Hyper IgM syndrome

- X-linked defect in CD40 ligand
- B cells are trapped at immature level producing only IgM
- Levels of other types of immunoglobulin are low/absent
- Opportunistic infections (PCP, cryptosporidium, candida) occurs.

Autoantibodies

- dsDNA : SLE

- anti-histone : drug-induced lupus

- anti-centromeric : limited scleroderma

- anti-Ro (SS-A) : SLE, primary Sjogren (anti-Ro only= SLE)

- anti-La (SS-B) : SLE, primary Sjogren

- anti-Sm : SLE

- anti-RNP : SLE, MCTD

- anti-Jo : polymyositis, dermatomyositis

- anti-Scl70 (topoisomerase 1) : diffuse scleroderma

Serotonin syndrome

- toxic hyperserotonergic state can be caused by ingestion of 2 or more drugs that increase serotonin levels (eg: SSRI with MAOI, dopaminergic drug or TCA)
- presents with agitation, confusion, tremor, diarrhea, tachycardia, hypertension and hyperthermia
- treatment: supportive,removal of causative agent, drugs with serotonin antagonist activity (cyproheptadine, methysergide)

Mucocutaneous leishmaniasis

- caused by L.b.braziliensis
- indurated or ulcerating lesions affecting mucosa or cartilage typically on lips or nose (espundia)
- diagnosis by culture of parasite or PCR
- treatment: sodium stibogluconate

Malignant melanoma

Clinical criteria for diagnosis (ABCDE)

A: Asymmetry of mole
B: Border irregularity
C: Colour variegation
D: Diameter more than 6mm
E: Evolving lesion with changes over time



Clarke's level (reflects level of invasion through dermis)
I : not invaded pass basement membrane
II: involvement of superficial dermis
III: involvement of deep dermis
IV: involvement of subcutis

Breslow's thickness

Tumor Depth	Approximate 5 year survival
<1 mm	95-100%
1 - 2 mm	80-96%
2.1 - 4 mm	60-75%
>4 mm	50%

Katayama fever

- acute schistosomiasis
- occurs 6 weeks to 3 months after initial infection especially by S.mansoni and S.japonicum
- snail vectors release cercariae that penetrates skin causing itchy papular rashes. Cercariae shed their tails to become schistosomules and migrate via lungs to liver.
- presents with fever, rash, myalgia, diarrhea, hepatosplenomegaly and pneumonitis
- diagnosis by serology and rectal biopsy (look for eggs)
- treatment: praziquantel

Blotting methods

Southern blot : DNA analysis (detection of specific DNA sequence)
Northern blot : RNA analysis
Western blot :  Protein analysis
Eastern blot : Protein post translational modification analysis (eg: lipids and glycoconjugate)
Southwestern blot : DNA binding protein analysis

Erosive osteoarthritis

- A form of OA marked by greater degree of inflammation and characterised by presence of erosions on plain radiograph
- predominantly affects postmenopausal women
- classically affects PIPJ and DIPJ
- gull's wing or inverted T pattern of erosion is typical
- commonly confused with RA, but there is no juxtaarticular osteoporosis

G protein

- located in cytoplasm
- coupled to transmembrane receptor (G protein coupled receptor) - seven helical membrane receptors
- ligand binding site is exposed outside surface of cell. Many ligands binds to GPCR, such as TSH, ACTH, serotonin and GABA
- Ligand binding initiates secondary messenger - cAMP or IP3
- best described human disease caused by mutation of G protein is pseudohypoparathyroidism (Albright's hereditary osteodystrophy)

Alport's syndrome

- combination of nephritis and sensorineural deafness
- X-linked
- autosomal recessive/dominant form cause renal disease without deafness or lenticonus
- males are affected more severely
- mutation of COL4A5 gene (80%), on X chromosome
- caused by abnormality in type IV collagen (alpha 5 chain)
- microsopic hematuria during first decade of life
- may present with acute macroscopic hematurie post URTI
- association: anterior lenticonus, retinopathy, posterior corneal dystrophy, bilateral dot fleck marks around fovea
- diagnosis is by renal biopsy