Congenital Hypothyroidism

Background

  • Lack of thyroid hormones from birth
  • Can result in irreversible neurodevelopmental and growth problems if not recognised early
  • ~1 in 4000 births; more common in girls (2:1)
  • Most commonly due to thyroid gland defects (75%- usually spontaneous/idiopathic) e.g. missing, small or poorly developed gland
    • Other causes include dysfunctional thyroid hormone production (10% and usually inherited); hypothalamic/pituitary dysfunction (5%)
    • Transient hypothyroidism is most often caused by maternal drugs or antibodies e.g. in maternal hashimoto’s or carbimazole

Presentation

  • Similarly to adults-
    • lack of energy e.g. sleepy/floppy; poor appetite (lack of feeds); skin/hair changes (dry); bradycardia, hyporeflexia, constipation etc

Diagnosis

  • Often diagnosed by the Guthrie Heel Prick test (along with phenylketonuria)

Management

  • Depends on cause but thyroid hormone replacement
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Pyoderma Gangrenosum

Background/Epidemiology

  • Rare but serious skin disease; may have an underlying associated condition e.g. Ulcerative colitis/Crohn’s disease (about 2% of IBD patients get PD and about 30% of PD patients have/get IBD); polyarthritis or gammopathy
  • Occurs usually between 20-50, female preponderance

Presentation

  • Begins classically as a collection of pustules/nodules which break down to form a rapidly enlarging ulcer, which has a raised violaceous border and boggy, necrotic base.
    • Often very painful; more common on the lower limbs and trunk; may be associated with trauma (including biopsy)
    • Can progress rapidly or more slowly

Investigations

  • Swabs for culture/sensitivity if infected
  • Workup for IBD
    • Bloods- FBC/inflammatory markers, autoantibodies (p-ANCA)
  • Pathergy test (skin-prick causes a pustule/nodule) may be positive

Management

  • Wound care with steroids (potent topical and systemic)

Myositis Ossificans

Background

  • Benign process characterised by heterotrophic ossification within large muscle groups
  • It is important because it often mimics more aggressive pathological conditions
  • Most common type is MO circumscripta – where new bone appears usually after trauma (common in young adults and paraplegics)
    • Other types/related conditions include MO progressiva (rare inherited disorder- progressive and ultimately fatal); panniculitis ossificans (similar to MOC but in subcut tissues)

Pathology

  • MO is extraosseous bone formation without inflammation which occurs in muscle.  It has zonal organisation
    • Peripheral well organised mature/lamellar bone
    • Intermediate osteoid region
    • Central, immature non-ossified cellular focus
  • The histopathology can appear similar to osteosarcoma- so a clear history is important to avoid inappropriate management

Investigation

  • Xray- lesion of dense peripheral calcification (other imaging may also be useful e.g. CT/MRI)

Management

  • Observation if otherwise asymptomatic, surgery (resection) if painful

Presentation

  • Painful, tender, enlarging mass, most commonly in the large muscles of the extremities, often following trauma

Bisphosphonates

Background

  • Analogues of inorganis pyrophosphate.  Inhibit bone resorption by inducing apoptosis of osteoclasts (>osteoblasts)
    • Used in the treatment of osteoporosis (including secondary to steroid use) (mainly alendronate) as well as Paget’s (risedronate) and bone destruction due to malignancy

Side effects/safety

  • GI adverse effects (mainly oesophagitis; also gastritis, dyspepsia, oesophageal reflux, nausea, abdominal pain, diarrhoea)
    • Recommend taking with a large glass of water either sitting up or standing; no food or other medications should be taken around that time if at all possible
    • Contraindicated if there are oesophageal motility disorders; inability to stand or sit upright; hypocalcaemia- (this must be corrected prior to starting)
      • Most patients on bisphosphonates should be co-prescribed calcium and vit D supplementation
  • Musculoskeletal pain, rash and headache are not uncommon
  • Uveitis/Iritis is a rare side effect
  • Osteonecrosis of the jaw is a very rare but serious side effect (more likely in patients on high doses e.g. cancer patients)
    • Dental procedures must be considered with caution
  • Atypical fractures (particularly of the hip) are also rare but serious, and patients who develop new hip/tight/groin/leg pain should be considered for an x-ray to evaluate this possibilit
  • NB IM injection may cause flu-like illness- co-prescribe paracetamol or ibuprofen may help

Measure bone mass density at 3-5 years

Doxycycline

Mechanism of Action

  • Member of the tetracycline family of antibiotics.  Act by inhibiting bacterial protein synthesis.  Mainly useful in treating intracellular bacterial pathogens e.g. Chlamydia, Mycoplasma; but can also be useful at treating H influenzae and Strep pneumoniae
    • Used in treating pneumonia (particularly in older patients)
  • Long acting (half life 18-22 hours), oral tetracycline

Pharmacology

  • Circulates mainly protein bound (90%)
  • Metabolised mainly by the liver and excreted in the bile/urine

Contraindications

  • Pregnancy, SLE, Myaesthenia gravis, porphyria

Side effects

  • Photophobia- avoid sun beds/overexposure to sun; use protection
  • Stomach upset/indigestion/abdominal pain
  • Diarrhoea
  • Headache
  • Thrush
  • Throat irritation (take with a large glass of water; sitting upright/standing)
  • NB Take doxycycline eithe 1 hour before or 2 hours after eating or taking any antacids, iron tablets, (basically medications containing metal compounds)
  • Can also cause liver toxicity; benign intracranial hypertension

Myocarditis

Background

  • Acute inflammatory condition affecting the myocardium
    • Can be infectious, toxic or autoimmune
      • Commonly Coxsackie, Influenza A and B
        • May occur several weeks after initial symptoms
      • Can be associated with Lyme’s disease
      • Drugs that can cause it include
        • Cocaine, lithium, doxorubicin (direct injury)
        • Penicillins/sulphonamides, lead and carbon monoxide (toxic/systemic reaction)
      • Autoimmune conditions include SLE and RA
    • Risk increased in immunosupressed patients (including steroid-use and radiation); previous myocardial damage and exercise
  • Infectious type more common in otherwise healthy younger individuals and can be a cause of unexpected death in this group

Presentation

  • Fulminant myocarditis often follows a viral prodrome (fever, lethargy, myalgia, headache etc) and results in severe heart failure or cardiogenic shock (i.e. fatigue/shortness of breath worse on exertion; chest pain; palpitations; collapse)
  • Acute myocarditis presents over a longer time period with features of heart failure (can lead to cardiomyopathy)
  • Chronic myocarditides (active and persistent) are rare but may cause chest pain/palpitations without LVD.

Investigation

  • ECG changes common but non-specific
    • T wave inversions and ST changes (elevation or depression)
    • Arrhythmias (more characterisitically ventricular)
    • There may also be signs of pericarditis (myopericarditis)
  • Troponins may be raised early on
  • Echo may show LV dysfunction
  • Cardiac MRI can reveal areas of cardiac inflammation or infiltration and is usually diagnostic, although endomyocardial biopsy can be used to confirm the diagnosis (rare)

Management

  • Most cases self-limiting
  • Avoid over-exertion (risk of arrhythmia)
  • If the patient has a history of GCA, steroids may be useful

Giant cell arteritis/Temporal Arteritis

Background/Epidemiology

  • GCA is a chronic vaculitis of medium-large sized arteries and arch of the aorta.
  • One of the most commoon causes of acute blindness (permanent/irreversible)
    • visual loss occurs in up to 20% of patients with GCA (delayed diagnosis and treatment
    • MEDICAL EMERGENCY- requires urgent referral to ophthalmology or rheumatology

Presentation

  • Acute onset, unilateral (often temporal) headache
    • Scalp pain (may cause problems combing hair
  • Jaw and tongue claudication (difficulty chewing)
  • Symptoms of polymyalgia rheumatica e.g. pain, stiffness, tenderness in procximal muscle groups (50%)
  • Constitutional symptoms e.g. fever, weight loss, tiredness
  • Visual symptoms
    • Classically ‘curtain’ like loss of visual field (amaurosis fugax), although blurring/double vision also possible
  • Other symptoms of claudication (large vessel involvement) e.g. paraesthesia or pain of the hands/feet/calves on exertion; asymmetrical pulses; bruits

Investigations

  • A raised ESR/PV is highly sensitive for GCA (95% will have an ESR >50mm/hour)
  • Temporal artery biopsy should be performed in patients with clinically suspected GCA within one week
    • NB biopsy is NOT required if patients respond to empirical steroid treatment
  • Imaging (only if there are symptoms/signs of large vessel involvement or severe systemic symptoms; or persistently high ESR/PV despite treatment)
    • CT (FDG-PET) or duplex USS (or MRI)

Diagnostic criteria

  • Any 3 of
    • Age >50
    • New headache
    • Abnormal temporal artery (e.g. tender, rubbery)
    • Raised ESR (>50) or PV
    • Positive temporal artery biopsy

Management

  • Steroids should be started as soon as the diagnosis is suspected
    • Start high-dose (60-80mg) for patients with claudication/visual symptoms/critical ischaemia
    • Medium dose steroids can be used for uncomplicated GCA (40mg)
    • Dose can be reduced after 4 weeks if both symptoms and serum inflammatory markers have normalised
      • Reduce by 10mg every 2 weeks to 20mg/day; then by 2.5mg every 2-4 weeks to 10mg/day; then 1mg every 1-2 months- provided there is no relapse
      • Assess patients at week 1, 3, 6 then every 3 months for first year (test FBC, U&Es, ESR/PRV, CRP, glucose)
      • NB 30-50% of patients can stop taking steroids after 2 years, but many require longer.  Patients should be educated about the long-term use of steroids and risk of adrenal suppression as much as other side-effects
        • If patients do relapse with complications, increase to start dose i.e. 60mg.  If without complications, revert to maintenance dose i.e. lowest dose where symptoms were controlled.
  • Also start low dose aspirin, bone protection (bisphosphonates; calcium and vit D supplementation) and a PPI (unless there are contraindications
  • Offer patients vaccinations for influenza and pneumococcal vaccination
  • Also offer a CXR (or abdo CT) every 2 years for signs of AAA/aortic dissection