Infectious diseases — USMLE Step 2 CK Notes

Respiratory

Pneumonia: Shunting; C02 low d/t hyperventilation

Community acquired pneumonia: Tx: Azithromycin/doxycycline

Typicals: S Pneu most common

H Influenza (most common in old smokers with COPD)

Atypicals: Resistant to beta lactams, hard to culture, can’t gram stain

-> subacute, dry cough and watery sputum

Mycoplasma: maculopapular rash, mild tranaminitis, Mild Anaemia d/t cold agglutinins

Legionella: GI Sx, mild tranaminitis, pulse-temp dissociation (relative bradycardia), hyponatremia

Legionnaires disease: Pulm + CNS Sx eg confusion; encephalitis

Chlamydia Psittaci: severe headache

Coxiella Burnetti: Q Fever (exposure to livestock), Flu like Sx and severe headache

Viruses: Influenza A and B (most clinically significant)

Fungal: Can all present chronically and mimic TB (constitutionalists Sx and cavitary lesions)

Histoplasma:

Soil contaminated by bat and bird droppings: Caves, chicken coops, Ohio/Mississippi River Valleys

Mild/asymp: Erythema nodosum or multiforme, arthralgias

Blastomyces:

Inhalation of mould spores in disturbed soil (outdoor occupations), Ohio/Mississippi River Valleys and Great Lakes; Skin Lesions, osteomyelitis (well circumscribed, lytic lesions)

Coccidiodes:

Soil, SW US and N Mexico (Valley Fever), Erythema nodusum or multiforme, arthralgias, subacute

Tx: Pulm blasto: Itraconazole (histo/coccoi don’t norm need tx); Severe fungal: Amphotericin B

Silver stain for PCP

Urinary Ag for Legionella (v sensitive), persists even after tx commences

Dx: CXR False neg CXR in neutropenia, dehydration, PCP infection and disease <24 hrs

Do CT if negative CXR but high suspicion in any case

Fremitus: Sounds norm only heard in large airways transmitted to periphery in Pneu, same principle for consolidation

Hemoptysis: MRSA associated necrotising pneumonia: preferentially attacks young pts with influenza

Cavitation lesions: Klebsiella, TB

Nosocomial Pneumonia

Hospital acquired (HAP) and Ventilation associated (VAP):

VENTILATED PTS CANNOT COUGH: mucociliary clearance impaired

Positive P impairs ability to clear colonisation

Pseudomonas (most common), Klebsiella etc

General Pneu SX: Pleuritic chest pain and cough (productive purulent sputum)

Repositioning of patient can increase V/Q mismatch (gravity), increased intrapulmonary shunt and

worsening hypoxaemia.

Aspiration Pneumonia

Anaerobic bacteria from upper airways: Peptostreptococcus, Fusobac, Prevotella, Bacteroides

Foul smelling sputum characteristic of anaerobes

CAP pathogens from oropharynx: S Aureus, S Pneu

Chemical pneumonitis d/t stomach acid can set patient up for bacterial superinfection

Tx: Ampicillin-sulfactam or Metronidazole + amoxicillin/Pen G

CF: Under 20 yrs: S aureus

Over 20 yrs: Pseudomonas

Repeated pneumonia in same area: check for malignancy

Parapneumonic Effusion: bacteria invade pleural space

Pleural fluid pH <7.2, glucose <2.2 mmol/l, LDH >1000

Can progress to Empyema: Frank pus aspirated/positive pleural fluid culture, large persistent, air-fluid layer ——>>>>>>>> Needs chest tube drainage

Management: CAP

CURBS 65:

Confusion, Uremia (BUN>20), RR (>29), BP (BP S<90 OR D<61), 65 (AGE >64) ## SCORE OF 3 OR MORE ADMIT

1-2 consider outpatient with close observation

EMPIRICAL CAP Tx: Cover common typicals and atypicals

Outpatients: PO Macrolide Or Doxycycline

If there are Risk Factors for MDR S Pneu in CAP:

ADD Antipneumococcal beta lactam: Amoxacillin (+/- clavulanic)/ ceftriaxone Or mono therapy: Resp fluoroquinolone (moxifloxacin or levofloxacin)

Inpatient CAP: IV Macrolide/Doxy + IV antipneumococcal beta lactam:

Or mono tx: Resp fluoroquinolone (IV)

High risk for Pseudomonas: Double Coverage: Mona’s Seafood Sketch

IV antipseudomonal beta lactam: Pip-tazo/ ceftazadine (3rd)/ cefepime, meropenem, imipenem

PLUS

IV antipseudomonal fluoroquinolone (covers atypicals too): Levo or Cipro

MRSA: Risk if recent Ab use —> Add Vancomycin or Linezolid

HAP/VAP: IV Pip-tazo/ cefepime/ levofloxacin.

—> Piperacillin has enhanced gram neg + anti pseudomonas

VAP: Occurs >48 hrs after intubation

Mostly d/t aspiration of oropharyngeal/gastric secretions

New pulm infiltrates; increased resp secretions; systemic sx + Worsened resp status and oxygenation

Dx: Sampling of LRT -> BAL

Prevention of VAP:

Head of bed elevation at 30-45 degrees to reduce retrograde movement of gastric secretions

Suction of subglottic secretions

Minimisation of pt transport to prevent movement of endotracheal tube

Limit use of gastric acid inhibition to reduce burden of microorganisms in gastric secretions

——-> PPIs a Risk factor

Influenza Pneu:

Complication of Influenza in high risk individuals

Acute worsening of sx, leukocytosis, bilateral diffuse interstitial infiltrates

Neuraminadase I (Oseltamivir and Zanamivir)

Other complications of influenza: Myositis, myocarditis, encephalitis and Transverse myelitis

Tx CAP for 5 days (only stopped if afebrile for 48HRS)

HAP/VAP for 7 days

Procalcitonin can monitor treatment (bacterial marker)

Buzzwords:

Just had Influenza: MRSA

Q Fever (Coxiella burnertti): Doxycycline

Tularaemia: Gentamycin

Lung Abscess:

Aspiration: Posterior segments of upper lobes and superior segments of lower lobes

Others: S Aureus, S Pneu, aerobic gram neg bacilli

Sputum sometimes blood tinged; Constitutional sx, cough etc

Dx: CXR: Thick walled cavitation with air-fluid levels

Tx: Clindamycin; AMP/AMOXICILLIN SUL/CLAV etc. —->>> VANC for S Aureus

Lemierre Syndrome: septic thrombophlebitis of int jugular vein

Usually d/t tonsillitis (also complication of dental work or mastoiditis)

Pt looks TOXIC w unilateral neck swelling/pain

Often d/t fusibacterium necrophorum:

——>> septic emboli to lungs —-> multiple periph lung nodules (some w cavitation)

Dx: US neck

Tx: IV ampicillin-sulbactam/ Clindamycin

Infectious Mononucleosis

25% false negative Monospot Test in first wk of illness

Transient hepatitis w LAD

Complications:

Acute airway obstruction

Autoimmune hemolytic anemia and thrombocytopoenia —> IgM cold Agglutinin 2-3 wks after onset

Tuberculosis

Aerobes

Primary TB usually asymptomatic; Pulmonary and constitutional sx

Pleural effusion poss, lower lobe, mediastinal LN involvement

Ghon and Ranke complexes are evidence of healed primary TB

Secondary TB: immunocompromised

Cough progresses from dry to purulent. Hemoptysis if advanced

Constitutional sx w Apical rales

Extrapulmonary TB

Any organ: LNs, pleura, Genitourinary tract, spine, intestine and meninges common

Miliary TB is hematogenous dissemination -> Common in HIV

Organomegaly, reticulonodular infiltrates on CXR, choroidal tubercles in eye

Obtain 3 morning sputum samples, takes 4-8 wks to culture

Granuloma (caseating) may not be present in later stages

Reactivation TB: lung apices/posterior (most oxygenated)

Diffuse reticulonodular pattern (millet seed): progressive primary TB or reactivation

Mediastinal or hilar opacities (also seen in histo or cocciodes)

Positive PPD if BCG vaccine, still treat with 9 months isoniazid

Organ transplant recipients, steroid users and HIV PPD <5

CXR to rule out active infection

With 3 negative sputum cultures ==> cannot rule out if negative (needs high burden of org)

NAAT higher sensitivity cf AFB stain but takes 24-48hrs

Initiate empiric tx if high suspicion: RIPE (2 mo) then 4 months of isoniazid w rifampin

The only ppl you give prophylaxis to if in contact with TB are kids <4 (INH for 9 months)

TB Meningitis ——> basilar Meningeal enhancement

—> presents over wks

Dx: NAAT or AFB CSF Smear

Rifampin: body fluids turn orange/red; induces CYP450

INH: Peripheral neuropathy and sideroblastic anemia (give B6); Hepatitis with mild bump in LFTs

Pyrazinamide: Benign hyperuricaemia

Ethambutol: Optic Neuritis and other colour vision abnormalities

Discontinue RIPE if LFTs rise above 3-5 times upper limit only as all hepatotoxic

Vit B6 deficiency: Stomatitis, glossitis, cheilosis, periph neuropathy, sideroblastic anemia

Negative tuberculin test in immunocompromised eg CKD and HIV

Invasive aspergillosis; neutropenia patient

Dx by biopsy and culture of lung mass

Eosinophilia

CXR shows nodular density (upper lobe) with surrounding ground glass opacity (Halo sign)

Shotty (pellet like) Cervical adenopathy

Triad: Pleuritic chest pain, fever and Hemoptysis (Bronchiecstasis) (Thick brown sputum)

Tx: Voriconazole +/- capsofungin

Allergic bronchopulmonary -> ABPA

RF: Poorly controlled asthma and CF

Hypersensitivity and impaired clearance

Bronchiecstasis with thick brown sputum

Pleuritic chest pain; Recurrent fleeting infiltrates

Dx: Positive skin test for Aspergillus; Eosinophilia; Aspergillus IgG; elevated Aspergillus and total IgE

Tx: Steroids; Itraconazole

Chronic Pulm Aspergillosis

Lung disease/damage (cavitary TB)

3 MONTHS; weight loss, cough, , fatigue

Cavitary lesion +/- mobile (positioning pt) fungal ball (aspergilloma-> Hemoptysis

Tx: resect aspergilloma if poss; voriconazole; embolisation if severe Hemoptysis

Acute Bronchitis

Usually has preceding viral illness

Small amounts of blood in sputum can occur

Cough >5 days to 3 wks with absent systemic findings

Symptomatic tx

Pertussis Postexposure Prophylaxis

Antibiotics in ALL regardless of immunisation: Macrolide

Fungi

Histoplasmosis

Most common endemic my obsession in US TB mimicking Disease

Pulmonary sx with mediastinal or hilar LNs/masses, arthralgias and erythema Nodosum

Hilar/Mediastinal LAD

Diffuse reticulonodular miliary/focal infiltrates

Caseating (most common) or non caseating granulomas

Disseminated disease:

Febrile, wasting disorder w SOB, Cough; mucocutaneous (papules/nodules) involvement

RES manifestations: LAD, Hepatomegaly

BM infiltration causes pancytopenia

Dx: Culture takes wks; Histo Ag in blood/urine confirms dx rapidly

Tx: Itraconaziole for mild/mod; IV liposomal AmpB for severe

Blastomycosis

Long incubation : 3-6 wks

Disseminated disease may occur in immunosuppressed

TB/Histo mimicking Disease

Lung: Acute and chronic pneumonia (usually mild to moderate)

Skin: Wartlike lesions, painless well circumscribed violaceous nodule/heaped up verrucous lesions,

skin ulcers —->> May evolve into microabscesses

Bone: Osteomyelitis and lytic bone lesions

CNS: Meningitis, epidural or brain abscesses

Tx: Depends on severity

Supportive/Oral Itraconazole/IV AmpB

Coccidiomycosis (Valley Fever)

Subclinical/ CAP; > 1 wk of resp sx

Arthralgias, erythema nodosum or erythema multiforme

Mild/moderate cases need no tx

Meningitis

Increased ICP: Increased opening pressure

Empiric tx: Vanc + Ceftriaxone + steroids if bacterial source suspected

Kernig sign: hip flexed to 90 degrees —> extending knee stretches meningeal lining of spinal cord

—> pain

Severe myalgias: Diffuse leg pain etc

Cold hands/feet Mottled skin/pallor

Bacterial:

High WBCs (>1000 PMNS), LOW GLUCOSE, HIGH PROTEIN

CSF cloudy

Aseptic: nonpyogenic

Lymphocytic pleocytosis is typical (<1000 WBCs)

GLUCOSE NORMAL, PROTEIN NORMAL/HIGH

CSF may be normal

Normal CSF: Lymphocytes and monocytes, NO PMNs, <5 WBCs

TB: Tx with RIPE + Steroids

LYME MEN: IV Ceftriaxone

Tx: ALL: Ceftriaxone and vancomycin (cephalosporin R pneumococci)

——->> Add ampicillin if over 50 or under 3 months to cover Listeria Cefotaxime + Amp only if meningitis suspected If neonate (cant have Ceftriaxone) ——> Trimethoprim-sul used as alternative

Ceftazadime if impaired cellular immunity (P aeruginosa)

===>>> immunosuppressed get cefepime/ceftazadime + vancomycin + ampicillin

Cefepime 4th gen and covers Step; Neis; Haem + Pseudomonas Penetrating skull injury: Vanc + cefepime

Prophylactic IM Ceftriaxone or rifampin for contacts

Encephalitis

Usually viral: HSV1, Arbovirus, Enterovirus (eg Polio)

Toxoplasmosis, cerebral aspergillosis

Non infectious: Metabolic encephalopathy, T Cell lymphoma

Prodrome of headache malaise and myalgia

Poss focal neurological findings and seizures

Dx: CSF PCR, MRI

HSV Encephalitis:

Altered mental state; personality changes; fever; headache; nausea

+/- Focal neuro findings: hemiparesis, CN Palsies, ataxia

CSF: RBCs, HSV DNA on PCR

Temporal lobe hemorrhage/oedema on MRI

—> Increased areas of T2 signal in frontotemporal localisation consistent with HSV1

EEG would show temporal lobe discharges

Tx: IV Acyclovir

Infections post transplantation:

<1 month likely bacterial

1-6 months opportunistic: CMV, Aspergillus, TB ——> in setting of high dose immunosuppressives

——>> Tissue Invasive CMV Disease: Pneumonitis, gastroenteritis and hepatitis

Zoonotes and Others

Cat Bites: Pasteurella Multocida —-> cellulitis; Anaerobic bacteria

Management

Copious irrrigation and cleaning

Prophylactic/Tx amoxicillin/clavulanate

Tetanus booster if indicated

Avoid closure

Suppurative Parotitis

Retrograde seeding of bacteria from oral cavity: Staph Aureus, oral flora

Firm, erythematous pre/post auricular swelling

Exquisite tenderness exacerbated by chewing and palpation

——> Often purulent fluid can be expressed

Trismus, systemic findings (fever, chills)

Elevated serum amylase w/o pancreatitis

Management: US/CT to assess obstruction/abscess

Hydration, oral hygiene (increase saliva)

Abs; Sialagogues (increase saliva flow)

Ludwig Angina

Rapidly progressive cellulitis of submandibular space

Often d/t dental infections in mandibular molars

Polymicrobial: oral aerobes (S. Viridans) and anaerobes —>> crepitus

Systemic sx and local compressive (oedema) manifestations:

Mouth pain, drooling, dysphagia, muffled voice, airway compromise

Submandibular area often tender and induration

Floor of mouth elevated d/t swelling, displacing tongue

Dx: CT (also to rule out abscess)

Tx: IV Abs and removal of offending tooth; Mechanical airway

Ramsay hunt Syndrome (herpes zoster oticus)

Ear pain

Facial weakness (palsy) —> reactivation in geniculate ganglion

Vesicular rash in ext auditory canal

Tx: Corticosteroids and antivirals

Herpes zoster pain

Acute: <30 days from rash onset: NSAIDs +analgesics

Subacute: less recent onset; Resolves within 4 months: NSAIDs +analgesics

Postherpetic neuralgia (PHN): pain > 3 months after rash healed

Tx: TCA, Gabapentin/Pregabalin

Anti viral tx (valcyclovir) can shorten course of acute shingles and reduce risk of PHN

——>>> PHN not associated with ongoing rep so antivirals useless

Chikungunya Fever

Aedes mosquito

Severe polyarthralgias

Headache, myalgias, conjunctions, maculopapular rash

Lymphopoenia, thrombocytopenia, transaminitis

Tx: Supportive

Chronic arthralgias/arthritis in >50% —->>> may need methotrexate

Leprosy

Well demarcated lesion, anesthetic, often hypo pigmentation or erythematous

Grows in cool ares eg skin and periph nerves —> neuropathy

Nearby nerves often become hairless, nodular and tender —–>> Loss in sensory and motor function

Lepromatous form: Thickened forehead etc (leonine facies) -> d/t no Th1 response

Paucibacillary (minimal lesions/tuberculoid) tx with Dapsone and Rifampin

Multibacillary (lepromatous) use Clofazimine —> Th2 response (humoral)

False positive on VLDR possible

Enterobius vermicularis (pinworm)

Tx: Pyrantel Pamoate/ Albendazole

Schistosomiasis

Tx: Praziquantel

Tick-borne paralysis

D/t Neurotoxin release

Progressive ascending paralysis over hours to days

May be localised or more pronounced in 1 leg or arm

Sensation normal; no AN Dysfunction (cf GBS)

CSF normal

Management: Meticulous search for ticks

Babesiosis (tick born Protozoa)

Ixodes Tic (NE USA)

RF for severe illness: Splenectomy

Flu like sx and leukocytosis

Severe: ARDS, CHF, DIC splenic rupture

Anaemia, thrombocytopenia, increased bilirubin/LDH/LFTs; mild hepatosplenomegaly

===> intravascular hemolytic anemia —> jaundice, dark urine etc

Dx: Thin blood smear (intraerythrocytic rings: Maltese Cross)

Tx: Atovaquone + azithromycin

Quinine + Clindamycin (if severe)

Ehrlichiosis (monocytes) / Anaplasmosis (granulocytes)

Lone star tic (ixodes spp)

Leukopenia/thrombocytopoenia

Nonspecific flu like sx

Tx: Doxycycline; Chloramphenicol (side effects inc blood dyscrasias)

Bartonella Henselae

Regional TENDER, erythematous LAD: epitrochlear, supraclavicular and cervical chains

Lyme Disease:

Early localised (days to 1 month): Erythema Migrans, fatigue, headache, myalgias, arthralgias

Early disseminated (wks to months):

Heart block, meningitis, Facial N Palsy (often bilateral), Carditis (AV Block)

Multiple erythema migrans; Migratory Arthralgias Late (months to years): Arthritis, encephalitis, Periph neuropathy

Tick must be attached for 48-72 hrs to cause disease

—-> pathogen only migrates after this level of feeding

Tx: Mild/Skin disease —> Oral Abs —> Amoxicillin/ Doxy if >8 yrs

Neuro/cardiac disease —> IV Ceftriaxone. —> IV Ceftriaxone if Meningitis to penetrate CFS

Malaria

Non African countries: P Vivax —> dormant hepatic phase

Fever, chills, flu like

Tx: Chloroquine preferred in non resistant areas; artemisin based combo tx;

primaquine for dormant phase (w/o pts will relapse)

Africa: P falciparum

Fever, chills, flu like

More severe (altered mental state; multi organ failure)

Tx: Chloroquine preferred in non resistant areas; artemisin based combo tx

Neutropenia Fever

Medical Emergency

Absolute neutrophil count <500

Never give DRE as can induce bacteraemia

Most commonly d/t pseudomonas

Mucositis secondary to chemo causes bacteraemia (usually from gut)

Add Vanc if line infection suspected or if in septic shock

Add Amphotericin B if no improvement and no source found in 5 days

NB Neutropoenic pt may not mount a fever with sepsis d/t decreased inflamm cytokines

Rash on wrists and ankles (palms and soles), fever and headaches

Rickettsia: DOXYCYCLINE even if kid!

Tick bite, no rash, headache, fever, headache, low Plts and WBC, increased ALT

Ehrlichiosis: DOXYCYCLINE FOR ALL

Ricky Mountain Spotted Fever w/o rash

Dx: morulae intracell inclusion

Cavitary lung dz (purulent sputum)

Gram + aerobic branching partially acid fast: NOCARDIA

Trim-Sulfa

Neck/face infection w draining yellow material (sulfur granules)

Gram + anaerobic branching: ACTINOMYCES

High dose penicillin for 6-12 wks

Parvovirus B19

Transient red cell aplasia

Acute symmetric arthralgias/arthritis: Resembles RA

Constitutional sx: fatigue

Nonspecific rash more common in adults than slapped cheek

Hepatic Infections

Hepatitis: EBV, CMV and HSV can cause hepatitis in immunocompromised

Hydatiform Cyst: Echinococcus Granulosa (dogs)

Eggshell calcification on CT

Tx: Resection with albendazole cover

Risk of anaphylactic shock

Botulism

Symmetric DESCENDING flaccid paralysis Spores only dangerous to infants —> Soil spores (California; Pennsylvania; Utah); honey

Preformed toxin required to infect adult -> inactivated at temperatures of 100 degrees Celsius

Toxin inhibits Ach release (presynaptic) at NMJ

Can be mild and self limiting or fatal

4Ds: Dry mouth, diplopia and/or dysarthria, limb paralysis occurs later

DX: Toxin

Tx: equine Antitoxin (toxoid) immediately if suspected

Tx: human derived antitoxin in kids

Wound Botulism

Spores contaminate puncture wound eg IVDU

Fever and leukocytosis Within ~10 days (cf hours in food borne)

Sensory abnormalities and confusion rare

Ptosis; dilated sluggish to react pupils

—-> descending motor paralysis w progressive resp compromise

—-> inability to hold head up; CN Palsy and resp failure

Autonomic dysfunction: Ileus, orthostatic hypotension, urinary retention

Tx: equine botulinum antitoxin (dont delay for confirmation)

Intra abdominal abscess Causes: osteomyelitis of vertebral bodies (retroperitoneal extension)

Dx: CT or US

Tx: Drainage and broad spectrum antibiotics

Shigella: Outbreaks in daycare centres (paeds)

Can cause HUS

Causes seizure in kids

Tx: Abs only if severe

Salmonella

Typhoidal: Typhoid fever (GI Sx less so)

Bacteraemia; fever; abdo pain

Rose spots; HSM; intestinal perforation

Contaminated food/water

Tx: Abs (ceftriaxone); can be fatal

Non typhoidal: GI Sx

Vomiting and diarrhoea (May be non bloody)

Under cooked poultry/eggs

Selflimited; Abs not usually needed

E Coli most common cause of bloody diarrhoea in absence of fever

C perfrigens: Non bloody diarrhoea and abdo pain

Rotavirus: Fever, vomiting and profuse watery diarrhoea —>> dehydration

Seizures and encephalopathy

Entamoeba Histolytica

Hepatomegaly w high alk phos and LFTs

Colitis: Diarrhoea, bloody stool and abdo pain

Liver abscess: RUQ Pain, Fever -> Dx serology; US

R lobe cystic lesion d/t greater portal blood supply; raised ALP

Complications: Rupture to pleura/peritoneum

Dx: Stool ova and parasites; stool Ag testing (colitis)

Tx: Metronidazole and intralumnal Ab (eg paromomycin)

Giardiasis

Disruption of epithelial tight junctions in SI

Malabsorption and acute weight loss

Watery, foul smelling diarrhoea w steatorrhea 1-2 wks post exposure

Sx usually self resolve within a months

Dx: Stool Ag or nucleic acid amplification test

Tx: Tinidazole (recommended for pts at high risk of disseminated disease or symptomatic pts)

Untreated can lead to chronic carriage and malabsorption in some —-> Vit def etc

Infections of Genitourinary Tract

E Coli MCC of UTI

Risk Factors:

Use of diaphragms and spermicides alters vaginal colonisation

Condoms/diaphragms associated w increased friction ==> UTI

Pregnancy

Spinal cord injury, DM

Uncircumcised males

Structural/functional abnormal that impedes urine flow eg BPH, Caliculi etc

Anal sex, sex with partner colonised by pathogens

Suprapubic tenderness

In lower UTIs fever absent

Dx: Dipstick analysis

Positive urine leukocyte esterase (pyuria—> WBCs/pus)

Positive nitrite (Enterobacteriaceae), lacks sensitivity for other organisms

UTI in pregnancy: Preterm labour, low birth weight and others, esp in late pregnancy

BACTERIURIA without WBCs: contamination -> >10 WBCs/uL is abnormal

Complicated UTI

Any UTI that spread beyond bladder/associated factors that increase the risk of antibiotic resistance or treatment failure

Do urine culture prior to Tx

Acute, uncomplicated UTI

Oral TMP/SMX, Nitrofurantoin, Fosfomycin, Fluoroquinolones

Phenazopyridine is a urinary analgesic for dysuria

Pregnant: Ampicillin, amoxicillin or oral cephalosporins

Nitrofurantoin first line

More than 2 UTIs per year give prophylaxis TMP/SMX

Pyelonephritis

E Coli most common,

N/V and diarrhoea may be present

Signs: Fever with tachycardia

Abdo tenderness on examination

Dx: Pyuria, Bacteriuria and LEUKOCYTE CASTS

Renal Function normally preserved

Imaging studies if complicated or fails to respond to treatment

Tx: Uncomplicated: TMP/SMX or fluoroquinolone for 10-14 days (gram negatives)

Amoxicillin for Gram positive

Single dose of ceftriaxone/gentamicin usually given initially Pregnant/Elderly/very ill/Urosepsis: IV Ampicillin + gentamicin/ciprofloxacin

If vomiting cannot give oral!

Prostatitis: boggy, tender prostate

Acute bacterial less common than chronic and more serious

Younger men

Fever, chills, pts appear toxic

Irritating voiding Sx

Perineal pain, low back pain and urinary retention

Avoid prostatic massage/DRE as can cause bacteraemia

Tx: TMP/SMX or fluoroquinolone and Doxycycline

Chronic Prostatitis: many asymp

Men 40-70 years (Young and middle aged)

E Coli causes 75%

Fever uncommon

Pts frequently have sxs of recurrent UTIs that transiently improve with Abs

Dull, poorly localised pain in lower back, perineal, scrotal or suprapubic region

Hx of antibiotic tx —>> transient improvement

Prostate may not be tender but is enlarged

Pain with ejaculation

Tx: Fluoroquinolone (v difficult to eradicate) for 6wks

Non bacterial prostatitis has no bacteria but form of chronic prostatitis

Acute Epididymitis

Age <35 STI eg chlamydia

Age >35 d/t bladder outlet obstruction so Colifirm bacteria eg E. coli

Dysuria, frequency w Coliform infection —-> not common in <35 yr old

Unilateral, posterior testicular pain

Epididymis oedema

Pain improved w testicular elevation (Prehn sign)

Dx: NAAT for Gon and chlamydia; U/A w culture

Sexually Transmitted Diseases

Genital warts: HPV

Causes verrucas etc

Chylamydia

80% Reactive Arthritis cases (STI no longer present)

Many people are coinfected with gonorrhea

Purulent, dysuria, fever, scrotal pain and swelling, AUB

Dx: Culture, enzyme immunoassay, PCR (higher sensitivity), not serology!

Sexually active adolescents should be screened even if asymptomatic

Risk factor for cervical cancer (increases with number of infections)

Complications:

Epididymitis and Proctitis

PID, Salpingitis, turbo-ovarian abscess, ectopic pregnancy and Fitz-Hugh-Curtis syndrome

Leading cause of female infertility d/t tubal scarring

Tx: Azithromycin (oral single dose) or doxycycline for 7 days

Gonorrhea

Usually asymptomatic in F but symptomatic in MEN

Infection of pharynx, conjunctiva and rectum can occur

Purulent discharge, dysuria, erythema and edema of urethral meatus, increased frequency

AUB, dyspareunia, sx of cervicitis/urethritis

Pharyngitis: norm asymp; edema; nontender cervical LAD

Disseminated infection (more common in F)

Fever, arthlagias, tenosynovitis (hands and feet) and pustular lesions on hands

Migratory polyarthriris/septic arthritis, endocarditis, meningitis

Skin rash (usually on distal extremities)

Complications:

PID with poss infertility and chronic pelvic pain

Epididymitis, Proctitis -> Tenesmus, mucopurulent anal discharge; pruritus

Salpingitis, turbo-ovarian abscess, Fitz-Hugh-Curtis Syn (perihepatitis, Increased LFTs, RUQ pain) Dx: Gram stain

Tx: IM ceftriaxone (single dose, also effective against syphilis)

Also give azithromycin/doxycycline for chylamydia coverage

Disseminated: Ceftriaxone IM/IV for 7 days

Urethritis in Men

Neisseria; Chlamydia; Mcoplasma genitalium; Trichomonas (rare)

Dysuria, discharge, urgency, increased voiding, pyuria

Dx: UA; Gram stain & Culture; NAAT —->> ‘culture negative’ likely chlamydia ——>>> as not recoverable on conventional culture nor Gram stained (use NAAT)

HIV and AIDS

Most common virus is HIV1

4 phases of infection:

Primary infection

Mono like syndrome post exposure

LAD and truncal maculopapular rash; Diarrhoea

Asymptomatic infection (seropositive but no clinical evidence)

Normal CD4 counts (>500)

Longest phase (4-7 years, varies widely)

Symptomatic HIV infection (pre-AIDS)

Evidence of immune system dysfunction

Persistent LAD

Localised fungal infections (nails, toes, mouth)

Recalcitrant vaginal yeast and trichomonal infections in F

Oral hairy leukoplakia on tongue

Seborrheic dermatitis, psoriasis exacerbations, molluscum, warts

Constitutional sx

AIDS

CD4 count <200

Untreated HIV CD4 count drops by about 50 per year

Continue to treat even if viral load undetectable

Dx: PCR RNA viral load test; P24 Ag Assay (viral load)

Seroconversion occurs 3-7 wks post infection, confirms dx

Negative ELISA excludes HIV (screen)

If ELISA Positive confirm with Western Blot (specific)

Dx of AIDS: Indicator condition or HIV1 seropositive person with CD4 <200

Tx: Antiretrovirals

Symptomatic pts/asymp pts with CD4 <500

Triple drug regimen HAART targets HIV rep at 3 different points in rep process:

2 Nucleoside reverse transcriptase inhibitors (requires phosphorylation) and 1 of:

Nonnucleoside reverse transcriptase inhibitor

Protease inhibitor (-navir)

Continued in pregnancy: <1000 viral load no C Section needed

Travel a lot for work…….

Acute retro viral Syndrome (looks like MONO)

Fever, fatigue, LAD, headache, pharyngitis, n/v/d, +/- aseptic Meningitis

Generalised maculopapular rash: oval, pink/red lesions; painful oral ulcers

New/bilateral Bell’s Palsy

Unexplained thrombocytopenia and fatigue

Unexplained >10% weight loss

Thrush, Zoster or Karposi Sarcoma

Zidovudine (AZT): GI, Leukopoenia and macrocytic anemia

Didanosine: pancreatitis, peripheral neuropathy

Abacavir: Hypersensitivity: rash, fever, n/v, muscle aches, SOB in first 6wks

—->> discontinue and never use again!

Indinavir: Nephrolithiasis and hyperbilirubinaemia

Tenovir: renal issue

Efavirenz: Sleepy, confuse, psycho

Post exposure prophylaxis: AZT, Lamivudine and nelfinavir for 4wks (Triple Drug Therapy)

Pneumonia

PCP

CD4 <200

Elevated LDH

Bilateral diffuse symmetrical Infiltrates on CXR ——>> Bronchoscopy with BAL to visualise bug

Tx: Trim-sulfa first line

IF ALLERGIC TO SULFA: trim-dapsone or pentamidine

Add steroids if PaO2 below 70

Prophylaxis if CD4 <200 until CD4 above 200 for 6 months

Trim-Sulfa/ Dapsone/ Atovaquone/ Aerosolised pentamidine (causes pancreatitis)

Common precipitation of SIADH and HIV pts at increased risk

TB

Screen all newly dx HIV for latent TB

HIV pts can have false negative PPD d/t low CD4

==> Positive PPD: Isoniazid + pyridoxine for 9 months

Or rifampin for 4 months

Diarrhoea

CMV

CD4 <50

Bloody, can see on biopsy

Tx: ganciclovir (neutropenia) or foscarnet (renal toxic)

MAC

CD4 <50

Diarrhoea, wasting, fevers, night sweats

Prophylaxis NO LONGER GIVEN

Tx with clarithromycin and ethambutol +/- rifampin

Cryptosporidium

CD4 <50

Swimming pools, dog feces

Watery diarrhoea with mucous

Oocysts are acid acid fast

Neurological signs

CD4 <200 —->> HIV associated neuro cognitive disorder (HAND) Long standing HIV (even with adequate HAART): Age >50

Ranges from asymp neurocognitive impairment to HIV associated dementia

Progressive decline in multiple cognitive domains

—> memory, attention, calculation, executive function

BG and nigrostriatal involvement —>> movement issues occur early in disorder

Personality changes, mood and behaviour disturbances

MRI shows diffuse brain atrophy, ventricular enlargement and increased white matter intensity Dx Clinical w neuropsychological testing Memory Problems or gait disturbance: AIDS Dementia complex

Multiple ring enhancing lesions: Toxo —> preference for basal ganglia

Tx: pyramethamine and sulfadiazine (+ leucovorin) for 6 wks

Primary CNS Lymphoma : One ring enhancing lesion

Mass lesion Most common in frontal cortex w Mass Effect

EBV and B cells

Tx: HAART

Seizure with de ja vu aura and 500 RBCs in CSF: HSV encephalitis (acyclovir)

Meningoencehalitis: Crytococcus

India Ink Stain; Ag; Culture on Sabouraud agar

CD4 <100

Develops over 2 wks

ICP sx d/t Blockage of CSF absorption

Neck stiffness and photophobia typically not present

Tx with Amphoteric B IV + flucytosine for 2 wks then fluconazole maintenance

CSF: Lymphocytosis w decreased glucose and increased protein

CD<50 CMV Retinitis (painless cf HSV)

PML

Hemisensory Loss, visual impairment, Babinski:

JC virus demyelination at grey-white jxn (not periventricular)

Multiple non enhancing lesions that do not cause mass effect

Sx are subacute and manifests reflect focal cortical involvement:

Altered mental status common

—> motor deficits (focal arm/leg weakness or hemiparesis), ataxia and vision abnormalities

MRI shows well delineated, asym (not diffuse) white mater lesions

Brain biopsy gold standard

Increased incidence in poorly controlled HIV

Vaccines given: ADULTS with HIV

HAV if chronic liver disease; IVDU; homosexual man

HBV

HPV ages 11-26

Meningococcus (A,C,W,Y) ages 11-18; large groups living in close proximity; splenic/complement def

Booster every 5 years

Pneumococcus: PCV13 once then PPSV23 8 wks later, 5 years later and at age 65

Tdap once (repeat with each pregnancy if F); Td every 10 years

Zoster if born post 1979 and no evidence of immunity

If CD4 <200 use recombinant inactivated but immune response likely blunted

Live vaccines CI: VZV; MMR if CD4 <200 If CD4 > 200 then should receive these vaccines if unimmunised!

Do not instigate HAART in setting of acute infection —->> immune reconstitution syndrome Delay for several wks

Opportunistic prophylaxis

CD4 <200: PCP

LDL elevated, BAL most accurate test

Use TMP/SMX

TB (Screen all yearly with PPD test)

Isoniazid with pyridoxine if PPD positive

CD4 <100:

MAC: Clarithromycin or azithromycin

Toxoplasmosis: TMP/SMX

Pneumococcal polysaccharide vaccine every 5-6 years

Influenza (Not nasal as live!) every year

Herpes Simplex

HSV1 lesions of oropharynx: Most ppl acquire in childhood (80% have HSV1)

HSV2 lesions of genitalia

Both can cause either

Replicates in dermis and epidermis

Lesions on erythematous base

Travels via SENSORY nerves to DRG (latent)

Transmitted via contact with active ulcerations or shedding from mucous membranes

Contracting one form of herpes confers some degree of cross immunity

Recurrence: Stress, fevers, infection and sun exposure

Tend to be shorter and less frequent over time

HSV1: Usually asymptomatic

Systemic manifestations (malaise, Fever) and oral lesions if sx

Oral lesions: Groups of vesicles on patches of erythematous skin

Herpes labialise (cold sores) most common on lips, painful, heal in 2-6 wks

HSV2: both PAINFUL w constitutional

Constitutional sx —-> Flu like achy etc

Tender inguinal LAD and vaginal and/or urethral discharge

Most transmission d/t asym viral shedding so abstinence when no outbreak not effective

Disseminated HSV

Immunocompromised usually

Encephalitis, meningitis, keratitis, chorioretinitis, pneumonitis and esophagitis

In pregnant women (rare) can be fatal to mother and child

Neonatal HSV (vertical transmission at delivery)

Congenital malformations, intrauterine growth retardation (IUGR), chorioamnionitis and even death

Ocular disease: HSV1/2: Keratitis, blepharitis and keratoconjunctivitis

Herpetic Whitlow: Infection of finger, common in healthcare workers

Painful vesicular lesions erupt at finger tip

Dx: Tzanck smear quickest test, use Wright stain -> Multinucleated giant cells.

Culture is gold standard

Tx: No cure

Mucocutaneous disease: Oral and/or topical acyclovir 7-10 days

Valcyclovir and famciclovir have better bioavailability

Oral acyclovir prophylaxis for frequent recurrences

Foscarnet for resistant disease in immunocompromised

Syphilis —> everything painless: Systemic disease with 4 stages:

Primary stage:

Chancre: PAINLESS, hard, crater like (indurated) lesion with clean base

Highly infectious

Inguinal LAD: Painless

Cannot be cultured so start tx regardless: IM benzathine pen G

Secondary stage: Maculopapular rash most common —>> extends to palms and soles

Flu like,

Epitrochlear LAD

Condylomata Lata: Raised, gray/white lesions that develop on mucosal surfaces (mouth, perineum)

Contagious stage

Latent stage: ASYM

Presence of positive serologic test in absence of clinical signs/sx

1/3 develop tertiary syphilis

Tertiary syphilis: Spirochetes invaded CSF

Up to 40 yrs post primary infection

Cardiovascular syphilis, neurosyphilis, gummas (subcutaneous granulomas)

Neurosyphilis: Dementia, personality changes and tabes dorsalis (post column degeneration)

Argyl-Robertsonian Pupils —->> accommodate but do not react to light

Dx: Dark field microscopy (definitive): sample of chancre shows spirochetes

Serology: Nontreponemal tests: RPF (high FN), VDRL (most common). Both +ve in SLE

-> Ideal for screening as high sensitivity

Treponemal tests: FTA-ABS (confirm), MHA-TP

More specific, confirmatory

Tx: Benzathine penicillin (one IM) -> Oral doxycycline for 2 wks if penicillin allergy

Latent/tertiary: Penicillin/ Ceftriaxone IM in 3 doses once a wk

Chancroid: EVERYTHING PAINFUL!

H. Ducreyi (Gram negative rod)

Rare in US (more in developing world)

Rarely systemic findings

PAINFUL genital ulcers: deep with ragged borders and soft, friable purulent base + yellow/grey exudate Satellite lesions poss

Unilateral tender inguinal LAD (BUBOES) appear 1-2 wks after ulcer, may suppurate

Dx: Clinically

Tx: Azithromycin, ceftriaxone, erythromycin or ciprofloxacin

Lymphogranuloma Venereum: C trachomatis Pain and Painless

PAINLESS small, shallow ulcers at site of inoculation, may go unnoticed

Tender Inguinal LAD (fluctuated Adenitis buboes) a few wks later (usually unilateral)

Poss constitutional sx

If untreated proctocolitis may develop

Obstruction of lymphatics may lead to elephantiasis of genitals

Dx: Serology

Tx: Doxycycline

Pediculosis pubis (pubic lice or crabs) Phthirus pubis

Transmitted through sex, clothing or towels

Severe pruritus in genital region, other hairy areas may be involved

Dx via examination

Tx: permethrin 1% shampoo

Granuloma inguinale: Painless and no LAD Klebsiella granulomatis (Donovanosis) -> beefy red lesions

Nodules coalescing in PAINLESS granulomatous ulcers-> nodules burst creating fleshy oozing lesions

Base may have granulation like tissue

No LAD!

Biopsy contains Donovan bodies (bipolar staining with safety pin appearance)

Nodule may be mistaken for LN (Pseudobuboe)

Constitutional sx poss

Vaccines

Live attenuated CI in those on immunosuppressives like TNF Antagonists eg adalilmumab for IBD

—-> YF, VZV, Influenza, MMR

HPV

Condylomata accumulata: AnoGenital warts: HPV 6 & 11

Range from smooth, flattened papules to exophytic/cauliflower like (verrucous) growths

Typically asymp and nontender but pruritic, friable lesions may occur

D/t chronic infection with low risk HPV strains

Pts with chronic tobacco use or immunosuppression (HIV) have elevated risk

Dx is clinical

Tx: Topical agents that chemically injure lesion (trichloroacetic acid, podophyllin resin) or

Stimulate immune response (imiquimod)

Surgical excision for larger lesions

AnoGenital warts in children usually self resolving -> Query sexual abuse in ages >4 to adolescences

May worsen during pregnancy d/t physiologic immunosuppression

Toxins/Poisons

Cyanide toxicity

Nitroprusside use in HTN emergency -> Metabolised to nitric oxide and cyanide ions

Prolonged infusions or high doses increase risk as does renal insufficiency (CKD)

Skin: Flushing (cherry red); cyanosis later

CNS: Altered mental state, HA, seizures and coma; hyperreflexia Cardiac: arrhythmias

Resp: Tachypnea followed by resp depression; pulm oedema

GI: Abdo pain, N/V

Renal: Metabolic lactic acidosis; renal failure

Carbon Monoxide Poisoning

Pulse oximetry usually normal as oximetry does no ddx between oxyHb and carboxyHb

AG metabolic acidosis d/t lactic acidosis

Permanent hypoxic brain injury can occur

Hyperintensity of globus pallidus on MRI

Cerebral hypoxia sx: headache, dizziness, confusion, DROWSINESS, seizure and coma

Tx: 100% O2 high flow

Acquired methemoglobinemia: Oxidising agents

Topical/local anaesthetics eg benzocaine; Dapsone; Nitrites (in infants)

Pulse oximetry often 85% regards of true oxygen saturation

—-> supplemental O2 does not improve cyanosis

Blood gas frequently shows falsely elevated oxygen saturation

==> So large oxygen saturation gap (>5% diff bet O2 sat on pulse oximetry & ABG)

Dark chocolate-coloured blood

Normal PaO2 Tx: methylene blue; high dose ascorbic acid if methylene CI (eg G6PD)

Acute Carbon monoxide poisoning induced MI: 1/3 of CO pts

Sx of myocardial ischemia:

Elevated Troponin I; chest pain w ECG changes; arrhythmias; pulm oedema

NO EVIDENCE OF CORONARY OBSTRUCTION

Arsenic Poisoning

Contaminated well water; Pressure treated wood; Pesticides/insecticides

Acute: Garlic breath, vomitting, watery diarrhoea, QTc prolongation

Chronic: Hypo/hyperpigmentation, hyperkeratosis, stocking glove neuropathy

Mild transaminitis, pancytopenia

Dx: arsenic in urine

Tx: Dimercaprol, DMSA (succimer)

Organophosphate Poisoning

Pesticides and Nerve Agents

Muscarinic sx

Nicotinic sx: Muscle weakness, paralysis, fasciculations

Management: Remove pts clothes, irrigate skin

Atropine reverses muscarinic sx

Pralidoxime reverses nicotinic sx (administer after atropine as can transiently INHIBIT AchEI and worsen)

DMARDs (antirheumatic drugs) MOA and Side Effects

Methotrexate: Hepatotoxic; stomatitis; cytopoenias

Leflunomide: Pyrimidine syn I —> hepatotoxic and Cytopoenias

Hydroxychloroquine: TNF & IL1 suppressor; antimalarial —> retinopathy

Sulfasalazine: TNF & IL1 suppressor —-> hepatotoxic; stomatitis; hemolytic anemia

TNF I eg etanercept/infliximab: infection; demyelination, congestive HF; Malignancy

Synthetic cathinone intoxication (bath salts)

Amphetamine analogs: ingested/inhaled/injected

Severe agitation, combativeness, psychosis, delirium, myoclonus, seizures

Mimics PCP but negative drug test

HTN and tachy

Prolonged duration of effect: can last up to a wk

Lead Poisoning

Basophilic stippling on periph smear

Neurological deficits: periph neuropathy (foot/wrist drop; cognitive dysfunc)

GI Sx (abdo pain; constipation)

Musculoskeletal sx: Joint pains; muscle aches

Fatigue and exertional SOB d/t microcytic, hypochromic anemia

NB Basophilic stippling also seen in Thalassemia and alcohol abuse

Tx: if >45 -> Succimer; Dimercapril + EDTA

Fetal hydantoin syndrome

Nail and digit hypoplasia; dysmorphic facies

Intellectual disability + Growth deficiency

Prenatal Cocaine exposure

Jitteriness; excessive sucking; Hyperactive Moro reflex

Neonatal withdrawal: LT effects on behaviour; attention and intelligence poss

Neonatal Abstinence Syndrome

Opiate withdrawal -> First few days of life and can last 4 wks

High pitched cry; sleeping and feeding difficulties

Tremors, seizures and AN Dysfunction (sneezing, sweating)

Tachypnea; Vomiting and diarrhoea

Tx: Supportive (soothing; low stimulation environment)

Medication if refractory

Prenatal opiate use

IUGR; Sudden infant death

Salicylate Intoxication

Mixed AG Metabolic acidosis w resp alkalosis

Use Winters Formula (CO2 will be lower than expected)

Near norm pH