ILOs 2 Flashcards
How is TB investigated?
The Mantoux test is the main technique used to screen for latent tuberculosis. (interferon-gamma blood test may be used if risk of false negatives)
Chest x-ray
upper lobe cavitation is the classical finding of reactivated TB
bilateral hilar lymphadenopathy
Sputum smear
3 specimens are needed, rapid and inexpensive
stained for the presence of acid-fast bacilli (Ziehl-Neelsen stain)
all mycobacteria will stain positive (i.e. nontuberculous mycobacteria)
Nucleic acid amplification tests (NAAT)
allows rapid diagnosis (within 24-48 hours)
more sensitive than smear but less sensitive than culture
Sputum culture
the GOLD STANDARD investigation
more sensitive than a sputum smear and nucleic acid amplification tests
can assess drug sensitivities
can take 1-3 weeks
How is active TB managed?
Initial phase - first 2 months (RIPE)
Rifampicin
Isoniazid
Pyrazinamide
Ethambutol
Continuation phase - next 4 months
Rifampicin
Isoniazid
How is latent TB managed?
latent tuberculosis is 3 months of isoniazid (with pyridoxine) and rifampicin OR 6 months of isoniazid (with pyridoxine)
Adverse effects of TB drugs?
rifampicin:
potent liver enzyme inducer
hepatitis, orange secretions
flu-like symptoms
isoniazid:
liver enzyme inhibitor
peripheral neuropathy: prevent with pyridoxine (Vitamin B6)
hepatitis, agranulocytosis
pyrazinamide:
hyperuricaemia causing gout
arthralgia, myalgia
hepatitis
ethambutol:
optic neuritis: check visual acuity before and during treatment
Presentation of TB?
Gradually worsening symptoms
Lethargy
Pyrexia and night sweats
Weight loss
Cough +/- haemoptysis
Lymphadenopathy
Erythema nodosum
What are Viral Exanthemas?
An “exanthem” is an eruptive widespread rash
Originally there were six “viral exanthemas”:
First disease: Measles
Second disease: Scarlet Fever
Third disease: Rubella (AKA German Measles)
Fourth disease: Dukes’ Disease
Fifth disease: Parvovirus B19
Sixth disease: Roseola Infantum
How can parvovirus B19 present?
asymptomatic
pancytopaenia in immunosuppressed patients
aplastic crises e.g. in sickle-cell disease
parvovirus B19 suppresses erythropoiesis for about a week
hydrops fetalis
parvovirus B19 in pregnant women can cross the placenta
How does parvovirus B19 cause hydrops fetalis? Mx?
parvovirus B19 in pregnant women can cross the placenta in pregnant women
this causes severe anaemia due to viral suppression of fetal erythropoiesis → heart failure secondary to severe anaemia → the accumulation of fluid in fetal serous cavities (e.g. ascites, pleural and pericardial effusions)
treated with intrauterine blood transfusions
What is the most common causative organism for viral gastroenteritis in kids?
rotavirus
Viral gastroenteritis is a self-limiting condition which lasts <14 days. The most common symptoms include:
Acute diarrhoea: passage of 3 or more stools per day, for a duration of less than 14 days
Watery and non-bloody
blood in the stool = suspicion of Shiga-toxin producing E-coli or Campylobacter infection
Vomiting
Mild fever : >38°C in children under 3 months old should raise suspicion of bacterial pathology
Any child under 3 months old with a temperature >38°C should be urgently admitted to hospital
Abdominal pain
What can cause anaemia in infancy?
Physiologic anaemia of infancy causes most cases of anaemia in infancy.
The other causes of anaemia in infants are:
Anaemia of prematurity
Blood loss
Haemolysis
Twin-twin transfusion
What can cause haemolysis in infancy?
Haemolytic disease of the newborn (ABO or rhesus incompatibility)
Hereditary spherocytosis
G6PD deficiency
What causes physiologic anaemia of infancy?
There is a normal dip in haemoglobin around 6-9 weeks of age in healthy term babies. High oxygen delivery to the tissues caused by the high haemoglobin levels at birth cause negative feedback. Production of erythropoietin by the kidneys is suppressed and there is reduced production of Hb by the bone marrow.
What causes anaemia of prematurity?
Less time in utero receiving iron from the mother
Red blood cell creation cannot keep up with the rapid growth in the first few weeks
Reduced erythropoietin levels
Blood tests remove a significant portion of their circulating volume
What causes haemolytic disease of the newborn?
When a mother is Rhesus negative and the foetus is Rhesus positive, the mother’s immune system will recognise the rhesus D antigen of the foetus as foreign and produce antibodies (sensitisation).
During subsequent pregnancies, the mothers anti-D antibodies can cross the placenta. If that foetus is rhesus positive, these antibodies attach themselves to the red blood cells of the fetus and causes the immune system of the fetus to attack = haemolysis, causing anaemia and high bilirubin levels
How can haemolytic disease of the newborn be investigated?
direct Coombs test (DCT) can be used to check for immune haemolytic anaemia
Give some sxs of anaemia
Tiredness
Shortness of breath
Headaches
Dizziness
Palpitations
Worsening of other conditions
Give some signs of anaemia
Pale skin
Conjunctival pallor
Tachycardia
Raised respiratory rate
Signs of specific causes of anaemia:
Koilonychia: iron deficiency
Angular chelitis :iron deficiency
Atrophic glossitis:iron deficiency
Brittle hair and nails : iron deficiency
Jaundice: haemolytic anaemia
Bone deformities: thalassaemia
How can anaemia in children be investigated?
FBC for haemoglobin and MCV
Reticulocyte count
Bilirubin (raised in haemolysis)
Ferritin (iron deficiency)
B12 and folate
Blood film
Direct Coombs test (autoimmune haemolytic anaemia)
Haemoglobin electrophoresis (haemoglobinopathies)
What can cause hyposplenism?
splenectomy
sickle-cell
coeliac disease, dermatitis herpetiformis
Graves’ disease
SLE
What may be seen on a blood film of a hyposplenic patient?
Howell-Jolly bodies
siderocytes
What are the risk factors for developing lymphoma?
EBV
Immunosuppression
Solid organ transplant
Prev cancer tx
How may lymphoma present?
Weight loss, Night sweats, Fevers (‘B’ sxs, associated with worse prognosis)
Non-tender lymphadenopathy is the most common examination finding
Mediastinal lymphadenopathy may present with cough, wheeze or other difficulty in breathing, and occasionally SVC obstruction or airway compromise
ddx for lymphoma?
reactive lymphadenopathy
leukaemia
metastatic cancer
How can lymphoma be investigated?
FBC
U&Es: tumour lysis syndrome can occur before treatment begins in lymphomas with rapid cell turnover
LDH (lactate dehydrogenase) levels are usually elevated
Imaging
USS
CXR may be required if there are symptoms of mediastinal node involvement.
A full body CT to determine extent of disease
Biopsy
Lymph node biopsy
How can lymphoma be staged?
Lugano Classification
Stage 1: single group of lymph nodes or a single organ
Stage 2: 2 or more groups of lymph nodes or organs on the same side of the diaphragm
Stage 3: lymph nodes or organs on both sides of the diaphragm
Stage 4: diffuse involvement of lymph nodes and organs such as the liver and bones
Treatment if lymphoma is with chemotherapy and possibly radiotherapy. Describe the prognosis and potential complications
The majority of children will recover completely, with Hodgkin’s lymphoma carrying a more favourable prognosis than non-Hodgkin’s lymphoma
Complications:
tumour lysis syndrome
neutropenia
alopecia
sub-fertility
Outline the pathophysiology of sickle cell disease
autosomal recessive condition affecting the gene for beta-globin on chromosome 11
One abnormal copy of the gene = sickle-cell trait
Two abnormal copies = sickle-cell disease
abnormal variant called haemoglobin S (HbS) results in sickle-shaped red blood cells.
Give some complications of sickle cell disease
Anaemia
Increased risk of infection
CKD
Sickle cell crises
Acute chest syndrome
Stroke
Avascular necrosis in large joints such as the hip
Pulmonary hypertension
Gallstones
Priapism (painful and persistent penile erections)
What is sickle cell crisis?
when the flow of blood is blocked to an area because the sickled cells have become stuck in the blood vessel- often very painful
can occur spontaneously or triggered by dehydration, infection, stress or cold weather
supportive mx