscopy
emporal lobe seizure
May occur with or without impairment of consciousness or awareness
An aura occurs in most patients
typically a rising epigastric sensation
also psychic or experiential phenomena, such as dejà vu, jamais vu
less commonly hallucinations (auditory/gustatory/olfactory)
Seizures typically last around one minute
automatisms (e.g. lip smacking/grabbing/plucking) are common
Frontal lobe (motor) seizure
Head/leg movements, posturing, post-ictal weakness, Jacksonian march
Parietal lobe (sensory) seizure
Paraesthesia
Hashimoto’s thyroiditis is associated with the development of
MALT lymphoma
Hashimoto’s thyroiditis features
Features
features of hypothyroidism
goitre: firm, non-tender
anti-thyroid peroxidase (TPO) and also anti-thyroglobulin (Tg) antibodies
Hashimoto’s thyroiditis Associations
Associations
other autoimmune conditions e.g. coeliac disease, type 1 diabetes mellitus, vitiligo
Hashimoto’s thyroiditis is associated with the development of MALT lymphoma
Porphyria cutanea tardaFeatures
Features
classically presents with photosensitive rash with blistering and skin fragility on the face and dorsal aspect of hands (most common feature)
hypertrichosis
hyperpigmentation
Porphyria cutanea tarda I + M
nvestigations
urine: elevated uroporphyrinogen and pink fluorescence of urine under Wood’s lamp
serum iron ferritin level is used to guide therapy
Management
chloroquine
venesection
preferred if iron ferritin is above 600 ng/ml
Cinacalcet
calcimimetic - a drug that ‘mimics’ the action of calcium on tissue by allosteric activation of the calcium-sensing receptor
Primary hyperparathyroidism
is caused by excess secretion of PTH resulting in hypercalcaemia. It is the most common cause of hypercalcaemia in outpatients and is often diagnosed following an incidental finding of an elevated serum calcium concentration. In 85% of cases a parathyroid adenoma is responsible.
Causes of primary hyperparathyroidism
85%: solitary adenoma
10%: hyperplasia
4%: multiple adenoma
1%: carcinoma
Gastroparesis
occurs secondary to autonomic neuropathy
symptoms include erratic blood glucose control, bloating and vomiting
management options include metoclopramide, domperidone or erythromycin (prokinetic agents)
Chronic diarrhoea
often occurs at night
Gastro-oesophageal reflux disease
caused by decreased lower esophageal sphincter (LES) pressure
Oesophageal cancer Adenocarcinoma
Lower third - near the gastroesophageal junction
GORD
Barrett’s oesophagus
smoking
obesity
Oesophageal cancer
Squamous cell cancer
Upper two-thirds of the oesophagus
Myeloma CRABBI
Use the mnemonic CRABBI:
Calcium
hypercalcaemia
primary factor: due primarily to increased osteoclastic bone resorption caused by local cytokines (e.g. IL-1, tumour necrosis factor) released by the myeloma cells
much less common contributing factors: impaired renal function, increased renal tubular calcium reabsorption and elevated PTH-rP levels
this leads to constipation, nausea, anorexia and confusion
Renal
monoclonal production of immunoglobulins results in light chain deposition within the renal tubules
this causes renal damage which presents as dehydration and increasing thirst
other causes of renal impairment in myeloma include amyloidosis, nephrocalcinosis, nephrolithiasis
Anaemia
bone marrow crowding suppresses erythropoiesis leading to anaemia
this causes fatigue and pallor
Bleeding
bone marrow crowding also results in thrombocytopenia which puts patients at increased risk of bleeding and bruising
Bones
bone marrow infiltration by plasma cells and cytokine-mediated osteoclast overactivity creates lytic bone lesions
this may present as pain (especially in the back) and increases the risk of pathological fractures
Infection
a reduction in the production of normal immunoglobulins results in increased susceptibility to infection
Hereditary angioedema screening between tests
C4
Glucagon-like peptide-1 (GLP-1) mimetics (e.g. exenatide
increase insulin secretion and inhibit glucagon secretion. One of the major advances of GLP-1 mimetics is that they typically result in weight loss
Dipeptidyl peptidase-4 (DPP-4) inhibitors (e.g. Vildagliptin, sitagliptin)
ey points
dipeptidyl peptidase-4, DPP-4 inhibitors increase levels of incretins (GLP-1 and GIP) by decreasing their peripheral breakdown
oral preparation
trials to date show that the drugs are relatively well tolerated with no increased incidence of hypoglycaemia
do not cause weight gain
NICE guidelines on DPP-4 inhibitors
NICE suggest that a DPP-4 inhibitor might be preferable to a thiazolidinedione if further weight gain would cause significant problems, a thiazolidinedione is contraindicated or the person has had a poor response to a thiazolidinedione
Hypokalaemia and hypertension
Hypokalaemia with hypertension
Cushing’s syndrome
Conn’s syndrome (primary hyperaldosteronism)
Liddle’s syndrome
11-beta hydroxylase deficiency*
IgA nephropathy Associated conditions
Associated conditions
alcoholic cirrhosis
coeliac disease/dermatitis herpetiformis
Henoch-Schonlein purpura
Pathophysiology
IgA nephropathy
Pathophysiology
thought to be caused by mesangial deposition of IgA immune complexes
there is considerable pathological overlap with Henoch-Schonlein purpura (HSP)
histology: mesangial hypercellularity, positive immunofluorescence for IgA & C3
Differentiating between IgA nephropathy and post-streptococcal glomerulonephritis
post-streptococcal glomerulonephritis is associated with low complement levels
main symptom in post-streptococcal glomerulonephritis is proteinuria (although haematuria can occur)
there is typically an interval between URTI and the onset of renal problems in post-streptococcal glomerulonephritis
Management IgA nephropathy
isolated hematuria, no or minimal proteinuria (less than 500 to 1000 mg/day), and a normal glomerular filtration rate (GFR)
no treatment needed, other than follow-up to check renal function
persistent proteinuria (above 500 to 1000 mg/day), a normal or only slightly reduced GFR
initial treatment is with ACE inhibitors
if there is active disease (e.g. falling GFR) or failure to respond to ACE inhibitors
immunosuppression with corticosteroids
Phenytoin MoA
Mechanism of action
binds to sodium channels increasing their refractory period
Phenytoin AE
Phenytoin is associated with a large number of adverse effects. These may be divided into acute, chronic, idiosyncratic and teratogenic. Phenytoin is also an inducer of the P450 system.
Acute
initially: dizziness, diplopia, nystagmus, slurred speech, ataxia
later: confusion, seizures
Chronic
common: gingival hyperplasia (secondary to increased expression of platelet derived growth factor, PDGF), hirsutism, coarsening of facial features, drowsiness
megaloblastic anaemia (secondary to altered folate metabolism)
peripheral neuropathy
enhanced vitamin D metabolism causing osteomalacia
lymphadenopathy
dyskinesia
Monitoring
Phenytoin
adjustment of phenytoin dose
suspected toxicity
detection of non-adherence to the prescribed medication