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

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.
  • Commonly associated with polymyalgia rheumatica
• 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

Amyloidosis

Background

• Amyloidoses are a group of acquired and hereditary disorders characterised by extracellular deposition of insoluble proteins, which can be localised or systemic
  • Clinical presentation depends on the organs involved

Types

• Reactive (AA) amyloidosis
  • Increased production of serum amyloid A as part of prolonged or recurrent acute inflammatory response
    • e.g. Chronic infection (TB, bronchiectasis, chronic abscess, osteomyelitis); Chronic inflammatory disease (chronic untreated/poorly controlled rheumatoid arthritis; familial Mediterranean fever)
  • Most patients present with non-selective proteinuria or nephrotic syndrome
  • May also have hepatosplenomegaly
  • On investigations there may be signs of hepatorenal problems e.g. raised urea and low serum albumin
• Light Chain amyloidosis (AL)
  • Increased production of monoclonal light chains
    • e.g. monoclonal gammopathies e.g. myeloma, benign gammopathies and plasmacytoma
  • Presents with features of restrictive cardiomyopathy, peripheral neuropathy/autonomic neuropathy, carpal tunnel syndrome, proteinuria, spontaneous purpura, amyloid nodules and plaques
    • Macroglossia occurs rarely but is pathognomonic
  • Prognosis is often poor
• Dialysis associated (Aβ2M) amyloidosis
  • Accumulation of circulating β2 microglobulin due to failure of renal catabolism in renal failure
    • associated with dialysis / renal failure
      • often 5-10 years from start of dialysis
  • Presents with carpal tunnel syndrome, chronic arthropathy and pathological fractures due to amyloid bone cysts formation
• Senile systemic amyloidosis
  • Normal deposition of transthyretin protein in tissues in older patients (>70)
    • Normal process of aging
    • Usually asymptomatic
• Hereditary systemic amyloidosis
  • Multiple forms – many mutations of the transthyretin gene; often autosomal dominant
  • Peripheral and autonomic neuropathy, cardiomyopathy (renal involvement is unusual- ~10%)
    • Many asymptomatic

Presentation

• Amyloidosis should be considered in all cases of unexplained nephrotic syndrome, cardiomyopathy and peripheral neuropathy

Investigation/Diagnosis

• Biopsy confirms diagnosis (affected organ, rectum or subcutaneous fat)
  • apple-green birefringent amyloid deposits (Congo red dye)
• Quantitative scintigraphy with radiolabelled SAP can estimate total body load

Management

• Largely supportive; prevent further deposition by treatment of any underlying cause, where possible
  • Liver transplantation may be an option

Azathioprine

Mechanism

• Cytotoxic agent (prodrug of mercaptopurine)

Indications

• Immunosuppression for many autoimmune conditions as well as in transplant patients
  • Usually used 2nd line to methotrexate in rheumatological conditions due to adverse affects (see below)

Monitoring

• Prior to starting treatment, FBC and platelets.
  • Also should check TPMT status (people homozygotic for TPMT should not be prescribed azathioprine)
• Then
  • FBC and LFTs weekly for 6 weeks, then continue every 2 weeks until stable dose for 6 weeks; then monthly. (If stable for 6 months, consider 3 monthly)
  • U&Es 6 monthly
• If WBC< 3.5×10^9/l; neutrophils <2×10^9/l; platelets <150×10^9/l or if ALT > twice the upper limit of normal- stop

Other side effects

• Nausea, vomiting, diarrhoea, anorexia, alopecia, rash
  • if rash/oral ulceration, withhold drug
• Likewise, if bruising or severe sore throat occur, withhold drug

Pyloric Stenosis

Background

• Hypertrophy of the pyloric sphincter causes narrowing of the gastric outlet
• Most common cause of gastric obstruction in patients 2-12 weeks old
• Risk factors include male (4:1); firstborn (2:1); white/caucasian; term infants; bottle-fed babies

Presentation

• Usually present around 3-6 weeks with a history of progressively worsening non-billious vomiting (may be projectile) after feeds
  • may be blood stained
• Associated with
  • poor weight gain, decreased urine output (fewer wet nappies) and stools, excessive hunger, dry mucous membranes and depressed fontanelle
  • rarely, once severe, tachycardia and jaundice may occur

• Assess degree of dehydration; weight
• Observe a normal feed
• Examination of the abdomen may reveal an epigastric ‘olive-shaped’ mass

Investigations

• Blood tests to consider include FBC, U&Es, venous acid-base, glucose, bilirubin
  • Hypokalaemia and hypochloraemia (possibly hyponatraemia)
  • Metabolic alkalosis
• USS can usually identify hypertrophied pylorus
  • Contrast studies may be used if USS unequivocal

Management

• Fluid resuscitation- correct any electrolyte disturbance (particularly hypokalaemia) prior to surgery
• Nil by mouth and nasogastric drainage or suction prior to surgery and between feeds
• Surgery
  • Pyloromyotomy