Dr. Rensimer has board certifications in Internal Medicine and Infectious Diseases, and special certifications in Tropical Medicine and Travel Medicine. These educational and training credentials and over 50,000 cases handled over 40 years since medical school graduation, along with several years working in Emergency Medicine and serving as Chief of Staff of a hospital with approximately 1,000 staff physicians, equip Dr. Rensimer to handle any type medical situation, especially in his areas of expertise, Infectious Diseases/Internal Medicine/Tropical Diseases. He has cultivated a practice that concentrates on complex and difficult to diagnose and manage cases which had often defied solution by others.

Our in-house pharmacy and support staff are experienced at rapid treatment plan approvals by insurers, such that we can often initiate same-day intravenous antibiotics outpatient when medically necessary and clinically safe, minimally disrupting the patient’s personal, work, or school life.

Atypical Mycobacterial Infection

Chronic lung infection with relatives of the tuberculosis bacterium


Staphylococcal soft tissue infections


Inflamed, tender soft tissue bacterial infection, often spreading progressively; sometimes not an infection, but often misdiagnosed and mistreated as one
Chronic Diarrhea

Difficult diagnostic challenge that can be due to a long list of causes: infection, intestinal malabsorption, intrinsic bowel disease, medications
Clostridium difficile Enterocolitis

Diarrhea due to toxin producing C. difficile, a bacterium induced to grow by prior antibiotics and increasingly resistant, dangerous, and difficult to treat

Heart valve infection, a medically high-critically, high fatality risk diagnostic and treatment challenge requiring the highest level of expertise
Fever of Unknown Origin (FUO)

Fever of at least 3 weeks’ duration that has defied the usual diagnostic tests and first and 2nd-line treatment approaches; perhaps the most challenging diagnostic dilemma in medicine with hundreds of possible causes, both infectious and non-infectious, and many life-threatening. Most often the cause is a fairly traditional problem presenting in an highly unorthodox way. FUO requires an expert diagnostician.
Foreign Body Infection

Joint Prostheses, Surgical Mesh, Traumatic FBs: Usually low-grade, subtle bacterial infections that cannot be resolved by antibiotics alone and which often require creative approaches for an optimal outcome
Hepatitis C

The most common cause of infection related liver failure, liver cancer, and liver transplantation in the U.S. Indications for hepatitis C screen testing: tattoos, illicit drug use (IV/snorting), body-piercings, transfused blood or blood products, birth from 1945-65

Chronic infection with Human Immune Deficiency Virus; normal life expectancy with expert care
Immune-Deficiency Infections

Opportunistic infections with unusual organisms exploiting weakened immune systems
Lyme Disease

Tick-bite associated infection due to Borrelia bacteria causing arthritis and other problems

Parasite blood infection from tropical countries transmitted by mosquitoes
MRSA (Methicillin Resistant Staphylococcus aureus)

Serious infections or recurrent boils due to staph germs highly resistant to antibiotics; often needing IV antibiotics
Multi-Drug Resistant (MDR) Bacterial Infections

Incresingly frequent bacterial infections with resistance to all the usual antibiotics: E.coli, Acinetobacter, Klebsiella, etc.

Bone infection
Pneumonia (recurrent, persistent)

Repeated bouts of pneumonia due to airway/lung disease dysfunction, aspiration of stomach contents, or immune deficiency
Prosthetic Device Infections
Implantable hardware or medical devices (hip prosthesis, orthopedic screws, spine rods, cardiac pacemakers and wires) sometimes become infected. We manage these problems.
Rabies Exposure

Management of risk of fatal rabies virus brain infection associated with certain animal bites or exposure

We are one of only 2 practices and 9 facilities  in or near Harris County with an in-house inventory of human rabies immunoglobulin (HRIG) and rabies vaccine and expertise in rabies evaluations, allowing timely initiation or continuation of post-exposure rabies preventive treatment. We routinely are referred cases from the U.S. Centers for Diseases Control (CDC) in Atlanta and the Harris County Public Health/Animal Control

Sexually Transmitted Diseases

STDs such as syphilis, gonorrhea, chlamydia, herpes, HIV
Sinusitis/Bronchitis (recurrent/persistent)

Sinus and/or airway inflammation and congestion unresponsive to routine medical and surgical approaches
TB Positive Tests: Quantiferon, PPD

Quantiferon, PPD positive test interpretation, including whether TB preventive medications are indicated or the “positive” tests are false positive
Tuberculosis/Atypical Mycobacterial Infections

Lung infections particularly associated with nodular lung disease, bronchiectasis, and COPD
Urinary Tract Infection (recurrent)

Persistent or recurrent UTIs failing traditional treatment approaches
Wound Infections (non-healing traumatic/surgical wounds or soft tissue ulcers/sores)

Wounds failing to heal completely following surgery or trauma; often these wounds or ulcers fail to heal due to unusual infecting agents (fungus, atypical TB, Nocardia, actinomyces, etc.), inadequate blood supply, foreign bodies (soil, sutures, hardware), etc. Diabetic foot ulcers are in this category.